Harmful Ingredients in Supplements: What to Look For

Excipients — binders, fillers, coatings, colorants — are what turn a powder into a stable tablet. Most are benign. But a few carry legitimate question marks, and because they provide no health benefit whatsoever, the risk–benefit math is simple: any nonzero concern outweighs a zero benefit. This is different from active ingredients, where a real benefit can justify tolerating some uncertainty.

What the current evidence supports flagging:

• —Titanium dioxide — white colorant. The EU withdrew its food-additive approval in 2022 because genotoxicity of its nanoparticles could not be ruled out. It remains legal in US supplements. Used only to make pills white.
• —FD&C synthetic dyes (Yellow No. 5, Yellow No. 6, Red No. 40) — purely cosmetic; some are subject to ongoing regulatory scrutiny. No reason to exist in a health product.
• —Talc (magnesium silicate) — anti-caking agent; concerns are mainly historical-contamination related, but it's trivially avoidable.
• —High-load maltodextrin — a filler with a high glycemic index; a caution flag mainly at large amounts and for people watching blood sugar.

A supplement with a clean excipient list but sub-clinical active doses is still a bad product — it just fails safely. The reverse also holds: one caution-rated colorant doesn't erase a well-dosed formula, it modestly discounts it. That's why BioStacks treats safety as a multiplier on the efficacy score rather than a separate grade you might never look at.