Semaglutide for weight loss: how Wegovy works, results, risks and cost

Semaglutide is the active ingredient in Novo Nordisk’s Wegovy, Ozempic and Rybelsus, and the brand approved for weight loss is Wegovy. It comes as a weekly shot or a daily pill. In the main trial, adults lost about 15% of their body weight over 68 weeks, and the most common side effects were stomach-related. Ozempic is the same molecule at lower doses, approved for type 2 diabetes, so using it for weight loss is off-label.

Prices are Novo Nordisk’s self-pay rates, checked November 2, 2026. The cost section below has the conditions attached to each one.

How does semaglutide work?

Semaglutide copies GLP-1 (glucagon-like peptide-1), a gut hormone that tells the pancreas to release insulin and tells the brain you are full. It is a long-acting version, 94% identical in sequence to the human hormone, with a half-life of about 1 week, which is why the shot is weekly. It lowers blood sugar, slows stomach emptying and reduces appetite. The Wegovy label says people eat fewer calories, likely through the effect on appetite, and lose more fat than lean mass.

Pills are harder to make work. The stomach normally breaks down a peptide like semaglutide, so the tablets include an absorption enhancer called SNAC and must be taken on an empty stomach with a small amount of water. Only about 1% to 2% of a tablet is absorbed, against 89% of an injection, according to the Wegovy label. That is why the daily pill dose (25 mg) is so much higher than the weekly shot.

Semaglutide acts on one receptor. Tirzepatide acts on two, GIP and GLP-1, and the investigational drugs add more.

Who is semaglutide for?

Wegovy is labeled for adults with obesity, and for adults with overweight who have at least one weight-related condition. The main 2.4 mg trial enrolled people with a BMI of 30 or more, or 27 to 29.9 with a condition such as high blood pressure or abnormal cholesterol. Always alongside a reduced-calorie diet and more physical activity, the label’s other uses are:

• Heart-risk reduction: adults with established heart disease and obesity or overweight, on the injection or the pill.
• Adolescents: ages 12 and older with obesity, on the injection only. The pill and the 7.2 mg dose are not labeled for them.
• MASH: adults with this fatty liver disease and moderate to advanced scarring, on the injection only, under accelerated approval.

Ozempic is for adults with type 2 diabetes. The injection is also labeled to lower heart risk in people with diabetes and established heart disease, and kidney risk in people with diabetes and chronic kidney disease. The tablets carry their own heart-risk use for adults with diabetes at high risk. If you have type 2 diabetes and want a pill for weight, note that the Wegovy label says the tablets were not studied for weight reduction in that group.

FDA approvals, in order

The two diabetes tablets now share one label: Rybelsus (3, 7 and 14 mg) and Ozempic tablets (1.5, 4 and 9 mg). The label says they “are not substitutable on a mg-to-mg basis,” so a 7 mg tablet of one is not a 7 mg dose of the other.

How much weight can you lose on semaglutide?

Average weight loss in trials was about 15% of body weight on Wegovy 2.4 mg and about 19% on 7.2 mg, reached over more than a year. Everyone in these trials also followed a reduced-calorie diet and activity plan.

How long does it take?

Plan on more than a year to see the full effect. The first 16 weeks of the Wegovy schedule are a climb to the full dose. In the SELECT heart trial, weight loss continued for 65 weeks and then held for up to 4 years, with people 10.2% lighter at 208 weeks against 1.5% on placebo. SELECT enrolled adults with heart disease, a different group from STEP 1, so the two are not directly comparable. In the two-year STEP 5 trial, average loss at week 104 was 15.2% versus 2.6%.

Averages hide a wide spread. In STEP 1, 86.4% of people on semaglutide lost at least 5% of their weight and 50.5% lost at least 15%, according to the published trial. Going higher helps some people: in STEP UP, 7.2 mg beat 2.4 mg head to head, 18.7% versus 15.6% in the published paper.

What happens when you stop?

On average, most of the weight comes back. In the STEP 4 trial on the Wegovy label, people who reached 2.4 mg and then switched to placebo gained 6.9% from week 20 to week 68, while those who stayed on the drug lost a further 7.9%. In the exploratory STEP 1 extension, people regained about two-thirds of what they had lost within a year of stopping, and most heart and metabolic improvements drifted back toward where they started.

