Reviewed by the PeptideMind Team · Updated August 31, 2026
Tirzepatide to Retatrutide Conversion Calculator
Thinking about switching from tirzepatide to retatrutide? This calculator shows an estimated dose range in either direction, plus the much lower dose people actually restart on. Free to use, no sign up needed. For learning only, not medical advice.
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Amount
mg
TirzepatideEstimated equivalent
mg
RetatrutideThis range lines up where each compound's dose lands on its own published weight loss results, not a direct head to head comparison. It is a rough estimate for learning purposes only, not a switching plan.
This is an educational estimate, not medical advice. Retatrutide is not approved for human use and is sold for research purposes only.
As seen on
Tirzepatide to Retatrutide Dose Chart
Here's the estimated range for every standard tirzepatide dose step. Remember that this shows how strong your dose is, not where to start.
| Tirzepatide (mg) | Retatrutide (mg) |
|---|---|
2.5 mg | 1 mg |
5 mg | 1 to 2 mg |
7.5 mg | 2 to 3 mg |
10 mg | 3 to 4 mg |
12.5 mg | 4 to 6 mg |
15 mg | 6 to 8 mg |
Ranges are rough estimates based on published study comparisons, not a switching plan.
Retatrutide to Tirzepatide Dose Chart
Here's the estimated range for every retatrutide dose step that has been studied.
| Retatrutide (mg) | Tirzepatide (mg) |
|---|---|
1 mg | 2.5 to 5 mg |
2 mg | 5 to 7.5 mg |
4 mg | 10 to 12.5 mg |
6 mg | 12.5 to 15 mg |
8 mg | 15 mg |
12 mg | 15 mg |
Ranges are rough estimates based on published study comparisons, not a switching plan.
How the conversion calculator works
Every result comes from three simple choices: which direction you're converting, your current dose, and reading back a range, not a single number. For learning purposes only.
Type in your current dose
Enter the dose you're on now in the amount box. The compound shown next to it, tirzepatide or retatrutide, tells the calculator what that number means.
Use the swap button to change direction
Tap the swap button to flip which compound you're converting from and to. Both directions work the same way.
Read the range, then read the restart note
The top result shows roughly how strong your dose is on the other compound. The note underneath shows where people actually begin, which is usually much lower.
How Dose Conversion Estimates Work
A tirzepatide to retatrutide conversion chart can only ever be a rough estimate. Here's what's really behind the numbers.
Two different compounds, not a straight swap
Tirzepatide works on two receptors. Retatrutide works on three. That extra target is why retatrutide does more per milligram, and it's also why no simple math turns one dose into the other.
The answer is a range, not one number
This tool never gives a single exact number. It gives a range instead, because that's a more honest picture of what's actually known about how these two compare.
Based on published research, not guesswork
The ranges here come from lining up where each compound's dose sits on its own published weight loss results. It's still an estimate, never a lab measured equivalent.
Where to buy Retatrutide
Compare real-time Retatrutide prices from vendors with third-party lab testing (COA), purity, and legitimacy, so you know exactly who's trustworthy before you buy.
Dose size
Chosen on COA purity, third-party testing, and service, no paid placements.
4 of 4 vendors third-party tested, COA purity 99.49–99.991% across published labs. Prices re-checked 16 days ago.
Switching From Tirzepatide to Retatrutide
If you're thinking about making the change, these three things matter more than any conversion number.
Start low, even if your last dose was high
The tolerance you built up on tirzepatide does not carry over. Most people restart around 1 to 2 mg of retatrutide a week, closer to a retatrutide microdosing protocol than to where they left off, no matter what dose they finished on.
Brand names can be confusing
Tirzepatide is sold as Mounjaro and Zepbound. Retatrutide has no brand name, because it has not been approved by the FDA and is sold as a research compound only.
New side effects are possible
A new compound can bring new or different side effects, even at a dose that looks similar on paper. Nausea and appetite changes often feel different on retatrutide than they did on tirzepatide.
Frequently Asked Switching Questions
Simple answers on dose ranges, restart doses, side effects, and brand names. For learning purposes only, not medical advice.
Before You Change Anything
This calculator is a starting point for a conversation, not a replacement for one.
Bring your result to the conversation
Print your result and bring it with you. It gives your doctor a starting point for the conversation, not a final answer.
Everyone responds differently
Body weight, how long you were on tirzepatide, and any side effects you had all affect what actually works for you. A chart can't account for all of that.
Retatrutide is not an approved medicine
Retatrutide is still in clinical trials and is not approved for human use anywhere. It is sold for research purposes only, so nobody can legally prescribe it to you today.
Calculate peptide dosages
Reference our peptide quantity, blend, and accumulation calculators for laboratory purposes. Enter vial size, reconstitution volume, and target research quantity to calculate exact draw volumes instantly. All calculators are for research use only and do not constitute dosing or administration guidance.
