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Semaglutide: what the trials show, status and safety

Status at a glance

MarketStatusDate
United StatesApproved, prescription only2017-12-05
European UnionApproved, prescription only2018-02-08
GermanyApproved, prescription only2018-02-08
United KingdomApproved, prescription only—
AustraliaApproved, prescription only—
CanadaApproved, prescription only—
SwitzerlandApproved, prescription only2018-07-02
Development stage
Approved
Strongest evidence
Phase 3 randomised trial
WADA status
Not listed
Last verified
2026-09-06
Version
1.0

This page lists no doses.

Semaglutide: what the trials show, status and safety

Summary

Semaglutide is a lab-made peptide that copies a natural gut hormone and switches on its docking point, the GLP-1 receptor. It is an approved medicine, available on prescription in eight markets, first licensed in December 2017. In its largest trial in people with obesity, body weight fell by an average of 14.9 percent over 68 weeks. In people with obesity but no diabetes it also cut serious heart problems by about a fifth, and in Alzheimer's disease it failed on the question it was built to answer.

Key findings at a glance

  • Licensed in eight markets, and everywhere on prescription only. The FDA approved it first, on 5 December 2017, and the European authorisation followed on 8 February 2018 [1], [2].
  • Body weight fell by 14.9 percent in 68 weeks, and by 15.2 percent in two years (104 weeks). The first figure comes from 1,961 adults with obesity and without diabetes, against 2.4 percent on the dummy treatment; the second from a smaller two-year trial in 304 adults, against 2.6 percent [3], [4].
  • About a fifth fewer serious heart events. In 17,604 adults with obesity and existing heart disease, the risk was 20 percent lower than on the dummy treatment (hazard ratio 0.80, range 0.72 to 0.90) [5].
  • The kidney and liver trials both came out positive. In 3,533 adults, the main kidney outcome occurred 24 percent less often, and in a liver trial the inflammation of a fatty liver cleared up in 62.9 percent of patients against 34.3 percent [6], [7].
  • It failed in early Alzheimer's disease. Two large trials with 3,808 participants found no difference in thinking and memory, and both were stopped [8].
  • A framed warning about thyroid tumours in rodents. Every American package insert states that nobody knows whether this matters for people [9].
  • Not banned in sport. It is missing from the 2026 prohibited list, but it is named in the monitoring programme [10], [11].

What it is

Semaglutide is a lab-made peptide of 31 building blocks, developed by Novo Nordisk under the codes NN9535 and NNC 0113-0217 [12]. It is a slightly altered copy of the human gut hormone GLP-1, matching it in 94 percent of its sequence, and it switches on the docking point for that hormone and nothing else [13].

Three brand names carry the same active substance. Ozempic covers the diabetes indications, Wegovy the weight-management indications, and Rybelsus the oral tablets [1], [14], [15]. Since 2025 the US register has also listed Ozempic tablets under the oral application, and since 2026 Wegovy tablets under the weight application [15], [14].

The chain itself is brewed with yeast. One building block is swapped so that the enzyme which normally cuts GLP-1 apart within minutes can no longer get a grip. A long fatty chain hangs off another position, and a third one, position 34, is altered so that only one such chain attaches [9].

That fatty chain sticks the peptide to a carrier protein in the blood, which is why it survives in the body for about a week [13]. The tablets contain an extra ingredient that helps the peptide cross the wall of the stomach [16].

Quick facts

FieldValueRef
INNsemaglutide[13]
Development codesNN9535, NNC 0113-0217[12]
ClassSwitches on the docking point of the gut hormone GLP-1[13], [2]
Structure31 building blocks, a long fatty chain at position 26, position 8 protected against the enzyme that would cut it[9]
Formula and massC187H291N45O59, 4,113.58 Da[9], [12]
How long it lastsAbout 1 week; still detectable roughly 5 weeks after the last dose[13]
How much of it reaches the blood89% when injected under the skin; more than 99% travels bound to a carrier protein[13]
How it is takenInjected under the skin, or swallowed as a tablet[13], [16]
StatusApproved and prescription-only in eight markets[1], [2]
DeveloperNovo Nordisk A/S[1]
ATC codeA10BJ06[2]
CAS registry number910463-68-2[12]
UNII53AXN4NNHX[17]
PubChem CID56843331; Wikidata also lists the record 122189768[12], [18]
InChIKeyDLSWIYLPEUIQAV-CCUURXOWSA-N[12]
ChEMBLCHEMBL3616752[19]
DrugBankDB13928[20]
MeSHD000099194[18]
RxNorm1991302[18]
WikidataQ27261089[18]

Semaglutide: what the trials show, status and safety

How it works

The approved package insert says outright how the medicine works, because that was assessed along with the trials [13].

  • The GLP-1 docking point. Semaglutide attaches to it and switches it on, and it leaves the docking points of related gut hormones alone [13].
  • Insulin and its counterpart. The body releases more insulin and less glucagon, the hormone that raises blood sugar, and it does both only when blood sugar is actually high [13].
  • The stomach empties more slowly. The package insert describes a small delay in the first phase after a meal [13].
  • The effect on the kidneys. The package insert states plainly that nobody knows why the risk to the kidneys falls [13].
  • What the body does with it. More than 99 percent travels bound to a carrier protein in the blood, the body dismantles the peptide and its fatty chain piece by piece, and about 3 percent leaves in the urine unchanged [13].

