Keratin is a naturally occurring protein that makes up and protects your hair, nails and skin. 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.
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What Are Keratin Supplements Used For?
Many keratin supplements are made by extracting keratin from the hooves, feathers or wool of animals. 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.
Keratin vs. Biotin
Keratin is a protein, while biotin is a vitamin. Keratin is the structural protein that's actually found in your hair, nails and skin. Biotin, on the other hand, is another name for vitamin B7, which helps your body break down keratin so it can be used in your hair, skin and nails.
Do Keratin Supplements Work?
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.
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 that a lack of biotin is rare, according to the Mayo Clinic. The vitamin is found naturally in foods 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, experiencing rapid weight loss or who have been tube-feeding for a long time or have an inherited condition. Cigarette smoking is thought to possibly contribute to low biotin blood levels as well, per the NLM.
Other symptoms of biotin deficiency include:
- A rash around the eyes, nose and mouth
- Tingling in the arms and legs
If you think you may need to supplement with biotin, you should discuss it with your doctor.
Side Effects of Keratin Supplements
The greatest dangers of keratin come from salon treatments that contain formaldehyde. Treatments that are added to hair externally, and then treated with high heat, such as for hair straightening, 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.
As for keratin and biotin oral supplements, the U.S. National Library of Medicine deems them likely be safe. The Mayo Clinic says doses of up to 10 milligrams have not been shown to cause any negative effects.
Be aware of taking biotin supplements if you take medications that are changed by the liver, as this supplement might minimize the effects of the medications you are taking. Some examples of these medications would be clozapine, cyclobenzaprine and fluvoxamine.
Speak to your doctor before taking any new supplement, especially if you take other medications.
- U.S. National Library of Medicine: "Biotin"
- Skin Appendage Disorders: "A Review of the Use of Biotin for Hair Loss"
- Mayo Clinic: "Biotin: Oral Route"
- U.S. Food and Drug Administration: "Hair-Smoothing Products That Release Formaldehyde When Heated"
- Occupational Safety and Health Administration: "Hair Smoothing Products That Could Release Formaldehyde"