How I found the best biotin supplements for hair growth
Biotin supplements have long been associated with hair growth. I’ve lost count of how many times I’ve scrolled past someone on my FYP crediting their glossy, waist-length hair to a daily biotin supplement. Available in everything from capsules and gummies to powders and liquid formulas, the ingredient is often touted as the secret to longer, stronger, and shinier hair, but is it actually an effective solution?
First, a bit of background: Biotin is a B vitamin known for promoting healthy hair and helping with brittle nails. It’s essential for the process by which cells create proteins. “Since our hair and nails are made of keratin, a type of structural protein, a biotin deficiency will negatively impact hair and nail growth,” says Kseniya Kobets, director of cosmetics dermatology at Montefiore Einstein Advanced Care.
One major symptom of biotin deficiency is alopecia (hair loss). But here’s the kicker: if you aren’t deficient in biotin (most people aren’t, FYI), taking biotin supplements probably won’t do much for you. The data on taking biotin to help grow your hair, skin, and nails just isn’t there. But anecdotally, many reviewers we spoke to say saw improvements in these areas after taking biotin — even when they’re not deficient.
So, what’s a gal looking to grow her strands to do? I spoke with dermatologists and dieticians for their recommendations on the best biotin supplements for hair growth. And a quick reminder that supplements are not always regulated, so it’s always best to do your own research and check in with a doctor before adding one to your diet, especially if you take any medications.
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How I tested biotin supplements for hair growth:
With social media awash with promises of Rapunzel-length hair courtesy of a daily biotin supplement, the Glamour team decided to put some of the most talked-about formulas to the test. I worked with my fellow editors to trial a range of biotin supplements to see whether they could actually support stronger, healthier-looking hair growth.
Each tester committed to taking one biotin supplement consistently for a minimum of four weeks. After the trial period, we assessed each formula based on how easy it was to incorporate into our haircare routines, whether we noticed any visible changes to their hair, nails or overall hair health, and whether the supplement felt worth the investment. At the end of the testing period, every product was rated against the following criteria:
- Ease of use – Was the supplement convenient to take daily? Were the capsules easy to swallow or the gummies enjoyable to eat?
- Efficacy – Did they notice any difference in hair strength, shine, shedding or growth over the four weeks?
- Taste – For gummies, powders and liquids, how enjoyable was the flavour?
- Value for money – Did the results justify the price, and would they continue taking it long term?
Why you can trust me
I’ve spent almost three years as a shopping writer at Glamour, following earlier roles writing for titles such as Cosmopolitan, Elle, and Harper’s Bazaar. Across that time, I’ve tested and reviewed a wealth of products spanning interiors, fashion, beauty and wellness, with the latter frequently including supplements. I’ve also attended numerous press days and interviewed dieticians, nutritionists, and industry experts so i'm up to date on the latest research on biotin supplements.
Ahead, the best biotin supplements for 2026, recommended by dieticians and tested by us.
- Tester: Mayola Fernandes, Commerce Writer.
- Type: Capsule.
- Dose: 8,000 mcg (8 mg).
- Pros: Free of dairy, soy, and gluten; one capsule serving size; rigorously tested.
- Cons: A bit pricier than other brands.
Glamour-tester review: "Thorne’s biotin supplement delivers a high potency dose of 8,000 mcg and is free from dairy, soy, and gluten. The recommended dosage is up to two capsules per day, though just one easy-to-swallow pill already provides well above the typical daily biotin requirement (around 30 mcg). I also appreciate that Thorne follows rigorous quality standards, with each batch undergoing four rounds of in-house testing to ensure purity and potency.
After taking the supplement consistently for six months, the most noticeable change has been in the condition of my hair strands. Rather than dramatic baby hair growth, the improvement has been in overall strength and texture – my hair feels a little softer, looks healthier, and experiences far less breakage. Despite years of heat damage, my hair has gradually become stronger over time. While the changes haven’t been dramatic, I have noticed a slight increase in growth compared to before."
- Tester: April Benshosan, Glamour Contributor.
- Type: Capsule.
- Dose: 5,000 mcg (5 mg).
- Pros: Lower dosage is more customisable; contains added calcium and phosphorus.
- Cons: Not for those who want a simple biotin supplement.
Glamour-tester review: "Solgar’s biotin supplement offers 5,000 mcg of biotin. Unlike some extra-strength supplements, which can contain double the biotin dosage, this pick from Solgar packs in a moderate amount of B7 so you can start slow and customise your dosage based on your results. The lower dosage also means you’re less likely to get side effects like an upset stomach.
What’s more, this formula also contains calcium and phosphorus, making it a great option for anyone seeking more than just a basic biotin supplement, says registered dietitian Stacey Woodson. It is also gluten-free, vegan-friendly, and dairy-free, and comes in a dark glass bottle designed to help protect the capsules from oxidation."
- Tester: Denise Primbet, Glamour Contributor.
- Type: Capsule.
- Dose: 10,000 mcg (10 mg).
- Pros: One capsule serving size; third-party-tested; vegan.
- Cons: High dose may cause minor side effects.
Glamour-tester review: "Now’s Extra Strength Biotin is non-GMO, vegan-friendly, and made with quality ingredients you can trust. It’s free from artificial sulfites and it’s CGMP [Current Good Manufacturing Practices] certified, meaning it meets requirements set by the FDA, and exhaustively tested for quality, purity, and potency in Now’s third-party accredited ISO [International Organisation for Standardisation] labs, says Lauren Manaker, a registered dietitian. Just one easy-to-take capsule provides a large dosage of 10,000 mcg of biotin.
