# Semaglutide — dosage, half-life & reference guide | PepVault

Source: https://pepvault.app/peptides/semaglutide

Last updated: 2026-09-26

[Library](https://pepvault.app/peptides) [Metabolic & GLP-1](https://pepvault.app/peptides#metabolic) reviewed September 2026

# Semaglutide Dosage, half-life & reference guide

Also known as Ozempic · Wegovy

A GLP-1 receptor agonist that mimics a gut hormone your body releases after eating: it reduces appetite and slows stomach emptying.

- **FDA label:** 0.25–2.4 mg starting dose 0.25 mg
- **How often:** Weekly
- **Half-life:** ~1 week
- **Evidence:** Established
- **Route:** SubQ injection

[Semaglutide dose guide](https://pepvault.app/lab/dosage/semaglutide)

## How it works.

GLP-1 receptor agonist that reduces appetite, slows gastric emptying, and improves glucose metabolism. FDA-approved for T2DM and obesity. Titrate dose slowly to minimize GI side effects.

**Commonly reported:** The constant background thoughts about food ("food noise") go quiet and portions shrink without effort, with nausea worst in the first days after each dose step. FDA-approved for type 2 diabetes, weight management, heart-risk reduction and MASH, with about 15% average weight loss at 68 weeks in its main trial.

### Half-life & active level

The half-life of Semaglutide is ~1 week (FDA label).

Here's how a typical Semaglutide schedule accumulates over four weeks (one-compartment estimate).

An estimate from the half-life above, not a measurement. See your own curve build live in [the half-life calculator](https://pepvault.app/tools/peptide-half-life-calculator).

## Where Semaglutide works.

- ### Heart & blood vessels

  **In people.** The 2023 SELECT trial showed semaglutide reduced cardiovascular events by 20% independent of weight loss.
- ### Appetite & metabolism

  **In people.** About 15% average weight loss at 68 weeks in its main trial.

An area lights for what a peptide is used for and what people report, with the evidence beside it. It isn’t a promise that it works there.

## Week by week.

What to expect in the first 8 weeks

- **Onset:** Days–2 weeks
- **Peak effect:** 60–68 weeks
- **Duration:** Ongoing

1. Day 1–28 · 0.25 mg RCT

   ### Gut is adapting

   The 0.25mg run-in is sub-therapeutic — it's letting your gut tolerate GLP-1 signaling. Nausea is often worst in week 1 then settles. Don't expect weight loss yet; eat small, stay hydrated.

   The science

   FDA Wegovy label 2025 specifies the 0.25mg step as GI adaptation, not weight loss. The first dose is usually the hardest — not because of dose magnitude but because it's a new signal the body hasn't seen before.

   Sources

   - FDA Wegovy label (2025)

   Updated Apr 2026
2. Day 29–56 · 0.5 mg RCT

   ### Appetite shifts are real now

   You're at 0.5mg, where the first clear appetite signal tends to show up. Commonly reported: portions shrinking on their own and the first quieting of 'food noise' — you're not chasing food between meals the way you used to.

   The science

   In a 20-week appetite trial in 72 adults, semaglutide cut the energy eaten at an all-you-can-eat lunch by 35% versus placebo, with less hunger and fewer cravings (Friedrichsen 2021). STEP 1 didn't measure appetite by dose step or "food noise"; that timing comes from user reports.

   Sources

   - Friedrichsen et al. (2021)

   Updated Sep 2026
3. Any day RCT

   ### What Semaglutide is built on

   Sema is the most-studied weight loss drug in history. Over 17,000 patients across STEP and SELECT, FDA approvals for diabetes and obesity, plus 20% cardiovascular risk reduction independent of weight loss.

   The science

   SELECT (Lincoff 2023 NEJM) was the first CV outcomes trial for an obesity drug in non-diabetic patients — 17,604 participants, 20% relative reduction in major adverse cardiovascular events at 2.4mg over ~40 months. Expanded the framing from "weight drug" to "metabolic disease modifier."

   Sources

   - Wilding et al. (2021)
   - Lincoff et al. (2023)

   Updated Apr 2026
4. With BPC-157 Community

   ### Why people add BPC-157 to Sema

   Sema titration comes with GI symptoms, and BPC-157, first studied as a stomach-protecting peptide, is added to ease them. Commonly reported: fewer GI side effects in the first weeks after each step-up.

