Trends in cross-border shopping for dietary supplements in South Korea with a focus on major types of health functional foods

Youngmin Nam; Linxi Huang; Jong-Youn Rha; Bongwon Suh; Jihyun Yoon

doi:10.4162/nrp.2025.19.2.241

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Nam, Huang, Rha, Suh, and Yoon: Trends in cross-border shopping for dietary supplements in South Korea with a focus on major types of health functional foods

Original Research

Nutrition Research and Practice 2025; 19(2): 241-256.

Published online: 28 March 2025

DOI: https://doi.org/10.4162/nrp.2025.19.2.241

Trends in cross-border shopping for dietary supplements in South Korea with a focus on major types of health functional foods

Youngmin Nam¹

, Linxi Huang¹

, Jong-Youn Rha²

, Bongwon Suh³

, Jihyun Yoon^1,⁴

¹Department of Food and Nutrition, College of Human Ecology, Seoul National University, Seoul 08826, Korea.

²Department of Consumer Science, College of Human Ecology, Seoul National University, Seoul 08826, Korea.

³Department of Intelligence and Information, Graduate School of Convergence Science and Technology, Seoul National University, Seoul 08826, Korea.

⁴Research Institute of Human Ecology, Seoul National University, Seoul 08826, Korea.

Corresponding Author: Jihyun Yoon. Department of Food and Nutrition, College of Human Ecology and Research Institute of Human Ecology, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Korea. Tel. +82-2-880-5706/8750, Fax. +82-2-884-0305, hoonyoon@snu.ac.kr

Received 27 November 2024 Revised 6 March 2025 Accepted 18 March 2025

The Korean Nutrition Society and the Korean Society of Community Nutrition

https://creativecommons.org/licenses/by-nc/4.0/

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (https://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

BACKGROUND/OBJECTIVES

Dietary supplements are popular among Korean consumers in the cross-border market. This study examined the cross-border shopping trends of dietary supplements in Korea, focusing on the major health functional foods.

MATERIALS/METHODS

This study analyzed the customs clearance data provided by the Korea Customs Service, spanning 2019–2021. The term ‘health functional foods,’ which are manufactured with functional ingredients specified by law, was distinguished from the broader concept of ‘dietary supplements.’ The trends in dietary supplements and the major types of health functional foods in cross-border shopping were analyzed. The top 10 most purchased health functional foods were identified and analyzed by consumer gender and age group.

RESULTS

Dietary supplements constituted 19.1% of all cross-border items, with the primary consumers being women aged 30 and 40 yrs. The most popular type of health functional foods was the ‘multi-nutrient product,’ comprising 14.5% of all health functional food items. ‘Protein’ was popular among men and younger age groups, while ‘probiotics’ was favored by women. In particular, 32.3% of health functional food items were related to blood health.

CONCLUSION

The cross-border market for dietary supplements in Korea is experiencing growth, with consumer preferences varying by gender and age. These findings can assist in the development of regulatory policies that align with market trends and consumer needs in cross-border shopping for dietary supplements.

Keywords: Dietary supplements, functional food, cross-border shopping, Republic of Korea

INTRODUCTION

Dietary supplements are a prevalent approach to healthcare, and the dietary supplement market has shown a consistent growth trajectory. The global market for dietary supplements was estimated to be worth approximately USD 178 billion in 2023 [1]. In Korea, ‘dietary supplements’ are broadly defined as ‘health functional foods,’ which are only certified if they contain functional ingredients. The market size of health functional foods in Korea exceeded KRW 6.2 trillion (USD 5.2 billion) in 2023, with reports suggesting that 8 out of 10 households purchased health functional foods at least once a year [2]. The market size of health functional foods in Korea exhibited accelerated growth, with a more than 27% increase since 2019.

The global online market of dietary supplements is expected to increase at a compound annual growth rate of 9.1% from 2024 to 2030 [1], suggesting an expected rise in cross-border transactions through online channels. Korean consumers also purchase dietary supplements from overseas through cross-border online shopping. Dietary supplements have been the most preferred item in the cross-border market in Korea since 2015 [3], accounting for approximately 70% of all food products purchased through cross-border shopping in 2020 [4].

Consumers can easily purchase food products containing various ingredients known to be beneficial to health. These products are referred to by several terms, including dietary supplements, functional foods, and nutraceuticals. The term ‘dietary supplements’ is commonly used as a general designation for these products despite the inconsistencies and contradictions in the definitions of these terms [5]. According to the U.S. Dietary Supplement Health and Education Act of 1994 [6], the term ‘dietary supplement’ is defined as “a product intended for ingestion that, among other requirements, contains a ‘dietary ingredient’ intended to supplement the diet.”

In Korea, ‘health functional foods’ are defined as “foods manufactured with functional raw materials or ingredients beneficial to the human body,” as outlined in the Health Functional Foods Act [7]. The Korean government has implemented a certification system to regulate the functional ingredients used in health functional foods. The Ministry of Food and Drug Safety Korea (MFDS Korea) approves ingredients that have been validated as ‘functional ingredients.’ As of 2023, the MFDS Korea approved more than 400 functional ingredients, including vitamins and other nutrients [8]. For a food to be classified as a ‘health functional foods,’ it must be manufactured in compliance with established criteria and standards using these functional ingredients. Certification marks are exclusively applied to health functional foods, allowing them to indicate their functional properties [9]. From 2021 to 2023, the health functional foods that were most commonly purchased in Korea were reported as follows: first place – red ginseng, second place – vitamins (multivitamins and single vitamins), and third place – probiotics [2].

