Did You Know Hair Experiences Multiple Forms of Damage? Here’s How to Identify Each Type—and How to Fix It

Hair damage certainly isn’t exclusive to winter, but as soon as the temperature drops, our strands are hit from all sides—dehydrating central heating, hat-induced friction, and the inevitable heat damage from over-styling. In reality, though, hair faces a year-round gauntlet of stressors, from chemical processing to UV exposure and pollution.

Hair damage isn’t one universal diagnosis; there’s a whole spectrum of causes and effects, and each different type of hair damage needs its own treatment plan. But how do you know what you’re dealing with? After all, what you assume is frizz caused by dryness might actually be cuticle disruption from heat styling, while lack of shine might be from environmental wear and tear that you weren’t even aware of.

To cut through the confusion, we’ve called on leading trichologists to decode the different types of hair damage and how to treat them. From what they look like and how they happen to the most effective ways to repair and prevent them. Consider this your one-stop shop to stronger, healthier hair, whatever the season.

What are the different types of hair damage?

First things first, what actually counts as hair damage? “We are really talking about the structure of the hair strand itself,” says Deborah Maguire, trichologist and founder of Seed and Soul. “The cortex is where strength lives and the cuticle is the protective shell around it, so anything that roughens, thins or lifts that cuticle will show as damage.” As for the damage itself, there are generally speaking four main types to consider.

• Chemical damage. This comes from chemical treatments. “Things like colouring, bleaching, relaxing and even keratin treatments when they are done too often,” says Maguire. “You will see rough texture, snapping, tangling, loss of shine and colour that won’t hold.”
• Heat damage. One of the most common types, this is caused by styling your hair with hair straighteners, tongs, and multi-stylers as well as blow-drying your hair. “Heat styling removes moisture and breaks down keratin, causing frizz, dullness and breakage, explains trichologist and Viviscal ambassador Hannah Gaboardi.
• Environmental damage. Maguire refers to this type of damage as the “quiet one”. This is exposure to things like UV rays, hard water minerals, chlorine and even central heating. “The signs are dullness, frizz on humid days, static on dry days and feeling that the hair is not behaving like it used to,” says Maguire.
• Mechanical damage. Finally, mechanical damage is caused by physically aggravating the hair shaft through hair brushing, extensions, tight ponytails and even sleeping on rough fabrics. According to Maguire, “the clues are short broken hairs around the hairline, thinning ponytails and frayed ends”.

How to treat hair damage

Generally, the foundations of tackling hair damage are the same no matter what type you’re dealing with. “The fundamentals are to stop the source of the damage and rebuild moisture and strength,” says Gaboardi “Heat-damaged hair responds well to hydration masks, bond repair and reducing heat use, and regular trims to remove weak ends and prevent further breakage will also help.” However, there are more specific steps that you can take if you have pinpointed the damage as being one of the four main types from the list above.

Chemical damage

“Chemical damage needs a combination of moisture and protein treatments because the cortex has been opened and weakened,” explains Maguire. And avoiding further chemical treatments until you’ve improved your hair health goes without saying.

Heat damage

Heat damage is similar in that taking a break from high temperatures will be most beneficial, making sure to use heat protectant when you can’t avoid it, and using regular hydration and bond repair masks.

Environmental damage

“Environmental damage responds best to hydration and protection,” says Maguire. “A shower filter, UV protection and an occasional clarifying shampoo to help remove mineral and chlorine build-up will help.”

Mechanical damage

And, finally, improving mechanical damage involves a switch of your daily habits. Gaboardi suggests using silk pillowcases or hair bonnets to reduce friction, using a gentle hair brush and avoiding brushing it while wet will also help.

Can you prevent hair damage?

Consistency is key when keeping hair healthy and preventing damage from occurring in the first place. “Regular hydrating hair masks help maintain moisture and elasticity, keeping the hair shaft resilient, reducing the frequency of hair tools and using a heat protectant when styling, and avoiding harsh chemical treatments will all help,” explains Gaboardi.

There’s also a lot to be said for an inside-out approach to hair heath. “Internally, make sure your iron, zinc, vitamin D, B12 and thyroid function are in a good place,” says Maguire. “A hair cycle lasts several years, so the choices you make today show up months down the line. Prevention is always easier than correction.”