Odds are that you’re pretty familiar with the basics of GLP-1 medications at this point, either because you’re taking one, because a friend or family member is taking one, or because you’ve been inundated by commercials for the various drugs every time you watch The Traitors: New Blood.
These weight-loss meds, including semaglutide (Wegovy) and tirzepatide (Zepbound), are so good at helping you shed pounds in part because they slow the pace at which your stomach empties, so you feel less hungry. But what the catchy jingles don’t tell you is that the same mechanism may also affect how your body absorbs and responds to other medications.
The good news is that most of the time, this problem can be resolved, and even avoided completely, with careful monitoring by your doctor and by adjusting other medications, says Caroline Apovian, MD, the director of Mass General Brigham Weight Center and a professor of medicine at Harvard Medical School. New research even suggests that certain combinations, like hormone therapy (HT) and GLP-1 drugs, may make your weight-loss journey more successful.
Here’s what you need to know if you take GLP-1 medications and any of the following types of over-the-counter and prescription drugs:
GLP-1s and Birth Control and Hormone Therapy
GLP-1 medications, particularly tirzepatide, have been shown to affect the absorption of oral contraceptives and make them potentially less effective. (Not ideal if you’re trying to avoid pregnancy.) “To be safe, we recommend that patients who take both medications follow what we call the four-week rule,” says Dr. Apovian. What that means: You use another form of contraception, like condoms, for four weeks after starting a GLP-1, and for four weeks after every time you increase your dose. Thankfully, methods that bypass the gut—like the birth control patch or vaginal ring, both of which contain a mix of estrogen and progesterone—don’t carry the same concerns, she adds.
As for HT, there haven’t been any published studies on whether GLP-1 drugs affect absorption, says Stephanie Faubion, MD, the director of the Mayo Clinic Center for Women’s Health. “Theoretically, we assume it’s the same as being on hormonal contraception: It probably impacts oral absorption, because of slower stomach emptying, but wouldn’t impact transdermal use at all,” she explains. “I’d recommend any woman who is on a GLP-1 drug or plans to go on a GLP-1 drug use the transdermal patch, gel, spray, or ring to be safe.”
In fact, some emerging research suggests that combining GLP-1s and HT may confer unique benefits. A February 2026 study she coauthored, which was published in The Lancet Obstetrics, Gynaecology & Women’s Health, found that postmenopausal women on HT lost 35 percent more weight on tirzepatide compared with those who took the weight-loss drug alone. Another 2024 study in Menopause, also coauthored by Dr. Faubion, found similar results among postmenopausal women who took both semaglutide (Wegovy) and HT.
Dr. Faubion cautions that these are small observational studies and that more research is needed to bear them out. But until then, she says the results suggest that GLP-1s and HT work “synergistically” to produce better weight-loss results. “We’re still not sure why, but one theory is that estrogen may have additional appetite-suppressing effects, as well as stimulate metabolism and the body’s ability to build lean muscle mass,” explains Dr. Faubion. “Women also often sleep better when they are on MHT [menopausal hormone therapy], which makes it easier to incorporate lifestyle changes like sticking to a healthy diet and regular exercise.”
GLP-1s and Medications for Chronic Conditions
If you are on medication to treat hypothyroidism (low thyroid hormone levels), heart failure, atrial fibrillation, high blood pressure, or type 2 diabetes, talk to your doctor, advises Dr. Apovian. You may need to tweak your dosage of the following drugs:
Levothyroxine for hypothyroidism. “Patients with hypothyroidism who start a GLP-1 often experience a significant drop in their thyroid-stimulating hormone (TSH) levels, which means their bodies require less thyroid hormone,” says Dr. Apovian (and thus potentially less thyroid medication). She recommends her patients with thyroid disease get their thyroid hormone levels checked every 8 to 12 weeks when they are on a GLP-1, to ensure they are on the correct levothyroxine dose. Digoxin for heart failure or atrial fibrillation (AFib). Since people with type 2 diabetes, obesity, or both are at higher risk for heart failure, these drugs can be used together, says Dr. Apovian. But it comes with risks. “Some studies suggest that GLP-1 medications can increase the amount of digoxin in the blood, which raises the risk of digoxin toxicity, which can be life-threatening,” she explains. While this could be managed by close monitoring, it’s often simply easier to switch you to another heart-helping medication that doesn’t carry this risk, she says, like a beta-blocker or ACE inhibitor.Blood pressure medications. Patients who take blood pressure drugs while on a GLP-1 are more likely to experience hypotension, or low blood pressure, which can lead to dizziness and even fainting, according to a Northwestern Medicine study of more than 42,000 adults, presented earlier this year at the Endocrine Society’s annual conference. “As people lose weight, their blood pressure often naturally decreases,” explains Talia Diker Cohen, MD, PhD, an endocrinologist at the Rabin Medical Center in Israel who has studied GLP-1 drug interactions with other medications. She recommends that you talk to your doctor about home blood pressure monitoring to make sure you don’t need to lower your blood pressure medication dose. Diabetes drugs like metformin. If you are already on metformin to manage your prediabetes or type 2 diabetes, your doctor may recommend that you stay on it initially while you start your GLP-1 drug. While they can be safely used together, research suggests the combo raises the risk of gastrointestinal side effects such as nausea and diarrhea. You’ll also need to have your blood glucose levels monitored every three to six months to make sure they don’t get too low over time, says Dr. Apovian. “Patients don’t believe it, but when it comes to combining these two medications, you can have too much of a good thing,” she stresses. If you can’t tolerate it, your doctor may have you stay on just one of the medications. GLP-1s and Over-the-Counter Pain Relievers
If you take two acetaminophen tablets to manage the pain of a sore knee or a headache, don’t be surprised if you don’t feel any better after half an hour. “Research shows that it takes longer for acetaminophen to get absorbed because of delayed gastric emptying,” says Dr. Diker Cohen.
The good news is you will feel the effects eventually; it just can take a bit longer. “The concern is if a patient doesn’t get relief and ends up taking more, which raises the risk of side effects and even toxicity,” explains Dr. Diker Cohen. (So just be patient, and don’t pop another one!)
Similar studies on over-the-counter NSAIDs like ibuprofen (Advil) and naproxen (Aleve) haven’t been done. But you may want to limit them anyway, says Dr. Diker Cohen, as they can cause GI upset that can make side effects from GLP-1s like nausea or heartburn worse.
The bottom line: If you’re on a GLP-1 or you’re about to start one, talk to your doctor about how it might interfere with any other medications you’re taking. Odds are it’s probably NBD, but better safe than sorry.
Member Exclusive: Read Our Trending Wellness Stories