Purchasing health functional foods through cross-border shopping may present a potential safety concern, considering the direct delivery of such products from foreign websites to consumers. The unregulated purchase and consumption of these products may result in adverse health outcomes [10]. The MFDS Korea is responsible for ensuring the safety of health functional foods purchased through cross-border shopping in Korea. The Korea Customs Service oversees the regulation of ‘hazardous food products for cross-border shopping,’ as prohibited by the MFDS Korea [11]. Nevertheless, the management of health functional foods purchased through cross-border shopping in Korea faces several challenges. The primary obstacles include difficulties in accurately understanding their status with the limited reporting that concentrates predominantly on the import volume and major product types [4 10 12]. Moreover, these reports do not differentiate between dietary supplements and health functional foods. Health functional foods are legally defined and must be distinguished from dietary supplements. The latter term is a general designation encompassing health functional foods, nutraceuticals, and functional foods.

Developing a regulatory policy for health functional foods requires a comprehension of the trends of cross-border shopping for these products. This study examined the trends of dietary supplements purchased through cross-border shopping in Korea, focusing on the major types of health functional foods. This study analyzed the customs clearance data from 2019 to 2021 provided by the Korea Customs Service. This study distinguished between ‘health functional foods,’ as defined by law, and the broader concept of ‘dietary supplements,’ which includes health functional foods. The major types of health functional foods were identified based on consumer demographics. These results and domestic sales and intake in Korea were compared to gain a comprehensive understanding of the purchase and consumption of health functional foods.

MATERIALS AND METHODS

Data

The customs declaration data for cross-border shopping from 2019 to 2021 were used. The data were anonymized and provided by the Korea Customs Service, ensuring systematic integrity and reliability. Approximately 197 million customs declaration items were collected. Customs for cross-border shopping in Korea can be cleared in 2 ways: list-clearance and general import declaration. The general import declaration data were used for this study because dietary supplements must be cleared through a general import declaration.

Data cleaning

The data-cleaning process was conducted in 5 steps, as shown in Fig. 1.

Fig. 1

Process of data cleaning.

HS, Harmonized System.

¹⁾HS codes for health functional foods (127 HS codes on the import declaration of health functional foods reported to the Ministry of Food and Drug Safety of the Republic of Korea in 2021).

The initial step involved the extraction of 21 columns from 40 columns comprising the general import declaration data. The extracted columns included information, such as the date of entry, anonymized personal customs clearance code, consumers' gender, age group, postal code, product name, brand name, product price (KRW), and country of origin.

The data for dietary supplements were extracted using Harmonized System (HS) codes in accordance with previous studies [3 10 12]. The HS codes represent product classification numbers established by the World Customs Organization (WCO) and are used in various fields, including tariffs, trade, and transportation [13]. The HS codes for health functional foods reported in import declarations to the Import Inspection and Management Division of the MFDS Korea in 2021 were used because HS codes were not specifically assigned to dietary supplements or health functional foods. The data for 48 million rows, representing approximately a quarter of the total data (197 million rows), were extracted using the 127 HS codes for health functional foods.

Any missing values were identified in the third step, and rows containing these were removed. Missing values were identified in the columns, including the product name, brand name, and country of origin. Approximately 2,200 rows were deleted because of missing values in these columns.

After deleting the missing values, the outliers in each column were processed using the following procedure. Entries outside 2019–2021 and consumer ages outside 10–80 yrs were identified as outliers and excluded. The three-sigma rule [14], a commonly used outlier detection method, was used on the product price. Deviations exceeding ± 3σ from the average price for each HS4 code were removed. In addition, data with prices below KRW 1,000 ($0.8) or above KRW 1 million ($840) were excluded. The average price of all products before and after removing outliers was KRW 59,850 (48,376,938 rows) and KRW 59,855 (40,885,863 rows), respectively, indicating minimal change.

Data identified as non-dietary supplements based on the product name were removed because the data extracted using the HS codes included various products, such as general food, beverages, and pharmaceuticals. The data were further refined by removing any instances where the product name included keywords indicative of general food items, such as “coffee,” “snack,” and “oatmeal,” as well as specific brand names, including “Starbucks,” “Crystal Light,” and “Haribo.” In addition, data containing keywords indicative of pharmaceuticals, such as “medicine,” “cough,” and “fever,” were excluded. The final data comprised 37.6 million (n = 37,679,220) rows used for the analysis.

Data analysis

Products using functional ingredients recognized by the MFDS Korea were classified as ‘health functional foods.’ The term ‘dietary supplements’ encompasses all products that use ingredients and components that confer health benefits, including functional ingredients. A search was conducted for 30,103 product names with more than 100 purchased items each to confirm the ingredients used in these products. The number of these product names purchased accounted for 89.5% (33,705,804 out of 37,679,220) of all items.

The numbers of items for all products, dietary supplements, and health functional foods purchased through cross-border shopping between 2019 and 2021 were compared. The major consumer group was identified by analyzing the number of consumers and purchased items by gender and age group. In addition, the average number of items per person and the price per product for dietary supplements purchased through cross-border shopping were examined. The proportion of consumers by gender and age group was analyzed based on the average number of items purchased per year and the average price range per product.