Tirzepatide works on two such docking points and is built on the frame of a different gut hormone. Semaglutide works on one, and is built on the frame of GLP-1 itself [13], [21].

What the trials found

Weight

Phase 3 RCT In the largest trial, 1,961 adults with obesity and without diabetes were assigned by chance to semaglutide or a dummy treatment for 68 weeks. On average they lost 14.9 percent of their body weight against 2.4 percent, a gap of 12.4 percentage points. At least a twentieth of their weight came off in 86.4 percent of them against 31.5 percent, and at least 15 percent came off in 50.5 percent of them against 4.9 percent [3].

STEP 1, body weight at 68 weeks
Placebo
−2.4%
Semaglutide
−14.9%

Late-stage trial, 1,961 adults with obesity and without diabetes, over 68 weeks. The estimated difference is 12.4 percentage points, with a 95 percent confidence interval from 11.5 to 13.4. Source [3].

Phase 3 RCT A second trial carried the same question out to two years in 304 adults. After 104 weeks they had lost 15.2 percent of their weight against 2.6 percent on the dummy treatment, a gap of 12.6 percentage points. At least a twentieth of their weight came off in 77.1 percent of them against 34.4 percent [4].

Phase 3 RCT A further trial enrolled 1,210 adults who also had type 2 diabetes. They lost 9.6 percent of their weight against 3.4 percent, a gap of 6.2 percentage points. The effect is much smaller in this group, so the two sets of figures cannot be swapped for one another [22].

Phase 3 RCT, withdrawal design In one trial, 803 adults were first treated for 20 weeks and only then split by chance into two groups. Between week 20 and week 68, those who carried on lost a further 7.9 percent, while those switched to the dummy treatment put 6.9 percent back on [23].

Phase 3b RCT One trial tested a higher dose level in 1,407 adults over 72 weeks. They lost 18.7 percent of their weight against 15.6 percent at the established level, a gap of only 3.1 percentage points, and against 3.9 percent on the dummy treatment. Odd skin sensations such as tingling were reported by 22.9 percent at the higher level against 6.0 percent at the established one [24].

Phase 3 RCT A trial in 201 young people aged between 12 and 18 measured body mass index rather than weight. It fell by 16.1 percent against a rise of 0.6 percent on the dummy treatment. Gallstones turned up in 5 of the 133 treated participants and in none of the others [25].

Blood sugar

Phase 3b RCT, everyone knew who got what One trial compared semaglutide with the related drug dulaglutide in 1,201 adults with type 2 diabetes who were already taking metformin. The long-term blood sugar marker, which reflects the average of the past two to three months, fell by 1.5 percentage points at the lower semaglutide level against 1.1 points at the lower dulaglutide level [26]. The trial was designed to show that semaglutide was no worse on blood sugar and better on body weight.

Phase 3 RCT A further trial followed 3,297 adults over 104 weeks and measured both blood sugar and heart events. It is described under the heart section below [27].

Cardiovascular events

Phase 3 RCT, built to show a difference The largest heart trial assigned 17,604 adults aged 45 and over, all with existing heart disease and obesity but without diabetes, by chance to one group or the other, and followed them for a median of 39.8 months.

A serious heart event struck 6.5 percent of the treated group, 569 people of 8,803, against 8.0 percent on the dummy treatment, 701 of 8,801. That is a fifth less risk (hazard ratio 0.80), and the 95 percent confidence interval around it runs from a tenth to almost a third less (0.72 to 0.90) [5].

SELECT, primary events over a mean follow-up of 39.8 months
Placebo701 of 8,801
8%
Semaglutide569 of 8,803
6.5%

Late-stage trial in 17,604 adults with obesity and existing heart disease but without diabetes. The risk was a fifth lower, hazard ratio 0.80, 95 percent confidence interval 0.72 to 0.90, p < 0.001. Twice as many people stopped because of side effects, 16.6 against 8.2 percent. Source [5].

The price of that result shows in who dropped out: 16.6 percent stopped because of side effects, against 8.2 percent on the dummy treatment [5].

Phase 3 RCT, built only to show it was no worse Another trial followed 3,297 adults with type 2 diabetes and a high risk of heart problems over 104 weeks. A serious heart event struck 6.6 percent against 8.9 percent, a risk about a quarter lower (hazard ratio 0.74, range 0.58 to 0.95). Heart attacks that people survived were fewer as well (hazard ratio 0.74), but by too little to rule out chance (p = 0.12) [27].

The same trial threw up a warning signal about the eyes. Complications of diabetic damage to the retina, checked by an independent panel, occurred in 3.0 percent against 1.8 percent, which is roughly three quarters more often (hazard ratio 1.76, range 1.11 to 2.78). The rise was larger among people who already had such damage, at 8.2 percent against 5.2 percent [27], [9].

Kidney

Phase 3 RCT A kidney trial in 3,533 adults with type 2 diabetes and long-standing kidney disease was stopped early, because an interim look at the data recommended it. People were followed for a median of 3.4 years. The combined main outcome, which counts kidney failure and death together, occurred 24 percent less often, 331 times against 410 (hazard ratio 0.76, range 0.66 to 0.88) [6].

The other measures pointed the same way. Deaths from heart causes were about 29 percent fewer (hazard ratio 0.71), deaths from any cause about 20 percent fewer (hazard ratio 0.80), and the kidneys lost their filtering capacity more slowly each year, by 1.16 mL/min/1.73 m² [6]. This trial is the basis of the American approval for kidney disease [1].

