Metabolic

Semaglutide

Acylated peptide · GLP-1 receptor agonist · 31 amino acids

FDA · APPROVED (OZEMPIC/WEGOVY)

Half-life

~7 days

Very long

minsdays

Route

SubQ injection

Evidence

Approved therapeutic

Risk

Standard

Overview

Known for

GLP-1 receptor agonist. FDA-approved as Ozempic (diabetes) and Wegovy (weight loss). The most widely prescribed weight loss medication globally. Weekly injection. Reduces appetite, slows gastric emptying, and improves blood sugar control. Significant cardiovascular benefits (SUSTAIN-6 trial). Semaglutide works on GLP-1 receptors only (unlike Tirzepatide which also hits GIP).

Mechanism

GLP-1 receptor agonist — mimics gut hormone to reduce appetite, slow stomach emptying, improve insulin sensitivity

Key facts

Format
Lyophilized powder
Mechanism targets
Classification
Authoritative
Supply & nature
ExogenousExogenous
FDA category
Approved (Ozempic/Wegovy)

Evidence & standing

Evidence base
Approved therapeutic
Risk level
Standard
Best studies
4 references
  • Wilding et al. (2021) STEP 1 Trial. NEJM 384(11):989-1002. DOI: 10.1056/NEJMoa2032183
  • SELECT Trial (2023): CV outcomes, NEJM. DOI: 10.1056/NEJMoa2307563
  • FDA Approved: Ozempic (2017, T2D), Wegovy (2021, obesity), Rybelsus (2019, oral)
  • ClinicalTrials.gov: NCT03548935 (STEP 1)

Dosage & protocol

Typical dose
0.25mg
Research range
0.25–2.4 mg
Cycle
Weekly injection
Onset
10 days first effects
Full effect
140 days
Half-life
~7d
~7 days (t½ ~168hrs)
Protocol

Titrate: 0.25mg → 0.5mg → 1mg → 1.7mg → 2.4mg weekly. SubQ once weekly. Increase every 4 weeks.

Time to effects

EARLY: 1-2 weeks

FULL: 16-24 weeks

Week 1-2: Appetite reduction noticeable quickly. Food noise decreases.

Week 4-8: Weight loss becomes visible. 3-5% body weight.

Week 12-16: Significant results. Cardiovascular benefits beginning.

Week 16-24: Approaching peak effect. ~15-17% total body weight loss in trials at 68 weeks.

Minimum commitment: 12 weeks. Most clinical data is at 52-68 weeks.

Recommended vial
  • 5mg vials

At 0.25-0.5mg/wk titration, 2mg vials are better (8 weeks — borderline). At 2.4mg/wk maintenance, 5mg = 2 weeks ✓. Semaglutide is more stable than most peptides.

Reference figures only

Dosing reflects published laboratory protocols and is not guidance for use in any living subject.

Safety

Reversibility
Not Reversible
Side effects

Nausea (20-44%), diarrhoea (15-30%), vomiting (8-24%), constipation (10-24%), abdominal pain (6-11%), headache (14%)

Interactions

Insulin/sulfonylureas (↑hypo risk), oral contraceptives, levothyroxine, warfarin (delayed absorption). All oral meds potentially affected.

Do not combine
CagrilintideCagrilintide Cagrilintide 5mg + Semaglutide 5mg (Blend)Cagrilintide 5mg + Semaglutide 5mg (Blend) RetatrutideRetatrutide SurvodutideSurvodutide TirzepatideTirzepatide

Handle with research caution

  • Do NOT combine with Tirzepatide or Retatrutide (never stack GLP-1 agonists)
  • Exception: CagriSema blend is the intended semaglutide + cagrilintide combination
  • Caution with insulin or sulfonylureas

Storage & handling

Lyophilised
56 days
room temp ≤30°C up to
Reconstituted
4–6 weeks
2–8°C

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