How GLP-1 Medications Work: A Complete Guide

GLP-1 receptor agonists have become an important category in weight-management care. On Varus, that includes Foundayo (orforglipron), an FDA-approved oral option, and oral semaglutide, the branded Wegovy pill. Compounded semaglutide is also available by consultation in limited patient-specific circumstances. All work by mimicking or activating a hormone pathway your body already uses in appetite regulation.

What is GLP-1?

GLP-1 (glucagon-like peptide-1) is an incretin hormone released by your gut after eating. It signals your brain that you're full, slows gastric emptying, and improves insulin sensitivity. In most people, this natural signal is modest and short-lived.

GLP-1 receptor agonists amplify this signal, which is why clinicians use them alongside diet and exercise in appropriate patients.

How GLP-1 Medications Reduce Appetite

These medications act on the hypothalamus, the brain region responsible for appetite regulation. They can reduce appetite and food cravings for some patients.

They also slow gastric emptying, meaning food stays in your stomach longer. This physical fullness, combined with the neurological appetite suppression, produces a natural reduction in caloric intake.

Injectable vs. Oral GLP-1s

Until recently, all GLP-1 medications were injectable peptides. Semaglutide is typically administered once weekly via a subcutaneous injection, and is now also available as oral semaglutide 25 mg. The newer option, Foundayo (orforglipron), is a small molecule taken as a daily pill. Foundayo is indicated along with diet and exercise for adults with obesity or overweight with a weight-related medical condition -- it is not for cosmetic weight loss.

The key difference: orforglipron is not a peptide, so it survives stomach acid and doesn't require the special formulation of oral semaglutide (Rybelsus). It can be taken any time of day, with or without food, and doesn't require refrigeration.

What the Clinical Evidence Shows

In the STEP clinical trial program of branded semaglutide (Wegovy), semaglutide 2.4 mg weekly was associated with average weight loss of about 15% over 68 weeks. The SELECT cardiovascular outcomes trial of branded semaglutide also reported a 20% reduction in major adverse cardiovascular events.

In the ATTAIN-1 trial, adults without diabetes taking Foundayo along with diet and exercise achieved average weight loss of 7.4% (17.2 lbs) at 5.5 mg, 8.3% (18.9 lbs) at 9 mg, and 11.1% (24.9 lbs) at 17.2 mg over 72 weeks, compared to 2.1% (5.3 lbs) for placebo. In a separate 72-week study of adults with type 2 diabetes, average weight loss was 5.1% (11.7 lbs) for 5.5 mg, 7% (15.9 lbs) for 9 mg, 9.6% (21.2 lbs) for 17.2 mg, and 2.5% (5.9 lbs) for placebo. Individual results may vary.

Who Should Consider GLP-1 Therapy

GLP-1 medications are generally prescribed for adults with a BMI of 30 or greater (obesity), or a BMI of 27 or greater with at least one weight-related health condition such as type 2 diabetes, hypertension, or high cholesterol.

They are not appropriate for everyone. Patients with a personal or family history of medullary thyroid carcinoma (MTC) or Multiple Endocrine Neoplasia syndrome type 2 (MEN2) should not use GLP-1 receptor agonists.

Common Side Effects

The most common side effects are gastrointestinal: nausea, vomiting, diarrhea, and constipation. These tend to be most pronounced during dose escalation and typically improve over time. A gradual titration schedule helps minimize these effects.

The Bottom Line

GLP-1 medications can be an important part of obesity treatment for the right patients. Combined with lifestyle modifications, they may produce clinically meaningful results, but they also require careful safety screening and ongoing clinician oversight.

As with any medical treatment, the decision should be made in consultation with a licensed healthcare provider who can evaluate whether GLP-1 therapy is appropriate for your specific situation. If you are reading about compounded semaglutide, remember that it is not FDA-approved and should not be assumed to perform identically to the branded products studied in clinical trials.