Initial dose of Retatrutide: When switching from Tirzepatide to Retatrutide?

Retatrutide is the latest weight-loss drug, and many people may have been using other weight-loss peptides, such as Semaglutide and Tirzepatide, before discovering it. What is the initial dose if I switch from other weight loss peptides to Retatrutide, and will the initial dose still be the minimum?

Dose range of Retatrutide

The Phase II clinical trail dose range for Retatrutide is 1mg, 4mg, 8mg, and 12mg. The doses of Phase III clinical trail are 2mg, 4mg, 6mg,9mg, and 12mg. Therefore, the standard dose of Retatrutide should start at 2mg per week and the maximum dose should not exceed 12mg per week.

When people first use peptides to lose weight, the principle of peptide use is to start with an initial dose of 2mg and then gradually increase the dose depending on drug tolerance and actual use effect. Retatrutide 2mg is a safe dose and was well tolerated when used in the experiment, so choosing a 2mg weekly dose is a very safe dose. Then increase to your target dose, such as 6mg,8mg, etc., up to 12mg per week.

In the phase II clinical trail, there is another data with reference significance, that is, the target dose. When the target dose is 4mg, the initial dose can be 2mg and 4mg respectively, and when the initial dose is 4mg per week, the weight loss effect is better after 36m weeks. When the target dose was 8mg per week, the initial dose was 2mg and 4mg, respectively, showing similar weight loss after 36 weeks. This data suggests that the most stable initial dose should be 2mg per week, or 4mg if your target dose is larger.

If you are already using Tirzepatide, what is the initial dose when switching to Retatrutide?

In the clinical trail, there is no relevant data. What you can see so far is some user experience data.

A user who switched from Tirzepatide 10mg to Retatrutide 5mg reported no side effects other than a little irritating effect and good weight loss.

Another user switch from Tirzepatide 15mg to Retatrutide 4mg with no side effects but no significant weight loss and will follow up with a weekly dose of 8mg Retatrutide.

There are also users who switched from Tirzepatide 7mg to Retatrutide 4mg and lost weight very quickly, but experienced some head-passing side effects. (Headache side effects may be related to electrolyte imbalance, which should be replaced during the use of weight loss peptides such as Retatrutide.)

We can see that after using Tirzepatide and then Retatrutide, people tend to start with 4mg. Therefore, as a reference, a initial dose of Retatrutide starting at 4mg and then increasing as needed would be a good choice. Of course, it is still more stable and safer to start with 2mg per week and gradually increase the dose.