Taking a GLP-1? Learn how it may affect your other medications
October 7, 2026
Injectable and oral glucagon-like peptide 1 (GLP-1) medications have changed the way we treat diabetes, obesity, and even certain forms of heart failure. The drugs can help with weight management, reset your relationship with food, and improve metabolic health.
While some physical changes associated with GLP-1s, such as weight loss and less food noise, are obvious, subtle adjustments are also happening below the surface – including shifts in how your other medications work.
Some of those changes are good and may even be part of your wellness goals. For example, you may need less insulin or lower doses of blood pressure medications while taking a GLP-1.
But other changes may be unexpected or potentially harmful, in part because of how these medications work.
GLP-1 medications reduce appetite and alter stomach emptying. While this can lead to significant weight loss, it may also affect how some medications are absorbed or dosed, particularly medications that depend on body weight or gastrointestinal absorption.
As more forms of these drugs are becoming more readily available, the need for well-rounded guidance on medications, nutrition, physical activity, sleep care, and whole-person health is increasing. Some patients may also benefit from behavioral health support. Talking with a doctor or an obesity specialist in the UT Southwestern Weight Wellness Program is a good first step toward making sure your GLP-1 medication works for your health rather than against it.
What medications can be affected by my GLP-1?
Starting a GLP-1 does not automatically mean you should stop taking other medications. In fact, some drugs may provide significant health benefits as you lose weight. GLP-1 medications are still relatively new, and researchers continue to learn more about their long-term effects.
Important: GLP-1 medications carry a warning based on findings of thyroid C-cell tumors in animal studies. Because of the potential risk, they should not be used by patients with a personal or family history of medullary thyroid carcinoma (a rare type of thyroid cancer) or those who have multiple endocrine neoplasia syndrome type 2 (a rare tumor-causing genetic condition).
Before you stop or start taking a medication alongside a GLP-1, talk with a doctor about the risks and benefits to your health. The medication changes that matter most typically fall into two categories: drugs that become more potent as health improves and medications whose absorption or dosage may change during treatment.
Diabetes medications
Many people take GLP-1s along with diabetes medications such as metformin. SGLT2 inhibitor drugs such as Jardiance and Farxiga may be prescribed not only for diabetes but also for heart and kidney health. These drug combinations typically are safe and often provide complementary benefits.
Medications that can cause low blood sugar, such as insulin and sulfonylureas, may need closer monitoring. As your blood sugar levels improve, you may need less of these drugs, if any.
Oral birth control
An often-surprising side effect from significant weight loss, regardless of how it is achieved, may be improved fertility. Obesity can increase estrogen levels and disrupt ovulation, leading to irregular menstrual cycles.
Weight loss associated with GLP-1 treatment may help restore more regular menstrual cycles and ovulation, which can lead to unexpected pregnancy in some patients who once had fertility challenges – a phenomenon called "Ozempic babies." Some patients with polyendocrine metabolic ovarian syndrome (PMOS, called PCOS until recently) may also notice more regular ovulation and menstrual cycles as their metabolic health improves.
Tirzepatide (Zepbound or Mounjaro) and orforglipron (Foundayo) may reduce the effectiveness of birth control pills. People taking tirzepatide should switch to a non-oral contraceptive or add a barrier method, such as condoms, for four weeks after starting treatment and after each dose increase. For Foundayo, the recommended interval is 30 days after starting treatment and after each dose increase.
Thyroid medications
If you take levothyroxine for an underactive thyroid, changes in body weight or medication absorption may affect your dose requirements. Oral semaglutide can also increase levothyroxine exposure. Your clinician may recommend additional thyroid blood tests, especially after substantial weight change or after starting oral semaglutide. Patients should report symptoms such as palpitations, tremor, sweating, or heat intolerance.
Blood pressure medications
It may be tempting to stop taking blood pressure medications when you start taking a GLP-1. Remember, high blood pressure is called the "silent killer" for a reason: It typically doesn't cause noticeable symptoms until a heart attack or stroke occurs. Do not stop blood pressure medications without consulting a doctor; some patients may need their blood pressure medication adjusted as weight loss progresses.
