Book a consultation
Book a consultation
Ingredient comparison

Semaglutide vs Tirzepatide

Beneath the brand names are two molecules. Here's how semaglutide and tirzepatide differ at the ingredient level — and what that means in South Africa.

Medically reviewed by an HPCSA-registered doctor Last updated 5 sources

The quick answer

Semaglutide (in Ozempic and Wegovy) targets one gut-hormone receptor (GLP-1). Tirzepatide (in Mounjaro) targets two (GIP + GLP-1), which is the leading explanation for its larger average weight loss. Both are once-weekly. Tirzepatide tends to win on results; semaglutide is cheaper and available in more SA brands and forms.

Semaglutide vs Tirzepatide: side by side

Side-by-side · indicative SA data · June 2026
FeatureSemaglutideTirzepatide
TargetsGLP-1 receptorGIP + GLP-1 receptors
SA brandsOzempic, Wegovy (Rybelsus oral, not yet sold)Mounjaro
Avg. weight loss~15% (STEP)~21% (SURMOUNT-1)
Head-to-head~13.7% (SURMOUNT-5)~20.2% (SURMOUNT-5)
Typical price / monthR1 900 – R3 750R3 500 – R4 600
Side-effect profileMainly GI, dose-relatedMainly GI, dose-related

Which might suit you

At the molecule level, tirzepatide is the more powerful for weight loss on average, while semaglutide offers more product choice and lower cost. Read the ingredient pages — semaglutide and tirzepatide — for the full picture.

This is general information, not a recommendation for your situation. The right choice depends on your health, budget, what's in stock and a clinician's judgement. Get a personalised assessment from a registered provider

Read more

Semaglutide in detail Tirzepatide in detail Best injection for SA Full price guide

Frequently asked questions

For weight loss, tirzepatide produced more average weight loss in trials, including a direct head-to-head comparison.

Broadly similar — mostly gastrointestinal and dose-related — though individual tolerance varies.

Sources & references

We cite primary sources and paraphrase them. Last reviewed June 2026. See our editorial policy and full sources hub.

  1. 1SURMOUNT-5 — tirzepatide vs semaglutide head-to-head — New England Journal of Medicine (Aronne et al., 2025). Direct comparison favouring tirzepatide (~20.2% vs 13.7% weight loss).
  2. 2STEP programme — semaglutide for weight management — New England Journal of Medicine (Wilding et al., STEP 1, 2021). Average weight loss with semaglutide 2.4 mg (~15% at 68 weeks).
  3. 3SURMOUNT-1 — tirzepatide for weight management — New England Journal of Medicine (Jastreboff et al., 2022). Average weight loss with tirzepatide (up to ~21–22.5% at highest dose).
  4. 4Manufacturer Patient Information Leaflets (Novo Nordisk / Eli Lilly) — Novo Nordisk; Eli Lilly. Approved dosing, administration and side-effect information.
  5. 5SAHPRA — registered health products & safety alerts — South African Health Products Regulatory Authority. SA registration status of medicines and counterfeit / falsified-product warnings.
Next step

Thinking about treatment?

These are prescription medicines, so they are not right for everyone and can't be bought over the counter. A registered provider can assess whether one is appropriate for you, start you safely and arrange a genuine product from a licensed pharmacy.

Book a consultation → Registered providers · genuine medicines · licensed pharmacies