Short answer: with permanent extensions, it is best to go to sleep with the hair completely dry, gently detangled and secured in a loose braid or a low, non-tight ponytail. Clip-in extensions, however, should be removed before sleeping.
The pillow itself is not the main problem at night: friction, moisture and uncontrolled movement of the lengths are what mainly encourage tangling and stress around the attachments.
Why should you not sleep with wet extensions?
Wet hair is more vulnerable to tension and tangles more easily during hours of movement. With permanent extensions, leaving the attachment area damp also adds friction exactly where the natural hair and the system need to remain orderly.
After washing, it is therefore important to dry both the lengths and the area around the attachments thoroughly, without concentrating excessive heat directly on adhesives, keratin or technical bases.
How should you secure your hair for the night?
A loose braid is often a simple option because it limits movement through the lengths without creating strong tension. A soft, low ponytail can also work. The aim is not to tighten the hair until it cannot move, but to prevent it from twisting, tangling or being pulled in random directions while you sleep.
Very tight elastics, high styles that pull on the attachments and tense hairstyles do not add protection; they add tension.
Should you brush extensions before sleeping?
Yes. If there are knots or overlapping strands, gently detangle them before bed, supporting the lengths and avoiding dragging the brush across the attachments. A suitable brush such as VELVET Bamboo Brush can be used from the ends upwards.
We have a separate guide dedicated to this: How to brush hair extensions.
What about clip-in extensions?
Clip-ins are designed to be removable. Sleeping with the set applied offers no benefit and leaves both the clips and natural hair exposed to unnecessary pressure and movement for hours. Systems such as VELVET Seamless Invisible Wire and Seamless sets should therefore be removed before bed.
In summary
The most sensible night routine is simple: dry hair, gently removed tangles and lengths secured without tension. There is no need to turn sleep into a NASA protocol; consistency in reducing friction and pulling is enough.