If you're buying this for thicker hair or stronger nails, here's the honest read: **biotin** has essentially zero clinical trials proving it works in people who aren't deficient — and true deficiency is rare. At 5,000mcg, you're taking roughly 167 times the ~30mcg your body needs daily, but the dose isn't the problem; the evidence outside of genuine deficiency simply isn't there.
Where biotin does help is documented deficiency or diagnosed brittle nail syndrome. If that's not you, you're megadosing for a benefit the research doesn't back.
Worth knowing: at this dose, biotin can throw off common blood tests — thyroid panels and cardiac troponin among them — causing false results. The FDA advises stopping it 72 hours before bloodwork, which NOW notes on the label.
BioStacks
Other Ingredients (4)
Rice FlourFiller
Rice-based ingredients carry risk of inorganic arsenic contamination (FDA and Consumer Reports). Rice accumulates arsenic from soil at higher rates than other grains. Used as a cheap filler — adds nothing beneficial.
Silicon DioxideAnti-caking
Fine silica powder used to prevent clumping
HypromelloseCapsule
Plant-derived capsule material from cellulose
Stearic AcidLubricant
Saturated fatty acid used as tablet lubricant
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Sources & Scoring
Nutrient data (RDA, UL, and safety thresholds) sourced from: NIH Office of Dietary Supplements and National Academies Dietary Reference Intakes (DRI).
This is not medical advice. Consult a healthcare provider before making changes to your supplement routine.
The score analyzes what's on the label: ingredient doses vs. clinical ranges, chemical forms, evidence levels, and known interactions. It does not verify label accuracy or test for contaminants — for that, look for third-party certifications like USP or NSF.