How to protect blonde hair from chlorine

Wet your hair with clean water before you swim, coat it with a barrier product (extra on the ends), put a cap over it, and rinse the moment you get out. Bleached, highlighted and color-treated hair is more porous, so it takes up more pool water and shows chlorine first.

What your colorist sees at the next appointment

Start with the outcome, because it is the part you will recognize. The blonde has faded faster than it should. It has gone brassy. There is a green cast on the ends. And the ends feel different from the root: drier, close to straw, tangling where the root still feels like hair.

Now rewind. Porosity is how easily hair takes water in, and hair takes up water like a sponge. Bleached and highlighted hair is more porous, so it soaks up more pool water than untouched hair does. Chlorinated water strips the natural oils that coat each strand and roughens the cuticle, the overlapping outer layer. Without that coating, hair dries out, tangles, breaks at the ends and lets color fade faster.

The green cast has a different source: copper and other metals in the water, such as copper pipes, heaters and copper-based algaecides. Chlorine reacts with the copper, and the reacted metal sticks to the hair, most visibly on light or porous hair. Pool chemistry varies, so a blonde can go green in one pool and never in another.

The routine for blonde and color-treated hair

1. Soak your hair with clean water first. The pool shower or a water bottle will do. Hair already full of clean water takes up less pool water. That reduces exposure. It does not block it.
2. Coat it, with extra on the ends. Work a barrier through damp hair and double up on the ends, which break more easily. AQUA GUARD Pre-Swim Hair Defense is $24.99 for 5.3 oz on Amazon, with 4.4 stars across 3,364 ratings. The listing says it "softens & protects for blonder blondes, vibrant color, and manageable curls," and it lists UV protection, which counts at an outdoor pool. Dampen your hair, apply a generous amount, give it 3 to 5 minutes to absorb, then swim.
3. Put the cap on over the coating. I know the cap advice is annoying to hear. It squashes your hair and nobody looks forward to it. Wear it anyway: it keeps most of the water off, not all, since water gets in at the edges, so it goes over coated hair and never instead of it.
4. Rinse the second you get out. Fresh water removes a lot of what is sitting on the surface. Do it at the pool shower, not an hour later at home.
5. Wash with a swimmers' shampoo, then condition. That kind of shampoo is formulated to lift chlorine and metal residue. AQUA GUARD Chlorine Clarifying Shampoo is $17.99 for 9.5 oz, and the listing says color safe. Conditioning puts moisture back, and Everyday Conditioner for Swimmers is $17.99, listed as "color safe." If you swim every day, make one wash a week a deep conditioner. SwimPlex Hair Mask is $13.99 for that.

For stylists: bring the pool into the consult

Ask a client how often they swim, not whether they swim. "Sometimes" can mean five mornings a week, which is a different color plan from two pool parties a summer.

Ask which water, too. Salt water pulls moisture out of hair and leaves salt behind as it dries, so an ocean swimmer gets the same dry, tangly result by another route. A green cast on the ends is a question about the pool, since that tint is metal.

Send them home with the routine in order, and write it down: barrier on the ends, cap over it, rinse at once, swimmers' shampoo and conditioner, plus a weekly deep-conditioning wash for daily swimmers.

One way to split it. Book toning when the problem is tone: the hair feels fine and the shade has drifted brassy. Treat it as porosity when the ends are dry and tangly and the color fades again soon after a fresh service.

Questions people ask

Does chlorine fade hair color?

Yes. Chlorinated water strips the oils that coat hair and roughens the cuticle, and hair in that state lets color fade faster. Porous hair, which includes bleached and highlighted, shows it first.

How soon after coloring can you swim?

Stylists commonly say to wait a few days after coloring, longer after bleach. Ask your own colorist for your timing.

Does purple shampoo protect blonde hair from chlorine?

No. Purple shampoo is for toning brassiness. The protection happens before you swim: wet, coat, cap, then rinse.

Can you swim with extensions?

Ask whoever installed them first. The answer depends on the type of extension and how it was attached.

Will a swim cap protect highlights?

It helps, but it is not a seal. Water gets in at the edges, and highlighted hair is more porous, so coat it first, extra on the ends, then put the cap over it.