Supplements have become a daily habit for millions of people — but the label rarely tells the whole story. Supplement quality varies widely, and some products contain dyes, coatings or inexpensive fillers that may be worth evaluating alongside the active ingredients. In our practice, we review every supplement our patients are taking — and these are the ingredients we flag first.
The Hidden Dangers Hiding in Your Supplements
The use of supplements has increased significantly due to recommendations from healthcare professionals who may not have expertise in nutritional science. While well-intentioned, this guidance may lead patients to consume products that contain harmful substances.
Hazardous Additives and Ingredients
Artificial Colors and Sweeteners
Artificial colors, such as FD&C Red No. 40 (E129 in Europe), and artificial sweeteners like aspartame (E951), are prevalent across the supplement industry. In January 2025, the US FDA went further and revoked authorization for FD&C Red No. 3 (erythrosine) in food, dietary supplements and ingested drugs, after it was shown to cause cancer in animal studies — over three decades after the same dye was banned from cosmetics [14]. Manufacturers have until 2027 to reformulate, so it may still appear on labels in the meantime. Despite FDA approval and corresponding European designations [1], there’s growing research and public concern about their safety. For instance, E129 has been investigated for its potential link to behavioral issues in children [2]. Similarly, E951, once hailed as a healthier sugar alternative, has been associated with increased risks of metabolic syndrome and diabetes [3].
In July 2023, the WHO’s International Agency for Research on Cancer classified aspartame as “possibly carcinogenic to humans” (Group 2B), citing limited evidence of a link to liver cancer — though the WHO’s expert committee left the acceptable daily intake unchanged [15]. The signal is modest rather than alarming, but it’s one more reason we favor supplements with no artificial sweeteners at all.
How they might appear on labels:
- FD&C Blue No. 1: Also listed as Brilliant Blue FCF, E133
- FD&C Red No. 3: Erythrosine, E127 (being phased out in the US by 2027)
- FD&C Red No. 40: Also known as Allura Red AC, E129
- FD&C Yellow No. 6: Sunset Yellow FCF, E110
- Titanium Dioxide: E171
- Aspartame: E951, sometimes simply listed as Aspartame, or under brand names like NutraSweet, Equal
- Sucralose: E955, marketed under the brand name Splenda
- Saccharin: E954, may be listed simply as Saccharin; also known as Sweet’N Low, Necta Sweet
Hydrogenated Oils
Known as trans fats, hydrogenated oils are a major health concern, linked to increased bad LDL cholesterol and decreased good HDL cholesterol, heightening the risk of coronary heart disease (CHD) [4]. Yet, they find their way into supplements as cheap fillers, misleading consumers about the health benefits.
How they might appear on labels:
- Partially Hydrogenated Oil: Often followed by the source, such as “Partially Hydrogenated Soybean Oil”
- Hydrogenated Vegetable Oil: Can specify the vegetable source, like palm, soybean, or coconut
Contaminants: Heavy Metals and PCBs
Mercury, polychlorinated biphenyls (PCBs), and other contaminants have been found in fish oil supplements. Accumulation of these substances in the body can pose serious neurological and cardiovascular risks [5,6]. A notable lawsuit in California highlighted the absence of warning labels on fish oil supplements about their cancer risk from high PCB levels[8].
These might not be listed on the label directly but be wary of products sourced from polluted areas or lower-quality fish oils, which are more likely to contain:
- “Molecularly Distilled Fish Oil” (this is a positive indication that it’s been purified, whereas the absence of this or similar phrases might raise concerns)
Talc (Magnesium Silicate) and Titanium Dioxide
Magnesium silicate, used as a filler and anti-caking agent, has raised safety concerns, especially regarding potential asbestos contamination, a known carcinogen [7,8]. Titanium dioxide (E171), used to color supplements and tablets white, has been linked to gut inflammation and possible genotoxicity. In 2021 the European Food Safety Authority concluded it can no longer be considered safe as a food additive, and the EU banned it from food and food supplements from 2022 [16,17]. It remains legal in supplements in the US and many other countries — so a product bought abroad may still contain it [9,10,11,12,13].
How they might appear on labels:
- Magnesium Silicate: Can be listed simply as Talc or Magnesium Silicate
- Titanium Dioxide: May be listed directly as Titanium Dioxide; sometimes referred to for its use as a colorant
Steering Clear of Harmful Supplements
The Art of Deciphering Labels
Avoiding these hazardous ingredients begins with mastering label literacy. Look beyond the nutritional facts to the “Ingredients” list, where the full spectrum of contents, including harmful additives, must be disclosed.
Selecting Safe Supplements
- Prioritize supplements derived from whole foods, as these are less likely to contain synthetic additives.
- Seek out products with trusted certifications (organic, non-GMO, third-party tested) that signify a commitment to purity and safety.
- Familiarize yourself with optimal nutrient forms for better absorption and health benefits, choosing supplements that adhere to these standards.
- Here are the supplements we choose for our patients: functional nutrition supplements
Advocacy for Better Health Choices
We wield power as consumers to influence the supplement market by supporting brands dedicated to health and transparency. Further, by spreading awareness about the hidden dangers in some supplements, we can collectively make more informed decisions.
Frequently Asked Questions
Is titanium dioxide in supplements safe?
In 2021 the European Food Safety Authority concluded titanium dioxide (E171) can no longer be considered safe as a food additive, and the EU banned it from food and food supplements in 2022. It remains permitted in supplements in the US and many other countries, so a product bought outside the EU may still contain it. Where possible, we recommend choosing supplements without it.
