Semaglutide
GLP-1 Receptor Agonist · Ozempic / Wegovy
Evidence grade 5 of 5, Settled. Read how the Atlas grades evidence.
Semaglutide holds grade 5 for its approved indications, glycemic control in type 2 diabetes and chronic weight management, backed by the pivotal SUSTAIN and STEP phase 3 programs and the 17,604-participant SELECT cardiovascular-outcomes trial (Lincoff, NEJM 2023), which reported a 20 percent reduction in major adverse cardiovascular events (HR 0.80, 95% CI 0.72 to 0.90). SUSTAIN-6 (Marso, NEJM 2016) similarly showed a 26 percent MACE reduction in type 2 diabetes, and STEP-1 (Wilding, NEJM 2021) showed roughly 15 percent mean weight loss over 68 weeks. The high grade applies to these labeled uses; emerging signals in addiction, Alzheimer's, and MASH remain earlier-stage and are not part of this rating.
- FDA
- FDA approved: Ozempic (injection) 2017 for type 2 diabetes, Rybelsus (oral) 2019 for type 2 diabetes, Wegovy (2.4 mg) 2021 for chronic weight management; later cardiovascular and kidney indications added.
- WADA
- Not prohibited
Reference only. Not medical advice.
What can go wrong
Lean mass loss (~25% of total weight lost, comparable proportionally to diet alone, but real); rebound weight gain on cessation; thyroid C-cell tumor black box warning; GI side effects during titration.
Talk to a clinician before taking this, particularly if you are pregnant or might become pregnant. The Atlas can tell you what has been studied about Semaglutide. It cannot tell you how it would interact with your body, your history, or anything else you are taking, and nothing on this page is a reason to start.
A GLP-1 receptor agonist FDA-approved for type 2 diabetes and obesity. Its lineage runs from a 1992 discovery in Gila monster venom through exenatide (2005) to semaglutide (2017). The GLP-1 commercial boom is the single biggest reason every other peptide entered mainstream conversation in 2023-2026.
The drug that pulled all of peptide medicine into the mainstream.
What people take it for
What it is taken for. Approval, where it exists, covers only some of these.
- Type 2 diabetes (Ozempic, Rybelsus)
- FDA-approved 2017 (injection) and 2019 (oral tablet) for blood-sugar control.
- Chronic weight management (Wegovy)
- FDA-approved June 2021 for obesity or overweight with a related condition, including adolescents 12 and older.
- Cardiovascular risk reduction (Wegovy)
- FDA-approved March 2024 to cut major cardiac events in adults with heart disease and obesity, based on SELECT.
- Kidney protection
- Supported by the FLOW trial in diabetic kidney disease, where it slowed kidney decline.
How it works
Semaglutide is a GLP-1 receptor agonist: a near-copy of the gut hormone GLP-1 that the body releases after eating. It tells the pancreas to release insulin only when blood sugar is high, suppresses the sugar-raising hormone glucagon, slows how fast the stomach empties, and acts on appetite centers in the hypothalamus and brainstem to cut hunger and food intake. A fatty-acid chain binds it to albumin so it lasts about a week, allowing once-weekly injection, and a daily oral tablet form also exists. It is the single most important reason the entire peptide and weight-loss category went mainstream.
Semaglutide is a 31-amino-acid peptide engineered from human GLP-1, sharing about 94% of its sequence. Two changes make it a drug rather than a hormone that vanishes in minutes: an aminoisobutyric-acid substitution at position 2 that blocks the DPP-4 enzyme, and a C18 fatty diacid chain that binds albumin and stretches the half-life to roughly seven days. Novo Nordisk selected it from 217 candidate molecules. Its deeper lineage is one of the great stories in drug discovery: GLP-1 biology led to exendin-4, a durable GLP-1-like peptide found in 1992 in the venom of the Gila monster, which became the first GLP-1 drug exenatide, then the daily drug liraglutide, and finally weekly semaglutide.
