If you are looking a DIY, cheaper alternative to prohibitively expensive treatments, one new study has discovered a baldness-curing ingredient that you can buy for as cheap as $1.39 —McDonald’s french fries.

A Japanese stem cell research team found that the same chemical found in McDonald’s french fry oil — dimethylpolysiloxane — could also be used to regrow hair on mice quickly. In the journal Biomaterials, the researchers outline how this chemical was key to mass-producing hair follicle germs in mice.