Does Biotin Actually Work for Hair? The Honest Evidence

TL;DR: Biotin is in nearly every “hair, skin & nails” supplement — but the evidence that it actually helps your hair is thin unless you’re genuinely deficient (which is rare), and high doses can interfere with important medical lab tests. Here’s the honest picture, and why Let It Thrive doesn’t lean on it. (General information, not medical advice.)

The promise vs. the evidence

Biotin (vitamin B7) is marketed as the hair-growth vitamin, and it’s in almost every hair gummy on the shelf. Here’s the part the packaging skips: a 2017 review found biotin only improved hair in people who had an underlying deficiency — and there’s no solid evidence it does anything for hair in people with normal biotin levels (Patel et al., 2017). And true biotin deficiency is rare; most people get plenty from a normal diet (NIH Office of Dietary Supplements). So for the vast majority of people, a biotin supplement is an expensive maybe.

The catch nobody mentions: your lab tests

There’s a genuine safety footnote, too. In 2017 the FDA warned that high-dose biotin — and hair supplements often contain many times the daily need — can interfere with lab tests, including troponin (used to diagnose heart attacks) and thyroid panels, with reported harm (FDA). If you do take biotin, it’s worth telling your doctor before any bloodwork.

So why is it in everything?

Because it’s cheap, it’s a vitamin (so it sounds healthy), and “biotin” on a label sells. That’s marketing, not evidence — and it’s exactly the kind of thing we’d rather not build a product on.

What we do instead

Here’s the honest framing, because we don’t do hype: Let It Thrive skips biotin entirely. It’s built on pumpkin seed and rosemary — two of the most-studied botanicals in scalp care — and it supports a healthy-looking scalp and the appearance of fuller, thicker-looking hair while conditioning lashes and brows. Cosmetic care, real ingredients, no padding the label with a hype vitamin.

To be clear about what it is: a cosmetic conditioner that supports the look of fuller, thicker hair — not a treatment for hair loss, and not a substitute for fixing a real deficiency (if you suspect one, get tested rather than guessing). Meet the line: the Let It Thrive Hair Tonic and Let It Thrive Eyelash Serum. Skip the hype — shop Let It Thrive.

FAQ

Does biotin regrow hair? Only if you’re deficient. In people with normal biotin levels there’s no good evidence it grows or thickens hair (Patel et al., 2017).

Is biotin safe? For most people, yes — but high doses can skew lab tests like troponin and thyroid panels, so tell your doctor if you take it before bloodwork (FDA).

Does Let It Thrive contain biotin? No — we don’t build on an ingredient the evidence doesn’t back. It uses pumpkin seed and rosemary instead.

Related reading: Minoxidil and cats: why pet owners skip it · Why Let It Thrive skips minoxidil, biotin and prostaglandins

Sources

• Patel DP et al. — A Review of the Use of Biotin for Hair Loss. Skin Appendage Disord. 2017. PMC5582478
• U.S. FDA — Biotin may interfere with lab tests. fda.gov
• NIH Office of Dietary Supplements — Biotin fact sheet. ods.od.nih.gov

Real ingredients. Real results.