All forms of vitamin A used in skincare — tretinoin, adapalene, retinol, retinyl esters — work the same basic way: they increase skin cell turnover. What differs is strength, and how tightly that strength is regulated. At the top sits tretinoin, a prescription-only medicine in Ireland and the UK. Below that sits adapalene, then over-the-counter retinol serums and creams. The real question isn't which is ‘strongest’ — it's which strength you can actually tolerate every night, because that's what determines whether it works at all.
What Retinoids, Retinol, and Retinyl Esters Actually Are
All are derivatives of vitamin A. They sit on a strength spectrum, and the difference mostly comes down to how much conversion each one needs before it becomes biologically active in the skin:
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Tretinoin — a prescription-only medicine, typically 0.025%–0.1%, prescribed by a doctor or dermatologist
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Adapalene (Differin) — a synthetic retinoid, commonly 0.1% (a stronger 0.3% gel is available on prescription), used mainly for acne vulgaris and sometimes keratosis pilaris
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Retinol — available over the counter as serums (up to around 2%) or creams (typically 0.5–1%); serums tend to be more irritating than creams at the same strength
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Retinyl esters (e.g. retinyl palmitate) — gentler, more stable derivatives that need extra conversion steps, and are correspondingly less potent but far better tolerated
Worth knowing: New EU regulation caps retinol, retinyl acetate and retinyl palmitate in leave-on face products at 0.3% retinol equivalent, from November 2025 for new products and May 2027 for existing stock. It's a ceiling on higher-strength products, not a minimum — lower-strength retinol products remain entirely legal and, for many people, are the more usable option.
What the Evidence Actually Shows
Tretinoin and adapalene reliably increase cell turnover and expose newer skin cells. They're used in acne vulgaris treatment and in improving pigmentation, and prescription retinoids have a role in skin cancer prevention regimens. That part is well established.
The nuance is in how they're used. A high percentage used once a week, because that's all the skin can tolerate, is often less effective than a lower percentage used consistently every night — the second approach is genuinely reaching the skin daily, the first is mostly recovering from irritation. And because retinoids work by exposing new, less protected skin cells, those cells need to be defended the next morning with a broad-spectrum SPF and ideally a vitamin C — without that, you can end up doing more harm than good.
Retinoids also aren't a standalone solution, however social media often presents them as one. For acne and texture, they usually work best alongside other actives — salicylic, glycolic, mandelic or lactic acid, and niacinamide for oil control — rather than in isolation. And if the skin barrier gets stripped in the process, it has to be actively restored, or the net effect is negative.
There was a real backlash against topical tretinoin in the UK and Ireland, driven partly by irritation and partly by it being oversold on social media as a stand-alone transformation. Retinoids are a genuinely useful tool, but they don't replace lasers, medical microneedling, radiofrequency microneedling or chemical peels, and they're best used as an adjunct rather than the whole plan. In clinic, acne is often managed with a combination — sometimes an oral antibiotic or a hormonal contraceptive alongside a topical retinoid — plus a proper exfoliating routine with oil-free moisturisers and oil-free sunscreen. That combination is what actually produces the result, not any single ingredient.
Who It Suits, and Who Should Be Cautious
Tretinoin and adapalene are rarely well tolerated by rosacea-prone, eczema-prone or generally reactive skin. In clinic, we see patients with recurrent perioral or periorificial dermatitis who are using topical retinoids, and barrier disruption from the retinoid appears to be a contributing factor in a number of these cases.
Topical retinoids are not considered safe in pregnancy. We've also observed, anecdotally, patients using a topical retinoid on the face alone whose acne on the back and shoulders improved without ever being treated directly — which suggests some degree of systemic absorption is possible. On that basis, we're cautious with these products generally, and women of childbearing age using them should be using reliable contraception.
Known Irritancy Profile and Interactions
If a patient is using adapalene or tretinoin, we're careful about what else goes into the routine. A salicylic acid cleanser is often one step too many — we'd usually favour gentler exfoliants like glycolic, polyhydroxy, lactic or mandelic acid instead, a richer moisturiser, and sometimes a vitamin B5 (panthenol) gel for its anti-inflammatory, barrier-supporting effect, specifically to head off the irritation retinoids are known for.
Why REFORM Formulates the Way It Does
As a skincare brand, REFORM can't sell tretinoin — it's a prescription medicine in Ireland and the UK, and should be prescribed by a doctor or dermatologist, not bought over the counter. REFORM's own products use retinyl palmitate, a much gentler ester that can genuinely be used every night around the eyes, face and neck without the irritation profile of stronger retinoids.
The thinking behind that choice: it's the retinol you actually keep using, night after night, that gives you a result — not the strongest version you can only tolerate once a week. Consistency beats intensity. If someone wants a faster, more aggressive resurfacing effect than a gentle nightly retinol can offer, our view is that an in-clinic chemical peel or laser treatment will get a better result, with a few days to a week of downtime, rather than an ongoing cycle of peeling and barrier damage from an aggressive at-home retinoid routine.
How to Introduce It Safely
Patch test first. If you're using a prescription-strength product, introduce it gradually rather than nightly from day one, and pair it with a hydrating cleanser and a moisturiser containing hyaluronic acid and niacinamide to offset the irritation. Always follow with a broad-spectrum SPF and a vitamin C the next morning to protect the newly exposed skin cells.
For acne, many patients find a gentle, consistent retinol genuinely useful as long-term maintenance. For anti-ageing specifically, our own clinical view is that the highest-strength tretinoin is often too irritating to be sustainable for most people long-term — which is exactly why the gentler, dermatologist-formulated route tends to win out over time.
The Takeaway
The most effective retinoid isn't necessarily the strongest one — it's the one you'll actually use, consistently, alongside sunscreen the next day. REFORM's retinyl palmitate-based products are formulated with exactly that in mind, for anyone who wants a gentler way in.