The major types of health functional foods purchased through cross-border shopping were analyzed. Functional ingredients were classified into 2 categories in Korea: approved functional ingredients, which are identified in the codes of health functional foods [7], and individually recognized ingredients that the MFDS Korea has approved. In contrast to approved functional ingredients, which may be used by any entity, individually recognized ingredients are restricted to use by approved businesses. The MFDS Korea categorizes all products that use individually recognized ingredients under the ‘individually recognized ingredients’ [15]. Thus, this study was conducted in accordance with this categorization.

The types were classified according to the functional ingredients when the health functional foods product contained only one approved functional ingredient recognized by law [7]. In the case of products containing more than one ingredient, they were classified into one of the following 3 types according to the ‘Imported Food Inspection Report 2021’ published by the MFDS Korea [16]: Multi-nutrient products, Multi-functional products, or Multi-nutrient/functional products.

Overall, 90 distinct health functional foods were identified, each using functional ingredients. For example, a product containing calcium, magnesium, and vitamin D (CalmaD) was classified as a multi-nutrient product. A product containing milk thistle extract, turmeric extract, and artichoke extract was classified as multi-functional. A product containing oil containing eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and vitamin E was classified as a multi-nutrient/functional product.

The top 10 types of health functional foods purchased through cross-border shopping with high purchase volumes from 2019 to 2021 were identified. The data were analyzed across different gender and age groups of consumers. This study compared the major types of health functional foods purchased through cross-border shopping and domestic sales and the widely used dietary supplements in Korea. The types of health functional foods with high domestic sales were identified using the ‘Production Performance of Food or Other Products’ report by the MFDS Korea each year from 2019 to 2021 [15 17 18]. The intake of dietary supplements was analyzed using the data from the Korea National Health and Nutrition Examination Survey (KNHANES) from 2019 to 2021.

The major functions of health functional foods purchased through cross-border shopping and domestic sales were compared. The top 10 functions with the highest sales based on the functions of the ingredients (e.g., intestinal health, improvement of blood circulation, and eye health) recognized by the MFDS Korea. The principle of double counting was applied when a single ingredient had multiple functions. All analyses used Python (version 3.11.1) and Excel (version 2015).

RESULTS

Trends of dietary supplements in cross-border shopping

Table 1 lists the trends in the dietary supplements purchased through cross-border shopping from 2019 to 2021. The number of purchased items revealed the extent of the cross-border market in Korea. The cross-border market in Korea has grown steadily, with the total number of purchased items exceeding 93 million in 2021, a more than twofold increase from 2019. In addition, the number of dietary supplements and health functional foods purchased through cross-border shopping showed a notable increase, each exceeding 15 million and 11 million in 2021, respectively. The average proportion of dietary supplements among all items was 19.1% over the 3 yrs, indicating an approximately 10% decline from 2019 (25.0%) to 2021 (16.4%). On the other hand, the proportion of health functional foods among dietary supplements showed an upward trend, with an average of 70.2% over the 3 yrs.

Table 1

Trends in cross-border shopping for dietary supplements

Items	Number of purchased items through cross-border shopping
Items	2019	2020	2021	Total
All items (n)	40,141,076	63,251,456	93,602,985	196,995,517
Dietary supplements¹⁾ (n)	10,019,594	12,308,414	15,351,212	37,679,220
Health functional foods²⁾ (n)	6,735,337	8,575,794	11,122,516	26,433,647
Dietary supplements/All items³⁾ (%)	25.0	19.5	16.4	19.1
Health functional foods/Dietary supplements⁴⁾ (%)	67.2	69.7	72.5	70.2

¹⁾“Products intended for ingestion that, among other requirements, contains a ‘dietary ingredient’ intended to supplement the diet” according to the U.S. Dietary Supplement Health and Education Act of 1994 [6].

²⁾“Foods manufactured with functional raw materials or ingredients beneficial to the human body” according to the Korean Health Functional Food Act [7].

³⁾The proportion of dietary supplements among all items purchased through cross-border shopping.

⁴⁾The proportion of health functional foods among dietary supplements purchased through cross-border shopping.

Table 2 lists the number of consumers and purchased items of dietary supplements in cross-border shopping, categorized by gender and age groups. The proportion of women was higher than that of men (41.1% for men and 58.9% for women). The main age groups were those in their 30s (30.5%) and 40s (26.6%). The proportion of purchased items was higher among women (58.3%) than men (41.7%), with the highest proportion observed in the age groups of 30s (32.7%) and 40s (29.4%). In conclusion, the primary consumer group for dietary supplements purchased through cross-border shopping was women in their 30s and 40s, who constituted more than one-third of the total number of consumers (34.0%) and purchased items (36.9%).

