Chlorine and salt: protecting hair through the summer
The most effective measure is to wet the hair with fresh water before entering the sea or a pool, because saturated hair absorbs far less chlorinated or salt water and the damage is measurably reduced.
gelisted editorial team · Updated 15 August 2026
The short version
- Hair can absorb up to 30 per cent of its weight in water.
- The green tint comes from copper in the water, not from chlorine.
- Rinsing must happen within the first minutes after swimming.
- A weekly reconstructive mask costs 12 € to 30 €.
Three months of daily swimming does more to a head of hair than any amount of straightening. The measure that protects most is taken before entering the water, not after.
What each agent does
Chlorine is an oxidising agent that strips the protective oils and leaves the cuticle open, so the hair loses shine and frizzes. Salt dehydrates by osmosis and leaves crystals between the scales that increase friction. And solar radiation degrades both keratin and pigment, natural and artificial alike, most intensely between 12 and 17 hours.
| Measure | When | Effect |
|---|---|---|
| Wet with fresh water first | before swimming | reduces absorption |
| Leave in oil or cream | before swimming | physical barrier |
| Loose tie or a cap | during | less exposure |
| Rinse with fresh water | within minutes after | removes salt and chlorine |
| Gentle shampoo and mask | same day | restores lipids |
| Hair sun protection | all day | protects the pigment |
| Weekly reconstructive mask | weekly | 12 to 30 € |
Why blonde turns green
Not because of chlorine but because of copper present in the water, from pipework or from certain algaecides. The copper oxidises and deposits on the fibre, and on light or lifted hair, where the cuticle is more open, that deposit reads as a green cast. A chelating shampoo used occasionally removes it, and rinsing immediately after swimming prevents it.
The seasonal routine
Before: soak the hair in fresh water and apply a leave in cream or oil. During: a loose tie that keeps it off the back and out of the sun. After: a thorough rinse within the first minutes, and a wash with a gentle shampoo the same day if it was a chlorinated pool. Once a week, a reconstructive mask left on for 5 to 10 minutes.
With that routine, lifted hair reaches September needing a single recovery treatment of 20 € to 45 € rather than losing 4 or 5 centimetres of length.
What to avoid
Combing wet hair with a fine toothed brush, because the wet fibre stretches by up to 30 per cent before breaking and that is when it snaps. Rubbing it dry with a towel. And stacking chemical processes in midsummer: a lifting service in August on hair already stressed by 6 weeks of sea and sun multiplies the breakage risk, and waiting until October is usually the right call.
Frequently asked
+What protects hair most?
Wetting it with fresh water before entering the water, since saturated hair absorbs far less.
+Why does blonde hair turn green?
Because of copper present in the water, which oxidises and deposits on the fibre, not because of chlorine.
+When should I rinse?
Within the first minutes after leaving the water, before the salt and chlorine dry on the hair.
+Can I comb it wet?
With a wide toothed comb and no pulling. Wet fibre stretches and that is when it breaks.
+Can I lift my colour in summer?
Better to wait. On hair stressed by sea and sun the risk of breakage rises sharply.
Sources
- 1Ministerio de Sanidad, Gobierno de España (August 2026)
- 2Govern de les Illes Balears, Govern de les Illes Balears (August 2026)