Medically reviewed by Kristin Hall, FNP
Written by Our Editorial Team
Last updated 1/21/2021
Your hair goes through a natural cycle of growth consisting of three phases. Roughly 90 percent of your hair is in the growth phase at any given time with the rest either in a period of transition or rest.
After these three phases have been completed, the old hairs are shed to make way for new growth.
The cycle of hair growth continues throughout your life.
Though the phases themselves remain the same, their length or the number of hairs in each phase can change.
Hormonal changes, chronic stress, and medications or medical conditions can cause the hair to move to the next phase prematurely, which can result in hair loss or thinning hair.
Hair loss is often considered primarily a male issue, but it is estimated that over 50 percent of women will experience noticeable hair loss in their lives.
In fact, female-pattern hair loss (androgenetic alopecia) affects 30 million women in the United States alone.
The good news is treatment options exist.
Topical treatments like minoxidil have been approved by the FDA for female-pattern hair loss but if you’re not quite ready to make that jump, you may want to try a natural supplement like biotin.
Below we’ve compiled the information you need to know to determine whether biotin is the hair growth remedy you’ve been looking for.
Read on to learn what biotin is, whether it works for hair growth, and how much you should take. We’ve also reviewed its safety and potential side effects.
Biotin is a water-soluble B vitamin, though it is sometimes known as vitamin H.
This nutrient plays a role in helping the body convert food into fuel by metabolizing carbohydrates and breaking them down into glucose.
Along with other B complex vitamins, biotin is required for healthy hair, skin, and eyes — it’s also important for healthy nervous system function.
It is quite rare to be deficient in biotin, as many foods contain biotin. Some of the richest food sources of biotin include eggs, meat (including organ meats), fish, nuts, and seeds.
Symptoms of biotin deficiency may include dry skin, hair loss, fatigue, swollen tongue, dry eyes, insomnia, and depression.
Biotin deficiencies may be seen in patients taking long-term antibiotics or antiseizure medications and people with digestive diseases like Crohn’s that interfere with the absorption of nutrients.
Biotin has become a popular over-the-counter supplement for hair growth, available in tablets as well as gummies.
The real question, however, is whether it actually works.
There is limited evidence to suggest increased biotin intake promotes hair growth, but several studies show that it may strengthen the hair and help reduce shedding.
Stronger hair means less breakage which, combined with reduced shedding, could help your hair look thicker or fuller even if you don’t actually experience any additional growth.
For some women, that’s more than enough.
In one 2015 study, women with thinning hair were given an oral supplement that contained biotin and several other ingredients or placebo twice daily for 90 days.
At the end of the study, participants taking the supplement with biotin and other ingredients experienced not only a reduction in hair shedding, but significant hair growth in the areas affected by hair loss.
A 2017 review of previous research found 18 cases of biotin use for changes in hair and nails.
In all cases, the researchers found that patients receiving biotin had an underlying pathology for poor hair or nail growth.
All of those cases showed clinical evidence for improvement with biotin supplementation.
Though there are a few small studies that show promising results, the National Institutes of Health (NIH) has concluded that there is insufficient evidence to rate the effectiveness of biotin for the treatment of hair loss.
What we’re trying to say is: the research behind biotin, although promising, is scarce, and much more research is needed before it can be said definitively how beneficial biotin is for hair growth.
Because biotin deficiency is fairly rare, the U.S. Food and Drug Administration (FDA) has not established a recommended dietary allowance for biotin.
That said, the Food and Nutrition Board of the Institute of Medicine has set recommended daily intake for adults over 19 years of age at 30mcg.
In most cases, you can meet that 30mcg recommendation through your daily diet.
The thing you need to remember about biotin is that it is a water-soluble vitamin which means the body doesn’t store it.
In order for it to be effective, it needs to be consumed and you need to take it daily.
It could take several months to notice the effects of supplemental biotin and the results will only last as long as you continue to take the biotin.
Before you start taking nutritional supplements, it’s a good idea to talk to your healthcare provider.
Even natural supplements have the potential to cause side effects and over-supplementation with certain vitamins and minerals can lead to health problems.
Many healthcare professionals caution against taking supplements unless you have a specific nutritional deficiency.
Fortunately, there is no evidence that biotin is toxic in humans at high intake levels.
Even studies involving daily intakes up to 50mg per day failed to produce symptoms of toxicity.
Though biotin hasn’t been shown to have any risk for adverse effects, daily use hasn’t been tested for safety in pregnant women, nursing mothers, or children.
If you have a medical condition or you’re taking medication, talk to your healthcare provider about the potential risks for side effects and drug interactions before taking biotin supplements.
It’s always better to be safe than sorry.
If you’re experiencing hair loss or hair thinning, biotin supplements could help.
Research suggests that increasing your biotin intake between 2mg and 5mg per day could improve the strength and thickness of your hair.
Just keep in mind that it isn’t an approved treatment for hair loss — it may simply help protect and improve the appearance of the hair you already have.
After starting a biotin supplement routine, you can expect to start seeing a difference in about three to four months. Results may vary depending on the amount and type of biotin you’re taking.
You can find biotin at most drug stores and in any vitamin shop. When shopping for biotin supplements, check the dosage and serving recommendations.
Biotin supplements generally range from 1,000mcg to 10,000mcg per serving, though some formulations may require you to take multiple tablets to reach the recommended serving size.
If you start to experience any negative reactions when taking biotin supplements, stop taking it immediately and talk to your healthcare provider.
Insider tips, early access and more.