Keratin Hair Supplements: Uses and Risks to Understand

Keratin is a naturally occurring protein that makes up and protects your hair, nails and skin, according to the Cleveland Clinic. Some people opt for keratin hair treatments in salons, while others buy "keratin vitamins" — keratins in supplement form — from drug stores or online.

Here's what you should know about keratin supplements, including the side effects of keratin pills and whether you should take keratin for hair growth.

Many keratin supplements are made by extracting keratin from the hooves, feathers or wool of animals, per the Cleveland Clinic. Most people who take them do so because they believe the powder or pills will help make their hair and nails stronger, longer and shinier.

There are many types of hair and nail supplements on the market today. Biotin, for example, is a supplement thought to help produce keratin, thereby strengthening hair and nails, and promoting growth.

Because keratin is the structural protein our bodies use to make our hair, taking keratin for hair growth makes sense on paper. But, unfortunately, there's no evidence that this actually works, according to the Cleveland Clinic.

The same goes for biotin. Your body needs this nutrient to keep your hair, skin and nails healthy, but research showing that biotin supplements work for hair loss is lacking.

According to an August 2017 review in ‌Skin Appendage Disorders‌, biotin supplements may be helpful for people with conditions that cause a biotin deficiency, but there's no evidence they work for people who are otherwise healthy.

Keep in mind a lack of biotin is rare, according to the Mayo Clinic. The vitamin is found naturally in foods high in biotin such as bananas, eggs and milk, per the U.S. National Library of Medicine (NLM), so most people get enough through their diet.

Biotin deficiency can affect people who are pregnant, malnourished or have an inherited condition. Cigarette smoking may contribute to low biotin blood levels as well, per the NLM.

Other symptoms of biotin deficiency, according to the Linus Pauling Institute, include:

• A rash around the eyes, nose and mouth
• Depression
• Hallucinations
• Tingling in the arms and legs

If you think you may need to supplement with biotin, you should discuss it with your doctor.

The greatest dangers of keratin come from salon treatments that contain formaldehyde. Certain treatments that are added to hair externally, and then treated with high heat, such as for hair straightening, may cause formaldehyde exposure, according to the U.S. Food and Drug Administration.

Formaldehyde is a potent, odorous gas and a serious health hazard, as outlined by the Occupational Safety and Health Administration. If you are exposed to the gas when it is applied to the hair, it can get into your lungs or eyes. It can then cause breathing problems, like wheezing and coughing, as well as skin rashes and itching. Formaldehyde exposure is also considered a cancer risk.

The NLM deems oral biotin supplements likely to be safe. With such minimal research surrounding keratin supplements, little is known about their safety.

There is no recommended amount of biotin to get daily in the U.S. because deficiency in this vitamin is so rare, but Canadian recommendations suggest doses up to 100 micrograms have not been shown to cause any negative effects, according to the Mayo Clinic.