Can you give an overview of what GLP-1s are and how they work?
GLP-1 is a natural hormone made by the intestine. It essentially tells your body that you just ate and food is on its way.
Medicines like semaglutide are medications that act like this natural hormone. People may have also heard of the drug tirzepatide (sold under the brand names Zepbound and Mounjaro), which mimic both GLP-1 and another intestinal hormone called gastric inhibitory polypeptide (GIP).
These medicines do several things. They help the body get ready for the carbohydrates in a meal, they help the blood sugar not rise so much after eating, and they tell the body that you’ve already eaten so that you feel full and eat less.
What are the conditions these drugs are intended to treat?
The older versions of these drugs were initially approved for the treatment of diabetes. Then, we found that they produce weight loss, and with the newer, more potent versions of these medications, weight loss has become a prominent reason to use them. Now, both semaglutide and tirzepatide are FDA-approved both for diabetes and weight loss.
Generally, what are the indications for a GLP-1 prescription?
Regarding weight loss, the FDA has approved these drugs for people whose body mass index (BMI) is greater than 30 kg/m2, or they have a BMI that is greater than 27 and have a weight-related health problem, such as high blood pressure, sleep apnea, or pre-diabetes.
What is a compounded GLP-1, and how does it differ from the FDA-approved GLP-1s?
Drug companies invest a lot of money into developing and testing medications to get approved by the FDA. The company has patent rights to the medications they invented, and those rights extend to the drug compound itself. For a number of years, while the patent is in effect, no one can manufacture and sell that compound except the company that invented it — unless it is in shortage.
Ultimately, compounding means that the company making a drug is not the original inventor of the drug. These compounded drugs have not been studied by the FDA for safety or efficacy. Although the FDA has the authority to provide oversight and demand information from the companies that manufacture and sell compounded forms of FDA-approved medications, the agency doesn’t have enough staff to monitor all the compounding that happens.
Some compounding pharmacies do a good job of making sure that they’re purchasing the raw material from a legitimate manufacturer with strong quality control practices, and they use care to prepare the medication for sale and administration — but other compounding pharmacies may not.
Compounded GLP-1s are now banned. Can you explain why that is?
The demand for semaglutide and tirzepatide was so high that the FDA declared a shortage of them, which made it legal for generic drug companies and compounding pharmacies to prepare and distribute these drugs.
Then, the FDA declared in late 2024 that tirzepatide was no longer in shortage, and it determined that semaglutide was no longer in shortage in early 2025. Legally, that compounding now has to stop — no compounders should be selling these compounded copies of semaglutide or tirzepatide anymore. However, there have been a lot of lawsuits pushing against this, so some companies are still producing and selling these drugs.
The FDA warns that compounded GLP-1s can be risky. What are the potential risks of compounded obesity medications?
It depends on where you get them from. If you get a compounded medication from a very reputable source, they should be able to tell you where it was manufactured and prepared and provide written evidence.
The biggest concern is that you could potentially get a product that has something harmful in it, but that is unlikely to happen. What is more likely is that you are not getting the right amount or concentration of the drug — you either get too little or too much, which could lead to side effects. With these drugs, the main side effects are nausea, vomiting, constipation, diarrhea, and other gastrointestinal issues.
Some people seek out compounded GLP-1s because they do not qualify for a prescription but want to lose weight. Are there any potential harms to someone who has a relatively healthy weight using compounded GLP-1s?
Every medicine has risks and benefits. If someone is healthy and not obese, then the benefits are less, but the risks are the same. These medicines can have a lot of side effects, including making people not hungry to the point that they don’t get enough calories and may experience vitamin deficiencies and lose lean body mass, including muscle. I think older people with minimal weight to lose could be more at risk of losing a clinically important amount of lean body mass.
It’s important to keep in mind that the medicine only works as long as you take it. If you think of it as a short-term tool, then what will likely happen is you will lose the weight, and once you stop taking the medicine, you will regain it. This up-and-down effect is not ideal.
If you’re someone who is looking to lose weight quickly, I urge you to examine what you are really trying to accomplish. What do you think about your own body, and can you be more accepting of yourself? In general, we should think about weight as a long-term issue — not a short-term issue.
With the new year, weight loss is a common resolution. In light of this topic, what would you like for people with this resolution to keep in mind?
For people whose weight is high and they have health problems related to it, talking to your doctor about obesity medications can help you learn more about whether these medications might be a good option for you. Brand name GLP-1 medications and other obesity medications that are prescribed by doctors can be helpful for people who have health problems related to their weight. Prices of these drugs should decrease over time, and there are more than 100 new medications for the treatment of obesity that are coming down the pipeline. I think it’s a very hopeful time for people who struggle with their weight.
If you are someone with modestly increased weight but are otherwise healthy, I think it’s important that you consider what you might change about your diet and physical activity to promote good health, as opposed to looking for a short-term tool to make the number on the scale go down quickly.
In general, get information from a doctor as opposed to online. I know it can be difficult to talk about because weight is stigmatized, and many people get criticized for it or feel internalized shame, though they shouldn’t. This is a biological problem, just like high blood pressure or high blood sugar. We don’t blame people for high blood pressure or cancer. Obesity is now viewed as a chronic metabolic health problem and not a lifestyle choice. As a physician, my job is to talk with patients to understand their goals and use my medical knowledge to help them make choices that promote their long-term health goals.
