Do GLP-1 Meds Affect Your Menstrual Cycle?

GLP-1 medications are in the spotlight and don’t seem to be slowing down any time soon. They’re prized as a fix for everything from stubborn weight to constant cravings, with results that can feel fast. But once you look beyond the headlines, some of the GLP-1 side effects are less discussed than others—menstrual changes included.

So what’s actually going on, and which changes are worth paying attention to?

What GLP-1s Can Do to Your Cycle

According to Gillian Goddard, MD, a board-certified endocrinologist in New York City and the author of The Hormone Loop, menstrual cycle changes are common in women on GLP-1 medications.

Part of the reason comes down to who’s taking these medications in the first place. First, she notes that women of reproductive age with overweight or obesity—a large share of people taking these medications—are more likely to have polycystic ovarian syndrome (PCOS). Irregular periods are a common symptom of the condition. Medications that improve blood sugar metabolism, including GLP-1s, can help women with PCOS have more regular periods, says Dr. Goddard. (Recent studies support this, too.) “Metformin, another diabetes medication, has already been shown to have this effect in women with PCOS, so it isn’t surprising that GLP-1 RAs would have this effect,” she adds.

That said, less welcome shifts in your menstrual cycle are also possible. “If someone loses too much weight, their periods can become more irregular or disappear completely,” notes Dr. Goddard. She adds that changes in menstrual flow can also occur. That might sound alarming, but it’s actually not that surprising. “When humans were evolving thousands of years ago, extreme weight loss was a sign there wasn’t enough food,” she explains. “In response to that perceived lack of food, the body shuts off ovulation to prevent pregnancy when resources are scarce.”

Are These Side Effects Due to GLP-1s or Weight Loss?

The answer varies. “These changes are likely both direct effects of the medications themselves on the hypothalamus in the brain and ovaries,” says Dr. Goddard. “It is also likely an indirect effect of weight loss. In someone with overweight or obesity, weight loss will also lead to more regular periods.”

However, she says that irregular periods could signal extreme weight loss and not be a direct effect of the medication itself. Rapid weight loss can also signal “stress” to the body, prompting it to conserve energy, including by dialing back reproductive functions.

Are Menstrual Changes on GLP-1s a Cause for Concern?

According to Dr. Goddard, the most common menstrual shifts on GLP-1 medications are shorter, more regular cycles. This is a welcome change for those who typically have irregular periods, including women with PCOS, overweight, or obesity.

But if your cycles are historically regular and that’s no longer the case, that could be a red flag. “Irregular or absent periods could be a sign that the body is losing weight too quickly and not getting the nutrients needed to support a healthy reproductive system,” says Dr. Goddard. In some cases, it could also point to something else entirely, like an unexpected pregnancy.

“You should definitely see your doctor if your regular periods become less regular or you stop having periods altogether,” she says. They may decide to lower the dose of your GLP-1 to slow the rate of weight loss or stabilize the weight, which can help rebalance your hormones and encourage menstrual regularity once again.

The Bottom Line

While many women take GLP-1s to lose weight, the medications have downstream effects on the rest of your body—including your hormones and in turn, your cycle. If your periods are historically irregular, achieving a healthier weight can work in your favor by encouraging more regular cycles. On the flip side, rapid weight loss from these drugs can trigger a stress response in your body and bring your hormones out of balance, which can lead to missed periods or deviate from your usual schedule. If the latter’s the case, be sure to consult your physician to ensure that your weight loss journey—and your broader health—remain safe and steady.