   The science

   BPC-157's origin as a gastroprotective compound fits the GLP-1 side-effect profile: in animal studies it supports gut mucosal integrity, reduces NSAID damage and modulates the gut-brain axis. No trial has tested the combination; the pattern comes from community reports.

   Sources

   - Sikiric et al. (2018)

   Updated Sep 2026
5. Any day RCT

   ### There is now an oral semaglutide for weight loss

   Since December 2025 there's an FDA-approved oral semaglutide for obesity — a 25mg daily Wegovy pill, the first oral GLP-1 cleared for weight loss. When taken as directed, the trial showed about −16.6% at 64 weeks, with roughly a third of people losing ≥20%. The needle-free option is real now, not investigational.

   The science

   OASIS-4 supported the December 2025 FDA approval of oral semaglutide 25mg (Wegovy) for obesity, launched in January 2026 — the first oral GLP-1 for weight management. On-treatment (adherent) analysis showed −16.6% at 64wk, with ~1/3 of participants reaching ≥20% loss. Oral absorption is sensitive to dosing conditions (empty stomach, limited water, wait before eating), which is why adherence framing matters for the effect size. This is distinct from Rybelsus, the lower-dose oral semaglutide approved for type 2 diabetes.

   Sources

   - OASIS-4 (2026)

   Updated Sep 2026
6. Any day RCT

   ### Semaglutide is now approved for fatty-liver disease

   Beyond weight: in August 2025 semaglutide gained an FDA approval for MASH (the inflammatory form of fatty liver). In the phase 3 trial it resolved steatohepatitis in about 63% of people at 72 weeks and improved liver fibrosis — a benefit that goes past the number on the scale.

   The science

   The ESSENCE phase 3 trial supported the August 2025 FDA approval of semaglutide for MASH (metabolic dysfunction-associated steatohepatitis): 62.9% achieved resolution of steatohepatitis without worsening fibrosis at 72wk, alongside fibrosis improvement. Tirzepatide is close behind in MASH but not yet approved for it. This positions the GLP-1 class as a liver-disease modifier, not only a weight drug.

   Sources

   - ESSENCE (2025)

   Updated Jun 2026
7. Any day Clinical

   ### Protein + lifting protect the muscle underneath

   A real share of weight lost on semaglutide is lean mass — across the GLP-1 class, roughly a quarter to 40% of the loss. The fix is in your hands: keep protein near 1.6–2.2g/kg and keep resistance training through the cut. Sema quiets appetite; protein and lifting decide whether the loss is fat or muscle.

   The science

   STEP and SURMOUNT body-composition data put lean mass at ~25–40% of total weight lost on incretin therapy. Muscle-sparing combinations are emerging in trials (bimagrumab + semaglutide: ~22% loss with ~92% from fat) but are not standard care. Protein intake and resistance training are the evidence-backed levers a user controls today.

   Sources

   - STEP program (2021)

   Updated Jun 2026

### After week 8

1. Day 57–112 · 1 mg RCT

   ### Clinically useful weight loss kicks in

   At 1mg the scale usually starts moving visibly, and many people pass 5% loss around this step. Commonly reported: eating less without effort feels very real now.

   The science

   STEP 1 data: 86% of 2.4mg-group participants hit ≥5% loss at the study endpoint (Wilding 2021); the per-step timing isn't reported. Users commonly describe food-noise reduction as the single biggest subjective change; STEP 1 didn't measure it, and the term came from patients.

   Sources

   - Wilding et al. (2021)

   Updated Sep 2026
2. Day 113–140 · 1.7 mg RCT

   ### Max submaximal step

   1.7mg is the option for people who don't tolerate the full 2.4mg, or want meaningful loss without chasing the highest dose. If you're doing well here, this is a legitimate maintenance point.

   The science

   Wegovy label recognizes 1.7mg as a valid maintenance step for users who can't tolerate the 2.4mg. Many Sema users plateau at 1.7mg or even 1mg without needing to escalate — clinical trial mean effect sizes come from the full 2.4mg arm, but individual responses vary widely.

   Sources

   - FDA Wegovy label (2025)

   Updated Apr 2026
3. Day 141–364 · 2.4 mg RCT

   ### Full dose — the working dose

   Full dose (2.4mg) — the working dose. Weight keeps coming off, more slowly over time, until about week 60, with STEP 1 showing −14.9% at 68 weeks. This is the payoff for the whole titration ladder.

   The science

   Wilding 2021 NEJM STEP 1: −14.9% body weight at 68wk on 2.4mg vs −2.4% placebo. 86% of participants hit ≥5% loss. Weight fell from week 4 and reached its lowest point around week 60.

