GLP-1 Medications for Weight Loss: How They Work, Benefits and Side Effects

GLP-1 medications are among the medicines with the largest average weight loss in clinical trials. Here is how they work, what results are realistic, which side effects to watch for, and how to start safely with a physician in Lehi, Utah or by secure video.

How GLP-1 medications work

GLP-1 (glucagon-like peptide-1) is a hormone your gut releases after you eat. GLP-1 medications act on the same receptors to help you feel full sooner and stay full longer, quiet constant “food noise”, slow how quickly the stomach empties, and improve blood sugar control. Tirzepatide also acts on a second hormone receptor (GIP).

Semaglutide

Wegovy weekly injection, and the Wegovy pill taken once daily (FDA-approved December 2025).

Tirzepatide

Zepbound weekly injection, available as pens or as lower-cost single-dose vials. See the real monthly cost without insurance.

Mounjaro (tirzepatide) and Ozempic (semaglutide) are approved for type 2 diabetes; using them for weight loss alone is off-label.

Benefits

Meaningful weight loss. In the main trials, which combined medication with a reduced-calorie diet and more physical activity, average weight loss was about 15% with Wegovy injections (about 2% with placebo) and 15% to 21% with Zepbound (about 3% with placebo) over 68 to 72 weeks. These are averages, not a promise; individual results vary.
Heart health. Wegovy is also FDA-approved to lower the risk of heart attack, stroke and cardiovascular death in adults with established heart disease and obesity or overweight.
Sleep apnea. Zepbound is also FDA-approved for moderate to severe obstructive sleep apnea in adults with obesity.
Blood sugar, blood pressure and cholesterol often improve as weight comes down, which we follow at your visits.
Long-term treatment. Obesity is a chronic condition. When these medicines are stopped, much of the lost weight usually returns, so plan with your physician for long-term use or a careful step-down.

Common side effects

Most side effects come from the stomach and bowels and are worst when starting or raising a dose: nausea, diarrhea, vomiting, constipation, stomach pain, indigestion, burping, bloating and tiredness. We raise doses slowly and adjust your plan if side effects get in the way. For constipation, see our constipation guide.

Serious side effects to know about

Thyroid C-cell tumors: seen in rodents; not known in people. Do not use if you or a family member has had medullary thyroid cancer or if you have MEN 2.
Pancreatitis: severe stomach pain that won’t go away, sometimes spreading to the back.
Gallbladder problems: including gallstones, especially with rapid weight loss.
Kidney problems from dehydration if vomiting or diarrhea is severe. Drink fluids, and call us if you can’t keep liquids down.
Severe stomach problems: not recommended for people with severe gastroparesis (very slow stomach emptying). Get urgent care for severe or constant stomach pain.
Low blood sugar when combined with insulin or sulfonylureas.
Serious allergic reactions: swelling of the face or throat, trouble breathing or a severe rash; call 911.
Diabetic eye disease: if you have diabetic retinopathy, tell us; rapid improvement in blood sugar can temporarily worsen it, so an eye check may be recommended.
Anesthesia: these medicines slow stomach emptying; tell any surgical or endoscopy team you take one.
Birth control: tirzepatide can make birth-control pills less effective. Switch to a non-oral method, or add a backup method such as condoms, for 4 weeks after starting and for 4 weeks after each dose increase.
Muscle loss: losing weight quickly can also reduce muscle. We set protein targets with you and encourage strength training.

Who may be a candidate

These medications are FDA-approved for adults with a body mass index (BMI) of 30 or higher, or 27 or higher with a weight-related condition such as high blood pressure, type 2 diabetes, high cholesterol or sleep apnea. They are not for use during pregnancy. At your first visit we review your history, medications and labs and decide together whether a GLP-1, another option such as phentermine, or a combined plan fits you best.

Already had weight-loss surgery?

Weight regain after a sleeve or bypass is common, and GLP-1 medicines can help. Read GLP-1s for weight regain after bariatric surgery, written by a bariatric surgeon.

Staying on track between visits

Readings from a smart scale, glucose sensor or home blood-pressure cuff can show trends between visits and help your physician decide on next steps. See virtual monitoring.

Ready to talk it through?

Book a visit in person in Lehi or by secure video. New weight-loss patient visit $199; monthly follow-up visit $149. Medication is billed separately by your pharmacy. See all prices.

Book a Weight-Loss Visit

Frequently asked questions

What is a GLP-1 medication?

A GLP-1 receptor agonist is a medicine that acts like a natural gut hormone that helps control appetite and blood sugar. Semaglutide (Wegovy) is a GLP-1 medicine; tirzepatide (Zepbound) acts on both the GLP-1 and GIP hormone receptors.

How much weight do people lose on GLP-1 medications?

In the large clinical trials, which combined medication with diet and activity changes, adults lost on average about 15% of body weight over 68 weeks with Wegovy injections and about 15% to 21% over 72 weeks with Zepbound, depending on dose. These are averages; individual results vary.

What are the most common side effects?

Nausea, diarrhea, vomiting, constipation, stomach pain, indigestion and fatigue are the most common. They are usually worst when starting or increasing a dose, which is why doses are raised slowly.

Do I need insurance?

No. Restoration Health is self-pay: a new weight-loss patient visit is $199 and monthly follow-up visits are $149. The medication is billed separately by your pharmacy, and both manufacturers sell self-pay options.

Do you prescribe compounded semaglutide or tirzepatide?

We prescribe FDA-approved, brand-name medications and help you compare their self-pay prices.

Related guides

Reviewed by a fellowship-trained physician at Restoration Health Medical Group. Last updated October 2026. This page is general information, not medical advice for you; whether a medication is right for you is decided at your visit. For a medical emergency, call 911.