Biotin is one of those compounds that seems to be ingrained in society’s psyche as something that helps your hair and nails grow longer and stronger, as well as improve your skin’s appearance. There are so many supplements out there that claim to do these things and contain a lot of biotin.

Real talk: there’s no good evidence that taking those supplements is going to do anything for your hair, skin, and nails if you already eat a healthy diet and don’t have a biotin deficiency, a rare condition.¹ The studies out there that show biotin’s efficacy in strengthening hair, skin, and nails are not well-designed, or are done on children who have mutations that lead to biotin deficiency and other conditions. Let’s get the story straight once and for all, and go through everything you need to know about biotin.

What is Biotin?

Biotin is Vitamin B7. Its main function is the breakdown and processing of carbohydrates, fats, and amino acids. We can get biotin from our diets through eating all sorts of foods, such as meat, salmon, eggs, peanuts, almonds, corn, cheese, milk, broccoli, tomato, strawberry, etc.² The biotin molecule is water-soluble, and excess biotin that’s consumed through supplements is simply excreted in urine. What’s great is that all the scientific evidence shows that biotin isn’t toxic and having an excess of it isn’t really going to hurt us; it’ll all just get excreted in our urine!³

The general recommended amount of biotin that we should consume every day (for adults, male and female) is 0.03 milligrams (mg), or 30 micrograms (mcg), according to the NIH.⁴ They also report that biotin intake from foods in western populations is pretty comparable, at about 35-70 mcg a day, and that people in those western countries consume enough biotin from their food every day.

Interestingly, biotin levels in the general population in the U.S. haven’t been established yet, which is something that definitely should be done. It’d be interesting to see how it compares to those levels from other western countries!⁴ 

Biotin Deficiency: What Conditions Cause It?

You can be certain that for the most part, you consume enough biotin from the food you eat every day, and that you’re not deficient. However, there are definitely a few conditions and situations that have been associated with biotin deficiency. Here are some of them:

A biotinidase deficiency

People who have a biotinidase deficiency have low levels of the enzyme, biotinidase. This is caused by an autosomal recessive mutation in the gene for biotinidase, leading to decreased production of the enzyme compared to healthy people. It can manifest as severe biotinidase deficiency, meaning the patient has less than 10% of normal biotinidase activity in their blood, or partial deficiency, which means the patient has 10-30% of normal biotinidase activity in their blood. Biotinidase is very important for the maintenance of biotin levels, because it’s involved in the recycling of biotin in the body.⁵ 

Biotinidase deficiency is usually detected in infants in the first few months of life through screening for a variety of symptoms, mostly neurological, and currently there is research being done to test for that deficiency by using amniotic fluid cells and blood samples. You would know if you have a biotinidase deficiency because you’d be taking biotin supplements your whole life. It’s pretty rare, though, and 1 in 31,000 to 80,000 births have either the partial or severe degree of biotinidase deficiency, respectively.⁶

Pregnancy

Pregnancy has been shown to be associated with lower biotin levels in the blood. This was established through the quantification of 3-Hydroxyisovaleric acid, a compound that is usually at lower levels when there is enough biotin in the body, which was found to be increased in the urine of pregnant women compared to controls.⁷

If you are pregnant, ask your doctor what they recommend regarding supplements that are most suitable for you.

Egg white injury syndrome

People who consume lots of raw egg whites may experience biotin deficiency, because avidin, a protein in raw egg whites, binds directly to biotin and causes it to become unavailable for intestinal absorption.^8,9 Don’t be afraid to eat cooked eggs, though. This has only been shown in a very small number of cases where the patients were eating a lot of raw egg whites over a long period of time, and it’s really, really rare!

Alcohol abuse

It’s been shown that chronic alcohol exposure can inhibit the absorption of biotin in pancreatic acinar cells.¹⁰ 

So If I’m Healthy, Will Biotin Supplements Do Anything?

There is no real evidence from well-designed studies that show that biotin does anything for nails. There are a few studies that show that nail thickness of study participants did increase with biotin supplementation, but some of the changes were not significant, there were no controls, there was no establishment of baseline biotin levels, and no placebo groups.^11,12,13 

As for hair, the only improvements in hair quality that have been observed with biotin supplementation were in children who had uncombable hair syndrome, a very rare condition of the hair shaft. Their hair was a lot healthier 3-4 months into taking biotin on a regular basis.^14,15

The efficacy of biotin has only been shown in skin for infants with alopecia and rashes/dermatitis.^16,17 

Conclusion

There is no evidence from well-designed, blinded, placebo-controlled, randomized studies showing that biotin supplements do anything for a healthy person’s hair, skin, and nails. Eating a healthy diet is a great way to support and maintain your biotin levels, and once again, is the better alternative to buying into a beauty fad.

There are so many fads out there that people just seem to eat up, literally, without understanding just how little evidence there is to support their spending. There are so many gummies, teas, creams, masks, etc., that prey on insecurities that people have. The products’ purported benefits are only based on loose evidence, and none of this stuff is FDA-regulated.

Do you think you have signs of a biotin deficiency, or are you unsatisfied with how your hair or nails are feeling? Definitely contact your doctor to become best informed about how you can help yourself.