Cholesterol medications
While better weight management can improve some health markers, cholesterol levels are influenced by many factors, including genetics. If you're doing well on a statin or another cholesterol medication, keep taking it unless your doctor recommends a change.
One important exception is a statin called simvastatin taken with Foundayo. This combination requires a medication review because Foundayo increases exposure to simvastatin’s active form; the prescribing information limits simvastatin to 20 mg daily when used together.
Heart failure medications
Semaglutide and tirzepatide have shown benefits in people with obesity and heart failure with preserved ejection fraction, a form of heart failure in which the heart does not relax and fill normally. Heart failure is a complex disease that can include complications with breathing, kidney function, and the liver. Talk with a doctor about the best medications to take for your condition.
Oral GLP-1 tablets and timing
A daily, oral pill form of Wegovy became available in January 2026 after it was approved by the Food and Drug Administration (FDA). It works like the injection form, except that it requires specific dosing conditions for absorption. Take the tablet in the morning on an empty stomach with no more than 4 ounces of plain water, then wait at least 30 minutes before food, beverages, or other oral medications. If you also take levothyroxine, ask your clinician or pharmacist to help coordinate the timing.
A new oral daily GLP-1, Foundayo, was FDA-approved in April 2026 and does not have the same fasting requirements as oral Wegovy.
Weight Wellness Day 2026
Learn practical, science-based information about achieving and maintaining a healthy weight at UT Southwestern's annual Weight Wellness Day. The free event will be from 9 a.m. to 2:30 p.m. Saturday, Oct. 10, at the UT Southwestern campus in Dallas.
Find out what’s fact and fiction about medications for weight management and other emerging therapies from UT Southwestern physicians, researchers, and other healthcare professionals. Also, enjoy a cooking demo, featuring tips and practical ways to eat healthy, nutritious foods. A complimentary lunch will be served. RSVP is required. Register here.
Comprehensive care for long-term weight wellness
GLP-1 treatment should never be viewed as just a prescription. Lasting success requires comprehensive care, including nutrition guidance, exercise recommendations, lab monitoring, and regular follow-up visits.
At UT Southwestern's Weight Wellness Program, patients get a comprehensive evaluation before starting treatment. In follow-up visits, we talk through medications you're taking and monitor for changes in blood pressure, nutrition, and overall health.
Because GLP-1s reduce appetite, you'll likely be eating less – and the quality of your nutrition becomes even more important. Working with a registered dietitian is key to building healthy habits that support lasting results. This team can help you understand the right amount of nutrients you need without sacrificing muscle mass, strength, and function.
First and foremost, you’ll need to prioritize protein at meals and snacks. Your daily target protein goal will be based on your weight as well as your age, body size, kidney function, and physical activity.
Protein shakes can be used as a supplement but shouldn’t take the place of whole foods. Healthy, protein-rich foods include:
- Chicken
- Eggs
- Fish
- Greek yogurt
- Lean meats
- Plant-based proteins (beans, edamame, chickpeas)
Here are a few more strategies we recommend for long-term weight management:
- Eat small meals and snacks throughout the day to get your nutrients in without feeling uncomfortably full.
- Increase fiber intake through fiber-rich foods such as whole grains, fruits, vegetables, beans, chickpeas, and edamame.
- Keep a water bottle nearby and drink consistently throughout the day – you may find that thirst decreases while taking a GLP-1, making it easy to become dehydrated.
- Include strength training or resistance exercises to help preserve muscle mass.
GLP-1 medications can help you achieve health goals that once felt unattainable. But they work best when combined with healthy nutrition, dedicated lifestyle changes, and team-based medical care.
If you're thinking about taking a GLP-1 or are already taking one, work with a doctor or weight wellness expert. We can help you craft a plan tailored to your health needs today and plan for a healthier future.
To talk with an expert about medication changes and GLP-1s, make an appointment by calling 214-645-2800 or request an appointment online.
