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Understanding semaglutide (GLP-1 RA): Are they the right choice for weight loss?

A person injecting semaglutide medication into their thigh.
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Health & Wellness

Semaglutide (GLP-1 receptor agonist) medications, marketed under names such as Ozempic® and Wegovy®, have made their way to your local pharmacy. These drugs aren’t just for celebrities anymore—more and more people are turning to the medication and others like it to help them lose weight.

But what are semaglutide (GLP-1 RA) drugs, and how do they work? Are they really a silver bullet for weight loss? And how can you tell if weight loss medication will work for you?

 

The diabetes drugs that are changing how we diet

Let’s start with the basics. Semaglutide  (GLP-1 RA) medications are a once-weekly injection prescribed to treat adults with type 2 diabetes.1 You read that right: It wasn’t originally designed as a weight loss drug at all.

Is semaglutide (GLP-1 RA) the same as drugs like Ozempic?

Brands like Ozempic® and Wegovy® are a semaglutide (GLP-1 RA).2 To understand how semaglutide (GLP-1 RA) medications work, we need to talk about the receptor in your body they’re mimicking: GLP-1.

GLP-1 is a naturally occurring hormone produced in your small intestine. It helps regulate your blood glucose levels. GLP-1 tells your pancreas to produce insulin while stopping your body from increasing your blood sugar levels. At the same time, it slows down how quickly your stomach empties and sends signals to your brain that make you feel full.

GLP-1 is really good at its job. The only problem: the effects don’t last very long. That’s where semaglutide drugs come in. They’re part of a class of medications known as GLP-1 receptor agonists, or GLP-1 RAs. They are designed to do everything the GLP-1 hormone does, but they last longer.

GLP-1 is a naturally occurring hormone that produces insulin and stops your blood sugar levels from increasing. It also helps you feel full, so you don’t want to eat as much.

How do semaglutide (GLP-1 RA) drugs help you lose weight?

Remember, GLP-1 RAs were designed to treat type 2 diabetes. Weight loss began as a side effect because the drug convinces your brain that you’re full more quickly and for longer periods of time than usual. This side effect helped the drug soar in popularity, even though Ozempic hasn’t been approved by the FDA for weight loss.1 Some doctors prescribe it off-label for patients looking to lose weight. However, the FDA has approved a similar semaglutide (GLP-1 RA) injection for weight loss: Wegovy.3

Even though many aren’t approved as weight loss drugs, semaglutide (GLP-1 RA) has proven weight loss effects. In fact, some studies found that semaglutide (GLP-1 RA) medications helped people lose an average of 9%-17% of their body weight in a little over a year.4

 

The side effects of semaglutide (GLP-1 RA)

So, what’s the catch? Some people using GLP-1 RAs have reported side effects. The most common include nausea, vomiting, diarrhea, abdominal pain, and constipation. A few more serious side effects, like pancreatitis and thyroid C-cell tumors, did appear in some trials, but more testing is needed.1

If you start taking a semaglutide (GLP-1 RA), you’ll also need to be mindful of how they may interact with other medications. GLP-1 RAs can slow how your body absorbs other drugs. Researchers are still looking into whether this means certain oral medications won’t be as effective.1 Make sure to review your medications with your doctor before taking a semaglutide (GLP-1 RA).

More to learn about the effects of semaglutide (GLP-1 RA)

Science is still learning about how semaglutide (GLP-1 RA) drugs affect the body, including how they may impact the way you respond to food. A 2020 study found that people taking a semaglutide (GLP-1 RA) reported a lower preference for high-fat foods.5 A 2024 study suggests that semaglutide (GLP-1 RA) drugs may lower your cravings for sweet foods by improving taste sensitivity, changing the gene expression on your tongue that’s responsible for taste perception, and even changing the way your brain responds to sweet tastes.6

Do you need lab testing while on a semaglutide (GLP-1 RA)?

Testing can monitor potential side effects and measure how your weight loss is reducing your chronic disease risk over time. Testing looks at biomarkers associated with thyroid, heart, kidney, and liver health, along with your diabetes risk, and measures how these levels change as you lose weight. Talk to your doctor about the following tests:

Life after weight loss medications

Despite their effectiveness, only about a third of people prescribed a semaglutide (GLP-1 RA) stay on the drugs for more than a year.7 The side effects contribute to that number, but they aren’t the only issue. Semaglutide (GLP-1 RA) medications are expensive: the drugs can cost around $1,000 per month, and they are not always covered by health insurance.8 Even if you can afford treatment, getting the drugs is another story. Because of their popularity, many GLP-1 RAs like Ozempic and Wegovy are experiencing supply shortages.9

Medication isn’t enough for long-term weight loss

What happens to those two-thirds of people who stopped taking this medication? One study found that a year after stopping treatment, participants gained about 67% of the weight back.10

This means that semaglutide (GLP-1 RA) drugs are not silver bullets for sustained weight loss. But they can help you reach a better weight baseline. If you really want long-lasting weight loss, you’ll need to pair the medication with healthy lifestyle changes like diet and exercise.

