Why Do Adults Still Get Acne?

Most people assume acne ends with their teenage years. The science says otherwise — and the reason it keeps coming back has nothing to do with dirty skin. In this episode, Jen, Chris, and Matt unpack the four biological processes behind every breakout and explain why they don't simply stop at the end of puberty. They cover the adult-specific triggers — hormonal shifts, cortisol, and diet — and bust two of the most persistent myths in skincare: that pores open and close, and that acne means your skin isn't clean. They also walk through what the evidence says actually works for treatment, including the timeline that most people get wrong, and reframe acne as a whole-body symptom rather than a surface skin issue. Timestamps 00:00 — Introduction 00:24 — The four biological processes behind every breakout 02:42 — The pores opening and closing myth, busted 05:29 — Why adult acne is triggered differently to teenage acne 08:29 — Diet, blood sugar, and the IGF-1 connection 12:04 — Why acne has nothing to do with dirty skin 13:33 — Treatments that work (and the timeline most people get wrong) 17:04 — Acne as a whole-body symptom Four Things Have to Go Wrong at Once [00:24] Acne isn't a surface issue. It starts inside the hair follicle, and for a breakout to develop, four processes have to align: excess sebum production driven by androgens; abnormal, sticky skin cell shedding that blocks the pore from the inside; bacterial overgrowth of C. acnes in the clogged follicle; and an immune-driven inflammatory response that creates the redness and swelling. As Matt put it: "It's like a project, isn't it? Without a project manager, everyone's doing their own thing and the outcome just seems to be mayhem and chaos." Those four processes are identical in teenagers and adults. What changes is what sets them off. Adult Triggers Are Different from Teenage Ones [05:29] In puberty, a steady surge in androgens drives acne. In adult life, it's the irregular hormonal shifts that cause problems. For women, cyclical acne tied to the menstrual cycle is the most common pattern, with breakouts clustering around the jawline and lower face — a location so consistent that persistent lower face acne in adult women is now treated as a hormonal flag in dermatology. Stress is a separate but significant driver. As Chris explained: "I'd say less of a case of stress creating acne from nothing. More like stress lowering the threshold at which everything that was already kind of quietly ticking over tips over the edge into a full on breakout." Diet runs through blood sugar: high-glycaemic foods trigger an IGF-1 spike that directly stimulates the sebaceous glands. A 2023 review found a consistent link between high-glycaemic diets and acne severity, particularly in adult women. Treatment Requires More Patience Than Most People Give It [13:33] Three over-the-counter actives have solid evidence behind them: benzoyl peroxide, salicylic acid, and adapalene. But the timeline is where most people go wrong. As Jen noted: "Most of them require a minimum of about six to eight weeks for any noticeable improvement, and three months really to properly evaluate its effectiveness." Treatments should be introduced one at a time — combining actives makes it impossible to know what's working and risks significant irritation. If consistent treatment over two to three months hasn't made a difference, or if acne is leaving scarring, it's worth a conversation with a doctor. Research has shown that adult acne significantly affects quality of life and self-esteem — and that alone is a legitimate reason to seek proper support. Acne Is a Whole-Body Symptom [17:04] The inputs behind acne — hormones, cortisol, blood sugar, systemic inflammation — are whole-body processes. The skin is simply where they become visible. As Chris put it: "The skin is the body's largest organ, but it's also the one we can see. So it can reflect things going on elsewhere in the body." Poor sleep, for instance, elevates cortisol directly, feeding into both sebum production and cellular inflammation. The lifestyle factors that support skin health are largely the same ones that support broader health outcomes. About So That's Why So That's Why is a weekly podcast where Jen, Chris, and Matt unpack the science behind everyday health questions. No jargon, no judgment — just genuine curiosity and proper research.