Table 2

Number of consumers and items of dietary supplements purchased through cross-border shopping (2019–2021)

Age groups	Number of consumers			Number of items
Age groups	Men	Women	Total	Men	Women	Total
20s and younger	717,588 (7.8)	735,475 (8.0)	1,453,063 (15.7)	2,303,042 (6.1)	2,063,521 (5.5)	4,366,563 (11.6)
30s	1,230,772 (13.3)	1,591,878 (17.2)	2,822,650 (30.5)	5,460,435 (14.5)	6,860,553 (18.2)	12,320,988 (32.7)
40s	909,170 (9.8)	1,550,579 (16.8)	2,459,749 (26.6)	4,008,085 (10.6)	7,052,464 (18.7)	11,060,549 (29.4)
50s	559,186 (6.1)	1,005,167 (10.9)	1,564,353 (16.9)	2,348,654 (6.2)	4,016,580 (10.7)	6,365,234 (16.9)
60s and older	383,068 (4.1)	559,466 (6.1)	942,534 (10.2)	1,576,966 (4.2)	1,988,920 (5.3)	3,565,886 (9.5)
Total	3,799,784 (41.1)	5,442,565 (58.9)	9,242,349 (100.0)	15,697,182 (41.7)	21,982,038 (58.3)	37,679,220 (100.0)

Values are presented as a number (%).

Fig. 2 presents the gender and age distribution of consumers who purchased dietary supplements through cross-border shopping based on the number and price of the purchased items. Consumers purchased an average of 2.6 dietary supplement items annually, showing minimal gender difference (2.7 for men and 2.6 for women). The average number of items purchased by consumers in their 20s and younger was 2.2, the lowest among all age groups. The proportion of consumers who purchased more than one item per year was the lowest among those in their 20s and younger (22.4%) and highest among those in their 30s (34.8%) and 40s (33.6%). Among those aged 30 yrs and older, consumers in the older age groups tended to purchase dietary supplements less frequently.

Fig. 2

Number and price of dietary supplements purchased through cross-border shopping by gender and age group of consumers.

¹⁾ The annual average number of dietary supplements was calculated as the mean of the purchase frequency for the years 2019, 2020, and 2021. The values in parentheses represent the minimum and maximum.

²⁾ The average price of dietary supplements was determined as the mean price per individual product. The values in parentheses represent the minimum and maximum.

The average price of dietary supplement products purchased through cross-border shopping was approximately KRW 60,000 ($51), based on the average exchange rate from 2019 to 2021. Men and older age groups exhibited a greater proclivity to purchase higher-priced products than women and younger age groups. The average price of products purchased by men (KRW 61,877) was approximately KRW 3,500 ($2.6) higher than that of women (KRW 58,403). The average price of products purchased by those aged 60 and older (KRW 66,549) was KRW 14,000 ($10.4) higher than that of those in their 20s and younger (KRW 52,549). Although the proportion of consumers who purchased products costing more than KRW 90,000 ($76) was only 10.8% for those in their 20s and younger, it increased gradually with age, reaching almost one-quarter (24.7%) for those aged 60 and older.

Major types of health functional foods in cross-border shopping

Table 3 lists the top 10 most popular types of health functional foods purchased through cross-border shopping from 2019 to 2021. The type most purchased was ‘multi-nutrient products,’ accounting for 14.5% (5.5 million items) of all health functional food items purchased through cross-border shopping. The next most popular types of health functional foods, excluding ‘individually recognized ingredients,’ were ‘probiotics’ (7.6%), ‘protein’ (6.9%), and ‘oil containing EPA and DHA’ (5.5%). These rankings remained consistent over the 3 yrs despite the 2020 pandemic.

Table 3

Top 10 most popular types of health functional foods purchased through cross-border shopping

Rank	2019		2020		2021		Total
Rank	Type¹⁾	Number of purchased item	Type¹⁾	Number of purchased item	Type¹⁾	Number of purchased item	Type¹⁾	Number of purchased item
1	Multi-nutrient products	1,440,581 (14.4)	Multi-nutrient products	1,727,051 (14.0)	Multi-nutrient products	2,282,040 (14.9)	Multi-nutrient products	5,449,672 (14.5)
2	Individually recognized ingredients²⁾	1,151,923 (11.5)	Individually recognized ingredients²⁾	1,609,850 (13.1)	Individually recognized ingredients²⁾	2,137,495 (13.9)	Individually recognized ingredients²⁾	4,899,268 (13.0)
3	Probiotics	733,658 (7.3)	Probiotics	937,290 (7.6)	Probiotics	1,186,642 (7.7)	Probiotics	2,857,590 (7.6)
4	Protein	701,819 (7.0)	Protein	816,941 (6.6)	Protein	1,099,644 (7.2)	Protein	2,618,404 (6.9)
5	Oil containing EPA and DHA	544,319 (5.4)	Oil containing EPA and DHA	714,566 (5.8)	Oil containing EPA and DHA	805,097 (5.2)	Oil containing EPA and DHA	2,063,982 (5.5)
6	Milk thistle extract	317,826 (3.2)	Milk thistle extract	321,347 (2.6)	Multi-nutrient/functional products	393,902 (2.6)	Milk thistle extract	1,013,009 (2.7)
7	Multi-nutrient/functional products	195,558 (2.0)	Multi-nutrient/functional products	273,037 (2.2)	Milk thistle extract	373,836 (2.4)	Multi-nutrient/functional products	862,497 (2.3)
8	Vitamin D	170,334 (1.7)	Vitamin C	256,811 (2.1)	Vitamin C	312,553 (2.0)	Vitamin C	724,240 (1.9)
9	Vitamin C	154,876 (1.5)	Magnesium	223,615 (1.8)	Vitamin D	302,569 (2.0)	Vitamin D	687,084 (1.8)
10	Magnesium	153,318 (1.5)	Vitamin D	214,181 (1.7)	Multi-functional products	292,423 (1.9)	Magnesium	610,413 (1.6)

Values are presented as a number (%).

