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Biotin For Hair Growth: Does It Work? What The Research Says & Usage Tips*

Kirsten Nunez, M.S.
March 13, 2022
Kirsten Nunez, M.S.
Contributing writer
By Kirsten Nunez, M.S.
Contributing writer
Kirsten Nunez is a health and lifestyle journalist based in Beacon, New York. She has a Master of Science in Nutrition from Texas Woman's University and Bachelor of Science in Dietetics from SUNY Oneonta.
March 13, 2022

If you're on a mission to grow healthy locks, you've likely heard of biotin.* The nutrient is a popular ingredient in not only hair and beauty supplements but multivitamins as well. But how does biotin work for hair growth, exactly? Read on to learn about the buzzy nutrient, plus what to look for in a supplement.   

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What is biotin?

Biotin, or B7, is a water-soluble vitamin. It's part of the B complex, which includes eight B vitamins that are essential for important cellular reactions in the body.* Case in point: Biotin plays a major role in energy production; specifically, it's a coenzyme for carboxylases1, or enzymes that help metabolize macronutrients (i.e., carbohydrates, fats, and proteins) into fuel for the body.* Carboxylases are also involved in biological processes like insulin release2, fatty acid production3, and gluconeogenesis4 or the synthesis of glucose. Moreover, biotin is a well-known beauty nutrient, as it can help support hair, skin, and nail health.*

Your body cannot make biotin5 on its own. And while the bacteria in your gut5 can produce it to a certain extent, they also need biotin to grow and survive6.* Thus, they might "compete" with the host (i.e., you), so you'll need to get biotin through the diet to meet your needs. Natural food sources include beef liver, salmon, animal meats, eggs, cheese, sunflower seeds, spirulina, and nutritional yeast. You can also find it in supplements, including B-complex vitamins that when complete, contain the other seven B vitamins (thiamin, riboflavin, niacin, pantothenic acid, folate, B6, and B12). Biotin is also a common ingredient in beauty supplements, particularly those with collagen, as both nutrients offer hair and skin benefits.*

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Biotin benefits for hair.

Biotin is a well-known hair vitamin—and for good reason, too. Here's what the nutrient can do for your locks:*


Decreased shedding

Research shows that not getting enough biotin2 can lead to hair shedding, but taking a biotin supplement can provide support.* (We should note that lacking biotin is rare in the U.S. population, however.) The vitamin helps nourish hair follicles, says board-certified Debra Jaliman, M.D.* This is important because each hair follicle is in charge of securing or "anchoring" each hair to the skin. According to Jaliman, biotin also stimulates the growth of existing hair, as it's involved in the production of keratin, the main structural protein in hair.* One small study found that women who took supplemental biotin experienced notable hair regrowth than the placebo group.*

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Shiny hair

Healthy, strong hair is often naturally shiny and glossy. But of course, like glowing skin, achieving healthy hair isn't just about using the right products. It also relies on adequate levels of nutrients that support hair growth and strength—like biotin.* After all, not getting adequate amounts of biotin can lead to dull and lackluster hair, according to board-certified hair loss surgeon William Yates, M.D.* Thus, "if your hair is dry and brittle, you might want to consider a biotin supplement,"* says Jaliman.


Improved scalp health

Did you know that your scalp has its own community of bacteria? Yes, it's true. They're collectively known as the scalp microbiome, and they're involved in regulating hair health and scalp issues, including flakes and the like. According to research, biotin is essential for supporting this unique microbiome7 and its functions for scalp health.*

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Hair fullness

Over time, hair shedding can make your mane look limp and thin. But as biotin supports healthy hair growth, it can also contribute to more voluminous and fuller-looking locks.* Similarly, biotin's role in healthy hair follicles and the scalp microbiome can strengthen your hair, ultimately making it appear fuller.*

What to know about finding a biotin supplement.

When shopping for a biotin supplement, here are a few things to keep in mind:

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More research is needed to determine the best biotin dosage for hair. While the National Academies8 recommends adults consume at least 30 micrograms of biotin daily for baseline nutrition needs, higher biotin doses (e.g., 300, 500, or 1,000 micrograms) can incrementally support your biotin needs and health pathways in the body, including hair.*

Your biotin needs might be higher if you have low levels, like between 5,000 to 10,000 micrograms (5 to 10 milligrams), according to Jaliman. Here are some other reasons you might need to pay special attention to biotin levels:

  • Digestive considerations. Biotin is absorbed in the small and large intestines9. But for some who may have gut concerns, it can be challenging to support healthy levels of biotin10.
  • Disruptions in gut microbial diversity. If a variety of microbes in your gut are not regularly replenished through diet and targeted supplementation, your gut microbial diversity might be suboptimal. This includes bacteria that help synthesize biotin11.
  • Alcohol consumption. Drinking too much alcohol hinders the absorption of biotin12.
  • Cigarette smoking. Smoking13 speeds up the absorption of many nutrients, including biotin.

 Additional ingredients

You can buy supplemental biotin on its own. But for optimal hair benefits, consider a supplement with complementary nutrients. One hair-healthy ingredient to look for is vitamin D3, a fat-soluble vitamin that's required for healthy hair follicle function. Almost all Americans are failing to consume just 400 I.U. of vitamin D from their daily diet, and clinical vitamin D insufficiency persists in almost half of the population (41%14, to be exact). Taking a supplement can help you obtain adequate levels, as there are only a few foods that naturally offer vitamin D. A few examples include cod liver oil and eggs. 

Also, keep an eye out for supplements with both biotin and collagen, which is the main structural protein in the skin.* Collagen contains amino acids that are necessary for keratin production and, therefore, hair growth.*


In general, biotin is considered to be a safe vitamin. It's also difficult to take too much of the nutrient due to its water-soluble nature. (In other words, excess amounts are simply excreted via the urine11.) But as with any supplement, it's important to check with your doctor before taking biotin. This will ensure the supplement won't interact with medications or other aspects of your health routine. Also, in some cases, high doses of biotin may affect hormone levels, including those related to healthy thyroid function15. Let your doctor know if you've been taking biotin, especially if you need routine hormone tests.

How long does it take?

If you're experiencing hair struggles due to a lack of biotin, you should see results in "two to three months once you increase your dosage to the recommended amount,"* says Jaliman. However, this time frame will be influenced by many factors, including the degree of your needs, the original health of your hair, and your hair routine.

Can you use it topically?

Biotin is a common ingredient in topical hair care products. In this form, it will strengthen the surface of your hair strands, according to Jaliman. However, biotin's hair benefits are less effective when applied topically, she adds. So, if you're looking to get the most hair benefits from biotin, supplements may be the way to go.* 

The takeaway. 

Biotin is a B vitamin that is often used in beauty and hair supplements as it can support healthy hair growth thanks to its role in keratin production and promoting scalp health.* If you're looking for a supplement to promote long, shiny locks—this may be the one for you.* For additional hair nutrient ideas, check out our full rundown of supplements for dry hair.*

If you are pregnant, breastfeeding, or taking medications, consult with your doctor before starting a supplement routine. It is always optimal to consult with a health care provider when considering what supplements are right for you.