Heart failure

Phase 3 RCT Two trials enrolled 1,146 adults who had obesity and a form of heart failure in which the heart still pumps normally but fills poorly, each over 52 weeks. Among those without diabetes, the symptom score improved by 16.6 points against 8.7, a gap of 7.8 points, and in six minutes they walked 21.5 metres further than before against 1.2 metres, a difference of 20.3 metres [28].

In the trial among people with diabetes, the symptom score improved by 13.7 points against 6.4, a difference of 7.3 points, and the walking distance by 14.3 metres more. Both trials measured how people felt and what they could do, not how often they ended up in hospital or how many died [29].

Liver

Phase 3 RCT, interim results A liver trial reported week 72 for its first 800 participants, all of whom had an inflamed fatty liver confirmed by tissue sample, with moderate to advanced scarring. The inflammation cleared without the scarring getting worse in 62.9 percent against 34.3 percent, a gap of 28.7 percentage points. The scarring itself improved without the inflammation worsening in 36.8 percent against 22.4 percent [7].

A question that came up empty Bodily pain scores changed no differently in the two groups [7]. The trial runs on to 240 weeks, and the American approval resting on this interim look was granted under the fast-track route [14].

Alzheimer's disease

Phase 3 RCT, negative Two trials enrolled 3,808 people aged between 55 and 85 with early Alzheimer's disease, confirmed by brain scan, for up to 156 weeks. Both failed on their main question about thinking and memory: the differences from the dummy treatment were tiny, −0.08 (p = 0.57) in the one trial and 0.10 (p = 0.46) in the other, and comfortably within the range chance produces [8].

Both trials were stopped once the result was in. Side effects during treatment occurred in 91.2 percent of participants against 84.8 percent [8].

Walking distance and joint pain

Phase 3b RCT One trial followed 792 adults with type 2 diabetes and narrowed leg arteries that caused pain on walking, over 52 weeks. The median maximum walking distance grew to 1.21 times the starting value against 1.08 times on the dummy treatment, so roughly 13 percent further overall (treatment ratio 1.13, range 1.06 to 1.21) [30].

Phase 3 RCT A trial in 407 adults with obesity and worn knee joints ran over 68 weeks. The pain score fell by 41.7 points against 27.5 points on the dummy treatment. That improvement of 27.5 points without any active drug is remarkably large, so the two groups only make sense read side by side [31].

Oral formulation

Phase 3 RCT A trial of the tablet enrolled 667 adults who were overweight or obese and had no diabetes, over 68 weeks. They lost 15.1 percent of their weight against 2.4 percent on the dummy treatment, which is much the same as the injection achieved in the largest trial [32], [3].

Phase 3 RCT, built only to show it was no worse A tablet trial followed 3,183 adults with type 2 diabetes and a high risk of heart problems for a median of 15.9 months. Serious heart events struck 3.8 percent against 4.8 percent (hazard ratio 0.79), but the range around that figure still includes no difference at all (0.57 to 1.11). Showing the tablet was better was neither the aim nor the outcome [33].

Phase 3 RCT, built to show a difference A larger tablet trial followed 9,650 adults with type 2 diabetes and heart or kidney disease for an average of 47.5 months. A serious event struck 12.0 percent against 13.8 percent, a risk about 14 percent lower (hazard ratio 0.86, range 0.77 to 0.96), and that result was solid enough to rule out chance (p = 0.006). The further questions the trial was meant to confirm, including a combined kidney measure, showed no clear difference [34].

What is still unknown

  • The thyroid tumours in rodents. Whether they mean anything for people is unresolved, and the package inserts say so plainly [9].
  • The liver result. It rests on an interim look at a trial that runs on to 240 weeks [7].
  • The sudden loss of vision. What the regulators found is a statistical link in observational studies, not a proven cause [35].
  • What heart failure treatment actually achieves. The two trials measured symptoms and walking distance, not hospital admissions or deaths [28], [29].
  • Whether the higher dose is worth it. It brought 3.1 percentage points more weight loss, and clearly more odd skin sensations with it [24].
  • How much the direct comparison is worth. In the trial against dulaglutide, everybody knew who was getting what [26].

Side effects and safety

Stomach and bowel complaints dominate the picture, and they are the main reason people stop. The figures below come from the pooled weight trials in adults as printed in the American labelling, with 2,116 people on the drug against 1,261 on the dummy treatment [9].

EventSemaglutidePlacebo
Feeling sick44%16%
Diarrhoea30%16%
Vomiting24%6%
Constipation24%11%
Belly pain20%10%
Headache14%10%
Tiredness or weakness11%5%
Upset stomach9%3%
Dizziness8%4%
Belching7%<1%
Hair loss3%1%
Stomach and bowel complaints overall73%47%
Severe stomach and bowel reactions4.1%0.9%
Gallstones1.6%0.7%
Inflamed gallbladder0.6%0.2%

Further points from the package inserts and the regulatory record:

