Dyeing the hair with chemical or natural dyes can damage hair. This is because the dye may affect proteins and lipids present in the hair, which contribute to hair health. Changes to the inner and outer structure of the hair shaft can damage hair, making it fragile and prone to breakage, which could eventually result in thinning hair or hair loss in areas.

Hair dyes can weaken hair, but people can take precautions to minimize potential damage if they still choose to dye their hair. Additionally, other tips are available to help replenish hair and keep it healthy.

What is hair dye?

Hair dye is a topical substance that changes the color of hair either temporarily, semi-permanently, or permanently. While dyeing hair is a common practice, it can damage the hair shaft, making it fragile and more prone to breakage.

Most permanent hair dyes use a combination of ammonia, hydrogen peroxide, and p-phenylenediamine (PPD) to color the hair. Ammonia opens up protein layers in the hair, which allows the dye to coat the hair shaft. Hydrogen peroxide strips hair of its natural color, and PPD then bonds into the hair to color it.

According to a 2020 article, PPD is an allergen that can cause allergic contact dermatitis. Along with skin irritation, PPD may also have a link to health problems such as congenital abnormalities (formerly known as birth defects) and liver and blood toxicity.

Sources reveal that bleaching hair with peroxide resulted in oxidative damage and protein loss in the cuticle and cortex of the hair.

Products labeled as “natural” or “organic” may also produce negative effects. Natural sources, such as plants, can still contain harmful or allergenic substances.

The Food and Drug Administration (FDA) states that because a product is organic or contains organic ingredients, it does not mean that it is automatically safer.

Additionally, reports suggest that some hair dyes may contain endocrine-disrupting compounds. These chemicals can mimic the effects of the hormone estrogen and may increase the risk of breast cancer.

Namely, research suggests that permanent dyes may contain higher concentrations of aromatic amines, which may be carcinogenic to humans.

Other potentially harmful ingredients may include ammonia and toluene. The former is a respiratory irritant that can trigger asthma attacks, and toluene is a known neurotoxin with links to congenital abnormalities, pregnancy loss, and allergic reactions.