If you have thin hair, you may be looking for special ways to care for it, whether you have fewer strands on your head naturally or from hair loss.

There are many specialty hair treatments to treat different hair types and conditions, including keratin treatments. This type of treatment is also known as the Brazilian blowout. Keratin treatments can help reduce frizz, enhance color, and straighten or tame curly hair, making it look shinier and healthier.

Hair stylists and product manufacturers generally recommend keratin treatments for coarse, thick, frizzy, or curly hair. If you have thin hair that is course or curly, you may want to try a keratin treatment. If your thin hair is fine or straight, keratin treatments may not be the best styling choice for you.

Keep in mind that keratin treatments can be toxic or cause other health conditions, so use caution with this treatment.

Keratin is a protein found naturally in the human body. You have keratin in your nails, skin, and hair. The keratin in your hair keeps it strong and healthy, and chemical treatments like coloring and bleaching can compromise the integrity of your hair strands.

Keratin treatments for hair generally include the application of extra keratin extracted from animal products like wool and chicken feathers. This treatment results in hair that may appear healthier and smoother.

Several studies have supported the use of keratin hair treatments to achieve healthier strands:

  • A 2018 study in the International Journal of Cosmetic Sciencefound that additional keratin particles smoothed hair and increased hair strength by 40 percent.
  • Another 2018 study in Biotechnology Reportsfound that applying the K31 protein made the diameter of chemically damaged hair bigger by 49 percent, and the diameter of bleached hair twice as big. The study also found that one hour-long keratin treatment straightened curly hair.

Keratin treatments are generally recommended for hair that is:

  • colored or bleached
  • frizzy
  • coarse
  • thick

Thin hair measured by the number of hairs on your head can come in different textures. You may consider keratin treatment if your thin hair is curly, coarse, or color-treated. Thin hair that’s fine and straight may not benefit from keratin treatments.

You may want your hair to have more volume if you have thin or thinning hair. In this case, there may be more effective treatments than keratin.

Before you seek keratin treatment in a salon or at home, talk to your stylist or read the packaging as well as research reviews online.

You can also use a website like the Environmental Working Group to look up specific products and ingredients to determine whether they’re safe.

Keep in mind that many companies label keratin treatments for hair as safe because keratin is derived naturally from humans and animals.

But keratin treatments also use harmful chemicals like formaldehyde. Formaldehyde can be toxic. Many keratin hair treatments contain amounts considered to be significantly above safe levels as determined by cosmetic products governing boards.

Even more concerning is that these products don’t always list formaldehyde as an ingredient because manufacturers rename it when they mix it with ingredients like water. Too much formaldehyde can be dangerous to you and to hair stylists who are exposed to these products often.

Keratin treatments may also irritate your skin and cause other physical reactions. Supplements that contain extra keratin are not regulated by the U.S. Food and Drug Administration (FDA) like over-the-counter and prescription medications.

A 2020 study in theJournal of Cosmetic Dermatologyhighlighted the risk of contact dermatitis and swelling from keratin hair treatments in those with sensitive skin. This is likely because of formaldehyde or other ingredients.

Other side effects from keratin treatments include:

  • a burning sensation in the eyes, mouth, and nose
  • strong smell during application

There are many ways to add keratin to your hair.

You may opt to go to a stylist to apply a keratin treatment in a salon. These treatments may take several hours and involve the application of heat to set the keratin treatment.

There are other over-the-counter keratin products available that you can apply to your hair.

Closely follow the directions and read reviews prior to purchasing and applying them.

Professional keratin treatments may last up to 6 months, depending on what you do with your hair after your initial treatment.

These treatments may last a shorter amount of time if you wash your hair frequently or style it with heat.

There are several other ways to keep your thin hair looking healthy and to treat thinning hair:

  • Eat a balanced dietfull of fruits, vegetables, dairy, protein, whole grains, and healthy fats to get the vitamins you need to keep your hair healthy and strong.
  • Look for products that volumize thin hair, such as shampoos, conditioners, and styling products. A stylist or an online video may provide tips for blow drying your hair to make it look fuller.
  • Consider wearing a wig or changing your hairstyle to find a style you like that works with your hair thickness.
  • Seek treatment for thinning hair. There are cosmetic products available to address this condition as well as oral medications, injectables, laser hair treatment, and hair transplants.

Thin hair may or may not benefit from a keratin treatment.

You may want to try keratin treatments if your hair is thin in terms of density on your head and is curly, frizzy, coarse, or damaged from color or bleach. Fine, straight hair may not need keratin, and other volumizing techniques may be useful.

Find out about the safety of a keratin treatment before getting this procedure or using products containing keratin. Maintaining a healthy diet and looking for other ways to address thinning hair can also be useful.