   Sources

   - Wilding et al. (2021)

   Updated Sep 2026
4. Day 365+ RCT

   ### Plateau territory — new baseline

   Plateau territory. In STEP 1 weight reached its lowest point around week 60 — most of the loss has landed. This is a maintenance medication, not a course: stopping usually means regaining most of the loss (around 10kg back in the first year in pooled data, trending toward baseline by ~18 months). Hold, taper slowly, or stop is a call for you and your clinician.

   The science

   STEP 1 extension (Wilding 2022) showed roughly 2/3 weight regain within a year of stopping semaglutide; a 2026 BMJ meta-analysis put regain for semaglutide and tirzepatide at about 9.9kg in the first year, back to baseline by about 1.5 years (West 2026). This reflects chronic-therapy pharmacology, not failure. SELECT (Lincoff 2023) separately showed 20% MACE reduction in non-diabetic patients at 2.4mg — a benefit independent of ongoing weight loss. The continue/taper/stop decision is yours, made with your clinician.

   Sources

   - Wilding et al. (2022)
   - West et al. (2026)
   - Lincoff et al. (2023)

   Updated Sep 2026

Day 1 is the day you start it.

Multiple Phase III RCTs (STEP 1–5). FDA-approved. Timelines are for weight management dose (2.4mg) on the label's titration.

Clinical trial data

## Mixing and a typical run.

Example numbers

### Reconstitution example

Reconstitute a 10 mg vial of Semaglutide with 2 mL of bacteriostatic water and a 0.25 mg dose is 5 units on a U-100 syringe, about 40 doses per vial.

- **Vial:** 10 mg
- **Water:** 2 mL
- **Amount:** 0.25 mg

Draw to **5 units**

0.3 mL insulin syringe · 30 units

[Mix it in the Reconstitution Lab](https://pepvault.app/lab) [Open the calculator](https://pepvault.app/tools/reconstitution-calculator)

### Run notes

- **Cycle:** FDA-approved for ongoing use. Community uses indefinitely or until goal weight reached, then tapers. Community practice — opinions vary. Not a clinical recommendation.
- **Timing:** Once weekly SubQ, same day each week. Can inject any time of day — consistency matters.
- **Route:** SubQ injection
- **Stacks:** BPC-157 (GI support), Tirzepatide (not combined)

## Safety.

### Common side effects

- Nausea
- Vomiting
- Diarrhea
- Constipation
- Decreased appetite
- Fatigue
- Pancreatitis risk

#### Interactions

Like the GLP-1 class, semaglutide delays gastric emptying and can affect absorption of oral medications — a label-level consideration; discuss oral-drug timing with your clinician. Combined with insulin or sulfonylureas, additive glucose-lowering increases hypoglycemia risk per the label, warranting clinician-guided monitoring. No specific documented interaction with SSRIs or anticoagulants beyond general caution; raise all medications and supplements with your clinician.

### Safety notes

Across the STEP and SELECT programs, semaglutide's adverse events are predominantly mild-to-moderate transient gastrointestinal effects; in SELECT, discontinuation for adverse events was higher than placebo (16.6% vs 8.2%), driven by GI events, while overall serious adverse events were actually lower than placebo. Gallbladder-related events were more frequent than placebo (2.8% vs 2.3% in SELECT, mostly gallstones), and acute pancreatitis was rare with no notable signal vs placebo across STEP 1-5. It shares the GLP-1-class rodent thyroid C-cell warning. These are trial/label findings — discuss with your clinician.

## Goes with.

- [BPC-157 GI support](https://pepvault.app/peptides/bpc-157)
- [Tirzepatide not combined](https://pepvault.app/peptides/tirzepatide)

## Compared with.

- [Semaglutide vs Tirzepatide](https://pepvault.app/peptides/compare/semaglutide-vs-tirzepatide)
- [Retatrutide vs Semaglutide](https://pepvault.app/peptides/compare/retatrutide-vs-semaglutide)
- [Orforglipron vs Semaglutide](https://pepvault.app/peptides/compare/orforglipron-vs-semaglutide)
- [Cagrilintide vs Semaglutide](https://pepvault.app/peptides/compare/cagrilintide-vs-semaglutide)
- [Liraglutide vs Semaglutide](https://pepvault.app/peptides/compare/liraglutide-vs-semaglutide)

## Questions people ask.

### What is Semaglutide?

A GLP-1 receptor agonist that mimics a gut hormone your body releases after eating: it reduces appetite and slows stomach emptying.

