You’ve seen this on TikTok. Here’s who should not be using it.

I’m not a prescriber. I can’t write you a prescription for a topical retinoid, I don’t sell one, and nothing here is a recommendation that you use one. I’m writing this because I’m asked about it most weeks. Usually by someone who’s watched a thirty-second video and wants to know whether they’ve been missing out.

If a strong retinoid is right for you, that conversation belongs with your GP, a dermatologist or a prescribing clinician who has looked at your skin and your medical history. What I can do is tell you what I see in the room when it goes wrong. Often that alone is worth ten minutes of your time.

Retinoids are a family, not a product. At the gentle end are retinyl esters, which the skin has to convert through several steps before anything happens. Then retinol. Then retinaldehyde, which is one step closer and noticeably more active. Adapalene sits above those and is available in the UK through a pharmacist rather than off the shelf. At the top are tretinoin and tazarotene, both prescription-only, and tazarotene is generally the most irritating of the whole family.

Each rung up is more direct, which means faster and also harsher. Starting at the top skips every opportunity the skin had to adapt. Usually that means a fortnight of soreness and then the tube in a drawer. The outcome I see most.

The strongest thing you can tolerate isn’t the same as the strongest thing that exists. Almost all of the benefit is in the years of use, not the percentage.

This isn’t an exhaustive list, and it is not medical advice. It’s the set of people I most often meet who are using something they shouldn’t be.

• Anyone pregnant, planning a pregnancy or breastfeeding. Topical retinoids carry pregnancy warnings for good reason, and this isn’t a judgement call to make from a comment section.
• Anyone in a rosacea flare, or with eczema or perioral dermatitis. The barrier is already failing. A retinoid asks it to work harder.
• Anyone already using an exfoliating acid most nights. Pick one. Both together isn’t twice the benefit. It’s simply too much.
• Anyone about to have a peel, microneedling or laser. Most practitioners, including me, will ask you to stop a fortnight beforehand.
• Anyone going somewhere sunny in the next month. Retinoids increase sun sensitivity, and holiday photos are a poor moment to discover that.
• Anyone whose skin is currently sore, tight or stinging from something else. Let that settle first, then look again in six weeks.

The word purging gets used to explain away almost anything. It has become the reason people stay on products that are quietly damaging them.

A genuine purge is existing congestion being brought to the surface faster than it would have arrived on its own. It happens in the places you already break out. It looks like your usual spots, in your usual pattern, more of them, sooner. It settles within about four to six weeks.

What isn’t a purge: spots appearing where you’ve never had them, burning rather than tingling, flaking around the mouth and eyelids, a fine red rash, or skin that stings when you apply water. Those are irritation, and irritation doesn’t become tolerance by being endured. It becomes a damaged barrier, and that takes months to rebuild.

Assuming it was prescribed for you, by someone who examined you: use a pea. One pea, for the whole face, spread thin. Most retinoid problems I see are dosage problems.

Twice a week for the first month, then three times if that’s been comfortable. Apply to dry skin, not damp. Damp skin absorbs more and stings more. Keep it off the eyelids, the corners of the mouth and the creases of the nostrils, which are where irritation starts. Buffer it with your moisturiser underneath if you need to. That isn’t cheating, it’s how most people tolerate it long term.

Nothing acidic on the same night. Sunscreen every morning, properly, not the trace amount in a foundation. And if your skin is sore, stop for a week and let it settle rather than pushing through.

Wear sunscreen daily for six months. That’s genuinely the biggest change available to almost everyone reading this, and it costs less than any retinoid.

Get the barrier working. A gentle cleanser, one moisturiser that suits you, and nothing that stings. If your skin currently reacts to things it used to tolerate, no retinoid is going to land well on top of that.

Then, if you still want one, start low and stay there for a year. A retinaldehyde you use three nights a week for five years will do more for your skin than a prescription tube you gave up on in February. That isn’t a compromise position. It’s what the long game looks like.