I get asked this all the time, usually by women in their thirties and forties who have never had acne before — or hadn't since high school — and suddenly do. Sometimes on their chin. Sometimes on their jawline. Sometimes right before their period every month.
The short answer is that adult hormonal acne is almost always driven by some combination of three things — and often more than one at once. It helps to know which is doing the work in your particular case, because the intervention is different.
1. Elevated androgens. Testosterone and DHEA-S drive sebum production directly. When they're high — often because of PCOS, or sometimes just because they've drifted upward with age — you get more oil, more clogged pores, more inflammatory acne. This pattern usually shows up on the jawline, chin, and sometimes the chest. It's often paired with other subtle androgen signals: chin hair, thinning hair on top, cycles that got irregular.
2. Insulin resistance. This is the one nobody thinks of. When fasting insulin is elevated, it drives an IGF-1 signaling cascade that ramps up sebum production and androgen activity — even if your testosterone is normal. You can be metabolically strained years before your glucose or HbA1c looks off. This pattern often shows up as adult acne plus skin tags, larger visible pores, and weight-management difficulty.
3. Cyclical estrogen shifts. Progesterone dominates in the second half of your cycle, and when estrogen falls relative to it, sebum production shifts. This is what causes the classic always the week before my period pattern. It becomes more noticeable in perimenopause when cycle-to-cycle hormone variability increases.
The blood tests worth running: fasting insulin, estradiol, and often testosterone and DHEA-S. That combination tells you which pattern is dominant. The JenSkin panel covers the first two as part of the standard nine, and we can help you decide whether to add the androgens.
What I keep telling women who come to me with adult acne: it's not a skincare problem. It's a signal.