GLP-1 Medication and Heart Disease Risk in Women

The trial behind the headline, and who was actually in it

The claim that a GLP-1 "reduces cardiovascular risk" traces back mostly to one landmark trial: SELECT, which randomised over 17,600 adults with overweight or obesity and existing cardiovascular disease to semaglutide or placebo and found a real, statistically significant reduction in cardiovascular death, non-fatal heart attack, or non-fatal stroke — a 20% relative risk reduction over roughly three years of follow-up¹. That result is genuine and important. What gets left out of most coverage is who was in the trial: SELECT's own published baseline-characteristics paper reports the study population was 72.5% male² — meaning fewer than three in ten participants were women. The topline benefit is real. Whether it applies identically to women specifically is a separate question the trial, by its own composition, was not well positioned to answer with precision.

This is not unique to SELECT — it's a pattern

This gap isn't a flaw specific to one study; it's a documented pattern across cardiovascular research generally. An analysis of women's participation in cardiovascular clinical trials from 2010 to 2017 found consistent underrepresentation relative to the actual burden of cardiovascular disease in women³, and a 2024 follow-up analysis found the same underrepresentation persisting, with trial design characteristics still shaping how many women get enrolled⁴. This matters beyond statistics: heart disease in women often presents differently than the "textbook" pattern established from largely male study populations — narrative reviews of ischemic heart disease in women describe both delayed diagnosis and different symptom patterns as a consequence of decades of cardiology research being disproportionately built on male subjects⁵⁶. A trial that is roughly three-quarters male sits squarely inside that broader pattern, not outside it.

Why this is a genuinely women's-health question, not a technicality

Cardiovascular disease is the leading cause of death in women, not a secondary concern behind breast cancer or other conditions more commonly associated with women's health — a fact both major reviews cited above open with, because it is so often underestimated³⁵. That combination — the leading cause of death in women, and the pivotal trial for a drug now widely used by women being weighted heavily male — is exactly the kind of gap this site exists to flag rather than gloss over. It does not mean the SELECT result doesn't apply to women. Biological mechanisms for cardiovascular benefit — improved blood pressure, lipids, inflammation, and weight — plausibly work similarly across sexes, and nothing in the trial suggests a different direction of effect in the women who were enrolled. It means the confidence interval on "how well-established is this specifically for women" is wider than the topline 20% number alone conveys.

What this means in practice

If cardiovascular risk reduction is a reason you or your provider are considering a GLP-1, that's a reasonable and evidence-supported goal — just hold it with appropriate nuance rather than as a settled fact specifically proven in women. It's worth asking your provider whether they're aware of the SELECT trial's composition, and treating your own cardiovascular risk factors (blood pressure, lipids, family history) as things to track directly rather than assuming a GLP-1 alone rebalances them. This ties directly into the broader risk picture our perimenopause and menopause guide covers, since cardiovascular risk rises sharply for women after menopause as estrogen's protective effects fade — timing that overlaps heavily with when many women start a GLP-1 in the first place. It's also worth knowing that SELECT tested semaglutide specifically; our semaglutide versus tirzepatide comparison covers what is and isn't established for each molecule individually, since cardiovascular outcomes data doesn't automatically transfer between them. This guide is educational only and not medical advice.