### How is Semaglutide dosed in research?

The FDA label range for Semaglutide is 0.25–2.4 mg, weekly SubQ, with a 0.25 mg starting dose.

### How long does Semaglutide last?

The half-life of Semaglutide is ~1 week (FDA label).

### What do people report on Semaglutide?

Commonly reported on Semaglutide: the constant background thoughts about food ("food noise") go quiet and portions shrink without effort, with nausea worst in the first days after each dose step. FDA-approved for type 2 diabetes, weight management, heart-risk reduction and MASH, with about 15% average weight loss at 68 weeks in its main trial.

### Is Semaglutide safe?

The research basis for Semaglutide is established: clinical trials or FDA-approved use exists. Common side effects in the library: nausea, vomiting, diarrhea, constipation, decreased appetite, fatigue and pancreatitis risk.

### What does Semaglutide stack with?

Common stacks for Semaglutide: BPC-157 (GI support) and Tirzepatide (not combined).

## Research.

The literature

### Search the latest research

[PubMed](https://pubmed.ncbi.nlm.nih.gov/?term=Semaglutide) [Google Scholar](https://scholar.google.com/scholar?q=Semaglutide)

Guide

### [What to take alongside each peptide](https://pepvault.app/guides/what-to-take-with-peptides)

Read the guide

## Reference.

- **Cadence:** Weekly Weekly SubQ
- **Half-life:** ~1 week ~1 week (FDA label)
- **Research basis:** Established Clinical trials or FDA-approved use exists

## More metabolic & glp-1 peptides

- [Semaglutide (oral) 1.5–25 mg](https://pepvault.app/peptides/semaglutide-oral)
- [Tirzepatide 2.5–15 mg](https://pepvault.app/peptides/tirzepatide)
- [Retatrutide 1–12 mg](https://pepvault.app/peptides/retatrutide)
- [Liraglutide 0.6–3 mg](https://pepvault.app/peptides/liraglutide)
- [Dulaglutide 0.75–4.5 mg](https://pepvault.app/peptides/dulaglutide)
- [Orforglipron 0.8–17.2 mg](https://pepvault.app/peptides/orforglipron)

## Free tools

- [Semaglutide dose guide](https://pepvault.app/lab/dosage/semaglutide)
- [Reconstitution Lab (3D)](https://pepvault.app/lab)
- [Injection guide (3D)](https://pepvault.app/lab/injection)
- [Peptide Sky (3D)](https://pepvault.app/lab/sky)
- [Peptide tier list](https://pepvault.app/lab/tiers)
- [Reconstitution calculator](https://pepvault.app/tools/reconstitution-calculator)
- [Half-life & active level](https://pepvault.app/tools/peptide-half-life-calculator)
- [GLP-1 titration planner](https://pepvault.app/tools/glp1-titration-calculator)

Track your progress

## Watch it *work.*

Weight, waist and photos in one arc.

[Download on the App Store](https://apps.apple.com/app/apple-store/id6779318649?ppid=616838ec-3248-400f-bd58-4b93f85f1a20&pt=129020030&ct=peptides-progress-band&mt=8)

**34.8 lbs** down since June

Model. Individual results vary.

PepVault for iPhone

## Track Semaglutide in PepVault

Log every dose, keep your vial and the doses left in it and watch its estimated active level. 7 days free on the yearly plan for new subscribers.

[Download on the App Store](https://apps.apple.com/app/apple-store/id6779318649?ppid=616838ec-3248-400f-bd58-4b93f85f1a20&pt=129020030&ct=peptides-cta&mt=8)

[Open the calculator](https://pepvault.app/tools/reconstitution-calculator) [How the vial count works](https://pepvault.app/peptide-vial-tracker-app) [Explore the live demo](https://pepvault.app/login)

Reviewed September 2026 [How we check the library](https://pepvault.app/about#library)

PepVault is a research and tracking resource, not medical advice. Ranges are what studies used, never a dose for you. Brand names are trademarks of their owners; PepVault is independent of them.

PepVault is a private research and tracking tool, not medical advice. The information here is reference material from published literature and community use — always verify it and discuss any protocol with a qualified clinician before changing it. Ozempic, Wegovy, Rybelsus, Mounjaro, Zepbound, Saxenda, Victoza and Trulicity are trademarks of their respective owners; PepVault is independent and not affiliated with or endorsed by any manufacturer.

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