- Class
- GLP-1 agonist
- Size
- 31 amino acids
- Half-life
- ~7 days
- Forms
- Weekly injection, daily pill
- Brands
- Ozempic, Wegovy, Rybelsus
- Doses
- Up to 2.4mg (7.2mg filed)
What The Hype Skips
Semaglutide is the rare blockbuster where the science is genuinely strong, so the honest job is to name what the marketing leaves quiet rather than to debunk it. Three things. First, it is no longer the most effective drug in its own class: in a head-to-head trial tirzepatide produced about 20% weight loss to semaglutide's roughly 14%, so the "most powerful" crown has moved. Second, roughly a quarter of the weight lost is lean mass, so without resistance training and adequate protein, real muscle goes with the fat. Third, and most underplayed, most people regain a large share of the lost weight within a year of stopping, which means it behaves like a lifelong medication rather than a cure, and the enormous wave of cosmetic use by people without a medical need is taking on exactly that open-ended commitment with far less discussion of it.
Safety in detail
The compounded-semaglutide gray market that grew during the 2022 to 2024 shortage rested on the FDA drug-shortage-list exception. The FDA declared the injection shortage resolved on February 21, 2025, and set enforcement-discretion end dates of April 22, 2025 for 503A pharmacies and May 22, 2025 for 503B outsourcing facilities, after which compounding essentially-copies of semaglutide is generally no longer permitted under that exception. These are completed regulatory actions; the Outsourcing Facilities Association filed a lawsuit challenging the resolution in February 2025.
- Gastrointestinal effects (nausea, diarrhea, vomiting, constipation) are by far the most common, concentrated during dose escalation and usually easing over time.
- Boxed warning for thyroid C-cell tumors from rodent data. Contraindicated with a personal or family history of medullary thyroid carcinoma or MEN 2.
- Pancreatitis and gallbladder disease, the latter partly tied to rapid weight loss.
- Hypoglycemia when combined with insulin or sulfonylureas, so those doses often need lowering.
- A possible link to a rare optic-nerve condition (NAION) emerged in 2024 and is still under investigation.
- Worsening diabetic retinopathy was seen in a diabetes trial as glucose fell quickly, worth monitoring in those with eye disease.
- Delayed stomach emptying raises aspiration risk under anesthesia, prompting guidance on pausing it before procedures.
- A suicidal-ideation concern was investigated by US and European regulators and not substantiated as causal, though mood is still worth watching.
- Roughly a quarter of weight lost is lean mass, so protein and resistance training matter.
- Weight is substantially regained after stopping unless treatment or a structural lifestyle change continues.
- Not recommended in pregnancy.
Children and teenagers
This is where semaglutide stands apart from every gray-market peptide in the library: it has a real, regulated pediatric use. Wegovy is FDA-approved for chronic weight management in adolescents 12 and older with obesity, based on the STEP TEENS trial, in which teens lost about 16% of their BMI versus a slight gain on placebo, with nearly half dropping below the clinical obesity threshold. Only semaglutide and liraglutide currently hold adolescent obesity approvals. It is not approved or established for children under 12, where use would be investigational. Even with approval, treating obesity pharmacologically in still-developing adolescents has prompted a serious and ongoing ethical debate among clinicians and families, weighing real metabolic and psychological benefit against the unknowns of starting a likely lifelong medication young. The contrast with peptides like BPC-157 is the point: here, pediatric use means a studied, approved indication with informed-consent debate, not unmonitored misuse.
What people get wrong
Often saidOzempic melts only fat
ActuallyAbout 25% of the weight lost is lean mass. Without resistance training and adequate protein, real muscle is lost, the same ratio seen with placebo, but it still matters.
Often saidStopping is easy
ActuallyMost users regain a substantial fraction of lost weight within a year of stopping. It behaves more like a chronic medication than a course of treatment.
Who profits, and who pushes back
Oprah Winfrey
Publicly disclosed GLP-1 use in late 2023 with no known Novo Nordisk compensation. Among the most consequential unincentivized endorsements in the drug's history.
Elon Musk
Posted about using Wegovy with fasting. Major driver of cultural mainstreaming.
Novo Nordisk / Eli Lilly
Sells this. Has a commercial interest in a product sold as this compound, as of July 2026.
Both run extensive direct-to-consumer campaigns with paid celebrity partnerships.
Kelly Clarkson
Confirmed GLP-1 use on her show in the context of a thyroid condition.
Dr. Brad Stanfield
Prescribing without a muscle-preservation protocol risks doing net harm.
FDA Black Box Warning
Thyroid C-cell tumor risk from rodent studies; contraindicated with personal or family history of medullary thyroid carcinoma.
SURMOUNT-5 (2025)
Tirzepatide produced 20.2% weight loss vs semaglutide's 13.7%, semaglutide is no longer the most effective option in its own class.
