Retatrutide Phase 3 Results: 28% Weight Loss in TRIUMPH-1 Trial — What It Means for South Africa

Published 5 June 2026 | Updated 5 June 2026 | By Weight Loss Diets SA

The weight loss world just got shaken up — again. On 21 May 2026, Eli Lilly announced the headline results from TRIUMPH-1, the pivotal Phase 3 clinical trial of retatrutide, their triple-agonist injectable weight loss drug. The numbers? Nothing short of extraordinary.

For context, that means a person weighing 113 kg could expect to lose roughly 32 kg — bringing them down to around 81 kg. That puts retatrutide on par with the results you would expect from bariatric surgery, but delivered via a weekly injection instead of an operating theatre.

For South Africans watching the GLP-1 revolution unfold — from Ozempic to Mounjaro to CagriSema — this is the next chapter. Here is everything you need to know.

What Is Retatrutide?

Retatrutide is a triple-agonist medication — meaning it activates three different hormone receptors simultaneously:

• GLP-1 (glucagon-like peptide-1) — the same pathway targeted by Ozempic and Wegovy
• GIP (glucose-dependent insulinotropic polypeptide) — the same additional pathway in Mounjaro
• Glucagon receptor — a completely new pathway that boosts fat burning and energy expenditure

Think of it as the evolution: Ozempic targets one pathway, Mounjaro targets two, and retatrutide targets all three. That third glucagon pathway is what researchers believe drives the superior weight loss — it increases your body's ability to burn stored fat for energy.

TRIUMPH-1 Phase 3 Results: The Numbers

The TRIUMPH-1 trial enrolled adults with obesity (BMI of 30 or higher) or overweight with at least one weight-related comorbidity. Here are the headline results at 80 weeks:

Even more impressive: among participants with a baseline BMI of 35 or higher who continued treatment to 104 weeks, average weight loss reached 30.3% (approximately 38.6 kg). And 45.3% of participants on the 12 mg dose achieved 30% or more total body weight loss.

Beyond the scale, Eli Lilly reported "clear improvements in assessed cardiometabolic health measures" — which typically includes blood sugar, cholesterol, blood pressure, and inflammation markers.

How Retatrutide Compares to Other Weight Loss Drugs

South Africans now have (or will soon have) several GLP-1 class options. Here is how retatrutide stacks up based on published clinical trial data:

Side Effects: What to Expect

As with all GLP-1 class drugs, gastrointestinal side effects are the most common. From the TRIUMPH-1 data:

• Nausea: 42.4% of participants (usually mild and decreasing over time)
• Diarrhoea: 32.0%
• Constipation: 26.1%
• Vomiting: 25.3%

Importantly, Eli Lilly reported that no cardiac or liver safety concerns were observed in the trial — a critical finding given that some earlier GLP-1 drugs faced scrutiny over cardiovascular risks.

Most side effects were mild to moderate and occurred primarily during the dose-escalation period (the first few months when your dose is gradually increased). Most participants were able to continue treatment.

When Will Retatrutide Be Available in South Africa?

Here is the realistic timeline based on the TRIUMPH-1 results:

1. Late 2026: Additional TRIUMPH data expected (TRIUMPH-2 for diabetes, TRIUMPH-3 for cardiovascular disease). Eli Lilly prepares FDA submission.
2. 2027: Expected FDA approval filing. If approved, US launch would follow.
3. 2027-2028: Eli Lilly submits to SAHPRA (South African Health Products Regulatory Authority). SAHPRA review typically takes 12-24 months.
4. 2028-2029 (optimistic): Potential South African market availability. Private pharmacies and obesity clinics would likely have access first.

Estimated Cost for South Africans

Pricing has not been officially announced, but based on how Eli Lilly prices tirzepatide (Mounjaro) in international markets:

• Estimated range: R4,500 – R8,000 per month
• Medical aid: Coverage will depend on your scheme. Discovery Health and Momentum have started covering some GLP-1 medications for qualifying patients. Watch for PMB (Prescribed Minimum Benefits) updates.
• Cash pay: Expect to budget R54,000 – R96,000 per year for the medication alone

For comparison, Ozempic currently costs around R2,500-R4,000/month in South Africa, and bariatric surgery costs R80,000-R150,000+ as a once-off procedure.

What Should South Africans Do Right Now?

Retatrutide is not available yet — and it will not be for a couple of years. But that does not mean you should wait around. Here is a practical action plan:

1. Talk to your doctor now about currently available options. Semaglutide (Ozempic) is available in SA today and delivers meaningful weight loss (15-17%).
2. Start with lifestyle foundations. Every weight loss drug works better when combined with a healthy diet and regular movement. Check out our SA-focused diet plans and exercise guides.
3. Focus on winter nutrition. It is June in South Africa — winter weight loss tips can help you stay on track with warming, nutritious meals like butternut soup, lean biltong snacks, and rooibos tea instead of sugary hot drinks.
4. Bookmark this page. We will update it as new TRIUMPH data and SAHPRA filing news comes in.

The Bigger Picture: Are We Entering the Post-Obesity Era?

Between Ozempic, Mounjaro, CagriSema, oral semaglutide, amycretin, orforglipron, and now retatrutide hitting 28% weight loss, the obesity treatment landscape is transforming faster than at any point in medical history.

For South Africa — where over 30% of women and 15% of men are classified as obese according to the South African Demographic and Health Survey — these drugs represent genuine hope. Obesity drives our epidemic rates of type 2 diabetes, hypertension, and heart disease. Effective treatment could ease the burden on an already stretched public health system.

The challenge will be access and affordability. At potentially R5,000-R8,000 per month, retatrutide will initially be out of reach for most South Africans. The question is whether medical aids, government programmes, and generic manufacturing (once patents allow) can bring the price down to where it matters most.

Frequently Asked Questions

How much weight can you lose on retatrutide?

In the Phase 3 TRIUMPH-1 trial, participants on 12 mg retatrutide lost an average of 28.3% of body weight (about 32 kg for a 113 kg person) over 80 weeks. Those continuing to 104 weeks lost up to 30.3% on average.

Is retatrutide better than Ozempic?

Based on clinical trial data, retatrutide produces significantly more weight loss (28.3%) compared to semaglutide/Ozempic (~15-17%). However, they have not been tested head-to-head, and Ozempic is available in SA right now while retatrutide is still years away.

Is retatrutide safe?

The TRIUMPH-1 trial found no cardiac or liver safety concerns. The most common side effects are gastrointestinal (nausea, diarrhoea, constipation, vomiting), which are typical for this drug class and usually improve over time. As with all medications, discuss risks with your doctor.

Can I buy retatrutide online in South Africa?

No. Retatrutide is not approved for sale anywhere in the world yet. Any website claiming to sell retatrutide is selling an unregulated, potentially dangerous product. Do not risk your health — wait for legitimate SAHPRA-approved products through licensed pharmacies.