Beauty & FitnessRetinol, vitamin C and acids: which one, and in what order
The three ingredients with real evidence behind them, how to start each without irritation, and the combinations to avoid.
Beyond cleanser, moisturiser and sunscreen, three ingredient families have solid evidence for improving how skin looks: retinoids, vitamin C and exfoliating acids. You don't need all three. Here's what each does and how to add one without wrecking your skin barrier.
Retinoids
Vitamin A derivatives — retinol over the counter, tretinoin on prescription — are the most studied anti-ageing ingredients in existence. They speed up cell turnover, thicken the deeper layer of skin and stimulate collagen. Results on fine lines and pigmentation show at around three months and continue for years.
How to start: a low strength (0.1–0.3% retinol), a pea-sized amount, twice a week at night, on dry skin, followed by moisturiser. Increase frequency every two weeks as tolerated. Some dryness and flaking in the first month is normal; stinging or redness means slow down. Always use sunscreen in the morning.
Who should avoid it: anyone pregnant or breastfeeding.
Vitamin C
An antioxidant that neutralises the free radicals generated by UV and pollution, brightens uneven tone and supports collagen. The best evidence is for L-ascorbic acid at 10–20%, ideally with vitamin E and ferulic acid. It's unstable — buy small bottles and store them away from light.
How to use: in the morning, under sunscreen, where it adds a layer of protection. It can tingle on first use.
Exfoliating acids
Alpha-hydroxy acids (glycolic, lactic) loosen the bonds between dead surface cells, smoothing texture and brightening. Beta-hydroxy acid (salicylic) is oil-soluble, so it gets into pores — the choice for congested or acne-prone skin.
How to use: two or three nights a week, on nights you're not using retinol. Daily use is more than most skin needs.
Combinations to avoid
- Retinol and acids on the same night: too much irritation for little extra benefit.
- Vitamin C with benzoyl peroxide: the peroxide oxidises the vitamin C.
- Starting two new actives at once: if something goes wrong, you won't know which one caused it.
A simple week
- Morning: cleanse, vitamin C, moisturise, sunscreen.
- Evening (Mon, Wed, Fri): cleanse, retinol, moisturise.
- Evening (Tue, Sat): cleanse, acid, moisturise.
- Evening (Thu, Sun): cleanse, moisturise. Skin needs rest nights.
What to do this week
- Choose one active based on your main concern: retinol for lines and firmness, vitamin C for dullness and dark spots, salicylic acid for congestion.
- Use it twice this week, never on consecutive nights, and note how your skin responds.