Best day and night serum for sensitive mature skin

Why it works

Peptides in skincare

Peptides are short chains of amino acids added to creams to signal skin to make more collagen, deliver minerals such as copper, or relax expression lines. A few, such as palmitoyl pentapeptide-4 and copper peptides, showed improvements in wrinkles or collagen in small studies. Overall the evidence is weak: studies are small, many results come from patents or supplier data rather than journals, trials often test peptides mixed with other actives, and it is unclear how well many peptides get through the skin barrier. They appear to be well tolerated. Dermatologists note that anti-aging products deliver modest results.

Retinol and retinaldehyde (cosmetic retinoids)

Retinol and retinaldehyde are vitamin A ingredients that skin converts into retinoic acid, the active form found in prescription creams. Retinoids speed up skin cell turnover and boost collagen, which can improve fine lines, texture and uneven tone over months. Retinol is roughly ten times weaker than prescription tretinoin. Several trials show benefit, but many were small, lacked a placebo cream, or used products whose retinol content and stability were uncertain. Irritation is the main side effect, and in darker skin it can leave dark marks, so start with a low strength every other night. Use at night with daily sunscreen, and do not use during pregnancy.

Hyaluronic acid and glycerin (humectants)

Humectants are moisturizer ingredients that draw water into the outer layer of skin and hold it there. Glycerin is regarded as the most effective humectant for hydrating the skin surface. Hyaluronic acid, a molecule the skin also makes naturally, is another humectant that dermatologists list for dry skin. Used on their own, humectants can pull water out of the skin into dry air and may even increase water loss, which is why well-made moisturizers pair them with occlusive ingredients that seal water in. They work best applied to damp skin after bathing.