How much weight can you lose with retatrutide?
Studies show that retatrutide at the highest dose of 12 mg produces on average around 11 kg more weight loss than no treatment. The initial results in people are clearly positive.
Retatrutide leads to an average weight loss of around 11 kg compared with no treatment, based on studies in people. The highest dose of 12 mg works best: people who received that dose were far more likely to lose at least 15% of their body weight than those who received no active treatment. For comparison, with tirzepatide the average loss in many studies combined was slightly higher (−12.78 kg) or broadly similar, but no direct head-to-head studies exist yet.
Most of that weight lost is fat. In a study of people with type 2 diabetes, participants on the 8 mg dose lost more than a quarter of their fat mass after 36 weeks. The ratio of fat loss to muscle loss was comparable to other obesity treatments: you do not lose a disproportionately large amount of muscle tissue. Participants also reported notably less hunger and less urge to overeat, which partly explains why the scales move so strongly in the right direction.
People with type 2 diabetes lose less weight on average than people without diabetes. That pattern applies to this entire class of medicines and holds for retatrutide as well, although the precise figures for this drug are less well studied.
The most common side effects are digestive complaints: nausea, vomiting and diarrhoea. Of all the medicines compared, retatrutide had the highest overall risk of side effects. Serious side effects were rare and no deaths were reported in the studies. Long-term safety data are still lacking: later-stage studies are ongoing, and there is not yet any information on effects on heart disease or lifespan. Always discuss use with your doctor, especially if you have other conditions or take other medicines.
This answer draws on several analyses that combined the results of existing studies, plus a study in people with type 2 diabetes. Almost all of the studies used were earlier-phase research; later-phase data are not yet available. The evidence on weight loss itself is reasonably consistent; the evidence on safety over many years, heart and blood vessel outcomes, and comparison with other medicines is thin or still absent.