The correct order to apply skincare, morning and night

Cleanser, serum, moisturiser, SPF — the sequence decides how much of each formula actually reaches your skin. A simple rule set for building a routine that works.

Most skincare disappointment is a sequencing problem rather than a product problem. Formulas are built to sit at a particular point in a routine, and applying them out of order changes how much active penetrates, how long it stays there, and whether it irritates.

The governing rule is thin to thick. Water-based products go on first, because an emollient cream applied underneath a watery serum will block it. Within that, an approximate order works for almost everyone: cleanse, treat (acid, vitamin C or another active), hydrate (a humectant serum), moisturise, then protect.

In the morning the last step is always sunscreen, applied as the final layer and never diluted into moisturiser. Two fingers' length for face and neck is the widely used shorthand for an adequate dose; most people apply roughly a third of what a laboratory test assumes.

At night the last step is your richest occlusive. This is also where retinoids and stronger exfoliating acids belong, on separate nights rather than stacked. If a retinoid stings on bare skin, apply moisturiser first and the retinoid on top — the buffered approach reduces irritation with little loss of benefit.

Wait times are less important than the internet suggests. Thirty seconds between layers, or simply until the previous step is no longer wet, is enough for everything except sunscreen, which benefits from settling for a couple of minutes before makeup.

One more principle: change one variable at a time. Introduce a single new product, use it for two to four weeks, and only then add another. It is the only way to know which product deserves the place in your routine.