What hydrogen peroxide really does to your hair

If you've ever considered dying your hair lighter, you've probably considered using hydrogen peroxide for a quick sun-kissed look. According to the Cleveland Clinic, hydrogen peroxide is a chemical commonly found in hair dye. But cosmetics giant L'Oreal compares it to bleach, noting that the last thing you want to do is use pure hydrogen peroxide on your hair. While the amount used in hair dye boxes is generally safe, L'Oreal warns that you should only ever do as the product instructions say, as doing anything different may cause serious issues.

By serious issues, we mean hair loss. According to The Belgravia Centre in London, hydrogen peroxide has the potential to cause not only hair thinning but hair loss. The Wimpole Clinic in London agrees, stating that if the chemical is too strong, it can cause hair to weaken and even irritate the scalp and preventing hair growth, especially if you dye your hair frequently.

Hydrogen peroxide can have side effects if used incorrectly on your hair

There's another serious issue that can potentially be caused by hydrogen peroxide. The Journal of Dermatological Science (via the United States Environmental Protection Agency) reports that hair dye and hydrogen peroxide are also known causes of dermatitis. Worse still, L'Oreal refers to the United States National Library of Medicine, which believes hydrogen peroxide may even cause scalp burn.

However, it's important to note that if hydrogen peroxide is used correctly, both at home and in the salon, there should be no side effects. If you want to be extra cautious Danielle Llewellyn, the UK Hair Ambassador for eSalon, recommends opting for quality hair dye products. Look for "a high-quality dye that will prevent damage, rather than cause it," she told Harper's Bazaar. She also adds that aftercare is key. "Always wash your hair with a shampoo and conditioner designed for color-treated hair as color-safe products are gentle and don't strip out moisture like sulphate-laden types do."