EPA, eicosapentaenoic acid; DHA, docosahexaenoic acid.

¹⁾Products containing only one approved functional ingredient were categorized based on the functional ingredient. Products containing a mixture of various ingredients were classified into one of the following three types: Multi-nutrient products, Multi-functional products, or Multi-nutrient/functional products.

²⁾Products that are manufactured or processed using individually recognized functional ingredients.

Table 4 lists the top 10 most popular types of health functional foods purchased through cross-border shopping by the gender and age group of the consumer. Excluding ‘individually recognized ingredients,’ ‘multi-nutrient products’ were the most popular among men (13.4%) and women (15.2%). The popularity of protein among men was significantly higher, accounting for 12.4% of all health functional food items purchased through cross-border shopping compared to only 3% for women. On the other hand, probiotics were significantly more popular among women (9.9%) than men (4.3%).

Table 4

Top 10 most popular types of health functional foods purchased through cross-border shopping by gender and age group of consumers (2019–2021)

Rank	Gender				Age group
	Men		Women		20s and younger		30s		40s		50s		60s and older
	Type¹⁾	Number of purchased item	Type¹⁾	Number of purchased item	Type¹⁾	Number of purchased item	Type¹⁾	Number of purchased item	Type¹⁾	Number of purchased item	Type¹⁾	Number of purchased item	Type¹⁾	Number of purchased item
1	Individually recognized ingredients²⁾	2,128,590 (13.6)	Multi-nutrient products	3,342,992 (15.2)	Protein	781,644 (17.9)	Multi-nutrient products	1,802,021 (14.6)	Multi-nutrient products	1,767,741 (16.0)	Individually recognized ingredients²⁾	1,003,754 (15.8)	Individually recognized ingredients²⁾	601,541 (16.9)
2	Multi-nutrient products	2,106,680 (13.4)	Individually recognized ingredients²⁾	2,770,678 (12.6)	Multi-nutrient products	554,974 (12.7)	Individually recognized ingredients²⁾	1,402,287 (11.4)	Individually recognized ingredients²⁾	1,405,585 (12.7)	Multi-nutrient products	889,318 (14.0)	Multi-nutrient products	435,618 (12.2)
3	Protein	1,952,252 (12.4)	Probiotics	2,176,548 (9.9)	Individually recognized ingredients²⁾	486,101 (11.1)	Probiotics	1,151,138 (9.3)	Probiotics	882,769 (8.0)	Probiotics	341,409 (5.4)	Oil containing EPA and DHA	193,209 (5.4)
4	Oil containing EPA and DHA	912,853 (5.8)	Oil containing EPA and DHA	1,151,129 (5.2)	Probiotics	363,828 (8.3)	Protein	1,066,560 (8.7)	Oil containing EPA and DHA	609,584 (5.5)	Oil containing EPA and DHA	331,855 (5.2)	Probiotics	118,446 (3.3)
5	Probiotics	681,042 (4.3)	Protein	666,152 (3.0)	Oil containing EPA and DHA	216,752 (5.0)	Oil containing EPA and DHA	712,582 (5.8)	Protein	467,306 (4.2)	Protein	226,396 (3.6)	Methylsulfonylmethane	76,846 (2.2)
6	Milk thistle extract	544,104 (3.5)	Multi-nutrient/functional products	599,525 (2.7)	Milk thistle extract	109,505 (2.5)	Milk thistle extract	400,805 (3.3)	Milk thistle extract	309,699 (2.8)	Milk thistle extract	140,415 (2.2)	Protein	76,498 (2.1)
7	Multi-nutrient/functional products	262,972 (1.7)	Vitamin C	479,894 (2.2)	Pantothenic acid	108,295 (2.5)	Multi-nutrient/functional products	329,593 (2.7)	Multi-nutrient/functional products	266,767 (2.4)	Vitamin C	139,587 (2.2)	Vitamin C	74,217 (2.1)
8	Magnesium	261,140 (1.7)	Vitamin D	474,689 (2.2)	Vitamin D	77,947 (1.8)	Vitamin D	240,876 (2.0)	Vitamin C	243,406 (2.2)	Multi-nutrient/functional products	127,602 (2.0)	Multi-nutrient/functional products	65,072 (1.8)
9	Multi-functional products	252,781 (1.6)	Milk thistle extract	468,905 (2.1)	Biotin	76,041 (1.7)	Magnesium	207,440 (1.7)	Vitamin D	211,810 (1.9)	Methylsulfonylmethane	122,148 (1.9)	Multi-functional products	60,262 (1.7)
10	Vitamin C	244,346 (1.6)	Magnesium	349,273 (1.6)	Multi-nutrient/functional products	73,463 (1.7)	Vitamin C	205,110 (1.7)	Magnesium	170,596 (1.5)	Magnesium	110,903 (1.7)	Propolis extract	54,325 (1.5)

Values are presented as a number (%).

EPA, eicosapentaenoic acid; DHA, docosahexaenoic acid.

²⁾Products that are manufactured or processed using individually recognized functional ingredients.

