Does chlorine damage hair?

Yes. Chlorinated water strips the oils that coat each strand and roughens the cuticle, the overlapping outer layer. The result is hair that feels dry and straw-like, tangles more, breaks more easily at the ends and loses color faster.

How much of that you see depends on your hair and on your pool.

What chlorine does to hair

Each strand carries a thin coating of natural oil, and the cuticle sits on the outside like a layer of overlapping scales. Chlorinated water strips the oil and roughens the scales. Hair without that coating is drier, snags when you comb it and snaps more easily at the ends. Color fades faster too.

Some hair takes it harder. Hair takes up water like a sponge, and porous hair takes up more. Bleached, highlighted, chemically treated, fine and already damaged hair are all more porous, which is why blondes and color-treated swimmers show chlorine effects first.

What chlorine does not do

Green hair is a copper problem. The tint comes from copper and other metals in the water, such as copper pipes and copper-based algaecides. Chlorine oxidizes the copper, and the oxidized metal binds to the hair, most visibly on light or porous hair.

One afternoon at the pool is a small event for most hair. A summer of lap swimming strips the oils again and again, and that repetition is where brittle ends come from.

Breakage at the ends and shedding at the root are two different things. Chlorine works on the strand, so what it produces is breakage, hair snapping off along its length. Shedding is hair letting go at the scalp, and a product applied to the hair cannot touch it. We are not going to guess at the cause of a change at the root. If you are losing hair from the scalp, ask a doctor or a dermatologist.

Pool chemistry varies, and that leaves one question this page cannot answer: what your pool does to your hair. Some pools turn light hair green and others never do. We cannot tell from here which kind you swim in. Your own hair is the better test, and the ends are where it shows first.

How to limit it

Protecting the strand before the swim beats fixing it afterwards, so most of the work happens at the pool deck.

1. Wet your hair with clean water before you get in. Hair that is already full of clean water takes up less pool water. That reduces exposure. It does not block it.
2. Coat it with a barrier. A product can smooth and protect hair, but it cannot rebuild a strand that has already snapped, which is why a barrier goes on first. AQUA GUARD Pre-Swim Hair Defense is made for this step. It is $24.99 for 5.3 oz on Amazon, with 4.4 stars across 3,364 ratings, and the listing says it "stops chlorine damage before it starts" and "smooths and protects from dryness and brittleness". The directions: dampen your hair, apply a generous amount with special attention to the ends, and allow 3 to 5 minutes for it to absorb.
3. Wear a swim cap if you have one. It keeps most of the water off your hair, but not all of it, because water gets in at the edges. Coat first, then cap.
4. Rinse with fresh water as soon as you get out. A rinse removes a lot of what is sitting on the surface of the hair.
5. Wash with a shampoo made for swimmers, then condition. These shampoos are formulated to lift chlorine and metal residue, and conditioning puts moisture back. AQUA GUARD Chlorine Clarifying Shampoo is $17.99 for 9.5 oz on Amazon, and the listing says "Remove Chlorine & Pool Hair Smell".

Questions people ask

Is chlorine bad for your hair every day?

Each swim strips the oils again, so daily swimming means daily stripping. Kids who swim many days in a row in summer are in the same position, and their hair is often finer and more porous than an adult's.

Does chlorine make hair fall out?

Chlorinated water makes hair break more easily at the ends. That is breakage, and it is the part a hair product can address. Hair that comes out from the root is shedding, a separate matter, and we cannot tie it to chlorine or diagnose it. If you are noticing it, see a doctor or a dermatologist.

Does chlorine damage color-treated hair more?

It shows up sooner. Bleached, highlighted and chemically treated hair is more porous, so it takes up more pool water, and chlorine lets color fade faster. Light or porous hair also shows the green tint from copper most.

Can damaged hair recover?

Partly. A product can smooth and protect the hair you have, and conditioning puts moisture back, but it cannot make a broken strand whole again. Hair that grows in after the season is new hair with no chlorine exposure yet.