Will a semaglutide (GLP-1 RA) work for you?

Most people who take semaglutide (GLP-1 RA) medications lose weight. But the drugs aren’t effective for about 14% of people who try them.11 For these people, that’s a lot of wasted time and expense (not to mention the discomfort of any side effects) for a drug that doesn’t work.

What if there were a better way to tell if weight loss medication was going to work for you without the trial and error? That’s where researchers hope precision medicine will one day be able to help.

Precision medicine pinpoints the right treatment for you based on your unique biological makeup. This is more personalized than the traditional approach of recommending a treatment to a large group of people based on broad factors.

Researchers are currently trying to pin down the biomarker signatures that indicate if a person will respond well to GLP-1 RAs.12 Once they identify such factors, testing will be able to tell you if you have these biomarkers. If you do, these medications will be more likely to work for you. If you don’t, you and your doctor can look for other ways of helping you lose weight.

If you're intrigued by what weight loss medication could mean for you, the best path forward is to talk to your doctor. Together, you can create a plan of action to help you reach and maintain a healthy weight.

References

  1. US Food and Drug Administration. Highlights of prescribing information. Revised December 2017. Accessed June 4, 2024. https://www.accessdata.fda.gov/drugsatfda_docs/label/2017/209637lbl.pdf
  2. National Library of Medicine. Semaglutide injection. Revised April 20, 2024. Accessed June 4, 2024. https://medlineplus.gov/druginfo/meds/a618008.html
  3. US Food and Drug Administration. FDA approves new drug treatment for chronic weight management, first since 2014. June 4, 2021. Accessed June 4, 2024. https://www.fda.gov/news-events/press-announcements/fda-approves-new-drug-treatment-chronic-weight-management-first-2014
  4. Chao AM, Tronieri JS, Amaro A, et al. Clinical insight on semaglutide for chronic weight management in adults: patient selection and special considerations. Drug Des Devel Ther. 2022;16:4449-4461. doi: 10.2147/DDDT.S365416
  5. Gibbons C, Blundell J, Hoff ST, et al. Effects of oral semaglutide on energy intake, food preference, appetite, control of eating and body weight in subjects with type 2 diabetes. Diabetes Obes Metab. 2021;23:581–588. doi: 10.1111/dom.14255
  6. Endocrine Society. GLP-1 has the power to change taste sensitivity in women with obesity. Newswise. May 29, 2024. Accessed June 26, 2024. https://www.newswise.com/articles/view/811572/?sc=mwhr&xy=10049345
  7. Terhune C. Exclusive: Most patients using weight-loss drugs like Wegovy stop within a year, data show. Reuters. July 11, 2023. Accessed June 4, 2024. https://www.reuters.com/business/healthcare-pharmaceuticals/most-patients-using-weight-loss-drugs-like-wegovy-stop-within-year-data-show-2023-07-11/
  8. Kolata G. Ozempic and Wegovy don’t cost what you think they do. The New York Times. October 22, 2023. Accessed June 4, 2024. https://www.nytimes.com/2023/10/22/health/ozempic-wegovy-price-cost.html
  9. ASHP Foundation. Semaglutide injection. June 2, 2024. Accessed June 4, 2024. https://www.ashp.org/drug-shortages/current-shortages/drug-shortage-detail.aspx?id=813&loginreturnUrl=SSOCheckOnly#:~:text=Reason%20for%20the%20Shortage,2%20mg/1.5%20mL%20presentation
  10. Wilding JPH, Batterham RL, Davies M, et al. Weight regain and cardiometabolic effects after withdrawal of semaglutide: the STEP 1 trial extension. Diabetes Obes Metab. 2022;24(8):1553-1564. doi: 10.1111/dom.14725
  11. Mosenzon O, Garvey WT, Hesse D, et al. Clinically relevant weight loss is achieved independently of early weight loss response to once-weekly subcutaneous semaglutide 2.4 MG (STEP 4). J Endocr Soc. 2021 May 3;5(Suppl 1):A7. doi: 10.1210/jendso/bvab048.013
  12. Formichi C, Fignani D, Nigi L, et al. Circulating microRNAs signature for predicting response to GLP1-RA therapy in type 2 diabetic patients: a pilot study. Int J Mol Sci. 2021;22(17):9454. doi: 10.3390/ijms2217945
Page Published: August 30, 2024

The Quest Editorial Team

Contributors:
Y. Fesko, MD
Vice President of Medical Affairs
Internal Medicine, Hematology, Oncology

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