Excluding ‘individually recognized ingredients,’ ‘multi-nutrient products’ (30s: 14.6%, 40s: 16.0%, 50s: 14.0%, 60s and older: 12.2%) were the most popular type across all age groups aged 30 and older. ‘Protein’ was the most popular type in the 20s and younger group, accounting for 17.9% of all health functional food items. On the other hand, its popularity decreased gradually with age, reaching only 2.1% among the 60 and older group. Methylsulfonylmethane did not feature among the top 10 most popular items among the younger groups, but it experienced increasing popularity beginning in those in their 50s, ultimately ranking fifth (2.2%) among the 60 and older group.

Table 5 lists the top 10 most popular types of health functional foods purchased through cross-border shopping and domestic sales and the most commonly used dietary supplements in Korea. From 2019 to 2021, ‘red ginseng’ was the most popular type in the domestic market, accounting for an impressive 57% of the total sales revenue. The types consistently ranking within the top five across cross-border shopping, domestic sales and intake were ‘multi-nutrient products’ containing vitamins and minerals, ‘probiotics,’ and ‘oil containing EPA and DHA’ with omega-3 fatty acids.

Table 5

Comparison of the top 10 most popular types: cross-border shopping and domestic sales of health functional foods, and Korean intake of dietary supplements (2019-2021)

Rank	Cross-border shopping of health functional foods		Domestic sales of health functional foods¹⁾		Korean intake of dietary supplements²⁾
Rank	Type³⁾	Number of purchased items	Type	Revenue (KRW 100 million)	Type	Number of dietary supplement users⁴⁾
1	Multi-nutrient products	5,449,672 (14.5)	Red ginseng	55,381 (57.0)	Multivitamins and minerals	4,777 (44.4)
2	Individually recognized ingredients⁵⁾	4,899,268 (13.0)	Individually recognized ingredients⁵⁾	20,044 (20.6)	Probiotics	3,658 (34.0)
3	Probiotics	2,857,590 (7.6)	Probiotics	13,624 (14.0)	Omega-3 fatty acid	2,828 (26.3)
4	Protein	2,618,404 (6.9)	Vitamins and minerals	12,131 (12.5)	Vitamin C	1,977 (18.4)
5	Oil containing EPA and DHA	2,063,982 (5.5)	Oil containing EPA and DHA	5,921 (6.1)	Calcium	1,287 (12.0)
6	Milk thistle extract	1,013,009 (2.7)	Fructo-oligosaccharide	3,570 (3.7)	Vitamin A and Lutein	1,156 (10.7)
7	Multi-nutrient/functional products	862,497 (2.3)	Methylsulfonyl-methane	2,625 (2.7)	Red ginseng	1,034 (9.6)
8	Vitamin C	724,240 (1.9)	Protein	1,000 (1.0)	Vitamin D	913 (8.5)
9	Vitamin D	687,084 (1.8)	Tagetes erect flower extract	927 (1.0)	Other vitamins and minerals	753 (7.0)
10	Magnesium	610,413 (1.6)	Milk thistle extract	887 (0.9)	Propolis	381 (3.5)

Values are presented as a number (%) or KRW 100 million (%).

EPA, eicosapentaenoic acid; DHA, docosahexaenoic acid.

¹⁾Data from the report ‘Production Performance of Food or Other Products’ by the Ministry of Food and Drug Safety of the Republic of Korea [15 17 18].

²⁾Analysis of the Korea National Health and Nutrition Examination Survey 2019–2021 data.

³⁾Products containing only one approved functional ingredient were categorized based on the functional ingredient. Products containing a mixture of various ingredients were classified into one of the following three types: Multi-nutrient products, Multi-functional products, or Multi-nutrient/functional products.

⁴⁾Multiple responses from 10,758 respondents who reported currently using dietary supplements (allowing multiple responses of up to 4 types of dietary supplements).

⁵⁾Products that are manufactured or processed using individually recognized functional ingredients.

In cross-border shopping, ‘multi-nutrient products’ emerged as the most popular type, accounting for 14.5% of all health functional food items. In contrast, ‘vitamins and minerals’ ranked fourth in domestic sales, representing 12.5% of the total sales revenue. An analysis of the 2019–2021 KNHANSE data showed that ‘multivitamins and minerals’ were the most commonly used dietary supplement in Korea, with 44.4% of respondents reporting its usage. ‘Probiotics’ were the third most popular type in cross-border shopping (7.6% of all health functional food items) and domestic sales (14.0% of the total sales revenue) and were the second most commonly used dietary supplements by Korean users (34.0% of the total respondents). The ‘oil containing EPA and DHA’ ranked fifth (5.5% of all health functional food items) in cross-border shopping and sixth (6.1% of the total sales revenue) in domestic sales. Among Korean users, it ranked third for ‘omega-3 fatty acids’ (26.3% of the total respondents).

Table 6 lists the top 10 functions of health functional foods purchased through cross-border shopping and domestic sales. Among the health functional foods with a large number of items purchased through cross-border shopping, the functions related to ‘intestinal health’ (13.7%), ‘improvement of blood circulation’ (13.0%), and ‘eye health’ (12.1%) were particularly prevalent. In contrast, the major functions of health functional foods with high domestic sales revenue were ‘improvement of blood circulation’ (13.0%), ‘improvement of memory’ (12.8%), and ‘enhancement of immune function’ (12.8%). ‘Improvement of blood circulation’ and ‘improvement of memory’ were ranked within the top five functions for cross-border shopping and domestic sales.

