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Semaglutide

Proven for weight, diabetes, heart risk and MASH. Failed in Alzheimer's.

A long-acting copy of the gut hormone , taken weekly as an injection or daily as a tablet for weight loss and type 2 diabetes. It also cuts heart attacks and strokes in people with heart disease and excess weight. A made by Novo Nordisk, also called Ozempic, Wegovy, Rybelsus and Wegovy pill.

C152H230N42O473,397.8 g/mol31 amino acidsChain only, without the fatty-acid side chain.

What the evidence shows

Weight loss in obesity
Proven
STEP 1: about 15% average loss at 68 weeks on 2.4 mg a week. STEP UP: 18.7% at 72 weeks on 7.2 mg, or 20.7% in people who stayed on it. OASIS 4: 16.6% on the 25 mg daily pill in people who stayed on it.
Type 2 diabetes
Proven
Approved as Ozempic injections and Rybelsus tablets.
Fewer heart attacks and strokes
Proven
SELECT (17,604 people with heart disease and excess weight but no diabetes): major cardiac events fell 20%.
Fatty liver with scarring (MASH)
Proven
Accelerated approval
US accelerated approval in August 2025. Conditional EU authorization as Kayshild in March 2026. In ESSENCE, liver inflammation cleared in about 6 in 10 people, against about 1 in 3 on placebo.
Knee arthritis pain with obesity
Supported
STEP 9 (407 people, 68 weeks): knee pain fell clearly more than on placebo.
Slowing Alzheimer's disease
Failed
Two large trials of the tablet (EVOKE and EVOKE+) found no slowing of decline.

Side effects and risks

Serious
Boxed warning for thyroid C-cell tumors, seen in rodents.
Serious
Pancreatitis and gallbladder disease, including gallstones.
Serious
A rare kind of sudden vision loss (NAION), listed by European regulators as a very rare side effect.
Common
Nausea, vomiting, diarrhea and constipation, mostly while the dose is rising.
Common
Muscle is lost along with fat. Weight returns after stopping: in one trial people regained about two-thirds within a year.
Common
Low blood sugar when combined with insulin or sulfonylureas.
Common
Food stays in the stomach longer. Tell the anesthesia team before any procedure.

Who should avoid it: Pregnancy or trying to conceive (stop at least two months before), medullary thyroid cancer or MEN 2 in you or your family, and past pancreatitis unless a specialist agrees.

Athletes: Monitoring. Not prohibited. On the monitoring program since 2024 so WADA can track use. Still listed for 2027. USADA advisory on 2027 WADA list, 2026-10

How it works

Where it acts
GLP-1 receptors in the pancreas, the stomach and the appetite centres of the brain.
What it changes
More insulin when blood sugar is high, less glucagon, a slower-emptying stomach and fewer hunger signals.
What people notice
A smaller appetite and earlier fullness within weeks. Nausea or constipation are common while the dose is being raised.

How it is taken

Weekly injection under the skin, starting at 0.25 mg and rising every four weeks to a maintenance dose of 2.4 mg, or 7.2 mg where that dose is approved. The weight-loss tablet is taken daily on an empty stomach with a sip of water, 30 minutes before food, stepping up from 1.5 mg to 25 mg. A prescriber sets the schedule.

Getting it in the United States

This describes what people do. It is not advice. The decision is yours.

What users report

Recurring themes in public forum posts, unverified and with no comparison group.

Reported benefits

  • Quieter thoughts about food
  • Steady loss over months
  • Fewer cravings for alcohol and snacks

Reported problems

  • Nausea and constipation in the first weeks at each dose
  • Tiredness, sulfur burps
  • Hair shedding during fast loss
  • Regain after stopping; cost and supply

The themes match the trial data closely, which is unusual for forum reports.

More contextCase reports, what public figures say, videos and articles, when options run out and the chemistry

Case reports

From journals, regulators and studies of users. One case proves little.

Benefit reportedtrial result in rare group - 64 people - 2026

Open-label single-centre trial in China of women with PCOS-related infertility and excess weight. Adding semaglutide to metformin restored periods in more women and improved insulin measures. No placebo, short follow-up, pregnancy outcomes not measured.