  • The framed warning about thyroid tumours. In rats and mice, semaglutide causes a rare kind of thyroid tumour, more often the more they get and the longer they get it, at amounts comparable to those used in people. Whether this matters for people is unknown. The same wording appears on all three American package inserts [9], [13], [16].
  • Who must not take it. Anyone who has had that particular thyroid cancer or has it in the family, anyone with a certain inherited hormone syndrome, and anyone who has previously had a serious allergic reaction to the drug [9].
  • Sudden inflammation of the pancreas. In the weight trials there were 4 confirmed cases against 1. On 29 January 2026 the British regulator tightened the warning for this whole class of drugs, pointing to cases in which tissue died and cases that ended in death [9], [36].
  • Gallbladder trouble. Gallstones and an inflamed gallbladder are both printed warnings, and in the trial among young people gallstones reached 3.8 percent against none at all [9], [25].
  • The other printed warnings. Blood sugar dropping too low when combined with insulin or similar medicines, sudden kidney damage after losing too much fluid, allergic reactions including deep swelling of the skin, complications of diabetic damage to the retina, a faster pulse, and stomach contents getting into the lungs during anaesthesia [9].
  • Broken bones in one trial. In the large heart trial, women broke a hip or pelvis in 1.0 percent of cases against 0.2 percent. Among women aged 75 and over the figures were 2.4 percent against 0.6 percent [9].
  • Never share a pen. The package inserts warn that a pen holding several doses must never be passed between people, not even with a fresh needle, because diseases carried in the blood can be transmitted that way [9], [13].

Sudden loss of vision, and where the markets disagree. Damage to the optic nerve caused by poor blood supply, known as non-arteritic anterior ischaemic optic neuropathy, is the one safety point on which the package inserts differ. The European committee finished its review in June 2025 and added it as a very rare side effect, meaning up to 1 in 10,000 people treated [35].

The European product information spells out how big that risk is. Several large population studies suggest that the risk roughly doubles in adults with type 2 diabetes, which works out at about one extra case for every 10,000 people treated for a year [2].

The British regulator published its own update on 5 February 2026. It counted three suspected reports since 2018, against roughly 10.2 million packs handed out over five years [37]. On 6 September 2026 the American package inserts still carried no entry on this at all [9], [13], [16].

Reports collected since the medicine went on sale add a paralysed or blocked bowel, severe constipation, sudden severe allergic reactions, deep swelling of the skin, an inflamed gallbladder, unpleasant skin sensations, stomach contents entering the lungs, sudden kidney damage and hair loss. How often any of these happen cannot be worked out reliably [13], [9].

Why this page lists no doses

Semaglutide is available only on prescription in every market where it is licensed, and choosing a dose is a matter for the approved product information and for the doctor writing the prescription. This page therefore refers to dose levels only as the lower, the established or the higher tested level, and reports what was measured at each of them.

Development and approval status

Approval and evidence timeline

  1. 2017First FDA approval on 5 December, for type 2 diabetesApproved as an entirely new active substance, ref [1]
  2. 2018Europe, Japan, Switzerland and Canada followRefs [2], [38], [39], [40]
  3. 2019-2020The tablet is approved in the United States, Japan and the European UnionRefs [15], [38], [41]
  4. 2021American approval for weight management on 4 June, and the first big weight trials appearRefs [14], [3], [22], [23]
  5. 2024Approved for lowering heart risk, in the United States in March and in the United Kingdom in JulyBased on the large heart trial, refs [14], [42], [5]
  6. 2025American approval for kidney disease in January and for fatty liver in August, and the eye warning added in Europe in JuneRefs [1], [14], [35]
  7. 2026British approval for fatty liver in July and for the weight tablet in June, and the Alzheimer programme is stoppedRefs [43], [44], [8]
  • 2017 — on 5 December the FDA approves the injection for type 2 diabetes, as an entirely new active substance [1].
  • 2018 — the European Commission authorises it on 8 February, Japan on 23 March, Switzerland on 2 July, and Canadian marketing begins on 22 February [2], [38], [39], [40].
  • 2019 — the tablet is approved in the United States on 20 September [15].
  • 2020 — the tablet follows in the European Union on 3 April and in Japan on 29 June [41], [38].
  • 2021 — the American approval for weight management comes on 4 June, and the European one on 6 January 2022 [14], [45].
  • 2024 — lowering heart risk is added as an approved use in the United States on 8 March and in the United Kingdom on 23 July [14], [42].
  • 2025 — the American approval for kidney disease follows on 28 January and the fast-tracked one for inflamed fatty liver on 15 August, and in June the European committee adds the eye warning [1], [14], [35].
  • 2026 — the United Kingdom approves a weight-loss tablet on 11 June and grants a conditional approval for inflamed fatty liver on 3 July [44], [43].
MarketStatusEarliest date confirmedWhat it is approved for
United StatesApproved2017-12-05Diabetes, heart risk, kidneys, weight, inflamed fatty liver
European UnionApproved2018-02-08Diabetes, weight
GermanyApproved2018-02-08Diabetes, weight
United KingdomApproved2024-07-23Diabetes, weight, heart risk, inflamed fatty liver (conditional)
AustraliaRegistered2022-09-01Diabetes, weight
CanadaMarketed2018-02-22Diabetes, weight
SwitzerlandApproved2018-07-02Diabetes, kidneys, weight, heart risk, inflamed fatty liver
JapanApproved2018-03-23Diabetes, obesity (with restrictions)

Two entries in this table need a word of explanation. The British date is the earliest milestone in the sources used here, not the date of first approval, which is not documented on this page [42]. Japan allows use in obesity only above set body mass index thresholds and only with certain accompanying illnesses [38].

The approved uses must not be lumped together across markets. The American package insert lists lowering heart risk and treating inflamed fatty liver as approved uses in their own right. The European text for the weight product covers weight management and merely refers to the clinical section for the heart results [9], [45]. Switzerland names lowering heart risk and treating inflamed fatty liver among its approved uses [39].

