You would never forget your sunscreen before a day at the beach. Yet every summer, the same scene plays out: the skin is protected, pampered, reapplied every two hours... and the hair goes into battle without the slightest armour. Come September, the verdict falls: straw-like lengths, colour that has turned, ends that break, shine gone.

The hair fibre is alive, sensitive, and just as exposed as the skin. Sun, salt, chlorine, wind and sand form a formidable coalition that, day after day, weakens the keratin and dehydrates the material. The good news: protecting your hair in summer is not complicated. It comes down to two gestures, a few well-placed reflexes, and a clear understanding of what is happening on your head under the sun.

Under the sun, the hair fibre takes it all

We often imagine hair as an inert material, a kind of decorative thread. In reality, each hair is a sophisticated protein structure, protected by a cuticle made of scales layered like the tiles of a roof. When these scales stay smooth and closed, light glides over them: that is what gives shine. When they lift, everything degrades in a cascade.

Why UV rays damage the hair fibre

Ultraviolet radiation acts exactly as it does on the skin, but without the slightest natural protection once the hair has left the scalp, because the length is, technically, a dead material that does not regenerate. UVB attacks the keratin and weakens the internal structure. UVA, more insidious, oxidises the melanin responsible for colour and degrades the lipids that hold the fibre together. The result: more porous, drier, more brittle hair, and a shade that fades week after week.

Coloured hair: a double penalty

Hair that is coloured, bleached or highlighted is already weakened by the passage of pigments. Its cuticle is more open, its porosity higher, its water-retention capacity reduced. Under the sun, this sensitive ground turns into a sponge: the colour escapes, blondes turn brassy, browns lose depth, and grey hair can yellow. If you invest in your colour, protecting it in summer is not a luxury, it is the condition for it to last until autumn.

Salt, chlorine, sand, wind: the real aggressors of summer

The sun never acts alone. It works as a team, and each teammate has its speciality.

Seawater and salt

Loved for its “wavy” effect, seawater has a downside. Salt is hygroscopic: it attracts water and, as it dries, literally pumps it out of the fibre. It also leaves tiny abrasive crystals that push the scales apart. In the moment, the texture is pretty; over time, the material becomes rough, dull and brittle.

Pool chlorine (and the infamous green tint)

Chlorine is a powerful oxidiser. It dissolves the protective sebum, dries out the cuticle and weakens the colour. As for the greenish tint that panics blondes every summer, it does not come from the chlorine itself but from the copper present in the water, which fixes onto a porous fibre. The lighter, more coloured or more damaged your hair, the more it captures this copper.

Wind, sand and dry heat

Wind tangles and creates knots which, once torn out, open the door to split ends. Sand acts like a very fine sandpaper on weakened lengths. And the ambient heat, combined with air conditioning in the evening, accelerates the evaporation of the water contained in the fibre. This is what we call dry summer hair: a chronic dehydration that sets in frizz, breakage and a lack of suppleness.

The first line of defence: hair sun oil

In the same way that an SPF stands between your skin and UV rays, a hair sun oil lays a protective film over the fibre. Its mission is twofold: to filter part of the radiation and to seal in hydration so the sun does not evaporate it. It is the founding gesture of any successful summer hair routine.

Still, you have to choose the right one. An oil that is too heavy weighs hair down and makes it greasy; one that is too volatile evaporates without protecting anything. The right balance is a light texture that penetrates the lengths without smothering them, nourishes without a greasy effect, and leaves a luminous rather than a flat finish. That is precisely the promise of the Myriam•K Paris® SUN Hair Oil: protection against UV rays, real nourishment for the fibre and a veil of shine, in a fluid texture designed for the beach as much as the pool.

The right reflex: apply it to damp hair before exposure, focusing from the lengths to the ends, then reapply after every swim. On long or thick hair, an extra dab on the ends midday extends the protection without overloading.

The second threat: heat from styling tools

We often forget that the sun is not the only heat source of summer. The hairdryer after the shower, the straightener to tame frizz, the curling iron before a dinner: each pass at high temperature, on a fibre already tested by salt and UV, adds a layer of stress. Dry heat evaporates the internal water, bursts the proteins and leaves the cuticle irreversibly lifted.

This is where the Myriam•K Paris® Thermo Protective Spray comes in. Sprayed on damp or dry hair before any heated tool, it forms a barrier that distributes the heat, limits breakage and retains shine. To be used systematically before the hairdryer, straightener or curling iron, and just as valuable on returning from the beach, when the salt-soaked fibre is at its most fragile and a simple blow-dry is enough to make it snap.

The practical guide, situation by situation

At the beach: before, during, after

The beach concentrates all the aggressors at once. A simple method is enough to change everything.

At the pool: saying goodbye to green hair

The strategy is the same as for seawater, with heightened vigilance on rinsing. Saturate the fibre with fresh water before going in, protect with an oil, and rinse thoroughly on the way out. If a green tint has already set in, a clarifying shampoo or a gentle baking-soda rinse helps dislodge the copper. For daily swimmers, a cap remains the most radical option.

Should you put oil on before going out in the sun?

Yes, without hesitation, as long as it is an oil designed for this use. A cooking oil or a pure plant oil can, in some cases, concentrate the heat rather than filter it. A hair sun oil formulated for protection, like the SUN Hair Oil, is designed to do the opposite: create a shield, not a magnifying glass.

Should you wash your hair every day?

No, and even less so in summer. Daily washing strips the hydrolipidic film that naturally protects the fibre, and pushes the scalp to produce more sebum. Space out your shampoos, simply rinse with clean water after swimming, and set aside a deep nourishing treatment once or twice a week to recharge the fibre.

How to keep a blow-dry during the holidays

Protect it from humidity and friction. A silk scarf at the beach, a satin pillowcase at night, a dry shampoo to revive the roots: these three gestures extend a blow-dry by several days. And even before you style, a veil of heat protectant guarantees a cleaner hold and a preserved fibre.

Avoiding split ends and keeping shine

A split end never really closes again: it all plays out beforehand. Do not detangle dry, always start at the ends and work up, and nourish the lengths every evening. For shine, one secret lies in a single gesture: finish every rinse with cold water. The cold tightens the scales, the light glides again, and the shine returns instantly.

Your summer hair routine in 5 steps

No need to multiply products. An effective routine comes down to five gestures, to be repeated throughout the season.

1. Nourish before you leave. A deep hydrating mask at the start of the week recharges the fibre and prepares it for the aggressions to come.
2. Protect before every exposure. On damp hair, apply the SUN Hair Oil from the lengths to the ends, and reapply after swimming.
3. Rinse and de-salt. On leaving the water, a rinse with clean water removes salt and chlorine before they dry on the fibre.
4. Secure the heat. Before the slightest hairdryer, straightener or curling iron, a veil of Thermo Protective Spray prevents the styling from costing more than it gives.
5. Seal in the shine. A final cold-water rinse, a satin pillowcase at night, a few drops of oil on the ends in the evening: the fibre stays smooth, supple and luminous.

Protecting your hair in summer is ultimately just a matter of anticipation. You do not wait for sunburn to bring out the cream; you do not wait for broken ends to bring out the oil. Give your lengths the same attention as your skin, and come September you will find hair that has enjoyed the summer without paying the price.

The editorial team at RACINE, the beauty journal by Myriam•K Paris®.