I’ve been taking these for months now, and I’ve absolutely seen a difference in my hair growth. After struggling with postpartum hair loss, I think these are definitely the way to go. The pills are a little big but no larger than other capsules. No odd tastes either.”
- Tester: Mayola Fernandes, Commerce Writer.
- Type: Softgel.
- Dose: 2,500 mcg (2.5 mg).
- Pros: Easy to take; USP-verified; affordable and widely available.
- Cons: Contains gelatin, so may not be suitable for certain diets.
Glamour-tester review: "This supplement offers 2,500 mcg of biotin, a dosage that’s especially great for those new to taking biotin who want to start slow. Nature Made’s biotin comes recommended by experts because it’s a quality supplement that’s also affordable and widely available at most drugstores. Nature Made is an excellent choice for a supplement as it bears the USP symbol, a third-party-verification seal that ensures quality products to consumers, says Woodson.
I personally found that these soft gels are small and very easy to swallow. I also made sure to take them with a meal, which helped prevent any stomach discomfort – a side effect that can sometimes occur with biotin supplements in general, and is reported in some of the reviews."
- Tester: Mayola Fernandes, Commerce Writer.
- Type: Capsule.
- Dose: 10,000 mcg (10 mg).
- Pros: Supports healthy hair, skin, and nails.
- Cons: High dose may cause minor side effects.
Glamour-tester review: "I’ve been taking the Natrol Fast Dissolve Biotin tablets (10,000 mcg, strawberry flavour) daily for a few months now, and I really like how easy they are to take. You simply let one tablet dissolve in your mouth or chew it – no water needed –which makes it ideal for those who struggle taking tablets. The strawberry flavour is quite subtle and no t overly sweet, too.
After around 12 weeks of continued use, I started noticing the benefits. My hair felt stronger and appeared to grow more steadily over time, which was especially noticeable with regular trims. I also saw a big improvement in my nails – after years of brittleness from acrylics and gel treatments, they became noticeably stronger and less prone to breaking."
All your biotin questions, answered:
What exactly is biotin?
Biotin goes by two other names — vitamin B7 and vitamin H — and plays a role in the production of keratin, a protein essential for healthy skin, hair, and nails. It’s a water-soluble vitamin, meaning it doesn’t build up in your body; rather, you excrete the excess through urine.
The recommended daily intake of biotin is 30 micrograms per day, according to the American National Institutes of Health (NIH), and we naturally hit that mark through our diets — most healthy adults get about 35 to 70 mcg per day, Woodson says. Some biotin-rich foods include meat (and organ meats), fish, eggs, nuts, seeds, and sweet potatoes.
What are the benefits of biotin?
Benefits of biotin (vitamin B7)
- Glucose: Biotin helps to process carbohydrates (glucose), fats, and proteins and convert them into energy for the body to use, says Marisa Garshick, a dermatologist at MDCS Dermatology in New York.
- Fatty acids: Biotin is necessary for the creation of fatty acids, which are essential for cell maintenance and energy storage, says Stacey Woodson, a registered dietitian.
- Amino acids: Biotin helps deconstruct amino acids, a.k.a. the building blocks of proteins. Amino acids are repurposed to create energy or support other metabolic needs, says Woodson.
Benefits of biotin supplements
- Hair growth: For people who have thinning hair because of a biotin deficiency, some studies suggest that biotin supplementation can reduce hair loss and stimulate hair regrowth. “Most people typically see significant improvements after consistent use for three months or longer,” Woodson says.
- Nail and cuticle health: Supplementing with biotin may help strengthen weak nails, as some studies show taking 2.5 mg per day can help with nail thickness. But the evidence isn’t crystal clear. The studies out there on using biotin for brittle nails are very small, and the researchers didn’t use placebo groups or check participants’ initial levels of biotin.
What is the downside of taking biotin?
Some people report mild digestive symptoms, like an upset stomach, when taking biotin supplements. Yet even in high doses, there isn’t any evidence that suggests biotin supplements are harmful or toxic, Woodson says. That’s because biotin is water-soluble and the excess gets excreted through urine, so it doesn’t build up in the body at toxic levels.
Still, you may not be in the clear, at least not on paper. Biotin may interfere with certain laboratory test results including thyroid and troponin levels (a marker used to detect heart attacks), according to the FDA. If you’re getting lab tests done, make sure to stop taking biotin beforehand and always remember to tell your doctor about all medications, including supplements (as well as multivitamins), you’re taking, Dr. Garshick says.
How much biotin should you take for hair growth?
Research shows that taking 5,000 mcg (5 mg) of biotin daily may help treat hair loss caused by a biotin deficiency. But remember, a biotin deficiency is pretty rare. And there isn’t much scientific evidence that supports biotin supplementation significantly improving hair health for those of us without a biotin deficiency.
“Generally speaking, the only people who should absolutely be taking biotin supplements are those who are deficient, which is generally rare,” Dr. Garshick says. “That said, although there isn’t much clinical evidence, if people are looking to try something for their hair and nails, they can consider it and if they are noticing an improvement, it is fine to continue with it.”
Meet our experts:
| Dr Marisa Garshick | A dermatologist at MDCS Dermatology in New York. |
| Stacey Woodson | A registered dietician. |
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This story originally appeared on GLAMOUR US.
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