Adult blemish-prone skin: why it starts later, and what the evidence actually shows

This one comes up in the Parnell shop most weeks. Skin was fine through the twenties, and now there are spots along the jaw and chin that take weeks to settle and leave a mark behind. The questions are always the same two. Why now, and what actually helps.

Two answers before anything else. Adult breakouts often have a hormonal driver that no cosmetic acts on. And acne is a medical condition, which means the most useful part of this article may be the part that tells you to see a doctor.

Acne is a medical condition, not a skincare problem

The American Academy of Dermatology publishes formal clinical guidelines for acne, the way it does for any disease. The current version covers adults, adolescents and children aged nine and older. Its strong recommendations are benzoyl peroxide, topical retinoids, topical antibiotics and oral doxycycline. Oral isotretinoin is strongly recommended where acne is severe, scarring, causing psychosocial burden, or failing standard therapy. The guideline also makes conditional recommendations for hormone treatments, including combined oral contraceptive pills and spironolactone (Reynolds et al., 2024).

Every one of those is a medicine. Not one is a cosmetic, and nothing we sell is a treatment for acne. If your breakouts are persistent, painful under the skin, leaving marks or scars, or affecting how you feel day to day, please see a GP or ask about a dermatology referral. You will get the same answer from us in store. Skincare is not a substitute for medical care and we will not sell it to you as one.

Why it can start later in life

A 2025 systematic review looked at what is linked to acne in women over 25. It pooled 20 studies. Three links came out strongest. Androgen hormones, which stimulate growth of the sebaceous glands and increase sebum. A family history of acne. And a high-glycaemic diet, which raises insulin, which raises IGF-1, which the authors describe as increasing sebum production and keratinocyte proliferation (Telkkälä et al., 2025).

Read that for what it is. It is a review of what is associated with adult acne. It did not test whether changing any of those things clears anyone's skin. The diet link rests on observational research. It is a plausible mechanism and that is as far as it goes.

The hormonal side is worth raising with a doctor. An expert committee convened by the Androgen Excess and PCOS Society recommends that serum androgens, including total testosterone, free testosterone and DHEAS, be measured with high-quality assays in all women with adult acne (Carmina et al., 2022). That is guidance written for clinicians, not a prompt to self-diagnose. Breakouts on their own do not diagnose a hormone condition. But if nobody has ever tested yours, it is a fair thing to raise at your next appointment, and no product on any shelf has a bearing on it.

The three ingredients people ask us about

Salicylic acid

Salicylic acid does appear in the current AAD guideline, as a conditional recommendation rather than a strong one (Reynolds et al., 2024). The Cochrane review is blunter. Against tretinoin it made little or no difference to how participants rated their own improvement, on low-quality evidence from a single 46-person trial. Against benzoyl peroxide, that outcome was not measured at all. The remaining salicylic acid comparisons rested on low or very low quality evidence (Liu et al., 2020).

So salicylic acid is widely used and widely recognised. That is not the same as proven better than anything else, and we are not going to pretend otherwise.

Azelaic acid

In the same Cochrane review, azelaic acid probably gave a worse patient-rated response than benzoyl peroxide. That result comes from one trial of 351 people, not from the review's full pool of 49 trials. Compared with tretinoin it probably made little or no difference, again on a single trial (Liu et al., 2020).

It matters what was being tested. Those comparisons put azelaic acid head to head with medicines such as tretinoin, clindamycin and adapalene. A cosmetic containing azelaic acid or one of its derivatives is a different formulation and has not been tested to that standard. If you have read about azelaic acid and want it, ask a pharmacist or your doctor what is available here rather than assuming a cosmetic version is the same thing.

Niacinamide

This is the one we get asked about most and the honest answer is thin. Four nicotinamide trials made it into the Cochrane review, all of them against antibiotics, and not one measured whether participants thought their own skin had improved. What those trials did show was no clear difference in dropouts or in minor side effects (Liu et al., 2020). Niacinamide has better evidence behind other cosmetic uses. For blemish-prone skin specifically, it is under-studied. Anyone telling you the case is settled is ahead of the evidence.

