There is more to onions than making food smell and taste good. It can be used for hair care. Shampoos like Tara, Mamaearth, Fable & Mane and Babaria have onion extract as the main ingredient, NBC News reported.

“Onion contains sulfur, which is a key building block for keratin, the protein that makes up your hair,” NBC News quoted Dr. Ross Kopelman, a hair transplant surgeon at Kopelman Hair Restoration, as saying.

“It also has antimicrobial properties that can support a healthier scalp environment.”

Hair care experts said users need not worry about smelling like onions, as the shampoos have lavender and rosemary scents. They, however, cautioned those with allergies and sensitive scalps not to use it.

Coincidentally, hair can also be used to keep another part of the body healthy.

Scientists at King’s College London found that keratin—which is also found in skin and wool — turns into enamel when mixed with saliva by attracting calcium and phosphate ions, BBC reports.

Researchers learned this in an experiment that involved extracting keratin from wool and applying it to the surface of a tooth. Contact with saliva turned the keratin into a coating around the tooth.

The findings of the scientists who grew a tooth in a laboratory were published in the journal Advanced Healthcare Materials.

The technology can be used to make toothpaste from hair keratin to repair and protect damaged teeth, according to BBC.