The overwhelming beneficiary is Novo Nordisk, the Danish company that developed and owns semaglutide and rode it to the top tier of global pharma. Around that core, the money spreads to telehealth platforms (now including a branded deal with Hims and Hers), pharmacies, and pharmacy-benefit managers who negotiate rebates that quietly decide coverage. During the shortage, compounding pharmacies and telehealth firms captured large demand with cheaper copies, a slice the manufacturer has spent 2025 and 2026 fighting to reclaim through lawsuits, FDA pressure, and its own discount pricing. The contrast with a gray-market peptide is total: here the profit is branded, enormous, and openly contested in court.
Where the research comes from
| Place | Share of published research |
|---|---|
| USA | 34% |
| Europe | 31% |
| Asia | 20% |
| Other | 15% |
Research published from: Global, 40+ countries.
How we got here
Semaglutide is a long-acting GLP-1 receptor agonist developed by Novo Nordisk, engineered from the earlier once-daily analogue liraglutide by adding a longer fatty-acid chain that binds albumin and extends the half-life to roughly a week. It reaches patients under three brand names for different indications: Ozempic as a weekly injection for type 2 diabetes, Wegovy as a weekly injection for obesity and weight management, and Rybelsus as a daily oral tablet for type 2 diabetes. The oral formulation carries its own Novo Nordisk development code, NNC0113-0217, distinct from the injectable NN9535 program.
Semaglutide's story runs through 120 years of incretin science and one lizard. GLP-1 was identified as a gut hormone that boosts insulin and curbs appetite, but it breaks down in minutes. In 1992 a physician found exendin-4, a durable GLP-1-like peptide, in the venom of the Gila monster, which became the first GLP-1 drug exenatide in 2005. Novo Nordisk took the human hormone itself, armored it against enzymes and bound it to albumin, and selected semaglutide from 217 candidates. Ozempic was approved for diabetes in 2017, the oral Rybelsus in 2019, and Wegovy for obesity in 2021. Then came celebrity disclosures, a cultural explosion, the SELECT cardiovascular win in 2023, a heart indication in 2024, and an oral obesity pill in 2025, by which point tirzepatide had overtaken it. It remains the molecule that started the modern era of weight-loss medicine.
- 1992Exendin-4, a durable GLP-1-like peptide, found in Gila monster venom.
- 2017Ozempic approved for type 2 diabetes.
- 2019Rybelsus, the oral tablet, approved for diabetes.
- 2021Wegovy approved for obesity; the cultural wave begins.
- 2022STEP TEENS leads to adolescent (12+) obesity approval.
- 2023SELECT shows cardiovascular benefit in 17,604 patients.
- 2024Wegovy approved for cardiovascular risk reduction; FLOW shows kidney benefit.
- 2025Oral Wegovy approved; tirzepatide overtakes it on weight and sales; high-dose 7.2mg filed.
The numbers behind the grade
- 2025 sales
- ~$33B
- Brands
- Ozempic, Wegovy, Rybelsus
- Pediatric
- Approved 12+
- CV benefit
- SELECT (20%)
- Half-life
- ~7 days
- vs tirzepatide
- 13.7 / 20.2
The people taking it
The drug that pulled all of peptide medicine into the mainstream. "Ozempic" became a household word and a verb, and semaglutide remains one of the most-discussed, most-prescribed and most-recognized medicines in the world, even after tirzepatide passed it on weight and on sales.
Semaglutide reaches an enormous and varied population, but unevenly. Diabetes use is fairly balanced across sexes, while obesity and cosmetic use have skewed strongly toward women. Uptake has concentrated among higher-income, privately insured patients, and analyses have repeatedly flagged racial and socioeconomic disparities in access despite higher obesity and diabetes burdens in some of those same groups. It is now approved and used in adolescents as well as adults. The defining demographic fact is the gap between who could medically benefit and who can actually afford and obtain it.
Prescribed worldwide for type 2 diabetes, obesity, and cardiovascular risk reduction, in both weekly-injection and daily-pill forms, across adults and approved down to age 12 for obesity. One of the most widely used medicines on earth, with demand still ahead of supply in many countries. Not prohibited in sport.