What none of these can do

• No cosmetic treats, clears, controls or cures acne. Acne is a medical condition and cosmetics are not medicines. We do not make therapeutic claims for anything on our shelves, and a brand that does is worth being wary of.
• None of the research above tested a Verdo product, or any specific product we sell. It is background on a topic, not evidence about a bottle.
• Nothing on a shelf acts on androgens, on a family history, or on a hormone disorder.
• No cosmetic prevents scarring. If you are already seeing marks or scarring, see a doctor sooner rather than later. The guideline treats scarring as a sign of acne that needs stronger medical options (Reynolds et al., 2024).

Washing, and what the research actually shows

The usual warning is that over-washing causes breakouts. The trial evidence is weaker than the confidence behind that advice. In a small single-blinded randomised trial, men with mild to moderate acne washed their faces once, twice or four times a day for six weeks. There was no statistically significant difference between the three groups. Within groups there was some movement. The twice-daily group improved on open comedones, and the once-daily group got worse, with increases in redness, papules and total inflammatory lesions. The authors concluded that excessive washing may not be as culpable as previously thought (Choi et al., 2006).

Two caveats worth holding onto. The comparison between groups, which is the one that counts, found nothing. And the participants were men with mild to moderate acne, which is not the person this article is written for.

The wider cleanser literature is thinner still. A systematic review searching back to 1951 found only 14 usable prospective studies covering 671 people in total, and concluded that reliable recommendations about cleansers cannot be formulated (Stringer et al., 2018). Anyone telling you a particular wash is proven for blemish-prone skin has gone well past what has been shown. That includes us.

One measurement is worth knowing about. In 316 Thai volunteers, transepidermal water loss was higher in the acne group than in controls, 13.16 against 10.63 g/m² per day, and highest of all in those using acne medicines (Sukanjanapong et al., 2024). The same study found higher sebum in the acne group and, less conveniently for a tidy story, higher skin hydration as well. It is cross-sectional, in one population, and the acne group averaged 34 years against 48.6 in the controls, so it cannot show cause and effect. Its authors suggest the findings support barrier-friendly moisturisers alongside acne medicines. That is their suggestion, not a tested outcome. It is still a fair argument for keeping a plain moisturiser in the routine instead of stacking more actives on top.

What "non-comedogenic" means, and what it does not

There is no single test a product must pass before a brand prints that word on a box. The research behind the idea is small. A 2006 re-evaluation used a modified human assay on six people with prominent follicular openings, patching finished cosmetics onto the upper back three times a week for four weeks. Its conclusion was that finished products made with so-called comedogenic ingredients are not necessarily comedogenic themselves, and its authors noted that only a finite number of products could be analysed (Draelos and DiNardo, 2006).

Read the word as a statement of intent from a brand. It is not a promise about your face. No brand, ours included, can guarantee a product will not cause a breakout on your skin.

What we stock, and what we are not claiming for it

We do sell cosmetics made for blemish-prone skin, so here is the plain version of what they are.

Medik8 Clarifying Foam is a foaming cleanser containing mandelic acid, salicylic acid, tea tree oil and niacinamide. Given the cleanser review above, we cannot tell you it is proven for blemish-prone skin, because that has not been shown for any cleanser. What we can say is that customers find it comfortable and it does not leave skin feeling tight.

Medik8 Blemish SOS is a small leave-on gel from Medik8's Direct Acids range, meant to be dabbed onto individual spots rather than spread across the whole face. If the rest of your skin is fine, that is a more sensible way to use an acid than covering everything. Acids increase sun sensitivity, so daily SPF matters, and patch test before the first use.

Neither one is a treatment. If treatment is what you need, that is a doctor, not us.

Where that leaves you

Book the appointment if the breakouts are persistent, sore, or leaving marks. Ask about androgen testing if you are a woman whose acne started in adulthood. Keep skincare gentle and unexciting while the medical side gets sorted, because comfort and tolerability are the honest things cosmetics have to offer here. And if a product promises to clear your skin, treat the promise itself as a warning sign.