Table 6

Comparison of the top 10 most popular functions: cross-border shopping and domestic sales of health functional foods (2019–2021)

Rank	Cross-border shopping		Domestic sales¹⁾
Rank	Function	Number of purchased items	Function	Revenue²⁾ (KRW 100 million)
1	Intestinal health	2,969,241 (13.7)	Improvement of blood circulation	25,468 (13.0)
2	Improvement of blood circulation	2,815,652 (13.0)	Improvement of memory	25,031 (12.8)
3	Eye health	2,609,229 (12.1)	Enhancement of immune function	25,109 (12.8)
4	Improvement of memory	2,076,543 (9.6)	Improvement of fatigue	22,972 (11.7)
5	Improvement of blood triglyceride levels	2,063,982 (9.5)	Antioxidant effect	22,966 (11.7)
6	Joint/bone health	1,596,750 (7.4)	Intestinal health	18,848 (9.6)
7	Decrease in body fat	1,318,654 (6.1)	Menopausal women's health	21,824 (11.1)
8	Improvement of blood cholesterol levels	1,084,988 (5.0)	Eye health	6,121 (3.1)
9	Liver health	1,038,341 (4.8)	Improvement of blood triglyceride levels	4,224 (2.2)
10	Blood pressure control	1,031,355 (4.8)	Joint/bone health	3,598 (1.8)

Values are presented as a number (%) or KRW 100 million (%).

¹⁾Data from the report ‘Production Performance of Food or Other Products’ by the Ministry of Food and Drug Safety of the Republic of Korea [15 17 18].

²⁾Double counting is applied when a single ingredient has more than 2 functional properties.

The analysis showed that blood health functions were a significant feature of health functional foods in cross-border shopping and domestic sales. Among the top 10 functions, 4 were related to blood health in cross-border shopping: ‘improvement of blood circulation,’ ‘improvement of blood triglyceride levels,’ ‘improvement of blood cholesterol levels,’ and ‘blood pressure control.’ Two of these functions (‘improvement of blood circulation’ and ‘improvement of blood triglyceride levels’) were also present in domestic sales. In particular, health functional foods with blood health functions constituted approximately one-third (32.3%) of all health functional food items purchased through cross-border shopping.

DISCUSSION

This study examined the trends of cross-border shopping for dietary supplements in South Korea and analyzed the major types of health functional foods purchased through cross-border shopping. The increasing number of purchased items indicated persistent growth in the cross-border market for dietary supplements, including health functional foods. This upward trend in cross-border shopping is a global phenomenon. In 2022, the estimated value of the global cross-border e-commerce market was USD 548,140 million, with projections indicating an increase to USD 1,443,340 million by 2029 [19]. The increased consumption of dietary supplements after the COVID-19 pandemic likely contributed to this trend. Nevertheless, there were no considerable changes in the trend of the cross-border market for dietary supplements before (2019) and after (2020 and 2021) the pandemic in this study.

In this study, dietary supplements constituted 19.1% (average from 2019 to 2021) of all items purchased through cross-border shopping in Korea. The Korea Customs Service [20] reported that dietary supplements consistently represented the largest category of cross-border shopping, accounting for 19.2% and 17.1% of the total customs clearance volume in 2020 and 2021, respectively. These findings align with the results of this study.

The primary consumer group for cross-border shopping of dietary supplements in Korea was identified as women in their 30s and 40s. Although women and the elderly consume more dietary supplements [21 22], younger age groups are actively engaged in cross-border shopping [23], which may explain these findings. The primary consumer groups for cross-border shopping in Korea in 2021 and 2022 were reported to be men in their 40s and women in their 30s [12 20]. Men in their 40s were likelier to purchase electronic appliances in cross-border shopping, while women in their 30s were more inclined to purchase dietary supplements [20].

A survey by the Korea Consumer Agency [3] showed that the average price for dietary supplement products in cross-border shopping was approximately KRW 53,700 per bottle, similar to the average KRW 59,855 reported in this study. Men and the elderly tend to incur higher monthly expenses for purchasing health functional foods [24], supporting the findings indicating higher prices for dietary supplements among these groups. Previous studies suggested that men are generally less price-sensitive and more optimistic about higher food prices than women [25], while older consumers exhibit lower price sensitivity [26]. These differences in price sensitivity based on gender and age may have also influenced cross-border shopping behavior for dietary supplements.

The most popular type of health functional foods was the ‘multi-nutrient product’ for cross-border shopping and Korean intake. The cross-border purchases for ‘multi-nutrient products’ comprised 14.5% of the total (average from 2019 to 2021). Multivitamins and mineral supplements are some of the most popular dietary supplements globally. In the United States, these products constituted 14% of the total purchases of dietary supplements in 2019 [27], with approximately one-third of adults reporting consumption [28]. As reported by the MFDS Korea [4], the import volume of ‘multi-nutrient products’ in 2021 was the highest among health functional foods, reaching 5,360 tons. A previous study examining the 2015 KNHANES indicated that ‘multivitamins and minerals’ are the most widely consumed health functional foods in Korea [29], in accordance with the results of the analysis of the 2019–2021 KNHANES in this study.

