Retinoids, from retinol to tretinoin: the ladder, the purge and the mistakes

Retinoids have the deepest evidence base in cosmetic dermatology. They increase cell turnover, normalise the follicular lining that produces comedones, and stimulate collagen. Dermatology consensus work keeps returning them to the top of the list for fine lines, wrinkles, dark spots and enlarged pores.

They are also the ingredient most people quit, because they start too strong, too often, and interpret the resulting irritation as evidence that it is working.

The ladder

All of these end up as retinoic acid in the skin. The difference is how many conversion steps that takes - and each step costs potency.

Adapalene deserves a specific mention for acne. It is well studied, targeted at the follicular process that produces comedones, and usually better tolerated than tretinoin. In India it is a pharmacy purchase - ask the pharmacist, and involve a doctor if your acne is inflamed or scarring.

Starting without a disaster

• Twice a week for the first month, on dry skin, at night. Not nightly, whatever the packaging suggests.
• A pea-sized amount for the entire face. Retinoid irritation is usually a quantity problem.
• Moisturise. The sandwich method - moisturiser, retinoid, moisturiser - materially reduces irritation and barely reduces efficacy.
• Avoid the eyelids, the corners of the nose and the corners of the mouth, where skin is thin and product pools.
• Sunscreen every morning, not because retinoids make you burn instantly, but because new skin is more vulnerable and because photodamage undoes what you are paying for.
• Increase frequency only when two weeks pass with no flaking or stinging.

Retinoid dermatitis - tight, flaking, red, stinging skin - is not the product working. It is a damaged barrier. Stop for a week, use a plain moisturiser, and restart at half the frequency.

What the purge is, and is not

Increased turnover can bring existing microcomedones to the surface faster, so acne-prone skin sometimes breaks out more in the first four to six weeks. That is the purge, and it appears where you usually break out.

New breakouts in places you never break out, or itching, swelling and widespread redness, are not a purge. That is irritation or a reaction, and pushing through it is the mistake that costs people a season of good skin.

Who should not use them

Retinoids are not advised in pregnancy or while trying to conceive, and oral retinoids are strictly contraindicated. If you are pregnant or breastfeeding, ask your doctor before using any topical retinoid - azelaic acid is a commonly suggested alternative.

People with active eczema, rosacea or a badly compromised barrier should stabilise the skin first. And anyone on a course of prescription acne treatment should not add products on top without telling the prescriber.

Buying one

• Opaque, air-restricted packaging. Retinoids degrade in light and air like vitamin C does.
• A stated concentration. A product that mentions retinol without a number is asking to be trusted rather than compared.
• A short, sensible formula. A retinoid plus four other actives makes it impossible to know what your skin is reacting to.
• Realistic expectations on time: acne improvements in eight to twelve weeks, texture and fine lines over six months and beyond.

This is a slow ingredient with a large payoff. The whole skill is staying on it long enough for the payoff to arrive.