Set against the alternatives
Semaglutide is the drug that defined the category, but it has been overtaken on its headline metric. In the SURMOUNT-5 head-to-head, tirzepatide produced about 20% weight loss to semaglutide's 14%, so on weight it now sits second among approved options. The new high-dose 7.2mg version narrows that gap to about 21% but is not yet approved. Below semaglutide sits its own predecessor liraglutide and the newer oral pill orforglipron; above it sit tirzepatide and the investigational triple agonist retatrutide at 28 to 30%. Where semaglutide remains a leader is depth of outcome evidence: its cardiovascular proof in SELECT and kidney proof in FLOW are among the strongest in the class. The honest read is that it is no longer the most powerful for weight, but it is one of the most thoroughly proven for health outcomes.
| Liraglutide (Saxenda) | GLP-1 (daily) | ~6 to 8% | Approved |
|---|---|---|---|
| Semaglutide (Wegovy) | GLP-1 (weekly) | ~15% (up to ~21% high dose) | Approved |
| Orforglipron (Foundayo) | Oral GLP-1 | ~11 to 12% | Approved 2025 |
| Tirzepatide (Zepbound) | GIP + GLP-1 | ~20 to 22.5% | Approved |
| Retatrutide | GIP + GLP-1 + glucagon | ~28 to 30% | Filing late 2026 |
Ozempic and Wegovy generated roughly $33 billion in 2025 and turned Novo Nordisk into one of the most valuable companies in Europe, though tirzepatide passed it to become the world's best-selling drug. The economics shape access at every turn. List prices around $1,349 a month collide with self-pay programs: in 2026 the TrumpRX initiative and telehealth deals brought branded Wegovy down toward $149 to $349 a month. During the shortage, compounding pharmacies and telehealth firms sold cheaper copies at scale, igniting a fight that ended with the FDA issuing dozens of warning letters, restricting the active ingredient, Novo suing the telehealth company Hims and Hers over "inauthentic" compounded semaglutide, and the two then striking a deal in early 2026 for Hims to sell only branded product. Counterfeit Ozempic pens have also been seized internationally. As with tirzepatide, this is a case study in how price and supply, not just biology, decide who gets the drug.
What we do not know
- How much post-cessation regain is avoidable, and what the right long-term strategy is.
- What decades of continuous use look like, including use started in adolescence.
- Whether the cosmetic-use wave in people without medical need is wise at a population level.
- Whether the Alzheimer’s, addiction and liver programs convert into new proven uses.
- How to close the access gap so the people with the greatest medical need are not the least likely to get it.
What could change
The oral eraThe newly approved oral Wegovy pill could broaden access for people who will not inject, reshaping the market.Higher dosesThe 7.2mg version aims to close the weight gap with tirzepatide.Alzheimer’s diseaseLarge dedicated trials (EVOKE) are testing whether semaglutide slows early Alzheimer’s, a major and unproven frontier.Addiction and liverSignals in alcohol and other addictions, and in fatty liver disease, are under active study.Adolescents and beyondWith teen approval in hand, the debate now extends to whether and how to treat obesity even earlier in life.
Legal status
Semaglutide is fully approved and among the most-prescribed drugs in the world, sold as Ozempic (diabetes injection), Rybelsus (diabetes pill), and Wegovy (obesity injection, and from late 2025 an obesity pill). It is obtained by prescription through pharmacies and, increasingly, telehealth. The 2023 to 2024 shortage spawned a huge compounded market that is now being wound down following the FDA declaring the shortage over and restricting the active ingredient. Unlike the gray-market peptides, it is a regulated medicine with a clear legitimate supply chain.
Status current as of July 2026. Regulatory positions change, sometimes quickly.
The market for this
What follows describes how this is bought and sold. It is not a buying guide and it is not an endorsement of any seller.
Prescription-only through pharmacies and telehealth as Ozempic, Rybelsus and Wegovy, with branded self-pay options now widely available at a fraction of list price. Compounded semaglutide, common during the shortage, is being restricted now that branded supply has recovered and the FDA is limiting the active ingredient. Counterfeit pens are a real risk, so verified pharmacy or the manufacturer’s channel matters.
List prices run near $1,349 a month, but few now pay that. In 2026 self-pay routes brought branded Wegovy down to roughly $149 to $349 a month through the TrumpRX program and telehealth deals, oral and injectable alike, and Novo offers savings cards for the commercially insured. Compounded versions had undercut this at $100 to $450 a month but are being phased out as the shortage ends. Insurance coverage for obesity, as opposed to diabetes, remains uneven, which keeps cost a central barrier despite the discount programs.
