Semaglutide, Explained

How does semaglutide work for weight loss?

Semaglutide imitates GLP-1, a hormone your gut releases after you eat. It slows stomach emptying, signals fullness to the brain, and helps regulate blood sugar. The practical result is that most people feel satisfied on less food and think about food less often. This is why it is a prescription medication, not a cosmetic supplement. The FDA cleared semaglutide for weight management in adults with a BMI of 30 or higher, or 27 or higher with at least one weight-related condition such as high blood pressure, type 2 diabetes, or high cholesterol.

What are the FDA-approved forms, and how do they differ?

Semaglutide is the molecule; the brands are different formulations and doses approved for different uses. Compounded semaglutide is a separate category entirely, covered in our compounded vs brand guide.

Ozempic is frequently prescribed off-label for weight loss because it is the same molecule as Wegovy, just at diabetes-labeled doses. Oral semaglutide now comes in two forms: Rybelsus (approved for diabetes) and, as of 2026, an oral Wegovy tablet approved for weight loss. On March 8, 2024, the FDA also approved Wegovy to reduce the risk of major adverse cardiovascular events in adults with established cardiovascular disease and either obesity or overweight, based on the SELECT trial.

How is semaglutide dosed and titrated?

Semaglutide is started low and increased slowly to limit side effects. The injectable schedule steps up roughly every four weeks: 0.25 mg, 0.5 mg, 1.0 mg, 1.7 mg, then the 2.4 mg maintenance dose. The full ramp typically takes about 16 to 20 weeks. Oral semaglutide is dosed differently by product. The diabetes tablet (Rybelsus) titrates from 3 mg to 7 mg to 14 mg, while the oral Wegovy tablet for weight loss follows its own labeled schedule, and oral semaglutide is taken on an empty stomach with a small amount of water. A responsible clinic follows a documented titration schedule rather than jumping you to a high dose to accelerate results.

What does the trial evidence actually show?

Semaglutide has one of the largest evidence bases of any weight-loss medication. Two trials anchor most of what is known:

• STEP 1 (2021, NEJM): 1,961 adults over 68 weeks. Semaglutide 2.4 mg produced 14.9% average body weight loss versus 2.4% with placebo, and 86% of participants lost at least 5% of body weight.
• SELECT (2023, NEJM): In adults with overweight or obesity and established cardiovascular disease, semaglutide reduced the risk of major adverse cardiovascular events by 20%. This supported the FDA's 2024 approval of Wegovy for cardiovascular risk reduction.

Two caveats matter. First, real-world results tend to run below trial averages, largely because trial participants get structured support and closer follow-up. Second, weight regain is well documented: STEP 1 extension data showed a large share of lost weight returns within about a year of stopping. That is why a maintenance and off-ramp plan is something to discuss with your provider before you start, not after.

What are the side effects and contraindications?

The most common side effects are gastrointestinal. In the STEP 1 titration phase, roughly 44% of participants reported nausea, and vomiting, diarrhea, constipation, and abdominal pain were also common. These usually cluster around dose increases and ease over time.

The serious warnings are more important than the common ones. Semaglutide carries a boxed warning for thyroid C-cell tumors seen in rodent studies. It is contraindicated in people with a personal or family history of medullary thyroid carcinoma (MTC) or multiple endocrine neoplasia type 2 (MEN 2). It should not be used in pregnancy. Other risks include pancreatitis and gallbladder disease. A legitimate clinic screens for all of these before prescribing. None of this is medical advice; it is what a licensed provider should review with you.

What does semaglutide cost, brand versus compounded?

Cost is where the brand-versus-compounded decision usually gets made, and it is also where clinics differ most in transparency.

Insurance coverage is inconsistent: many commercial plans cover semaglutide for diabetes (Ozempic) but fewer cover it for obesity (Wegovy). Compounded pricing is lower, but availability tightens as the FDA resolves brand-name shortages, and the lower price reflects the absence of FDA oversight, not a better deal on the same product. For a fuller breakdown, see our GLP-1 cost guide.

How should you choose a semaglutide clinic?

The medication is only as safe as the clinic behind it. Whether a provider prescribes brand-name or compounded semaglutide, the questions that matter are the same: Is there a named, licensed prescriber? Is there a real clinical evaluation before a prescription is written? Are contraindications screened? Is the medication source disclosed, with a named pharmacy? Are baseline labs required? Is pricing published and itemized?

Those are the exact dimensions GLP-1 Grades scores against. See our grading methodology for how each dimension is weighted, and compare graded clinics side by side. Many semaglutide providers are telehealth-based; our telehealth guide covers what to check there.

This guide is informational and is not medical advice. It does not recommend taking any medication. Decisions about semaglutide should be made with a licensed healthcare provider who knows your history.