Onions contain a chemical called quercetin, a strong antioxidant and anti-inflammatory agent, known to improve the appearance of scars. In fact, quercetin is an active ingredient in scar medications like Mederma. Due to its antioxidant properties, quercetin is used in medicine to heal and repair damaged cells. For this reason, onions have also been used as home remedies for stretch marks for years. If you don't mind smelling like onions, there are a few different methods of using them to get rid of stretch marks.
Chop up a fresh red onion in round strips. Rub the onion strips directly onto the stretch marks a few times during the morning and afternoon. Massage the onion strips onto the stretch marks for at least 60 seconds. Refrigerate the onion between uses.
Grind the chopped onions in a food processor after using the ground onions a few times early in the day. Grind until you have a thick mash. Massage the ground-up onion onto the stretch marks every few hours for the rest of the day.
Before bedtime, strain the onion mash. Soak a clean washcloth into the onion water. Wrap the washcloth around the part of your body containing stretch marks and leave on overnight.
Remove the washcloth in the morning and start the process all over again. Try to save some of the onion from each step to reuse the next day. Simply set aside and refrigerate a fraction of the chopped strips, ground mash and onion water.
Use a new onion every other day for best results and to prevent the onion from growing stale. Diffuse the onion scent with some fresh lemon juice. Wear old, dark sweats after applying the onion onto your stretch marks to prevent your clothes from becoming soiled. Be patient as it may take several months before the stretch marks have faded away completely.