Does semaglutide protect the heart?

For adults with heart disease and excess weight, yes, in one large trial. SELECT enrolled 17,604 adults aged 45 or older with existing heart disease and a BMI of 27 or more, but no diabetes. Over a mean follow-up of 39.8 months, a heart attack, stroke or cardiovascular death occurred in 6.5% of people on Wegovy 2.4 mg and 8.0% on placebo, a 20% relative reduction (hazard ratio 0.80). This is the basis for the March 2024 heart-risk use on the label.

How do you take semaglutide?

Wegovy injection starts at 0.25 mg once a week and rises every 4 weeks through 0.5, 1 and 1.7 mg to a 2.4 mg maintenance dose from week 17. The label allows a further step to 7.2 mg (Wegovy HD) for adults who have tolerated 2.4 mg for at least 4 weeks and need more weight loss. Wegovy tablets start at 1.5 mg a day and step up every 30 days through 4 mg and 9 mg to 25 mg. Ozempic injection starts at 0.25 mg weekly and tops out at 2 mg.

The semaglutide dosage chart has every step, pen strength and missed-dose rule. If you are using a compounded vial, the mg/mL to units converter turns a milligram dose into syringe units.

What are the side effects of semaglutide?

The most common side effects are stomach-related. In the Wegovy label’s adult weight trials, nausea affected 44% of people on 2.4 mg versus 16% on placebo, diarrhea 30% versus 16%, vomiting 24% versus 6%, and constipation 24% versus 11%. Most happened around dose increases. 6.8% of people stopped Wegovy because of side effects, versus 3.2% on placebo.

The 7.2 mg dose adds one new signal: dysesthesia, an altered skin sensation described as sensitivity, pain or burning. It affected 22% of people on 7.2 mg in the label’s trial, against 6% on 2.4 mg. The FDA said it usually resolved on its own or with a lower dose, and that it is investigating further.

The serious warnings on the label are pancreatitis, gallbladder disease (gallstones were reported by 1.6% of adults on Wegovy injection versus 0.7% on placebo), low blood sugar with insulin or a sulfonylurea, kidney injury from dehydration, severe stomach reactions, severe allergic reactions, diabetic eye complications in people with type 2 diabetes, a faster resting heart rate, and food entering the lungs under anesthesia. A June 2026 addition says a multi-dose FlexTouch pen must never be shared, even with a new needle, because of the risk of passing on blood-borne infections.

The semaglutide side effects guide has the full tables, what helps and when to call.

How much does semaglutide cost?

Without insurance, semaglutide costs $149 to $499 a month through Novo Nordisk, depending on the product and dose. The list price is about $1,349 for Wegovy and $1,028 for Ozempic, but a cash buyer does not pay that. These are Novo’s self-pay prices, checked November 2, 2026:

Three things that table does not show. The $149 pill price buys the starting dose, and the label’s maintenance dose of 25 mg is $299. A month of Wegovy pens is a box of 4, so a full year takes 13 boxes, or $4,537 at $349. And Novo says pricing will be updated after December 31, 2026, the day the $199 offer ends.

Can you pay less than the standard cash price?

Novo also sells 3-, 6- and 12-month Wegovy subscriptions through some telehealth providers, announced March 31, 2026. Pens are $329, $299 or $249 a month. The 9 mg and 25 mg pills are $289, $269 or $249 a month. Wegovy HD was not included at launch, and terms vary by platform, so confirm the current price and any membership fee before committing. NovoCare home delivery takes FSA and HSA cards and offers a 90-day supply.

Does insurance cover semaglutide?

Coverage depends on the plan and the reason for the prescription. With commercial insurance that covers the drug, Novo’s savings offer can bring the cost to as little as $25 a month. The offer takes off at most $100 a month, so a $200 copay would become $100. Government beneficiaries are excluded, though they may use self-pay prices outside their insurance. Self-pay spending does not count toward a deductible or out-of-pocket maximum.

