Semaglutide (Wegovy, Ozempic) for weight loss: uses, risks and what to ask a clinic

Semaglutide is a prescription injectable drug. One brand, Wegovy, is FDA-approved for weight management, and it is meant to be used with a reduced-calorie diet and more physical activity.¹

This page covers what the approved label says, what the FDA says about copies of the drug, and what to ask a clinic that offers it. It gives no dose. Whether it is right for you is a question for a doctor who knows your health.

What it is

Semaglutide is a GLP-1 receptor agonist, and the active ingredient in two brands: Wegovy and Ozempic. Wegovy is the FDA-approved semaglutide injection for weight management.¹

The label lists these uses, always in combination with a reduced-calorie diet and increased physical activity. The weight uses start at age 12 and over.¹

The liver use was approved on an accelerated basis, and the label says continued approval may depend on a confirmatory trial. The label also covers a tablet form; this page covers the injection.¹

The label doesn't say semaglutide is a cosmetic treatment, and it doesn't describe it as a med spa service.¹ If a clinic offers it, the questions below apply.

Ozempic

Ozempic is also semaglutide, with a different label. It lists type 2 diabetes uses in adults: improving blood sugar control, lowering the risk of major cardiovascular events in people with type 2 diabetes and established cardiovascular disease, and lowering the risk of kidney decline, end-stage kidney disease and cardiovascular death in people with type 2 diabetes and chronic kidney disease.⁴ Weight management is not among its listed uses.⁴ It carries the same boxed warning on thyroid tumors seen in rodents.⁴

Who should not use it

The label has a boxed warning, its strongest kind. In rodents, semaglutide caused thyroid C-cell tumors. It is unknown whether it does in humans.¹ The label says Wegovy is contraindicated, meaning it must not be used, in people with a personal or family history of medullary thyroid carcinoma or the genetic condition MEN 2, and in people who have had a serious allergic reaction to semaglutide.¹

Tell a prescriber your full history before any GLP-1 drug, including your family's.

On pregnancy, the label says Wegovy may cause fetal harm.¹ It tells prescribers to stop it when pregnancy is recognized, and at least 2 months before a planned pregnancy, because of how long the drug stays in the body.¹ Tell your prescriber if you are pregnant, planning a pregnancy or breastfeeding.

Side effects

Most side effects are in the stomach and gut. The Wegovy label pools three placebo-controlled trials: 2,116 adults took Wegovy for up to 68 weeks and 1,261 took placebo. Nausea was reported by 44% on Wegovy and 16% on placebo, diarrhea by 30% and 16%, vomiting by 24% and 6%, constipation by 24% and 11%, abdominal pain by 20% and 10%, headache by 14% and 10%, fatigue by 11% and 5%, and hair loss by 3% and 1%.¹ The label also lists dysesthesia (unusual skin sensations), indigestion, dizziness, bloating, belching, gas, gastroenteritis and reflux, and, in people with type 2 diabetes, low blood sugar.¹

In those trials, 6.8% of people on Wegovy and 3.2% on placebo stopped treatment permanently because of side effects. Nausea (1.8% vs 0.2%), vomiting (1.2% vs 0%) and diarrhea (0.7% vs 0.1%) were the most common reasons.¹ The label says rates from one drug's trials can't be directly compared with those of another drug, and may not reflect what happens in practice.¹

The label's warnings and precautions name more serious problems.¹

The label also warns that a person who is going to have general anesthesia or deep sedation may be at risk of food or liquid entering the lungs. It tells patients to inform their providers of any planned surgery or procedure.¹

Compounded semaglutide

Some clinics sell semaglutide made by a compounding pharmacy, not the approved Wegovy. The FDA says compounded drugs are not FDA-approved and that it does not review them for safety, effectiveness or quality before they are marketed.²

The FDA's position is that compounded drugs should be used only when a patient's medical needs can't be met by an approved drug.² It has also reported cases of harm:

- Adverse events, some needing hospitalization, that may be related to dosing errors with compounded injectable semaglutide, from patients measuring the wrong dose and from providers miscalculating it.² - Reports of patients prescribed doses beyond what the approved label provides, with symptoms including nausea, vomiting, diarrhea, abdominal pain and constipation.² - Fraudulent products with false label information, including pharmacy names that don't exist or didn't make the product.² - Complaints of injectable products arriving warm, or with too little ice to stay cold.²

The FDA's advice is to get a prescription from your doctor and fill it at a state-licensed pharmacy.² Its warning signs include a company that offers medicine at deep discounts or at prices that seem too good to be true, that doesn't require screening and a prescription from a licensed doctor, that has no licensed doctor available to answer questions after you receive the medicine, or that sends a product that looks different from its pictures or arrives broken or without instructions.²

At the clinics we list

3,194 of the 7,475 med spas we list offer weight loss. That doesn't say which drug, who prescribes it or whether it is compounded, so ask.³

Here is what to bring to a consultation.

Cost

We don't give prices on this page. Insurance and payment are covered in our guide to paying for med spa treatments.

Common questions