Semaglutide
Semaglutide is a synthetic analogue of human GLP-1 (glucagon-like peptide-1), a hormone the gut releases after eating. It's approved, under prescription, as both a diabetes medicine and a weight-management medicine — and it's also one of the compounds most commonly sold, unregulated, as a "research peptide" in South Africa. Those are two very different regulatory situations for the same molecule.
How it works
Semaglutide binds and activates the GLP-1 receptor. That does three main things: it prompts the pancreas to release insulin only when blood glucose is elevated (glucose-dependent, so it doesn't drive hypoglycemia the way some older diabetes drugs can), it slows gastric emptying so food leaves the stomach more slowly, and it acts on appetite-regulating centres in the hypothalamus and brainstem to increase satiety. The net effect is lower post-meal blood sugar and reduced food intake — which is why the same molecule works for both type 2 diabetes and obesity.
Approval history
- 2017: first approved (as Ozempic) for type 2 diabetes.
- 2021: approved (as Wegovy) for chronic weight management in adults with obesity or overweight plus a weight-related condition.
- March 2024: Wegovy's approval extended to reduce the risk of major cardiovascular events — heart attack, stroke, cardiovascular death — in adults with established cardiovascular disease and obesity or overweight.
- More recently: an oral Wegovy tablet was approved for weight management, and the label has been extended to a liver condition (MASH) in some markets, per the manufacturer's own regulatory filings.
Source: FDA-approved prescribing information for Wegovy (semaglutide) injection (opens in new tab), accessdata.fda.gov.
What the clinical trials showed
In the trials that supported the weight-management approval, participants on semaglutide lost significantly more body weight than those on placebo alongside diet and exercise — on the order of 15% of body weight on average over roughly a year and a half, in the pivotal STEP program. Later trials (including the oral formulation's OASIS program) reported similar double-digit percentage weight loss. These are trial averages under medical supervision, not a guarantee for any individual, and not something to extrapolate to an unsupervised, unregulated product.
Side effects
Per the FDA label, the most common side effects in trials (each reported by more than 5% of participants) were gastrointestinal: nausea, diarrhea, vomiting, constipation, abdominal pain, headache, fatigue, dyspepsia, dizziness, abdominal distension, and belching. Most were mild-to-moderate and more frequent while the dose was still being increased.
The label also carries a boxed warning about thyroid C-cell tumors observed in rodent studies (it isn't known whether the same risk applies to humans); semaglutide is contraindicated for anyone with a personal or family history of medullary thyroid carcinoma or Multiple Endocrine Neoplasia syndrome type 2. Other warnings on the label include acute pancreatitis, gallbladder problems (gallstones, cholecystitis), acute kidney injury (usually linked to dehydration from GI side effects), worsening of diabetic retinopathy in people who already have it, and hypoglycemia when combined with insulin or a sulfonylurea. Screening for these risk factors before a first dose is exactly what a prescriber is meant to do — screening an unsupervised online purchase skips entirely.
Cost in South Africa
Prices for unregulated "research-grade" semaglutide vary by dose and vendor. Among the vendors we've verified: New You Lab lists 5mg at R1,150, Peptide Labs South Africa lists 20mg at R1,200, and ReGen-X lists 30mg at R1,400. These aren't pharmacy prices for the prescription version (Ozempic or Wegovy) — they're what unregulated online sellers charge for a vial marketed as a research chemical, with none of the pharmacy dispensing, prescriber screening, or dosing counsel that comes with the registered medicine. See our vendor comparison for how we score these sellers on documentation and transparency.
See our how we rate for the full regulatory context.
Frequently asked questions
Is semaglutide legal in South Africa?
The prescription medicine (Ozempic/Wegovy) requires SAHPRA registration and a valid prescription. The "research-grade" vials sold online as semaglutide are not SAHPRA-registered medicines, and SAHPRA has publicly warned against unregistered peptide products sold this way — buying them for personal use sits in a legal grey area, not a clearly regulated one. This isn't legal advice.
What's the difference between prescription Wegovy/Ozempic and "research-grade" semaglutide sold online?
The prescription product goes through pharmacy dispensing, prescriber screening for the contraindications and warnings above, and regulatory oversight of manufacturing. A research-grade vial bought online has none of that — no prescriber check, no pharmacist, and (per our vendor reviews) documentation of what's actually in the vial ranges from a named third-party lab report to no testing claim at all.
How much does semaglutide cost in South Africa?
Among vendors we've verified selling it as a research chemical, published prices range from roughly R1,150 to R1,400 depending on dose and vendor — see Cost in South Africa above. Pharmacy-dispensed Ozempic/Wegovy follows a different pricing and distribution model entirely.
What are the most common side effects?
Gastrointestinal ones — nausea, diarrhea, vomiting and constipation — reported by more than 5% of trial participants, per the FDA label. See Side effects above for the full list, including the boxed warning and other risks a prescriber screens for.
Related guides
This page is educational information about a molecule and its regulatory history. It is not medical advice, not a recommendation to use semaglutide outside a prescription, and not an endorsement of any vendor.