Protect your hair from the sun and salt at night: the summer silk reflex

In short: summer, sun, salt, and chlorine dry out and weaken the hair fiber. At night, on a cotton pillowcase, friction finishes the job: breakage, frizz, and dull lengths. Silk changes the game — night cap, pillowcase, and scrunchie form a protective layer that finally lets your hair rest. I’ll explain how and share my evening routine in four steps.

Every summer, I see the same scenario upon waking: lengths drier than in June, ends that snag when detangling, and color that has lost its shine. We blame the sun and the sea — rightly so. But we often forget the easiest link to fix: the night. That’s exactly where I focus my efforts, and silk plays the leading role.

Why summer weakens your hair

From June to September, three aggressors take turns damaging the fiber:

• UV rays degrade keratin and pigments. The cuticle becomes more porous, rougher to the touch, and color fades faster — blondes turn brassy, brunettes dull.
• Sea salt is hygroscopic: it draws water out of the hair and leaves micro-crystals when it dries, making the texture rough, stiff, and prone to tangling.
• Chlorine in pools dissolves the natural lipid film that protects the fiber. Hence that straw-like feeling after swimming and split ends.

The common factor among these three: they dehydrate and make hair much more vulnerable to friction. And friction is something we encounter daily but often overlook — in bed.

The night: when everything happens (or unravels)

We spend nearly a third of our lives with our head on a pillow. Multiply that by seven or eight hours of micro-movements, position changes, and rubbing, and you get hundreds of tiny frictions per night. On a cotton pillowcase, two things happen:

• The slightly rough surface catches the cuticle already opened by sun and salt. This is the direct cause of breakage, split ends, and morning frizz.
• Cotton is absorbent: it draws out hydration, natural oils, and the night treatment you just applied.

In other words, a night on cotton can undo much of your daytime efforts. Or, conversely, become your best beauty ally — provided you change the surface that touches your hair.

How silk protects your hair during sleep

Mulberry silk has an exceptionally smooth surface. Hair glides instead of catching: less friction means less breakage and frizz upon waking. Silk is also much less absorbent than cotton, which helps preserve hydration and natural oils instead of soaking them up. Specifically, three pieces share the protection:

The night cap offers the most complete protection: it encloses the lengths away from any friction and holds in the treatments applied at night. If you prefer to sleep with your hair loose, the silk pillowcase already makes a huge difference — I detail all its benefits in this article on pillowcases and beauty. Finally, swap your elastic for a silk scrunchie: it holds your hairstyle without creating creases or tension points, two common causes of breakage at the tie.

My summer hair routine in four steps

Nothing complicated: four habits I follow in two minutes before bed, especially after beach days.

1. Rinse before sleeping. After the sea or pool, a simple rinse with clear water removes most of the salt and chlorine. It’s the step I never skip, even when tired.
2. Feed the ends. A small amount of vegetable oil or leave-in treatment on the lengths and ends only — never on the roots, to avoid weighing hair down.
3. Tie without tightening. A loose braid or soft bun, held with a silk scrunchie, limits knots upon waking and distributes the lengths.
4. Wrap up. The night cap on top, or if not, your head resting on a silk pillowcase. That’s where the protection really works, for eight hours straight.

Nothing spectacular on its own — but after a week, the difference is immediately noticeable when detangling, and the ends hold up much better through the season.

Choosing your silk: a question of momme

Not all silks are equal, and this detail makes the difference between a night cap lasting one season or ten years. Momme measures the weave density: the higher it is, the denser, softer, and more durable the silk. For a night cap or pillowcase, I recommend aiming for 19 to 22 momme — the right balance of softness, structure, and longevity. A grade 6A, which designates the longest and most uniform silk threads, guarantees this perfectly smooth surface: the one that makes all the difference against friction.

Frequently Asked Questions

Does silk replace a hair treatment?

No, it extends it. Silk doesn’t nourish hair: it prevents the night from undoing what your treatments have done by reducing friction and preserving hydration. It’s protection, not treatment — the two complement each other.

Night cap or silk pillowcase: which to choose for summer?

The night cap protects the entire hair and holds treatments better: ideal for dry, colored, curly, or kinky hair. The pillowcase is enough if you sleep with your hair down. Ideally, combine both.

Does silk make you hot at night in the middle of summer?

On the contrary. Silk is naturally thermoregulating and stays cool to the touch: a silk night cap is nothing like a wool cap. I discuss this in more detail in our article on silk thermoregulation.

How to care for your night cap or silk pillowcase?

Hand wash or delicate cycle, cold water, with a gentle detergent, then lay flat to dry away from direct sunlight. Well cared for, silk keeps its shine for years.

Discover our silk night caps →

— Mei, for the StudioSoie Journal