Tirzepatide to Semaglutide Conversion Chart: Switching Doses Safely

Switching a research protocol from tirzepatide to semaglutide is not a simple swap. The two compounds work on different receptors, so milligram numbers do not line up one to one. This page gives approximate equivalence ranges, explains why no official conversion exists, and shows how to recalculate syringe units for the new compound.

This is reference information for lab and educational use only. Both peptides are research compounds, not approved for human use. Nothing here is dosing advice. Any real switching decision belongs with a licensed clinician.

Why there is no FDA conversion formula

Tirzepatide is a dual GIP and GLP-1 agonist. Semaglutide acts on GLP-1 only. Because tirzepatide adds the GIP pathway and binds differently, a given milligram of tirzepatide is generally considered more potent than the same milligram of semaglutide. No regulator publishes an official equivalence table, and the manufacturers do not provide one. Any chart you see, including this one, is an estimate built from approximate potency, not a validated formula.

Approximate equivalence ranges

These ranges reflect commonly cited approximate potency, where tirzepatide is often estimated as roughly 2 to 4 times stronger per milligram. Weekly amounts shown for reference only:

• Tirzepatide 2.5 mg is often mapped to roughly semaglutide 0.25 mg (starting tier)
• Tirzepatide 5 mg is often mapped to roughly semaglutide 0.5 mg
• Tirzepatide 7.5 mg is often mapped to roughly semaglutide 1 mg
• Tirzepatide 10 mg is often mapped to roughly semaglutide 1.7 mg
• Tirzepatide 12.5 to 15 mg is often mapped to roughly semaglutide 2 to 2.4 mg (top tier)

Notice the ceilings. Semaglutide reference protocols commonly top out near 2.4 mg weekly, so the highest tirzepatide amounts have no clean semaglutide match. This is one reason a direct swap rarely works cleanly. For a side by side of the two compounds, see semaglutide vs tirzepatide.

A conservative step-down switching plan

Most reference protocols do not jump straight to the matched tier. They restart lower and titrate up, because tolerance to one compound does not fully carry over to the other. A common conservative pattern:

1. Stop the tirzepatide schedule before starting the new compound
2. Begin semaglutide at a low reference tier such as 0.25 mg weekly, regardless of the prior tirzepatide amount
3. Hold each tier for about 4 weeks before any increase
4. Step up only as a protocol and clinician direct, toward the mapped equivalent tier
5. Do not stack the two compounds in the same week

Calculating the new units

Once you know the target semaglutide amount in milligrams, the syringe units depend entirely on how the new vial is reconstituted. The concentration changes with the water you add, so old units mean nothing for the new compound. Run the target mg through the semaglutide dosage calculator to get the unit mark for your specific vial.

Worked example. Say a 5 mg semaglutide vial is reconstituted with 2 mL of bacteriostatic water. That gives 2.5 mg per mL. A 0.25 mg target is 0.1 mL, which is 10 units on a U-100 insulin syringe. A 0.5 mg target is 0.2 mL, or 20 units. Change the water volume and these unit marks change, which is why you recalculate every time.

For the prep math behind that concentration, the reconstitution calculator handles powder mg, water volume, and target dose together. If you are unsure how to read the syringe, see how to read an insulin syringe for peptides.

Key takeaways

• No official tirzepatide to semaglutide formula exists, ranges are estimates only
• Tirzepatide is often estimated as roughly 2 to 4 times stronger per milligram
• The top tirzepatide tiers have no clean semaglutide match
• Conservative protocols restart low and titrate, they do not swap tier for tier
• Always recalculate units for the new vial, old units do not transfer

For the reverse direction, see tirzepatide to semaglutide conversion context alongside the tirzepatide dosage chart. This page is educational only and not medical advice. See the disclaimer.