In every market listed, the substance is dispensed on prescription only, and Australia classes it as a prescription-only poison [46]. Every entry describes the position on 6 September 2026.

Who pays is a separate question. In Germany the health insurers do not cover it for weight, because it counts as a lifestyle medicine there, while they do cover it for diabetes [47]. The wider framework is set out under are peptides legal and FDA-approved peptides.

Anti-doping

Semaglutide is not banned in sport. It does not appear on the 2026 prohibited list, either in or out of competition, and that list requires no special medical exemption for it [10].

Instead it sits in the monitoring programme, which simply watches how often such substances are used and carries no penalty. Section 6 of that programme reads: "Markers of Semaglutide and Tirzepatide: In and Out-of-Competition" [11].

The 2026-27 list for American college sport names no drug of this kind, although a catch-all clause covers related substances [48]. The wider picture is at peptides banned in sport.

Compared with related peptides

SubstanceWhich gut hormone docking points it usesStatusBest weight result in its own trialHow long it lasts
SemaglutideGLP-1Approved in eight markets14.9% less body weight after 68 weeks, in 1,961 people [3]About 1 week [13]
TirzepatideGIP and GLP-1Approved in eight markets20.9% less body weight after 72 weeks, in 2,539 people [21]About 5 days [21]
RetatrutideGIP, GLP-1 and glucagonStill in late-stage trials, approved nowhere24.2% less body weight after 48 weeks, in only 338 people [49]Not stated here
LiraglutideGLP-1Approved in many markets8.0% less body weight after 56 weeks, in 3,731 people [50]Not stated here
OrforglipronGLP-1, but not a peptideApproved in the United States11.2% less body weight after 72 weeks, in 3,127 people [51]Not stated here

Those five figures come from five different trials. The people enrolled, the length of treatment, the starting weights and the way the results were calculated all differ, so that column ranks trials rather than drugs.

Two of the neighbours differ in kind, not merely in degree. Retatrutide works on a third docking point as well and is approved nowhere [49]. Orforglipron is a small molecule rather than a peptide, and it is swallowed [51]. Semaglutide is still the only one of the five that has met its goals for the heart, the kidneys and the liver in trials built for exactly that [5], [6], [7].

Common misconceptions

  • "The three brand names are three different drugs." They are one and the same active substance under three names, differing in the form it comes in and in what it is approved for [1], [14], [15].
  • "The approved text is the same everywhere." It is not. What the American, European, Swiss, Japanese and British authorities allow it to be used for differs in scope, and one of those approvals is only conditional [9], [45], [39], [38], [43].
  • "Semaglutide and tirzepatide can be swapped for one another." They are separate substances from separate manufacturers, with separate approvals. One works on a single gut hormone docking point, the other on two [13], [21].
  • "Semaglutide mixed in a pharmacy is the same medicine." It is not. The FDA declared the supply shortage over on 21 February 2025, and the grace periods for compounders ran out on 22 April and 22 May 2025 [52].
  • "It worked for everything that was studied." No. The Alzheimer trials failed on their main question, and the confirming measures in the large tablet trial showed no difference. The liver trial came up empty on its pain score, and complications of diabetic eye damage were more common in one of the heart trials [8], [34], [7], [27].
  • "The numbers from the trials apply to everyone." They are group averages, from clearly defined groups of people, under trial conditions, with support for diet and exercise on top. Compared with the dummy treatment, the difference was 12.4 percentage points in people without diabetes and 6.2 in people with it [3], [22].
  • "Tablet and injection can be swapped as you like." The American package insert states that the two tablet brands cannot be exchanged milligram for milligram [16]. The British regulator has also warned about mix-ups when a patient changes from one form to another [53].

Frequently asked questions

Is semaglutide a prescription medicine?

Yes, in every market on this page. It is fully licensed in the United States, the European Union, Germany, the United Kingdom, Australia, Canada, Switzerland and Japan, and in all of them it is available on prescription only. Getting hold of it outside that chain breaks medicines law rather than sitting in some grey area.

How much weight did people lose in the semaglutide trials?

In the largest trial, 1,961 adults with obesity and without diabetes lost an average of 14.9 percent of their body weight over 68 weeks, against 2.4 percent on a dummy treatment. A two-year trial held a loss of 15.2 percent at 104 weeks. In adults who also had type 2 diabetes the figure was noticeably smaller, at 9.6 percent.

Does semaglutide reduce cardiovascular events?

In one clearly defined group it does. Among 17,604 adults with obesity and existing heart disease, but without diabetes, the risk of a serious heart event was about 20 percent lower than on the dummy treatment (hazard ratio 0.80, range 0.72 to 0.90). In a separate trial in people with type 2 diabetes the risk was about 26 percent lower (hazard ratio 0.74).

What are the most common side effects of semaglutide?

Nausea, diarrhoea, vomiting and constipation. Across the pooled weight trials, 44 percent of participants felt sick against 16 percent on the dummy treatment, and stomach and bowel complaints of any kind affected 73 percent against 47 percent. Severe complaints of that sort occurred in 4.1 percent against 0.9 percent.

What is the boxed warning on semaglutide about?

All three American package inserts carry a framed warning about a rare kind of thyroid tumour. In rats and mice, semaglutide causes such tumours, and the more they get and the longer they get it, the more often it happens, at amounts comparable to those used in people. Whether the same is true in people is unknown. It must not be used by anyone who has had that thyroid cancer, or has it in the family, or who has a particular inherited hormone syndrome.

