With the current explosion in access to GLP-1 medications and the social media buzz around it, there is a lot of conversation being stirred up around its effectiveness and potential as a treatment for weight loss. This month’s newsletter will dive into this class of medications, look at what the research suggests for usage, and clear up some confusion.
What are GLP-1 drugs?
Let’s start off with understanding what GLP-1 agonist drugs are and what they do. Essentially, Glucagon-like peptide-1 (GLP-1) agonist drugs are a class of medication that have been approved by the FDA for treatment of Type 2 Diabetes (T2DM). However, you have likely been introduced to GLP-1s as a “weight-loss drug” and have seen many begin treatment for solely that reason. A few of the different types of GLP-1s have been FDA-approved for weight management, though there are certain requirements that a person must meet to be eligible – but more on that later!
Currently, there are five different formulations of GLP-1s that are FDA-approved:
- Dulaglutide (Trulicity)
- Liraglutide (Victoza, Saxenda)
- Semaglutide (Ozempic, Wegovy, Rybelsus)
- Exenatide (Byetta, Bydureon)
- Tirzepatide (Mounjaro, Zepbound)
While all GLP-1s can have the side effect of weight loss, only 3 brand-name drugs (Saxenda, Wegovy, Zepbound) have been FDA-approved for use specifically for weight loss purposes. These drugs are currently only available in injectable form. Overall, dosage for GLP-1s can vary, ranging from daily to weekly, depending on the titration.
How do they work?
GLP-1 agonists work by helping the body respond to the presence of glucose, or sugar, in the bloodstream. When we eat, our body turns food into sugar (called glucose), which goes into our blood. Normally, our body sends out a helper called insulin to move that sugar from the blood into our muscles and other places where it’s needed for energy. In people with type 2 diabetes, the body doesn’t respond to sugar as well as it should. It doesn’t send out enough insulin, or the insulin doesn’t work properly. That means sugar stays in the blood too long, which can cause health problems. This is where GLP-1 medicines come in.
They help the body in a few smart ways:
- They tell the body to release more insulin when sugar levels go up.
- They stop the liver from making too much sugar.
- They help muscles absorb sugar better, so it doesn’t stay in the blood.
- They can also lower blood pressure and cholesterol, and even reduce appetite, which can help with weight loss.
Who can be prescribed GLP-1 drugs?
As mentioned earlier, these drugs are most often prescribed for people with T2DM who are having trouble managing their BG or A1C levels with first-line treatments, like metformin, or are unable to take those treatments for other reasons. For prescriptions particularly intended for weight loss, there are two criteria that individuals must meet:
- Have a BMI of 25 or greater
AND
- Currently have or be at risk for developing a chronic illness, such as diabetes, heart failure or other cardiovascular diseases
Additionally, people may be considered for GLP-1 treatments under several other conditions:
- Individuals with obstructive sleep apnea (OSA) that is related to, or could be improved by, weight management.
- Those with polycystic ovarian syndrome (PCOS) are often prescribed GLP-1s to help reduce their risk of developing T2DM.
- Individuals with a history of cardiovascular or kidney disease may also be considered for these treatments, due to the potential benefits in reducing the risk of cardiovascular events and slowing the progression of chronic kidney disease.
It’s important to note that insurance coverage for these treatments can be complex. You should discuss with your medical provider whether, and for how long, these treatments might be covered.
So what’s the catch?
As with all medications, GLP-1s come with their fair share of side effects. Some of the short-term side effects of these treatments include nausea, vomiting, diarrhea, heartburn, headaches, and dizziness. Additionally, itching and redness at injection sites is not uncommon. While long-term studies on these drugs are limited because of their recency, there is data to suggest an increased risk of osteoporosis, and gallbladder or kidney disorders. Finally, these drugs are not recommended for individuals with a history of pancreatitis, thyroid cancer, or women who are pregnant or lactating.
How can diet and exercise help?
The good news is that sustained nutrition and exercise are known to help offset some of the side effects of GLP-1 medications. With how effective GLP-1s are at reducing appetite, nutrition support can be vital in making sure that you are still eating enough to maintain your bodily functions. Furthermore, nutrition and exercise support can work to ensure that your bones and muscles retain their function and strength; GLP-1s are not known to specifically target fat cells, so it is not uncommon for users to lose muscle mass as they shed the pounds. Current research shows that GLP-1s have the best overall health outcomes when taken in combination with protective measures like exercise and dietary changes.
In summary, GLP-1 agonists are a class of drugs that have been FDA-approved for T2DM management. In some cases, approval for usage of GLP-1s in obesity management can be obtained if a patient meets certain criteria. These drugs work by stimulating insulin secretion, increasing the amount of sugar your muscles absorb, and reducing appetite. So, are GLP-1 medications for you? As always, talk to your doctor about the risks and benefits of starting a GLP-1 agonist. If you are already on a GLP-1 agonist, make sure you continue to follow up with both your doctor and health coaches to monitor your progress and overall health.
Author: Hafsah Khan, Dietetic Intern
References
Collins L, Costello RA. Glucagon-Like Peptide-1 Receptor Agonists. [Updated 2024 Feb 29]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK551568/
Jensen, S. B. K., Sørensen, V., Sandsdal, R. M., Lehmann, E. W., Lundgren, J. R., Juhl, C. R., Janus, C., Ternhamar, T., Stallknecht, B. M., Holst, J. J., Jørgensen, N. R., Jensen, J. B., Madsbad, S., & Torekov, S. S. (2024). Bone Health After Exercise Alone, GLP-1 Receptor Agonist Treatment, or Combination Treatment: A Secondary Analysis of a Randomized Clinical Trial. JAMA network open, 7(6), e2416775. https://doi.org/10.1001/jamanetworkopen.2024.16775
Silver, H. J., Olson, D., Mayfield, D., Wright, P., Nian, H., Mashayekhi, M., Koethe, J. R., Niswender, K. D., Luther, J. M., & Brown, N. J. (2023). Effect of the glucagon-like peptide-1 receptor agonist liraglutide, compared to caloric restriction, on appetite, dietary intake, body fat distribution and cardiometabolic biomarkers: A randomized trial in adults with obesity and prediabetes. Diabetes, obesity & metabolism, 25(8), 2340–2350. https://doi.org/10.1111/dom.15113