Biotin: The Beauty Supplement of Choice?

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Biotin is a popular dietary supplement for enhancing the appearance of hair, skin and nails. Does it work? Let’s take a closer look at the evidence.

What is it?

Biotin is an essential vitamin, meaning you have to get it from your diet. It belongs to the B vitamins, and is also known as vitamin B7, though this name is rarely used. 

What does it do?

Biotin’s main effect of interest when it comes to beauty is its ability to boost the production of keratin. Keratin is a strong structural protein present in nails, skin and hair. Insufficient keratin makes these structures fragile and causes a deterioration in visual appearance. Hair and nails break easily and lose their shine, while skin becomes dull, dryer, and more prone to sagging and wrinkling. Biotin supplements may be helpful for people with certain hair, nail or skin conditions, but it has been suggested that consuming biotin supplements may benefit healthy people, even those who consume the recommended quantity of biotin in their diets.

Additionally, biotin has various effects on the metabolism of macronutrients (carbohydrates, fats and proteins) that may have some general health benefits, such as reduced blood sugar and cholesterol.

What’s the evidence?

Biotin first caught the interest of the beauty industry after a small pilot study in 1990. This study found that 22 women with brittle nails had significantly thicker, less fragile nails compared to the control group after taking 2500 microgrammes of biotin per day for 6 months. For context, the recommended dietary intake of biotin is about 30 micrograms, while it is not hard to buy supplements containing 10,000 micrograms of biotin.

Unfortunately, not that many studies followed up on these findings. A review from 2017 concludes that biotin supplements could be beneficial for people with nail and hair conditions, but that this evidence was somewhat limited and that there was insufficient evidence for the effects of biotin on people without nail or hair conditions. Not much has really changed since then – biotin remains an understudied supplement in healthy people. The state of the evidence concerning the effects of biotin supplements on the skin is similar. So, while there are clearly mechanistic reasons to think that biotin might improve nail, hair and skin quality, the science to back this up doesn’t exist yet.

It’s worth noting that while biotin supplements may address a biotin deficiency, a person eating a normal diet will not be biotin deficient unless they have a genetic condition. Pregnancy, breastfeeding and smoking may increase the required intake of biotin, so it is possible that biotin supplements benefit these people, but again this is not well established in scientific studies. 

There’s also some evidence that biotin supplements may decrease circulating levels of triglycerides and VLDL-C cholesterol in people with type II diabetes mellitus. However, once again, this evidence is currently not that strong and larger studies are needed to further investigate the benefits of biotin.

Is it safe?

Biotin appears to be very safe, as excess biotin is quickly excreted into the urine by the kidneys, making overdosing difficult. There are no reports of harm caused by taking too much biotin. There are also no known adverse interactions between biotin and other drugs. Despite its safety, you still need to tell your physician if you take biotin because it can interfere with some lab tests. People with diabetes should also be aware that excessive biotin consumption (which, as mentioned, is very hard to achieve) can cause symptoms similar to hyperglycaemia (thirst and increased urination).

The take-home message

Biotin supplements are safe and may be beneficial for both beauty and general health, so it’s unfortunate that they are not very well studied. You are unlikely to suffer any adverse effects from taking biotin supplements, but you might not benefit either unless you have a condition that can be addressed by increased keratin production. 

It is always best to consult with a doctor before taking any new drug, supplement, or making significant changes to your diet.