How Effective Are GLP-1 Agnoists For Weight Loss?

Craig Primack, MD, FACP, FAAP, FOMA

Reviewed by Craig Primack, MD, FACP, FAAP, FOMA

Written by Lauren Panoff

Published 04/07/2024

If you’re like us, you may constantly hear new acronyms and wonder what they stand for. Well, if you’ve been wondering, “what does GLP-1 stand for,” wonder no longer. GLP-1 agonists, short for glucagon-like peptide-1 receptor agonists, have been in the spotlight lately as more people add them to their weight loss toolbelt — and for good reason, as these drugs are very effective.

So, what are GLP-1 receptor agonists? These medications were initially developed as type 2 diabetes drugs, but are becoming stars in obesity treatment.

The success of GLP-1 agonists for weight loss isn’t just anecdotal. While more research is always helpful, clinical studies continue to demonstrate that they can help you manage your weight. 

We’re looking at the available data supporting GLP-1 for weight loss, including how they work, potential side effects, alternatives and how to use them effectively. 

GLP-1s are popular for managing type 2 diabetes and supporting weight loss goals, but how does GLP-1 work?

The answer lies in how these medications affect glucose metabolism and appetite regulation. 

GLP-1 weight loss drugs are so effective because they mimic the GLP-1 hormone that your intestines naturally secrete when you eat. When you take GLP-1 medications, they bind to GLP-1 receptors on your pancreas, triggering the release of insulin. 

When you eat, you digest carbs into glucose, which circulates in your bloodstream. Insulin is needed to move this sugar into your tissues, where it can be used for energy. Basically, GLP-1s help get this process going without you eating carbs, so your body is using more of the glucose already in your blood.

GLP-1 agonists also decrease the production of glucagon (stored glucose), further reducing blood sugar levels. 

Furthermore, these weight loss medications slow down how quickly your stomach empties its contents. This helps minimize spikes in blood sugar and slows nutrient absorption. 

In addition to all these blood sugar-reducing properties, GLP-1 agonists make you feel fuller. This reduces your appetite, which can ultimately help you lose weight.

In addition to better blood sugar control and reduced body weight, GLP-1s help lower blood pressure, improve blood lipid disorders and reduce fatty liver.  Some may also lower the risk of heart attack, stroke and death for people who have heart disease and type 2 diabetes.

Some GLP-1s were approved for obesity 10-20 years ago, but many of us are just hearing about them now. 

Currently, the only FDA-approved GLP-1 medications for weight loss are the following injections:

Other GLP-1 agonists are FDA-approved for blood sugar management in type 2 diabetes but not for obesity, including:

  • Victoza® (liraglutide)

  • Trulicity® (dulaglutide)

  • Ozempic® (semaglutide) 

  • Byetta® (exenatide)

  • Mounjaro (tirzepatide)

However, some of these GLP-1s are being used off-label for this purpose, which means doctors are prescribing them for weight loss despite their lack of FDA approval for obesity. In most cases, they’ll be prescribed alongside diet and exercise.

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Good candidates for using GLP-1 for weight loss have a body mass index (BMI) of 30 kg/m2 or higher

BMI is a measure of body fat. For reference, a healthy BMI range is 18.5 to 24.9 kg/m2.

Alternatively, your doctor may recommend GLP-1s if your BMI is at least 27 kg/m2, but you also have weight-related health conditions like heart disease, sleep apnea, high blood pressure, high cholesterol or type 2 diabetes. 

How Effective are GLP-1s for Weight Loss?

GLP-1 agonists continue to garner attention for their success in helping people achieve their weight loss goals. And it’s not just anecdotal evidence — clinical trials have shown that GLP-1 medications for weight loss are more effective than placebo or other diabetes medications. 

What research specifically shows, time and time again, is that GLP-1 weight loss medications can target appetite reduction, enhance fullness, and slow digestion — all of which promote weight loss. 

But of course, not every medication works for everyone in the same way. For example, GLP-1 agonists are consistently more effective for weight loss among people who don’t have diabetes than for people with diabetes.

In one review of 14 studies, researchers found GLP-1 agonists led to an average weight loss difference of 4-6.2 percent in people with diabetes versus 6.1-17.4 percent in people without diabetes. Furthermore, semaglutide was more effective than liraglutide for chronic weight management. 

Because results may vary, it’s important to talk to your healthcare provider regarding the best GLP-1 for you. 

