¹Cava, Edda, et al. “Preserving Healthy Muscle During Weight Loss,” Advances in Nutrition, vol. 8, issue 3, 2017:511-519 https://pmc.ncbi.nlm.nih.gov/articles/PMC5421125/
It’s not approved yet in the UK, but people are already talking about retatrutide on social media. Some are saying on social media sites like Reddit that it’s ideal for bodybuilding, because it helps burn fat while preserving muscle.
Key Takeaways
- Retatrutide doesn't block muscle building, but it won't build muscle for you either
- It's not approved in the UK and isn't intended for bodybuilding purposes
- Research shows it preserves similar amounts of muscle compared to other weight loss medications while promoting greater fat loss
- Strength training and high protein intake (1.2-1.6g/kg/day) are essential to maintain muscle during weight loss
- Never buy retatrutide from unregulated sources
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Can you build muscle while on retatrutide?
Yes, you can. Retatrutide doesn’t block or inhibit muscle building at all. But it won’t magically do the work for you.
If you want to build muscle while on retatrutide, you’ll need to do it the old-fashioned way: regular strength training and eating a nutritious diet (including enough protein).
How might retatrutide influence fat vs muscle?
Online, people are claiming that retatrutide can help you shed fat without losing any muscle.
That isn’t completely true. In a phase 2 clinical trial, people with type 2 diabetes lost more fat on retatrutide than dulaglutide and placebo. Though the proportion of muscle mass lost was similar to that on other weight loss treatments. We cover this in more detail in our guide on GLP-1s and muscle loss.
This suggests that retatrutide is able to preserve the same amount of muscle as existing treatments while leading to a greater drop in weight. So, it might be slightly better at burning fat, but there’s still some loss of muscle.
Retatrutide bodybuilding dosage
To be clear: retatrutide isn’t approved in the UK yet, so it can’t be prescribed or used outside clinical trials.
If you’re wondering about using retatrutide for bodybuilding, it isn’t for that. After approval, it will likely be licensed for medical weight loss in people who are overweight or have obesity, because that is what it has been studied for, not muscle gain. There’s no such thing as a “retatrutide bodybuilding dosage”.
Heads up: retatrutide appears to be available on the so-called “grey market”, which is when you buy products through unofficial channels. Don’t do this: this market isn’t regulated and there’s no guarantee that the products you buy are safe—nor that they are what they say they are. It’s not worth the risk.
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How long does retatrutide take to kick in?
There isn’t loads of research on retatrutide. But the data we have so far suggests that you could notice changes within a month.
In clinical research, the average loss is around 2-5% body weight after four weeks, depending on the dose. And in a recent phase 3 trial, people lost an average of 28.7% body weight at 68 weeks on the highest dose (12 mg).
How does that compare to what’s currently on the market? To give an example: the average loss on Wegovy 2.4mg weight loss injections is around 17% at 68 weeks, whilst the higher 7.2mg dose achieves approximately 20% at 68 weeks.
Good to know: in clinical studies, the starting retatrutide dose was low and increased every four weeks—just like with other weight loss medicines.
Bodybuilding on retatrutide: tips if you want to keep muscle
Again, you shouldn’t use retatrutide for bodybuilding.
But when losing weight, some degree of muscle loss is to be expected. However, there’s ways you can prevent this:
- Eat enough protein. High protein intake helps preserve lean body and muscle mass during weight loss. Go for about 1.2–1.6 g/kg/day, distributed across 3–4 eating occasions
- Hit the gym. Strength training helps to build muscle and improve strength. Aim for at least 2-3 sessions per week
Even if you don’t want a bodybuilder’s physique, it’s super important to maintain your muscles. They keep you fit and healthy: regulating your metabolism, supporting heart health, helping you move, and more.
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