A mayonnaise hair mask might help people with curly, wavy hair increase moisture and reduce frizz. But there’s no research to back up other claims, like strengthening hair or killing lice.

A mayonnaise hair mask is touted as an alternative hair treatment that can potentially leave your strands soft and smooth. While primarily used for people with wavy and curly hair, this hair mask could offer potential benefits to others, too.

Learn more about the hype around the mayonnaise hair mask and how you can make your own at home.

A quick internet search of mayonnaise hair masks will reveal numerous supposed benefits that will help improve the health of your hair. While some of these claims might have some backing, others are unfounded.

Increased moisture?

To understand the potential benefits of this hair mask, it’s important to first learn about its ingredients.

Mayonnaise is classified as an oil. It primarily consists of canola or soybean oil, along with egg yolks, vinegar, and lemon juice. Some brands may have a few additional ingredients, such as olive oil and Dijon mustard.

In theory, mayonnaise can make your hair a little oilier since the product is primarily made of oil. This could potentially benefit curly and wavy hair types, which usually lack sebum (natural oil) in the middle and ends of the hair cuticle.

In contrast, naturally straight hair doesn’t usually need any added oils because sebum can make its way easily from the scalp throughout the rest of the hair.

Less frizz?

Reduced frizz is a natural side effect of proper moisture balance. Mayonnaise can potentially make your hair less frizzy from humidity and excessive dryness.

However, you will also need to practice other frizz-free hair habits, such as reducing your dependence on heated tools and patting your hair dry instead of rubbing it or using a hair dryer.

Stronger hair?

According to some beauty websites and blogs, mayonnaise also purportedly strengthens your hair and protects color treatments.

However, there’s no scientific research backing these claims. Mayonnaise is primarily an oil, so there isn’t enough of other ingredients (like egg yolks and lemon juice) to make such an impact.

Hair growth?

Some people also believe that a mayonnaise hair mask can make your hair grow. It’s thought that an amino acid in mayonnaise called L-cysteine does this trick.

One study on menopausal women with hair loss looked at the role of nutritional amino acids, including L-cysteine. Researchers found that this amino acid is important in building keratin, a type of protein, in the hair, which makes it strong and helps it grow.

L-cysteine was also described as being more effective when combined with vitamin B-6, which can also help with the absorption of other nutrients that are important to hair growth, including zinc and iron.

Still, the study focuses on diet and supplemental forms of L-cysteine, not on the application of the amino acid directly to the hair via mayonnaise. The lack of scientific research leaves unclear whether a mayonnaise hair mask can actually promote hair growth.

Natural lice treatment?

Other claims about a mayonnaise hair mask include its ability to treat head lice. The theory is that the thickness of the mayonnaise can suffocate head lice, similar to other alternative treatments such as butter or margarine.

However, none of these treatments are backed by the U.S. Centers for Disease Control and Prevention. If you do put mayonnaise in your hair for the treatment of lice, it may make the lice inactive temporarily, but it doesn’t kill them, according to the American Academy of Dermatology.

While some of the above benefits are more reputable than others, it’s unlikely that a mayonnaise mask would actually do any harm. The major exception would be if you have an allergy to any of the ingredients in the mayonnaise, such as egg yolks.

Here’s how to use a mayonnaise hair mask:

  1. Wet your hair.
  2. Apply one cup of mayonnaise, starting from your scalp and working it out to your ends. Use more mayonnaise as needed, making sure that your hair is covered evenly.
  3. Massage the product or use a wide-tooth comb to ensure even application.
  4. Cover with a cap and wait 20 minutes.
  5. Rinse out thoroughly and shampoo as normal.

For best results, use the mayonnaise mask once a week to keep your hair soft and smooth.

It’s unclear if a mayonnaise hair mask delivers the benefits many of its proponents claim. However, it may be beneficial if you’re looking for a moisturizing frizz-tamer, especially if you have wavy or curly hair.

Aside from using masks to add more moisture to your hair, there are other things you can do to balance out the oil in wavy and curly hair:

  • Make sure you don’t use an oily shampoo on ends that are already dry as this will increase frizz.
  • You can shampoo your scalp only and add conditioner to your ends.
  • Washing your hair every other day instead of daily can also help. If your scalp gets oily in-between shampoos, spritz on a dry shampoo to tide you over.