Do you know what a serum is for? Know all its benefits

20s: prioritize SPF in day creams for long-term skin protection

A serum is the most concentrated step in your routine. What it does, when to use it and how to pick the right one for your skin.

Most of the ageing we see on a face is sun damage that happened years earlier. A light day cream with SPF, worn every morning, does more for your skin at forty than any serum you buy at forty.

• Choose a cream you like the feel of, or you will not wear it.
• Use two fingers' length of product for the face and neck.
• Top up at lunchtime when you are outside.
• Keep a small bottle in your bag.

30s: use antioxidant-rich creams to fight environmental damage

Pollution and sun create free radicals that break down collagen. Vitamin C in the morning and a richer cream at night help skin repair itself while you sleep.

40s: focus on firming creams with peptides

Peptides tell the skin to make more collagen. They work slowly, so give a new cream two months before you judge it.

50s: opt for creams rich in ceramides

Ceramides are the mortar between skin cells. As skin makes fewer of them, a cream that puts them back keeps moisture in and irritation out.

The best routine is the one you keep: a cleanser, a moisturiser and sunscreen, every day.

60s: select hydrating, soothing creams for sensitive skin

Skin gets thinner and drier. Rich, fragrance-free creams and a gentle cleanser are worth more now than anything active.