Home tests, dietary supplements and health: distinguishing marketing from medicine
Authors:
M. Broul
Authors‘ workplace:
Krajská zdravotní, a. s. – Nemocnice Litoměřice, o. z. Urologické oddělení.
; Univerzita Jana Evangelisty Purkyně v Ústí nad Labem Fakulta zdravotnických studií
; Krajská zdravotní, a. s. – Masarykova nemocnice v Ústí nad Labem, o. z. Sexuologické oddělení.
Published in:
Prakt. Lék. 2026; 106(3): 109-114
Category:
Of different specialties
Overview
Background: Physicians in ambulatory care repeatedly encounter commercial wellness offers combining direct-to-consumer laboratory testing, dietary supplements, coaching and subscription-based sales. These offers often use the language of prevention, personalization, hormonal balance, immunity, inflammation, longevity or metabolic health and may resemble medical advice despite being embedded in a sales scenario.
Objective: This practical narrative review provides physicians across clinical specialties with a clinical and communication approach for distinguishing evidence-based care from commercially driven health claims at first contact and for discussing these issues with patients in a non-confrontational manner. It draws on a sexual medicine and andrology perspective, because this field clearly illustrates how a complex clinical symptom may be reduced to a single biomarker, hormone, supplement or “personalized” test.
Main message: Dietary supplements are regulated as foods intended to supplement the usual diet; they should not be presented as preventing, treating or curing disease. Direct-to-consumer testing may be useful in selected contexts, but analytical availability does not automatically imply clinical validity, clinical utility or safe interpretation. The combination of unclear professional qualification, conflicts of interest, interpretation outside clinical context and product-linked sales is particularly problematic.
Conclusion: Physicians can help patients by using a simple set of questions focused on qualification, test validity, follow-up care, conflicts of interest, cost and the nature of health claims. Non-judgemental, factual counselling protects patients better than dismissing a supplement or test outright.
Keywords:
dietary supplements – health marketing – direct-to-consumer testing – misleading health claims – commercial determinants of health – ambulatory care
Sources
1. Abdelhamid AS, Brown TJ, Brainard JS, et al. Omega-3 fatty acids for the primary and secondary prevention of cardiovascular disease. Cochrane Database Syst Rev. 2020; 3: CD003177.
2. Ayala-Lopez N, Nichols JH. Benefits and risks of direct-to-consumer testing. Arch Pathol Lab Med. 2020; 144(10): 1193–1198.
3. Balasubramanian A, Thirumavalavan N, Srivatsav A, et al. An analysis of popular online erectile dysfunction supplements. J Sex Med. 2019; 16(6): 843–852.
4. Bhasin S, Brito JP, Cunningham GR, et al. Testosterone therapy in men with hypogonadism: an Endocrine Society clinical practice guideline. J Clin Endocrinol Metab. 2018; 103(5): 1715 – 1744.
5. Campbell N, Clark JP, Stecher VJ, et al. Adulteration of purported herbal and natural sexual performance enhancement dietary supplements with synthetic phosphodiesterase type 5 inhibitors. J Sex Med. 2013; 10(7): 1842–1849.
6. Dubin JM, Aguiar JA, Lin JS, et al. The broad reach and inaccuracy of men’s health information on social media: analysis of TikTok and Instagram. Int J Impot Res. 2024; 36(3): 256–260.
7. European Commission. Nutrition and health claims [online]. Dostupné z: https://food.ec.europa.eu/food-safety/labelling-and - -nutrition/nutrition-and-health-claims_en [cit. 2026-05-17].
8. Gilmore AB, Fabbri A, Baum F, et al. Defining and conceptualising the commercial determinants of health. Lancet 2023; 401(10383): 1194–1213.
9. Kloner RA, Burnett AL, Miner M, et al. Princeton IV consensus guidelines: PDE5 inhibitors and cardiac health. J Sex Med. 2024; 21(2): 90–116.
10. Ministerstvo zemědělství ČR. Zdravotní a výživová tvrzení u doplňku stravy [online]. Dostupné z: https://mze.gov.cz/public/portal/mze/potraviny/doplnky-stravy/souvisejici-informace - -k-doplnkum-stravy/vyzivova-a-zdravotni-tvrzeni-k-doplnkum - -stravy [cit. 2026-05-17].
11. Orth M. Direct to consumer laboratory testing (DTCT): opportunities and concerns. EJIFCC. 2021; 32(2): 209–215.
12. Shih P, Sandberg S, Balla J, et al. Direct-to-consumer testing as consumer initiated testing: compromises to the testing process and opportunities for quality improvement. Clin Chem Lab Med. 2025; 63(2): 262–269.
13. Státní ústav pro kontrolu léčiv. Jaký je rozdíl mezi lékem a doplňkem stravy? [online]. Dostupné z: https://sukl.gov.cz/faq/ jaky-je-rozdil-mezi-lekem-a-doplnkem-stravy/ [cit. 2026-05-17].
14. Státní zemědělská a potravinářská inspekce. Právní předpisy vztahující se k doplňkům stravy a obecné informace o doplňcích stravy [online]. Dostupné z: https://www.szpi.gov.cz/clanek/pravni-predpisy-vztahujici-se-k-doplnkum-stravy-a-obecne-informace-o-doplncich-stravy.aspx [cit. 2026-05-17].
15. World Health Organization. Commercial determinants of health [online]. Dostupné z: https://www.who.int/news-room/fact-sheets/ detail/commercial-determinants-of-health [cit. 2026-05-17].
Labels
General practitioner for children and adolescents General practitioner for adultsArticle was published in
General Practitioner
2026 Issue 3
Most read in this issue
- Home tests, dietary supplements and health: distinguishing marketing from medicine
- The impact of 24-hour movement behaviour on school performance in adolescents – a systematic review of studies from 2020–2025
- The impact of weight reduction and regular physical activity on lipid profile: a case report of an active senior
- The impact of acute stroke on the social domain of patients’ quality of life