Safety and Potential Side Effects
Like any drug, GLP-1 agonists have potential side effects. The most common GLP-1 side effects are gastrointestinal, like nausea, vomiting, diarrhea, indigestion, abdominal pain and constipation. Some people may experience acute kidney injury from fluid loss if they’re experiencing long-term diarrhea.

Others report mild symptoms like dizziness, headaches, reactions at the injection site and nasal inflammation. 

Still, everyone responds differently to medications. If you experience GLP-1 agonist side effects, let your healthcare provider know so they can determine if you need a medication adjustment or alternative. 

You can also report side effects from using Ozempic to the FDA’s MedWatch Safety Information and Adverse Event Reporting Program.

Counterfeit Ozempic in the U.S.
In 2023, the U.S. Food and Drug Administration (FDA) learned about fake Ozempic entering the United States drug supply, likely taking advantage of GLP-1 shortages. Since then, thousands of units of the product — which are labeled with lot number NAR0074 and serial number 430834149057 — have been seized. 

The investigation is ongoing, but the analysis also found the needles with the drug were fake and could be unsterile. 

The bottom line? Only get Ozempic with a valid prescription from your healthcare provider and pick it up from a state-licensed pharmacy. 

Out of extra caution, check it for signs your Ozempic is counterfeit, such as the lot and serial numbers or anything else that looks suspicious. You can report any concerns to the FDA consumer complaint coordinator

If you don’t respond well to GLP-1 drugs for weight loss, there are alternatives to consider. 

One class of medications is called DPP-4 inhibitors. This includes drugs like Januvia® (sitagliptin) and Tradjenta® (linagliptin), which slow the breakdown of the GLP-1 produced in your body and extend its activity. DPP-4 inhibitors are generally well-tolerated but may not lead to as much appetite reduction or weight loss as GLP-1 agonists. 

Another option is a category called SGLT-2 inhibitors, which includes Jardiance® (empagliflozin) and Farxiga® (dapagliflozin). These increase the amount of glucose leaving your body when you pee, which lowers your blood sugar levels. 

Additional weight loss treatments are available through our personalized prescription program. One of these, a combination of naltrexone and bupropion, can help curb cravings and target patterns of binge eating by acting on the appetite and reward centers in your brain. 

Other options include metformin and topiramate. Metformin is a diabetes medication commonly used to reduce appetite, lower blood sugar levels and support weight loss. Topiramate also helps to suppress appetite and has been shown to reduce body fat mass.

If you’re unsure whether a GLP-1 alternative would be better for you, speak with your healthcare provider. You can also take our free custom weight loss medication quiz

GLP-1 agonists and other medications are effective tools for weight loss, but they’re just one piece of the puzzle. Drugs alone aren’t a long-term solution to healthy weight management. 

Pair medications with healthy lifestyle changes like: 

  • Regular exercise: Aim for at least 175 minutes of intensive physical activity per week for weight loss. This could include a combination of swimming, biking, high-intensity interval training (HIIT), sports and resistance training.

  • A nutrient-dense, calorie-reduced diet: Weight loss requires a calorie deficit, meaning you consume fewer calories than you burn. Typically, this is 500-750 calories below your estimated daily needs. Nutritional quality counts too, so prioritize plenty of fruits, vegetables, whole grains, nuts, seeds, legumes and lean proteins.  

  • Social support: Positive social support helps people reach their weight loss goals more successfully. Find yourself some cheerleaders and peers on a similar journey.

  • Better sleep: Getting better sleep is associated with more weight and fat loss among people trying to lose weight. Experts recommend seven to nine hours of sleep per night. 

GLP-1 agonists can help you reach your weight loss goals, but adopting habits like the above will provide health benefits for life — beyond reaching a number on the scale. 

If you need help getting started, find a registered dietitian and/or fitness expert to help you create an individualized action plan. 

GLP-1 medications for weight loss aren’t for everyone, but when used as directed, they’re an effective tool for the treatment of obesity. If you’re considering GLP-1s, keep these things in mind: 

  • They’re only one piece of the puzzle. GLP-1s should be combined with healthy lifestyle habits for long-term success. Prioritize nutrition, exercise, sleep and positive social support in addition to your prescribed meds. 

  • They may cause side effects. Every drug has potential downsides, including GLP-1s. While the most common ones are related to digestion, everyone responds differently. Report any concerns to your primary care provider. 

  • There are alternatives. GLP-1s not a good fit for you? Other weight loss medications like metformin, topiramate or a combo of naltrexone and bupropion may be appropriate. 

Ready to break the weight loss cycle? Start by taking our free weight loss assessment.

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