Good Question!

Part 2: Biotin — Does it REALLY help your hair, skin, and nails?

Photo by jagadshd on Unsplash

In a post a couple of weeks ago, I teased my take on supplements:

When it comes to supplements, I have so much to say that it deserves a post all its own. The short version: I’m not “pro” or “anti” supplements. I’m all about targeted supplementation — first figuring out if you truly need a supplement, and if you do, regularly monitoring the dose and duration.

While I still owe you an in-depth piece about supplements, a question I was asked at a recent in-person event allows me to address one supplement in particular: biotin.

The question was about the “hair, skin, and nails” supplements that are all the rage right now. Countless formulations fit into this category, but the main nutrient these supplements lean on is biotin.

If I had to guess, biotin-containing supplements for the purpose of supporting hair, skin, and nail growth are near the top (if not at the top) of the list of the most common supplements my patients report taking.

So what is biotin? Does it work? And is it safe?

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First, a bit of info about biotin (also known as vitamin B7):

• Like other members of the B-vitamin family, biotin helps convert food into energy by acting as a coenzyme (“helper”) in several metabolic processes.

• Biotin deficiency is rare because it is found in so many common foods: eggs, nuts & seeds, beans & lentils, whole grains, fish, meat, dairy, sweet potatoes, & avocados.

• Most adults need ~30 mcg biotin per day.

Most hair, skin, and nail supplements contain up to 10,000 mcg biotin per dose, which is over 300 times the estimated need.

So my question is: Do these extra-high doses actually work?

My go-to resource for unbiased evidence-supported information on supplements is examine.com. While the platform recently added a paid option, basic safety and effectiveness information continues to be free.

The information on examine.com about biotin confirms what I have read in the past — there has been little research done about biotin and hair, skin, and nail health in humans.

While some human research shows that biotin improves hair, skin, or nail quality, this is primarily in people with biotin deficiency or conditions like brittle nail syndrome.

The good news is that biotin doesn’t appear to be harmful at the mega-doses found in common hair, skin, and nail supplements.

The biggest concern is that biotin-based supplements can interfere with blood tests, potentially leading to falsely high or low results, or to missed or misdiagnosed conditions.

This is because some testing technology uses biotin as an “ingredient” in the testing process, and excess biotin in the test sample can disrupt how these tests work. This most commonly affects thyroid, hormone, and cardiac marker tests.

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Takeaways

• It is unclear if the common hair, skin, & nails supplements actually work for already healthy people.

• I recommend starting with food first to meet your biotin and other needs.

• If you are concerned about hair loss, brittle nails, or other symptoms, check with your healthcare provider to test for a possible biotin deficiency or other underlying causes.

• If you decide to try or continue biotin, consider a standard multivitamin, which typically contains the daily recommended needs for biotin.

• If you take a high-dose biotin supplement, always let your healthcare provider know and stop taking it for at least one week prior to getting any labwork done.

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Thank you for the great questions. Please keep them coming!

Thanks for being here,

~Allison

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Check out my upcoming in-person events!

Vintage House Sonoma - February 12, 2026

Sonoma Community Center - February 21, 2026

Brannan Center Calistoga - February 28, 2026

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This information is meant to inform and inspire—but it’s not medical advice. Be sure to check in with your own healthcare provider before making any changes to your routine.