If your cycle has felt different since starting a GLP-1 medication — semaglutide (Ozempic, Wegovy) or tirzepatide (Mounjaro, Zepbound) — you're not imagining it, and you're also not alone in not finding a straight answer. Here's what's actually known.
GLP-1 medications work in part by slowing digestion and changing hunger and satiety signals. They also tend to cause meaningful weight loss for many people, and weight change itself is a well-established influence on menstrual regularity — significant weight loss can shift cycle length, flow, and ovulation timing, independent of the medication's other effects. For some people who were not ovulating regularly at a higher weight, GLP-1-related weight loss has restarted more regular cycles.
Beyond the weight-change pathway, there isn't strong published research yet on whether GLP-1 medications affect the menstrual cycle, PMS, or perimenopause symptoms more directly. Most of what circulates — heavier or lighter periods, longer or shorter cycles, mood changes tied to specific days after a dose — comes from patient reports rather than controlled studies. That doesn't mean those reports are wrong; it means the research hasn't caught up to what people are actually experiencing.
Track your doses and your cycle in the same place, log side effects as they happen rather than trying to recall them later, and bring what you notice to your prescriber — especially any change in cycle regularity, unusually heavy bleeding, or a missed period, since those are worth a clinical conversation regardless of the cause.
Sicavie tracks your cycle and your GLP-1 doses on the same timeline, so the pattern — if there is one — becomes visible instead of guessed at.
Try it free for 7 daysThis page is general information, not medical advice, and isn't a substitute for care from your doctor or pharmacist. If you notice a significant change in your cycle, unusually heavy bleeding, or a missed period while on a GLP-1 medication, talk to your clinician.