Source: Metabolism and Target Organ Damage, 2026-03

FDA adverse event reports for compounded GLP-1 drugs

Harm reportedcase series - 2024

By late November 2024 the FDA had received more than 392 adverse event reports for compounded semaglutide and more than 215 for compounded tirzepatide. The agency says the true number is likely higher because most state-licensed pharmacies do not have to report.

Source: FDA, 2024

Overdoses from compounded semaglutide vials and syringes

Harm reportedcase series - 2024

The FDA described reports of people drawing up 5 to 20 times the intended amount from multi-dose vials, and of prescribers miscalculating when converting between milligrams, millilitres and syringe units. Some patients were hospitalised. Reported effects included vomiting, fainting, dehydration, acute pancreatitis and gallstones.

Source: FDA alert, 2024

US poison centre calls on GLP-1 drugs

Harm reportedpoison centre data - 22966 people - 2025

US poison centres logged 22,966 GLP-1 agonist exposure cases from 2019 to 2025, a rise of nearly 1,500 percent in calls. Most were accidental dosing errors. With compounded products, some callers had taken ten times the intended amount after misreading syringe units.

Source: America's Poison Centers, 2025

What experts and influencers say

Recommend15
Mixed view18
Warn against25

Paraphrased from the linked sources.

Pledged swift action against firms mass-marketing copycat semaglutide after a telehealth company tried to sell a compounded version of the Wegovy pill. FDA then sent 30 warning letters over misleading compounded GLP-1 claims.

Source: Fierce Pharma, 2026-03

Marty MakaryXWarns against

FDA Commissioner

Judges each peptide separately. He sees no use case for BPC-157: no human evidence, animal data mostly from one lab, and claims that keep widening. He is not a proponent of growth-hormone peptides such as CJC-1295, citing short studies and no long-term safety data. He says elamipretide makes sense only for Barth syndrome, that the risks of melanotan II probably outweigh a cosmetic tan, and that he stopped prescribing bremelanotide. He regards the GLP-1 drugs as clearly effective.

Source: Peter Attia, AMA 83 show notes, 2026

Peter AttiaInstagramMixed view

Physician and podcast host

Said people microdosing semaglutide or tirzepatide are in effect test subjects, because neither the benefits nor the risks of very small doses have been studied.

Source: STAT, 2025-11

Reshma RamachandranWebsiteWarns against

Physician and health services researcher, Yale School of Medicine

Photo source: medicine.yale.edu

Watch and read

Explainers, reporting and podcasts worth your time. Summaries are ours. No sellers.

Video - PBS NewsHour - 5 Oct 2026 - 7 min

As GLP-1s reshape America, questions and new uses emerge

William Brangham, correspondent; Julia Belluz, journalist and author

Traces the GLP-1 story from Gila monster hormone to blockbuster drugs, weighing benefits beyond weight loss against regain, side effects, lawsuits and cost.

Recent, balanced overview of the whole GLP-1 landscape

Podcast - Science Vs (Spotify Studios) - 14 Mar 2024 - 38 min

Ozempic: Is It Scarier Than We Thought?

Wendy Zukerman, host; guests include endocrinologist Dr Vibha Singhal and gastroenterologist Dr Michael Camilleri

Fact-checks claims about GLP-1 drugs, from stomach paralysis to muscle loss and suicidal thoughts, finding most risks rare or comparable to other weight loss.

Careful, evidence-first look at the main safety worries

Video - Amanpour and Company (PBS, via GPB) - 13 Mar 2023 - 18 min

Obesity Doctor on Everything You Need to Know About Ozempic

Dr Fatima Cody Stanford, obesity medicine physician

An obesity medicine specialist answers broad questions about Ozempic in a short broadcast interview.

Short, plain interview with a practising obesity specialist

When options run out

Uses people turn to when standard treatment has failed.

Alcohol use disorder

Who
People with heavy drinking who have not been helped by, or do not want, the few approved addiction medicines.
Evidence
One 48-person, nine-week randomized trial in people not seeking treatment showed less craving, fewer drinks per drinking day and fewer heavy drinking days than placebo. Not approved for this use. Larger trials are needed.

