Skincare
Retinol and retinoids: what is actually proven
Few ingredients are advertised so often and explained so rarely. What retinoids actually do, how retinol and tretinoin differ, and who should not use them.
Skincare
What actually changes the skin.
Most skincare products promise more than they can deliver. A small number of active ingredients, however, change the skin measurably. This overview ranks the most important ones by the strength of the evidence behind them.
Active ingredients
Six ingredients, ordered by evidence.
What matters is not the number of products but whether the ingredients they contain are supported by evidence and present at an effective concentration.
Retinol and retinoids
The best-studied ingredient against photoageing. Prescription retinoids are more potent than over-the-counter retinol products. Not to be used in pregnancy.
Level of evidence: Strong
Sun protection
The only measure demonstrated to slow skin ageing rather than merely conceal it. It works preventively — and therefore all the more the earlier it begins.
Level of evidence: Strong
Vitamin C
An antioxidant with indications of benefit for pigmentation and skin appearance. The effect depends heavily on concentration, pH and the stability of the formulation.
Level of evidence: Moderate
Niacinamide
A well-tolerated ingredient with data on the skin barrier, redness, sebum production and pigmentation. The effect is solid but moderate.
Level of evidence: Moderate
Hyaluronic acid (topical)
Binds moisture at the skin surface and smooths it in the short term. Applied topically it does not reach the deeper layers — which sets it clearly apart from injectable filler.
Level of evidence: Moderate
Peptides
A highly heterogeneous group with inconsistent evidence. Individual peptides do show effects, but marketing claims usually go far beyond the data.
Level of evidence: Limited
This rating is a deliberately simplified orientation. It describes how robust the published evidence is for the main indication — not how well a treatment will work in an individual case. Details are given in the corresponding article.
Routine
Three steps are enough for most people.
An effective routine is short. It only needs to get longer when a specific skin condition requires it.
01
Morning: cleanse and protect
Gentle cleansing, a moisturiser if needed, then sun protection. Sun protection is the step with the largest demonstrated benefit.
02
Evening: cleanse and treat
Cleansing, then the active ingredient itself — for skin ageing typically a retinoid, introduced slowly to avoid irritation.
03
What can usually be left out
Toners, essences, ampoules and layered serums are rarely necessary. They mainly increase cost and the risk of irritation, not the effect.
Which products are genuinely worthwhile
A product is worthwhile if it contains an evidence-backed ingredient at a sufficient concentration, the skin tolerates it, and it is used consistently. Price, brand and packaging say nothing about this. Expensive formulations may feel more pleasant — that does not make them demonstrably more effective.
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Medical disclaimer
The information on this website is provided for general medical education and does not replace individual medical examination, diagnosis or treatment. It does not constitute a treatment recommendation for any individual case. If you have health concerns, or before undergoing any treatment, please consult a physician.
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