Almost every woman who asks me this is in her thirties or forties, never had acne as a teenager, and is completely blindsided by it now. If that's you — you're not imagining it, and it's not a skincare problem. It's a signal.
Sudden adult acne is nearly always driven by one of three overlapping patterns.
Insulin-driven. Elevated fasting insulin drives IGF-1 signaling, which ramps up sebum production. Often shows up as adult acne on the jawline, paired with skin tags, larger pores, and metabolic changes. Insulin often shifts years before your HbA1c or glucose do.
Androgen-driven. Elevated testosterone or DHEA-S drives sebum directly. Often shows up on the jawline and chin, paired with subtler androgen signs — chin hair, thinning scalp hair, irregular cycles. Common in PCOS, which sometimes surfaces or worsens in the thirties.
Cyclical estrogen shifts. Estrogen was quietly keeping sebum in check for you your whole adult life. When perimenopause makes estrogen fall while androgens hold steady, the ratio shifts. Usually the classic "always the week before my period" pattern.
What to measure: fasting insulin, estradiol, and often free testosterone or DHEA-S. The combination tells you which pattern is yours — and the intervention is different for each.
The JenSkin panel measures fasting insulin and estradiol as part of the standard nine.