September is our busiest month for one particular conversation: hair that was fine in May and is now dry at the ends, tangled at the nape, lighter than it should be, and snapping when brushed. If that is your hair right now, nothing has gone wrong. It has simply had four months of sun, sea and pool.
What the summer actually did
UV
Ultraviolet light degrades keratin, the protein hair is built from, and oxidises its pigment. That is why colour fades and lightens over summer even if you never touched a bottle of lightener. UV also damages the protective lipid layer on the cuticle surface, which is why hair feels rougher.
Salt water
Salt draws moisture out of the hair fibre by osmosis. Wet, swollen hair then dries stiff, and the cuticle is left raised and rough — which is exactly why beach hair tangles so badly and why brushing it causes breakage.
Chlorine
Chlorine strips sebum and lipids and makes hair porous. On its own it dries hair out. Combined with copper in pool water, it produces the green tint that blondes know well.
Heat
And then, on top of all of it, hot air, hot cars and a blow dryer on damaged hair.
The result is a hair fibre that is porous, protein-depleted and lipid-stripped, all at once. Which matters, because the fix depends on which of those three is dominant.
Work out what your hair actually needs
Take a single clean, wet strand and stretch it gently.
- It snaps almost immediately → protein and bond damage. You need a bond builder or protein treatment before anything else.
- It stretches a long way and stays stretched, feeling gummy → too much moisture, not enough protein. Same answer: protein first.
- It stretches a little and springs back, but feels dry and rough → moisture and lipids. Masks and oils, no protein needed.
Getting this wrong is why some people mask their hair religiously and it keeps getting worse. Dry, brittle hair treated with more and more moisture and no protein becomes limp and mushy.
A four-week recovery plan
Week 1: clarify, then repair
Start with a clarifying or chelating wash to remove salt, chlorine, minerals and months of product build-up. Nothing you apply afterwards works properly through that layer — this step is not optional.
Then go straight into repair. If your strand test said protein, the K18 Leave-In Molecular Repair Hair Mask on towel-dried hair for four minutes is the fastest route back. If it said moisture, the Kerastase Soleil Masque Après-Soleil was formulated specifically for post-sun hair.
Week 2: rebuild the routine
Switch your everyday shampoo to something gentle and replenishing rather than clarifying — the Soleil Bain Après-Soleil, or anything in our anti-breakage range. Mask twice this week. Stop heat styling if you possibly can, and if you cannot, use a protectant every single time.
Week 3: seal and protect
Porous hair loses moisture as fast as you put it in unless you seal it. A lightweight oil on damp mid-lengths and ends after every wash makes a visible difference — Olaplex No.7 Bonding Oil or the Kerastase Soleil Huile Sirène. Continue masking weekly.
Week 4: assess and book a trim
Repeat the strand test. Most hair is noticeably stronger by now. What treatments cannot fix is split ends — once a strand has split, it keeps splitting upward, and the only solution is scissors. A small trim at this point protects the work you just did.
The masks worth your money
For dryness and roughness, Olaplex Rich Hydration Mask and MOROCCANOIL Weightless Hydrating Mask (the better choice for fine hair) both deliver. For dullness after a summer of fading, MOROCCANOIL High Shine Gloss Mask restores the reflectivity UV took away. The full range is in our hair masks collection.
Next summer: prevention is cheaper
Everything above takes a month. Preventing it takes about forty seconds a day.
- Wet your hair with clean water before swimming. Saturated hair absorbs far less salt or pool water. This is the single most effective thing on this list and it costs nothing.
- Leave-in with UV filters before you go out. Our sun and chlorine protection range covers this — the Soleil Summer Trio bundles the wash, mask and oil.
- Rinse immediately after the sea or pool. Not that evening. Straight away.
- A hat on long beach days. Unglamorous and extremely effective.
Frequently asked questions
Will cutting my hair fix the damage?
It removes the damaged ends, which is the only real fix for splits. It does nothing for the fibre further up, which still needs treatment.
How often can I use a protein or bond treatment?
Intensively for four to six washes while you are repairing, then roughly every two to four weeks for maintenance. Continuous heavy protein use on hair that does not need it makes hair brittle.
My hair went lighter over summer. Can I get the colour back?
Sun-lightened hair needs a toner or gloss in salon — home products can shift tone slightly but not restore depth. Go in with a photo of where you want it.
Is sea water good for hair?
No. The texture it creates looks good for an afternoon; the dehydration and raised cuticle underneath are damage. Texturising sprays give you the look without the cost.
How do I get rid of the green tint from the pool?
A chelating shampoo removes the copper causing it. Several washes may be needed if it has built up over a whole summer.
Start here
If you want one product to begin with, make it a clarifying wash — everything else works better afterwards. Then pick your lane from the strand test: repair if it snaps, hydration if it is just dry. Not sure? Message us and describe what your hair is doing.