What ingredients should I avoid in supplements?
The most concerning are artificial dyes (such as FD&C Red No. 3, Red No. 40 and Yellow No. 6), artificial sweeteners (aspartame, sucralose, saccharin), hydrogenated oils (trans fats), titanium dioxide and talc (magnesium silicate). These add nothing nutritionally — they’re used for color, coating or as cheap fillers. Always read the full ingredients list, not just the nutrition panel.
Is magnesium stearate bad for you?
Magnesium stearate is one of the most feared supplement fillers, but the evidence against it at the tiny amounts used is weak, and most people tolerate it without issue. We pay far closer attention to artificial dyes, titanium dioxide and contaminants like heavy metals, which carry clearer risks. The form and quality of the active ingredient matter far more than a small amount of magnesium stearate.
Why was Red Dye No. 3 banned?
In January 2025 the US FDA revoked authorization for FD&C Red No. 3 (erythrosine) in food, dietary supplements and ingested drugs, after studies showed it caused cancer in male rats — over thirty years after it was already banned from cosmetics. Manufacturers have until 2027–2028 to reformulate, so it may still appear on some labels until then.
How can I tell if a supplement is high quality?
Look for third-party testing or certifications (such as NSF, USP or Informed Choice), branded and well-absorbed nutrient forms rather than the cheapest version, and a short ingredients list free of artificial dyes, titanium dioxide and unnecessary fillers. Whole-food-derived supplements are generally less likely to contain synthetic additives — but the form and dose of the active ingredient matter more than the marketing on the bottle.
Concluding Thoughts
The takeaway is simple: a supplement is only as good as what’s actually inside the capsule. The cleanest products carry the fewest unnecessary additives, use well-absorbed nutrient forms, and are tested by an independent third party. Read the full ingredients list — not just the front of the label — and when you’re unsure, ask a clinician who knows what to look for.
Not sure what’s hiding in your current supplements? As part of every patient’s plan, we review the full label of what you’re already taking and recommend only third-party-tested, clinically appropriate forms. Book a 15-minute Health Strategy Call and we’ll help you build a clean, effective protocol.
References
- Regulation (EC) No 1333/2008 on food additives. EUR-Lex. https://eur-lex.europa.eu/eli/reg/2008/1333/oj
- McCann D, et al. Food additives and hyperactive behaviour in 3-year-old and 8/9-year-old children in the community: a randomised, double-blinded, placebo-controlled trial. The Lancet. 2007;370(9598):1560–1567. https://doi.org/10.1016/S0140-6736(07)61306-3
- U.S. FDA. Overview of Food Ingredients, Additives & Colors. https://www.fda.gov/food/food-ingredients-packaging/overview-food-ingredients-additives-colors
- U.S. FDA. Trans Fat. https://www.fda.gov/food/food-additives-petitions/trans-fat
- National Institutes of Health, Office of Dietary Supplements. Omega-3 Fatty Acids — Health Professional Fact Sheet. https://ods.od.nih.gov/factsheets/Omega3FattyAcids-HealthProfessional/
- American Heart Association. Fish and Omega-3 Fatty Acids. https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/fats/fish-and-omega-3-fatty-acids
- Merliss RR. Talc-treated rice and Japanese stomach cancer. Science. 1971;173(4002):1141–1142. https://doi.org/10.1126/science.173.4002.1141
- U.S. FDA. Select Committee on GRAS Substances (SCOGS) Database — Magnesium silicate. https://www.hfpappexternal.fda.gov/scripts/fdcc/index.cfm?set=SCOGS
- Choi G-S, et al. Titanium dioxide exposure induces acute eosinophilic lung inflammation in rabbits. Industrial Health. 2014;52(4):289–295. https://doi.org/10.2486/indhealth.2013-0105
- Chang X, et al. Effects of Th1 and Th2 cells balance in pulmonary injury induced by nano titanium dioxide. Environ Toxicol Pharmacol. 2014;37(1):275–283. https://doi.org/10.1016/j.etap.2013.12.001
- Makumire S, et al. Immunomodulatory activity of zinc peroxide (ZnO2) and titanium dioxide (TiO2) nanoparticles. Toxicol Lett. 2014;227(1):56–64. https://doi.org/10.1016/j.toxlet.2014.02.027
- Gui S, et al. Intragastric exposure to titanium dioxide nanoparticles induced nephrotoxicity in mice. Particle and Fibre Toxicology. 2013;10:4. https://doi.org/10.1186/1743-8977-10-4
- Nogueira CM, et al. Titanium dioxide induced inflammation in the small intestine. World J Gastroenterol. 2012;18(34):4729–4735. https://doi.org/10.3748/wjg.v18.i34.4729
- U.S. FDA (15 Jan 2025). FDA to Revoke Authorization for the Use of Red No. 3 in Food and Ingested Drugs. https://www.fda.gov/food/hfp-constituent-updates/fda-revoke-authorization-use-red-no-3-food-and-ingested-drugs
- WHO/IARC (14 July 2023). Aspartame hazard and risk assessment results released. https://www.who.int/news/item/14-07-2023-aspartame-hazard-and-risk-assessment-results-released
- EFSA (6 May 2021). Titanium dioxide: E171 no longer considered safe when used as a food additive. https://www.efsa.europa.eu/en/news/titanium-dioxide-e171-no-longer-considered-safe-when-used-food-additive
- Commission Regulation (EU) 2022/63 of 14 January 2022 — withdrawal of titanium dioxide (E171) as a food additive. https://eur-lex.europa.eu/eli/reg/2022/63/oj