Branded semaglutide is manufactured by Novo Nordisk under cGMP, with large investments in new capacity to resolve the shortage. Compounded product during the shortage drew on active ingredient of varied and sometimes disputed origin, often imported, which the FDA and Novo have challenged. As with any high-value drug, counterfeits have entered some supply chains, so provenance through a verified pharmacy is the only reliable assurance.
United States & European UnionManufactured by Novo Nordisk under cGMP, with major investment in new capacity, including the acquisition of fill-finish plants, to end the shortage that defined 2023 and 2024. A controlled, traceable chain.Compounded supply (shortage era)When branded product ran short, compounders sold copies, and the FDA and Novo have alleged some used active ingredient of questionable or "inauthentic" origin, often imported. This channel is being squeezed now that the shortage is over.Counterfeit riskFake Ozempic pens have been seized in several countries, drawing FDA and WHO warnings; verified pharmacy or the maker’s channel is the only reliable route.Rest of worldSupplied through Novo and distributors as approvals and capacity expand, with demand still outpacing supply in many markets.
At a glance
- Avg. weight loss
- 14.9% (STEP 1, 68 wk)
- Lineage
- Gila monster venom (1992)
- Dosing
- Once weekly
- 2024 revenue
- >$50B (GLP-1 class)
What this entry does not yet cover
What follows is unfinished work on our side, not a finding about Semaglutide.
Nothing outstanding on this one.
Sources
STEP-1 phase 3 RCT: once-weekly semaglutide 2.4 mg plus lifestyle intervention produced roughly 15 percent mean weight loss over 68 weeks
SUSTAIN-6 CV-outcomes RCT: semaglutide reduced the composite of CV death, nonfatal MI, and nonfatal stroke by 26 percent versus placebo in type 2 diabetes (HR 0.74, 95% CI 0.58 to 0.95)
Marso et al., Semaglutide and Cardiovascular Outcomes in Patients with Type 2 Diabetes, NEJM 2016
SELECT CV-outcomes RCT: in 17,604 adults with overweight/obesity and established CVD but no diabetes, semaglutide reduced MACE by 20 percent versus placebo (HR 0.80, 95% CI 0.72 to 0.90, p<0.001)
SUSTAIN-6 registration on ClinicalTrials.gov: 3,297 adults with type 2 diabetes, once-weekly semaglutide, CV and long-term outcomes
Rybelsus (oral semaglutide) FDA-approved September 2019 as the first oral GLP-1 analog for type 2 diabetes, supported by the PIONEER program (>9,500 participants across 10 trials)
Wegovy (semaglutide 2.4 mg) FDA-approved June 4, 2021 for chronic weight management, based on the STEP phase 3a program
FDA declaratory order resolving the semaglutide injection shortage, the regulatory basis ending the shortage-list compounding exception
FDA set enforcement-discretion end dates for compounded semaglutide: April 22, 2025 (503A pharmacies) and May 22, 2025 (503B outsourcing facilities); Outsourcing Facilities Association sued to challenge the resolution
Foley & Lardner client alert, GLP-1 Drugs: FDA Removes Semaglutide from Drug Shortage List
Weight regain and cardiometabolic reversal after semaglutide withdrawal, supporting the chronic-medication framing (roughly two-thirds of lost weight regained within a year of stopping)
Wilding et al., STEP 1 trial extension, Diabetes, Obesity and Metabolism 2022
SELECT prespecified analysis: continued weight loss over 65 weeks sustained to 208 weeks with mean 10.2 percent weight reduction versus placebo
The studies that matter
STEP 12021
14.9% mean weight loss over 68 weeks on the 2.4mg injection in adults with obesity.
SELECT2023
20% reduction in major cardiovascular events across 17,604 adults with established cardiovascular disease and obesity, without diabetes.
SURMOUNT-52025
Head-to-head: tirzepatide produced 20.2% weight loss versus semaglutide 13.7% at 72 weeks.
OASIS-42025
Oral semaglutide 25mg produced 16.6% mean weight loss at 64 weeks with full adherence.
STEP UP2026
Wegovy HD (7.2mg) produced 20.7% mean weight loss; roughly one in three participants reached 25% or more.