Source: USC Today, 2025-02

Add-on to insulin in type 1 diabetes

Who
Adults with type 1 diabetes and obesity who struggle with weight and glucose targets despite automated insulin delivery.
Evidence
One 72-person, 26-week randomized trial funded by a type 1 diabetes charity. About a third on the drug hit combined glucose and weight targets, none on placebo. No ketoacidosis, and severe lows were equal in both groups. Off-label. Lead author Viral Shah has called for a registration trial.

Source: Indiana University School of Medicine, 2025-06

Idiopathic intracranial hypertension

Who
People with this rare pressure-on-the-brain condition who face vision loss, shunt or stent surgery, or side effects from standard tablets.
Evidence
US records study of 1,110 matched patients found fewer symptoms and procedures in GLP-1 users, semaglutide included. Retrospective, drugs not compared. No randomized trial yet.

Source: NeurologyLive interview with Dennis Rivet, 2025-08

Legal last-resort routes

Expanded access (compassionate use)

For a serious or life-threatening condition with no comparable alternative and no trial you can join. Your physician asks the company for the drug, then files with FDA and an ethics board. The company can refuse. Costs are often not insured.

Source: FDA, expanded access for patients

Right to Try

For a life-threatening condition after approved options are exhausted and no trial is open to you. The drug must have finished Phase 1 and be in active development. Your doctor asks the manufacturer directly. FDA does not review requests.

Source: FDA, Right to Try

Trial finders

Search ClinicalTrials.gov by condition or drug name, check eligibility and call the listed site. ResearchMatch is a free NIH-funded registry that lets researchers find you. Discuss risks with your own clinician before enrolling.

Source: NIH, finding a clinical trial

Personal import for serious conditions

FDA may not object when a US citizen imports up to about three months of a drug for a serious condition with no effective US treatment, with written personal-use confirmation and a US doctor's details. It is discretion, not a right.

Source: FDA, personal importation

Patient-specific compounding

When the approved product cannot meet a specific need of an identified patient, a prescriber can order a compounded version from a licensed pharmacy. Lower price alone does not qualify. Ingredients must be pharmaceutical grade.

Source: Oregon Board of Pharmacy, Feb 2025

Amino-acid sequence

Water-avoidingWater-lovingPositive chargeNegative chargeStructural

Position 20 carries a fatty-acid side chain. Ringed tiles are amino acids not found in natural proteins.

Questions people ask

Are Ozempic and Wegovy the same drug?

Yes. Both are semaglutide from Novo Nordisk. Ozempic and the Rybelsus tablet are approved for type 2 diabetes, while Wegovy, as a weekly injection or a daily pill, is the weight-loss brand.

How much weight do people lose on semaglutide?

In the STEP 1 trial, average loss was about 15% at 68 weeks. A higher dose reached 18.7% at 72 weeks in STEP UP, and the daily pill reached 16.6% in people who stayed on it in OASIS 4.

What are the side effects of semaglutide?

Nausea, vomiting, diarrhea and constipation are common, mostly while the dose is rising. Serious risks include pancreatitis, gallbladder disease, a boxed warning for thyroid C-cell tumors seen in rodents, and a very rare kind of sudden vision loss (NAION).

What happens when you stop taking semaglutide?

Weight usually returns. In one trial people regained about two-thirds of the lost weight within a year of stopping.

How much does Wegovy cost without insurance in the US?

The maker's self-pay prices in October 2026 were $149 to $299 a month for the pill and $349 a month for the injection, or $399 for the highest dose, with a new patient's first two months at $199. Large-scale compounding lost its legal basis when the shortages ended in 2025, and FDA has sent warning letters over compounded versions that are still sold.

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Sources

  1. Novo Nordisk: FDA approves the Wegovy pill (22 Dec 2025)
  2. Drugs.com: Wegovy approval history
  3. EMA: Wegovy product page
  4. EMA: Kayshild product page
  5. NovoCare: Wegovy self-pay prices
  6. Health Canada: first generic semaglutide (28 Apr 2026)
  7. Health Canada: first generic semaglutide for weight loss (29 Jun 2026)
  8. Novo Nordisk: half-year report 2026
  9. Gallup: GLP-1 use reaches new high (7 Jul 2026)

Structure: PubChem