Since July 1, 2026, Medicare Part D members who meet clinical criteria can get Wegovy for weight management through the temporary Medicare GLP-1 Bridge for a $50 monthly copay. You need a BMI of 35 or more, or a lower BMI with certain conditions. The Bridge is not for people who have type 2 diabetes, moderate-to-severe sleep apnea or fatty liver disease, or who already get a GLP-1 through their Part D plan.

Are prices changing in 2027?

List prices are. Novo says the list price of all doses of Wegovy, Ozempic and Rybelsus falls to $675 a month on January 1, 2027, and that this does not affect self-pay prices. Also on January 1, 2027, Medicare’s negotiated price for semaglutide takes effect: $274 for a 30-day supply, per CMS. That is what Medicare pays, not a price anyone can get at the counter.

The cheapest GLP-1 without insurance guide compares every brand, and the GLP-1 price tracker keeps the history.

How does semaglutide compare with other GLP-1 drugs?

Tirzepatide caused more weight loss in the one head-to-head trial, SURMOUNT-5: 20.2% versus 13.7% at 72 weeks, with semaglutide capped at 2.4 mg. Wegovy has things Zepbound does not, including a pill and a heart-risk use for people without diabetes. Tirzepatide’s own heart-risk use, added to the Mounjaro label in August 2026, is for adults with type 2 diabetes at high risk. The semaglutide vs tirzepatide comparison covers the doses, side effects and prices in full.

The other weight-loss pill is Foundayo (orforglipron), approved April 1, 2026, which is not a peptide. If you want to see how these drugs fit with non-drug options, start with the weight loss overview.

Is compounded semaglutide the same thing?

No. Compounded semaglutide is pharmacy-made, is not FDA-approved, and is now lawful only in narrow patient-specific cases. Wegovy went on the FDA shortage list in March 2022 and Ozempic in August 2022, which let pharmacies make copies. The FDA declared the shortage resolved on February 21, 2025, finding that Novo’s supply was “meeting or exceeding demand.” State-licensed 503A pharmacies had to stop making copies by April 22, 2025, and 503B outsourcing facilities by May 22, 2025.

Compounded product comes in multi-dose vials measured in syringe units and has been linked to overdoses from unit confusion. The compounded semaglutide guide covers the rules, the 2026 enforcement actions and the math. Products sold online “for research use only” are a different category again: they are not legal to use on people, and the FDA urges consumers not to purchase them.

Questions to ask a prescriber

• Do I meet the label’s criteria, and which product fits: the pen, the pill or something else?
• Do I have a personal or family history of medullary thyroid carcinoma or MEN 2?
• Have I had pancreatitis, gallbladder disease, kidney problems, diabetic eye disease or severe gastroparesis?
• Do any of my medicines need adjusting, especially insulin, a sulfonylurea, or an oral drug that needs close monitoring?
• What is the plan if I cannot tolerate a dose increase?
• Which maintenance dose are we aiming for, and how will we judge whether it is working?
• Am I planning a pregnancy, surgery or a procedure under anesthesia?
• What will this cost me after any introductory offer ends, and what happens if I stop?

The boxed warning and who should not use semaglutide

Every semaglutide label carries a boxed warning about thyroid C-cell tumors. Semaglutide caused these tumors in rodents at clinically relevant exposures, and whether it does in humans is unknown. For that reason the labels say it must not be used by anyone with a personal or family history of medullary thyroid carcinoma, or with Multiple Endocrine Neoplasia syndrome type 2, or after a serious allergic reaction to semaglutide or an ingredient in the product. Symptoms worth reporting are a lump or swelling in the neck, hoarseness, trouble swallowing or shortness of breath.

The labels also flag groups for prescriber judgment: people with a history of pancreatitis, diabetic retinopathy, kidney problems or severe stomach or bowel disease, and anyone on insulin or a sulfonylurea. The Wegovy label says combining it with any other semaglutide product or another GLP-1 drug is not recommended. Because semaglutide stays in the body for weeks, about 5 to 7 weeks after the last dose, the label advises stopping at least 2 months before a planned pregnancy. Breastfeeding is not recommended on the tablets. For approval changes as they happen, check the FDA status tracker.