Why do the European and US semaglutide labels differ on eye damage?

The European committee finished its review in June 2025 and added a sudden loss of vision caused by damage to the optic nerve (non-arteritic anterior ischaemic optic neuropathy) as a very rare side effect, meaning up to 1 in 10,000 people treated. The British regulator followed in February 2026. On 6 September 2026 the American package inserts still carried no such entry.

Did semaglutide work in Alzheimer's disease?

No. Two large trials in 3,808 people with early Alzheimer's disease, confirmed by brain scan, failed on their main question about thinking and memory. The differences from the dummy treatment were tiny, −0.08 (p = 0.57) in the one trial and 0.10 (p = 0.46) in the other, and well within what chance produces. Both trials were stopped once the result was in.

Why does this page list no semaglutide doses?

Because semaglutide is available only on prescription wherever it is licensed, and choosing a dose is a matter for the approved product information and for the doctor writing the prescription. This page refers to dose levels only as the lower, the established or the higher tested level, and reports what was measured at each.

Is semaglutide banned in sport?

No. It does not appear on the 2026 prohibited list of the World Anti-Doping Agency, either in or out of competition, and that list requires no special medical exemption for it. Since 2024 it has been in the monitoring programme, joined by tirzepatide in 2026, and being there carries no penalty.

Is compounded semaglutide the same as the approved medicine?

No. Preparations mixed in a pharmacy go through no licensing procedure, and nobody checks them in the same way for what they actually contain, how pure they are, whether they work or whether they are sterile. The FDA declared the supply shortage over on 21 February 2025, and the grace periods for compounders ran out on 22 April and 22 May 2025.

