B7 Biotin: The Hair Hype Check

If you’ve walked past a “hair, skin, and nails” display, you’ve met biotin — vitamin B7. It’s the poster child of beauty supplements, splashed across gummies and serums with promises of thicker hair and stronger nails. Time for the frank conversation.

First, what biotin actually does: it’s another B-complex member helping your body convert food into energy and build fats. Standard, useful, unglamorous metabolism work.

Will it grow your hair?

This is the question, so let’s answer it straight. For most people, taking biotin will not give you better hair, skin, or nails. The marketing got way out ahead of the evidence.

Here’s the nuance that makes it honest:

• If you are genuinely biotin-deficient, supplementing can help with hair and nail problems — because you were short to begin with.
• If your biotin levels are already normal — which is the vast majority of people — extra biotin hasn’t been shown to do much for your hair at all.

And true deficiency is rare, because biotin is widely available in food. So the typical buyer of a biotin gummy is correcting a problem they don’t have. You can’t “top up” past full and expect a glow-up.

Two things actually worth knowing

The nail evidence is slightly less hopeless — a few small, not-very-strong studies suggested thicker nails with biotin. “Small and not very strong” is doing a lot of work in that sentence, so hold the celebration.

More importantly, a genuine heads-up: high-dose biotin can interfere with certain lab tests, including some thyroid and heart tests, throwing off the results. If you take biotin and you’re getting bloodwork, tell whoever’s ordering it. This is a real, documented issue worth more attention than the hair promise ever earned.

Where to get the perfectly adequate amount you need, for free, from food:

• Eggs (especially the yolk)
• Nuts and seeds
• Sweet potatoes
• Salmon

The takeaway: biotin only helps hair and nails if you’re actually deficient — which is rare — so the famous beauty gummies are mostly buying you a promise food already kept.

Next lesson: B9, folate — small word, huge deal, especially in pregnancy, and the reason it’s quietly added to half the food on your shelf.