Protein was the most popular type among those in their 20s and younger, accounting for 17.9% of all health functional food items, surpassing the popularity of multi-nutrient products. This finding may be because young men consume protein supplements to increase muscle mass [30 31]. Women purchased three times more ‘probiotics’ items than men. ‘Probiotics’ are recognized for their beneficial effects on intestinal health [32]. This suggests that the higher popularity of probiotics may be attributable to the higher prevalence of conditions such as irritable bowel syndrome and inflammatory bowel disease among women [33].

The major types of health functional foods purchased through cross-border shopping must be examined to address any associated nutritional concerns. ‘Multi-nutrient products’ were widely purchased and consumed by consumers of all age groups and gender. This popularity indicates a preference for complex nutrient formulations over single-component supplements. On the other hand, numerous concerns exist regarding the excessive consumption of these supplements. The use of multivitamin and mineral supplements may contribute to the risk of excessive intake [34] and exceed the Tolerable Upper Intake Level for certain nutrients [35]. Furthermore, the risk of excessive intake is heightened when multiple types of dietary supplements, including multivitamin and mineral supplements, are taken simultaneously. According to the 2018–2020 KNHANES, more than 50% of dietary supplement users reported simultaneous consumption of 2 or more products [36].

‘Protein’ was highly popular among younger individuals and men, while ‘cissus extract’ has gained significant popularity among women. This popularity can be attributed to the anticipated effects of protein on increasing muscle mass and the cissus extract in reducing body fat. The present study identified body fat reduction as the seventh most prevalent function of health functional foods purchased through cross-border shopping. Previous studies reported a growing trend of consuming dietary supplements for cosmetic purposes, particularly among younger individuals, such as university students [37 38]. Dietary supplements should be used as an adjunct to a well-balanced diet to enhance overall health and well-being. From this perspective, using dietary supplements for cosmetic purposes may lead to their misuse.

The indiscriminate purchase and consumption of health functional foods have potential adverse effects. These concerns regarding health functional foods purchased through cross-border shopping underscore the necessity for government-level management and regulation. On the other hand, the existing regulatory framework for these products in Korea is insufficient. The accuracy and consistency of the declared information are unproven because the responsibility for making the import declaration lies with the individual consumer. Despite efforts to extract dietary supplements based on HS codes and product names, a limitation due to data constraints resulted in an incomplete distinction.

A comprehensive understanding of market trends and consumer needs is essential for developing an effective management system for cross-border health functional food purchases, requiring preliminary measures to enhance the import declaration system for accurate data collection. Providing consumers with clear instructions and illustrative examples would facilitate accurate information input. Implementing a system for the identification and filtration of irregularities would also enhance the overall accuracy of the data. The allocation of designated codes within the HS code system for dietary supplements or health functional foods would enhance the clarity of the regulatory process. Moreover, the pertinent authorities, such as the MFDS Korea and the Korea Customs Service, must maintain consistent surveillance and administration of the quality of import declaration data.

Efforts must be made to enhance awareness regarding the appropriate purchase and consumption of health functional foods. In the United States, the 2020–2025 Dietary Guidelines for Americans provide specific guidance on consuming dietary supplements for nutrients such as vitamin D and folic acid [39]. In contrast, nutritional education in Korea is focused primarily on hygiene and diet management and does not provide recommendations for using dietary supplements. Therefore, it is necessary to develop comprehensive guidelines and nutritional education programs on health functional foods that provide detailed information, including guidance on safe product selection and methods to avoid excessive intake. Moreover, education targeting young individuals who tend to consume health functional foods for cosmetic purposes, as well as pregnant and lactating women who are advised to supplement, is needed.

The cross-border market for dietary supplements in Korea is experiencing growth, with projections indicating a continued upward trend. Although this study analyzed the most recent data (2019–2021) available at the time of research, updated data will be required to understand the state of the cross-border market for dietary supplements in Korea. This study did not address the actual intake of dietary supplements purchased through cross-border shopping or their impact on the nutritional status because the purchasers and consumers may not be identical. Therefore, future research should analyze the intake of dietary supplements purchased through cross-border shopping and explore aspects related to the manufacturing of dietary supplements and their expiration dates. In addition, further research will be needed to examine the impact of the expanding cross-border market for dietary supplements on the domestic market.

This study is the first to differentiate between dietary supplements and health functional foods in the context of cross-border shopping in Korea. These findings offer a valuable contribution to the broader understanding of the cross-border market for dietary supplements. The results support the need to improve the management system for cross-border shopping, particularly regarding health functional foods. The identified preferences for health functional foods across genders and age groups can be used to develop guidelines and educational materials that encourage informed choices and safe consumption of health functional foods. Health functional foods can be used more wisely as supplementary measures to promote health by combining enhanced awareness with systematic management. These findings provide valuable insight for informing policy development in other countries because the growth of the cross-border market for dietary supplements observed in this study is a global trend rather than one limited to Korea.

Notes

Funding: This work was supported by Seoul National University Research Grant in 2021.

Conflict of Interest: The authors declare no potential conflicts of interest.

Author Contributions:

Conceptualization: Yoon J.
Formal analysis: Nam Y.
Investigation: Nam Y.
Methodology: Nam Y, Yoon J.
Supervision: Yoon J.
Writing - original draft: Nam Y, Huang L.
Writing - review & editing: Rha JY, Suh B, Yoon J.

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