Sources

  1. Drugs@FDA / openFDA, NDA 209637 (semaglutide injection, diabetes application), approval and supplement history. Retrieved 6 September 2026; original approval 5 December 2017, kidney supplement 28 January 2025. https://api.fda.gov/drug/drugsfda.json?search=application_number:%22NDA209637%22
  2. European Medicines Agency, EPAR Ozempic (semaglutide), EMEA/H/C/004174, authorised 8 February 2018, marketing authorisation holder Novo Nordisk A/S, ATC A10BJ06; product information sections 4.4 and 4.8, source of the NAION frequency estimate. https://www.ema.europa.eu/en/medicines/human/EPAR/ozempic
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  8. Efficacy and safety of oral semaglutide in early-stage symptomatic Alzheimer's disease (evoke and evoke+): two randomised, double-blind, placebo-controlled phase 3 trials (2026). The Lancet 407(10544):2167-2179. PMID 41865758. DOI 10.1016/S0140-6736(26)00459-9
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  10. World Anti-Doping Agency, The 2026 Prohibited List, in force 1 January 2026. Checked in full text on 6 September 2026: semaglutide, GLP-1 receptor agonists and incretin mimetics are not listed. https://www.wada-ama.org/en/prohibited-list
  11. World Anti-Doping Agency, The 2026 Monitoring Program, section 6. https://www.wada-ama.org/sites/default/files/2025-09/2026_list_monitoring_program_en_final_clean_september_2025.pdf
  12. PubChem, Compound CID 56843331 (Semaglutide). National Library of Medicine; source of the development codes NN9535 and NNC 0113-0217. https://pubchem.ncbi.nlm.nih.gov/compound/56843331
  13. OZEMPIC (semaglutide) injection — US Prescribing Information. Novo Nordisk, revision 01/2025. DailyMed setid adec4fd2-6858-4c99-91d4-531f5f2a2d79. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=adec4fd2-6858-4c99-91d4-531f5f2a2d79
  14. Drugs@FDA / openFDA, NDA 215256 (semaglutide, weight-management application), approval and supplement history. Retrieved 6 September 2026; original approval 4 June 2021, cardiovascular supplement 8 March 2024, accelerated MASH supplement 15 August 2025. https://api.fda.gov/drug/drugsfda.json?search=application_number:%22NDA215256%22
  15. Drugs@FDA / openFDA, NDA 213051 (oral semaglutide tablets), approval and supplement history. Retrieved 6 September 2026; original approval 20 September 2019, cardiovascular supplement 17 October 2025. https://api.fda.gov/drug/drugsfda.json?search=application_number:%22NDA213051%22
  16. Oral semaglutide tablets — US Prescribing Information. Novo Nordisk, revision 01/2026. DailyMed setid 27f15fac-7d98-4114-a2ec-92494a91da98. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=27f15fac-7d98-4114-a2ec-92494a91da98
  17. DailyMed Web Services API v2, structured product labelling XML; UNII 53AXN4NNHX taken from the activeMoiety element. https://dailymed.nlm.nih.gov/dailymed/services/v2/spls/adec4fd2-6858-4c99-91d4-531f5f2a2d79.xml
  18. Wikidata, Q27261089 (semaglutide); source of the MeSH, RxNorm and alternative PubChem identifiers. https://www.wikidata.org/wiki/Q27261089
  19. ChEMBL, CHEMBL3616752 (SEMAGLUTIDE). https://www.ebi.ac.uk/chembl/compound_report_card/CHEMBL3616752/
  20. DrugBank, DB13928 (Semaglutide); identifier verified through Wikidata. https://go.drugbank.com/drugs/DB13928
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  22. Davies M, Faerch L, Jeppesen OK et al. (2021). Semaglutide once a week in adults with overweight or obesity and type 2 diabetes (STEP 2). The Lancet 397(10278):971-984. PMID 33667417. DOI 10.1016/S0140-6736(21)00213-0
  23. Rubino D, Abrahamsson N, Davies M et al. (2021). Effect of continued weekly subcutaneous semaglutide vs placebo on weight loss maintenance in adults with overweight or obesity (STEP 4). JAMA 325(14):1414-1425. PMID 33755728. DOI 10.1001/jama.2021.3224
  24. Once-weekly semaglutide at a higher dose level in adults with obesity (STEP UP): a randomised, controlled, phase 3b trial (2025). The Lancet Diabetes & Endocrinology 13(11):949-963. PMID 40961952
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  26. Pratley RE, Aroda VR, Lingvay I et al. (2018). Semaglutide versus dulaglutide once weekly in patients with type 2 diabetes (SUSTAIN 7): a randomised, open-label, phase 3b trial. The Lancet Diabetes & Endocrinology 6(4):275-286. PMID 29397376
  27. Marso SP, Bain SC, Consoli A et al. (2016). Semaglutide and cardiovascular outcomes in patients with type 2 diabetes (SUSTAIN-6). New England Journal of Medicine 375(19):1834-1844. PMID 27633186. DOI 10.1056/NEJMoa1607141
  28. Kosiborod MN, Abildstroem SZ, Borlaug BA et al. (2023). Semaglutide in patients with heart failure with preserved ejection fraction and obesity (STEP-HFpEF). New England Journal of Medicine 389(12):1069-1084. PMID 37622681. DOI 10.1056/NEJMoa2306963
  29. Kosiborod MN, Petrie MC, Borlaug BA et al. (2024). Semaglutide in patients with obesity-related heart failure and type 2 diabetes (STEP-HFpEF DM). New England Journal of Medicine 390(15):1394-1407. PMID 38587233. DOI 10.1056/NEJMoa2313917
  30. Bonaca MP, Catarig AM, Houlind K et al. (2025). Semaglutide and walking capacity in people with symptomatic peripheral artery disease and type 2 diabetes (STRIDE): a phase 3b, double-blind, randomised, placebo-controlled trial. The Lancet 405(10489):1580-1593. PMID 40169145. DOI 10.1016/S0140-6736(25)00509-4
  31. Bliddal H, Bays H, Czernichow S et al. (2024). Once-weekly semaglutide in persons with obesity and knee osteoarthritis (STEP 9). New England Journal of Medicine 391(17):1573-1583. PMID 39476339. DOI 10.1056/NEJMoa2403664
  32. Knop FK, Aroda VR, do Vale RD et al. (2023). Oral semaglutide in adults with overweight or obesity (OASIS 1): a randomised, double-blind, placebo-controlled, phase 3 trial. The Lancet 402(10403):705-719. PMID 37385278. DOI 10.1016/S0140-6736(23)01185-6
  33. Husain M, Birkenfeld AL, Donsmark M et al. (2019). Oral semaglutide and cardiovascular outcomes in patients with type 2 diabetes (PIONEER 6). New England Journal of Medicine 381(9):841-851. PMID 31185157. DOI 10.1056/NEJMoa1901118
  34. McGuire DK, Marx N, Mulvagh SL et al. (2025). Oral semaglutide and cardiovascular outcomes in high-risk type 2 diabetes (SOUL). New England Journal of Medicine 392(20):2001-2012. PMID 40162642. DOI 10.1056/NEJMoa2501006
  35. European Medicines Agency, Meeting highlights from the Pharmacovigilance Risk Assessment Committee (PRAC), 2-5 June 2025; NAION review closed, added as a very rare adverse reaction to the product information of all semaglutide-containing medicines. https://www.ema.europa.eu/en/news/meeting-highlights-pharmacovigilance-risk-assessment-committee-prac-2-5-june-2025
  36. MHRA, GLP-1 receptor agonists and dual GLP-1/GIP receptor agonists: strengthened warnings on acute pancreatitis, including necrotising and fatal cases. Drug Safety Update, 29 January 2026. https://www.gov.uk/drug-safety-update/glp-1-receptor-agonists-and-dual-glp-1-slash-gip-receptor-agonists-strengthened-warnings-on-acute-pancreatitis-including-necrotising-and-fatal-cases
  37. MHRA, Semaglutide: risk of non-arteritic anterior ischaemic optic neuropathy (NAION). Drug Safety Update, 5 February 2026. https://www.gov.uk/drug-safety-update/semaglutide-wegovy-ozempic-and-rybelsus-risk-of-non-arteritic-anterior-ischemic-optic-neuropathy-naion
  38. Pharmaceuticals and Medical Devices Agency (Japan), List of Approved Products — New Drugs, April 2004 to February 2026. Injection approved 23 March 2018, tablets 29 June 2020, obesity indication 27 March 2023 with defined body mass index and comorbidity criteria. https://www.pmda.go.jp/files/000281190.pdf
  39. Swissmedic, list of authorised packs for human medicinal products (XLSX, as at 31 August 2026). Authorisation 66604 from 2 July 2018, 68798 from 20 March 2023 and 69865 from 28 November 2025; all dispensing category B. https://www.swissmedic.ch/swissmedic/en/home/services/listen_neu.html
  40. Health Canada, Drug Product Database API. Drug codes 96058 (first marketed 22 February 2018), 101167 (status date 23 November 2021) and 98740 (first marketed 19 April 2020); schedules PRESCRIPTION and SCHEDULE D. https://health-products.canada.ca/api/drug/drugproduct/?lang=en&type=json&brandname=OZEMPIC
  41. European Medicines Agency, EPAR Rybelsus (semaglutide), EMEA/H/C/004953, authorised 3 April 2020, revision 17 of 22 April 2026. https://www.ema.europa.eu/en/medicines/human/EPAR/rybelsus
  42. MHRA. MHRA approves GLP-1 receptor agonist semaglutide to reduce risk of serious heart problems in obese or overweight adults. Press release, 23 July 2024. https://www.gov.uk/government/news/mhra-approves-glp-1-receptor-agonist-semaglutide-to-reduce-risk-of-serious-heart-problems-in-obese-or-overweight-adults
  43. MHRA. Semaglutide approved to treat form of liver disease. Press release, 3 July 2026; conditional marketing authorisation for MASH with moderate to advanced liver fibrosis. https://www.gov.uk/government/news/semaglutide-wegovy-approved-to-treat-form-of-liver-disease
  44. MHRA. First GLP-1 tablet for weight loss approved in the UK. Press release, 11 June 2026. https://www.gov.uk/government/news/first-glp-1-tablet-for-weight-loss-approved-in-the-uk
  45. European Medicines Agency, EPAR Wegovy (semaglutide), EMEA/H/C/005422, authorised 6 January 2022, revision 18 of 26 August 2026, with the product information sections 4.1 and 5.1. https://www.ema.europa.eu/en/medicines/human/EPAR/wegovy
  46. Therapeutic Goods Administration, ARTG entries 356285 (registered 1 September 2022) and 446290, and the Therapeutic Goods (Poisons Standard) Instrument, entry SEMAGLUTIDE — Schedule 4, prescription-only medicine. https://www.tga.gov.au/resources/artg/356285
  47. Section 34(1) sentence 7 of the German Social Code Book V, the statutory exclusion of medicines for weight reduction, appetite suppression and body weight regulation from statutory health insurance cover.
  48. 2026-27 NCAA Banned Substances. Checked in full text on 6 September 2026: no GLP-1 receptor agonist is named under peptide hormones, growth factors, related substances and mimetics; a catch-all clause covers chemically or pharmacologically related substances.
  49. Jastreboff AM, Kaplan LM, Frias JP et al. (2023). Triple-hormone-receptor agonist retatrutide for obesity — a phase 2 trial. New England Journal of Medicine 389(6):514-526. PMID 37366315. DOI 10.1056/NEJMoa2301972
  50. Pi-Sunyer X, Astrup A, Fujioka K et al. (2015). A randomized, controlled trial of liraglutide in weight management (SCALE Obesity and Prediabetes). New England Journal of Medicine 373(1):11-22. PMID 26132939. DOI 10.1056/NEJMoa1411892
  51. Orforglipron, an oral small-molecule GLP-1 receptor agonist, in adults with obesity (ATTAIN-1) (2025). New England Journal of Medicine. PMID 40960239. DOI 10.1056/NEJMoa2511774. NCT05869903
  52. FDA. FDA clarifies policies for compounders as national GLP-1 supply begins to stabilize. Drug Alerts and Statements; semaglutide shortage declared resolved on 21 February 2025, transition periods lapsing 22 April and 22 May 2025. https://www.fda.gov/drugs/drug-alerts-and-statements/fda-clarifies-policies-compounders-national-glp-1-supply-begins-stabilize
  53. MHRA, oral semaglutide tablets: transition to new formulation and risk of medication error. Drug Safety Update, 17 December 2025. https://www.gov.uk/drug-safety-update/rybelsus-r-semaglutide-tablets-transition-to-new-formulation-and-risk-of-medication-error
  54. ClinicalTrials.gov, registry query for semaglutide; 748 registered studies as at 6 September 2026. https://clinicaltrials.gov/search?intr=semaglutide

