Semaglutide
Also called Ozempic, Wegovy, Rybelsus
The original of the modern weight-loss injections and still the most widely used.
This one has been through full clinical trials and is an approved medicine somewhere in the world. The ranges below are drawn from those trials and from what the community reports using.
410,198 posts67,008 people9 communities
of community reporting analysed for this compound. That is the part you cannot find anywhere else — the trial data below it, you could look up yourself.
USA · FDA · Ozempic / Wegovy / Rybelsus
EU · EMA
Canada
Japan
China
- Body composition
- Fat loss & metabolic
The quick answer
The original of the modern weight-loss injections and still the most widely used. One lever: GLP-1. Appetite down, stomach empties more slowly, fullness arrives sooner and lasts longer.
What it is not
Not gentler than the newer ones. It is the one with the most reported nausea.
Why people use it
Appetite suppression that most people describe as the food chatter going quiet. Blood sugar control. It has the longest track record and the largest body of human data of anything in this category.
What people report using
These are ranges other people have reported running. They are here so you can see what has actually been done — they are not medical advice and not a recommendation for you.
People report running this anywhere from 1.7mg to 2.4mg, once weekly.Where somebody sits in that range depends on what they are using it for and what they are starting from — the low end is a deliberate choice a lot of people make, not a half-hearted version of the high end.
Fat loss & metabolic
- How often
- Once weekly
- Route
- subcutaneous
- Where this comes from
- Approved medicine
Food noise dropping in the first week or two is the near-universal report, often before any weight moves.
Grey-market vials are commonly 5mg or 10mg. 5mg vial + 2ml BAC water = 2.5mg/ml: 0.25mg draws at 10 units, 0.5mg at 20 units, 1mg at 40 units. 10mg vial + 2ml = 5mg/ml: 0.25mg draws at 5 units, 2.4mg at 48 units. Check your own vial strength and use the calculator — the same unit count is a different amount of peptide in every vial.
Work out your own units on the reconstitution calculator — the most common serious mistake in this area is arithmetic, not chemistry.
What to expect, and when
Week 1-2: adjustment, and this is where most of the discomfort lives. Week 2-3: appetite shifts. Week 4-12: weight follows. This is a months-long compound. Stopping is its own phase and people who plan for it do better than people who do not.
Side effects, and what people do about them
Nausea is the common one and it is manageable: it clusters around dose increases rather than lasting, and sitting at a step longer before climbing is the lever most people use. Lighter, lower-fat meals the day after help. For comparison when you are choosing between the two, semaglutide draws more nausea reports than tirzepatide - 39.4% against 28.6% across 29,172 people.
Go deeper
Open these only if you want them.
How it actually works
GLP-1 receptor agonist.
More on the evidence
Approved GLP-1 agonist with one of the largest phase 3 programmes of any modern drug - STEP for weight, SUSTAIN for diabetes, SELECT for cardiovascular outcomes. The dosing here is label dosing, not convention. Where this row leaves the trials is in describing grey-market vial use, and it says so where it does.
What people report, in full
People who have run both usually say tirzepatide was easier on the stomach, and semaglutide is the one most likely to make somebody feel genuinely rough in the first month. It is also the one most people have heard of, which is why it is where most start.
The texture of the reports is specific. Sulphur burps are semaglutide's signature complaint and the community's own fix is the sensible one: less fat in a sitting, smaller meals, and time. The feeling of food sitting undigested for hours is described often, and the advice is to stop eating earlier in the evening rather than to push through. Constipation is near-universal past the first month. Facial volume loss gets talked about a lot, and the community is fair about it - it is weight loss, not a drug effect, and it happens faster when the loss is faster, which is one of the arguments for going slower.
Two themes dominate the later conversation. The first is stopping: appetite comes back, and people who had no plan for that describe regaining. The consensus that has formed is that a maintenance dose is the normal end state rather than a failure. The second is protein and resistance training, raised constantly by people further along. A reproductive signal appears in community reports that is absent from the label - cycle changes and irregular bleeding - at low but consistent rates.
Worth knowing
Worth knowing rather than finding out later: the weight comes back. In STEP 4, people who stopped at week 20 regained most of what they had lost over the following year, while those who continued kept going down. Nobody disputes this and it is not a mark against the compound - it behaves like blood-pressure medication rather than like a course of antibiotics. But it means the honest question to answer before you start is what your plan is at month twelve, not month one. Anyone selling you a twelve-week supply as a finished project is selling you a twelve-week project.
Sources and review
Most of what is useful about these compounds comes from people who have used them, not from trials. These are published analyses of what communities reported. We did not read the posts ourselves and we do not claim to.
410,198 posts67,008 people9 communities
Reports from 2019-05 to 2025-06
Sehgal NKR, et al. Self-Reported Side Effects of Semaglutide and Tirzepatide in Online Communities. medRxiv 2026 / Nature Health.
Preprint then journal. Self-selected posters, not a cohort.
STEP 1 — Wilding JPH et al. Once-Weekly Semaglutide in Adults with Overweight or Obesity. N Engl J Med 2021;384:989-1002.2.4mg weekly, 68 weeks: -14.9% body weight vs -2.4% placebo.
STEP 4 — Rubino D et al. Effect of Continued Weekly Semaglutide vs Placebo on Weight Loss Maintenance. JAMA 2021;325:1414-1425.Withdrawal at week 20 led to regain of most of the lost weight over the following year.
SELECT — Lincoff AM et al. Semaglutide and Cardiovascular Outcomes in Obesity without Diabetes. N Engl J Med 2023;389:2221-2232.20% relative reduction in major adverse cardiovascular events.
community analysis410,198 posts / 67,008 users; 29,172 reporting an effect. Proportions of posters, not of users.
product testing12 no-prescription products ordered, 3 received. Very small sample; only independent grey-market assay in the literature.
harm surveillanceUS poison centre GLP-1 calls rose from ~1,000-1,500/yr pre-2021 to >8,000 in 2023. Calls are not confirmed harms.
Last reviewed 2026-09-08.
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