Retinol Sandwich

The sandwich method is a tolerance technique. You apply a plain moisturiser, wait a few minutes, apply the retinoid, then apply moisturiser again on top. The retinoid sits between two buffering layers instead of going straight onto bare skin.

What this changes is the rate of delivery, not the destination. Moisturiser underneath slows penetration and dilutes the initial contact; moisturiser on top reduces the water loss that makes retinisation feel like sandpaper. The retinoid still reaches its receptors — the effect is gentler onset, not a weaker outcome, though during the first weeks a slower ramp genuinely does mean slower results.

It is worth using when a retinoid is causing flaking, stinging or redness that stops you being consistent, and consistency is the variable that determines outcomes with this class. It is unnecessary if you already tolerate your retinoid comfortably.

Two practical notes. Damp skin increases retinoid penetration, so let the first layer settle rather than applying onto a wet face. And the old warning about moisturiser 'deactivating' retinol is not a real concern — there is no chemistry there, only the reduced penetration that is the entire point of the technique.