Cite this page

The facts on this page were checked on 6 September 2026, and the register searches behind the status table were run on that date. Approved medicines gain new uses and new warnings over time, so the version and the date matter as much as the text. On that day, the ClinicalTrials.gov registry listed 748 registered studies of this substance [54].

myPeptides Research & Editing. (2026). Semaglutide: what the trials show, status and safety. Version 1.0, 6 September 2026. myPeptides Peptide Register. Retrieved from https://mypep.app/peptides/semaglutide

How pages in this register are compiled and graded is described under methodology; the full register is at peptides.

VersionDateChange
1.02026-09-06Initial publication

Last verified: 6 September 2026. Next review: on a labelling change in any covered market, on publication of the full ESSENCE trial, or on any change in the anti-doping classification.

Identifiers

IdentifierValue
CAS number910463-68-2
PubChem CID56843331
UNII53AXN4NNHX
InChIKeyDLSWIYLPEUIQAV-CCUURXOWSA-N
DrugBankDB13928
ChEMBLCHEMBL3616752
WikidataQ27261089
Molecular formulaC187H291N45O59
Molecular weight4113.58

Related peptides

Cite this page

Use this reference when you quote the page, and the JSON export when you process it automatically.

myPeptides Research & Editing (2026). Semaglutide: what the trials show, status and safety (Version 1.0). myPeptides. https://mypep.app/peptides/semaglutide

Machine-readable version (JSON)

Last reviewed: September 2026

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