What is Semaglutide?
Semaglutide is a GLP-1 receptor agonist, a synthetic analogue of glucagon-like peptide-1, the incretin hormone the gut releases after eating. Novo Nordisk developed it, and it is now approved under the brand names Ozempic (type 2 diabetes), Wegovy (obesity) and Rybelsus (oral form).
Semaglutide works on several fronts at once. It slows gastric emptying so you feel full for longer, dampens appetite signals in the hypothalamus, and increases insulin secretion in response to meals. In the STEP weight-management trials, that combination produced large, sustained weight loss (the figures are below).
Below is what the peer-reviewed trials show, mainly the STEP and SUSTAIN programmes, plus the dosing used in clinics and in research.
Effects, what does the research say?
Weight Loss, Clinical Trial Data
The STEP trials (Semaglutide Treatment Effect in People with Obesity) are the largest evidence base here:
- STEP 1 (2021, n=1961): Average 14.9% body weight reduction with semaglutide 2.4 mg weekly vs 2.4% with placebo over 68 weeks
- 86% of participants lost ≥5% body weight; 69% lost ≥10%; 50% lost ≥15%
- Results sustained with continued treatment; weight regain observed upon discontinuation
“Once-weekly subcutaneous semaglutide at a dose of 2.4 mg was associated with a sustained, clinically meaningful reduction in body weight and improvements in cardiometabolic risk factors in adults with overweight or obesity.”
Wilding JPH et al. (2021), Once-Weekly Semaglutide in Adults with Overweight or Obesity (STEP 1). New England Journal of Medicine. · PMID 33567185 ↗
Cardiovascular Protection
Beyond weight loss, semaglutide shows cardiovascular benefits that appear independent of the weight effect:
- SUSTAIN-6 trial (2016, n=3297): 26% reduction in major cardiovascular events (heart attack, stroke) vs placebo in patients with type 2 diabetes and high CV risk
- Significant reduction in non-fatal stroke (39%) and non-fatal MI (26%)
- SELECT trial (2023): cardiovascular benefits confirmed in non-diabetic obese patients
“Semaglutide was superior to placebo with respect to the primary composite outcome of death from cardiovascular causes, nonfatal myocardial infarction, or nonfatal stroke in patients with type 2 diabetes.”
Marso SP et al. (2016), Semaglutide and Cardiovascular Outcomes in Patients with Type 2 Diabetes (SUSTAIN-6). New England Journal of Medicine. · PMID 27633186 ↗
Blood Sugar & Metabolic Markers
- HbA1c reductions of 1.5-2.0% in diabetic patients (clinically significant)
- Improved insulin sensitivity and fasting blood glucose
- Reduction in liver fat (NASH/NAFLD relevance)
- Improvements in blood pressure, cholesterol and inflammatory markers
Dosage, what is being researched?
Important note: Semaglutide is an approved pharmaceutical with established clinical dosing. The following reflects approved and research dosing contexts.
| Indication | Dose | Protocol | Form |
|---|---|---|---|
| Type 2 Diabetes (Ozempic) | 0.5-2 mg/week | Escalating SC injection | Approved |
| Obesity (Wegovy) | 2.4 mg/week | Escalating over 16 weeks | Approved |
| Research protocols | 0.25-1 mg/week | Slow titration | Research compound |
Storage & Reconstitution
- Approved pens (Ozempic/Wegovy): Refrigerate at 2-8°C. Once in use, can be stored at room temperature up to 56 days.
- Research compound (lyophilised): Refrigerator (2-8°C), protected from light, up to 24 months
- After reconstitution with bacteriostatic water: max. 28 days refrigerated
- Do not freeze. Add water slowly along the glass wall, do not shake.