How Chlorine Damages Hair: Effects and Prevention Tips

Going for a swim in the pool is excellent exercise and good for the soul, but what does chlorine do to your hair? Here, we’ll talk about how chlorine can potentially damage hair, how to protect your hair from its effects, and if there’s anything you can do to fix chlorine-damaged hair (this one’s for you if your blonde hair turned green after a dip).

Read on for more.

As you probably know, chlorine is a chemical added to swimming pools to kill germs and prevent bacteria, and neutralize “swimmer’s waste (which is what you think it is, but also things like body lotion, perfumes,  and natural oils).

One quick dip in the pool isn’t going to wreck your strands, but over time, chlorine can damage hair, causing hair to look and feel dry, dull, frizzy, or more prone to breakage. One 2015 animal study found that the fur of rats who swam regularly for 12 weeks in a chlorinated pool became “increasingly dry and lackluster, and significant signs of hair loss were observed during the last month.” There’s no research suggesting that chlorine causes hair loss in humans. However, it can have other damaging effects.

Anyone who swims regularly may notice changes to their hair from chlorine. However, people with fine, thin hair,  bleached or chemically treated hair, or those whose hair is already damaged from heat are more at risk of severe chlorine damage because the hair is already fragile or vulnerable.

There are several ways chlorine can affect your hair, which we’ll outline below.

Chlorine can strip hair of natural oils. When chlorine dissolves in water, it creates hypochlorous acid, which can strip sebum from the scalp and hair. Natural oil helps to moisturize hair and keep it shiny and flexible, and when hair doesn’t have enough natural oil, it can be dry, brittle, and prone to damage.

Chlorine Can Change the Color of Your Hair

You're not imagining things if you’ve been swimming a lot and notice your light or blonde hair has a greenish tinge. An older study from 2000 looked at the hair of professional swimmers and nonswimmers and found that 61 percent of swimmers showed signs of hair discoloration, compared with zero nonswimmers.

This happens because chlorine is an oxidizing agent, which means it can change the color of things it comes in contact with (the same is true of rust and bleach, for example).

Chlorine Can Make Your Hair More Porous

Chemicals, including chlorine, can damage the cuticle of your hair (the outermost layer of the hair shaft) and increase hair’s porosity, which is a measurement of how much water hair absorbs and retains. When hair is too porous, it’s prone to frizz, tangling, and breakage.

It May Make Your Scalp Itchy or Irritated

If you’ve ever gotten out of the pool and felt itchy or tight, you already know that chlorine affects the skin, too. People with sensitive skin may notice an itchy or irritated scalp after swimming in chlorinated water.

According to the American College of Allergy, Asthma, and Immunology, this type of reaction is not an allergy but is actually “‘irritant dermatitis’ caused by hypersensitivity to this natural irritant. Chlorine is also drying to the skin and can irritate existing dermatitis.”

Fortunately, you don’t have to skip the pool on a hot day to save your hair. Instead, there are things you can do to protect your hair from damage.

Rinse Your Hair Before Swimming

You probably expected us to say rinse your hair after swimming in a chlorinated pool (and we will say that soon), but rinsing your hair with fresh water before swimming is also a good idea. Dry hair will suck up pool water, but hair that’s already wet cannot absorb as much water.

Create a Protective Barrier

After rinsing and before getting in the pool, you can coat your hair in a leave-in conditioner or argan or coconut oil (or whatever your favorite oil is). This acts as a physical barrier, preventing (some) chlorine from getting in and adding moisture back into the hair.

Wear a Swim Cap

Instead, swim caps are a great way to prevent chlorine damage by preventing it from getting into your hair.

Wash Hair After Swimming

Wondering how to wash chlorine out of your hair? Well, the sooner you do it, the better.

If your pool has a shower, wash your hair immediately after swimming — if not, try to wash your hair at home as soon as possible. This helps to remove excess chlorine from your hair. Some brands make special “swim shampoos” designed with chlorine removal in mind, but any detox or clarifying shampoo will do the trick. Just make sure to use a moisturizing shampoo when you don’t swim, as overusing clarifying shampoo may be drying over time.

Swim Outside

If given the choice (and weather permits) try to swim in an outdoor pool as opposed to indoor. Research shows that indoor pool facilities have been found to have more chlorine in the air.

The good news is that there are things you can do to help fix hair that’s been damaged from chlorine.

• As we mentioned, a clarifying shampoo is a good way to remove chlorine from the hair.

• If you swim regularly, you may also want to consider getting a filter for your shower so you can be sure you’re washing your hair with the freshest water possible.

• Use a deep conditioner or a hair mask to add moisture to your hair.

• If your hair is color-damaged from chlorine, consider seeing a professional. Some say that mixing baking soda with your shampoo or using apple cider vinegar can help negate the greenish hue that can happen, but always check with a hairstylist first.

To learn more, take a look at our guide to how to fix damaged or dry hair.

Here’s the TL;DR on how chlorine affects your hair.

• Chlorine exposure can dry out, discolor, and weaken hair over time, especially for those with fine, chemically treated, or damaged hair. It strips natural oils, increases porosity, and can even leave a green tint in lighter hair.

• Preventive steps, like rinsing hair before swimming, using protective products, wearing a swim cap, and washing hair immediately after swimming, can significantly reduce chlorine damage.

• To repair chlorine-damaged hair, use clarifying shampoos, deep conditioners, and hair masks, and seek professional help for severe color changes or persistent issues.

If you’re wondering what other common practices may be damaging your hair, check out our guides on whether brushing causes hair loss.