Switching From Semaglutide to Tirzepatide: How the Switch Is Handled

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The two medications are more alike than different in everyday use. Both are once-weekly injections that act on the GLP-1 receptor; tirzepatide also acts on the GIP receptor. The reasons for switching usually fall into a few groups:

SURMOUNT-5, in the New England Journal of Medicine in 2025, is the one randomized head-to-head trial in adults with obesity and no diabetes. It was open-label, it compared the branded products rather than compounded preparations, and a difference in group averages says nothing about where any individual lands. A stall also has several possible causes, only one of which is the medication, which is covered in why am I not losing weight on semaglutide. Starting on tirzepatide without trying semaglutide first is also reasonable; nothing in either label or in compounding law requires a sequence.

People search for a semaglutide-to-tirzepatide conversion because it seems as though a given semaglutide dose should equal a given tirzepatide dose. It does not work that way.

• They are different molecules. Semaglutide is a GLP-1 analogue; tirzepatide is built on GIP and acts at two receptors. Milligram for milligram they are not comparable.
• The ladders are different. Pepti's semaglutide runs from 0.25 mg to 2.5 mg weekly; tirzepatide runs from 2.5 mg to 15 mg weekly. A number on one ladder has no matching rung on the other.
• Tolerance does not fully transfer. Gastrointestinal side effects cluster around starting a medication and each increase. The GIP arm is new to the body, which is why the usual approach is to start lower and step up again.

So the right question is not "what is my equivalent dose" but "what does my physician want my first tirzepatide vial to be". That is answered on your prescription after a review of your history, how semaglutide went for you, and where you are now. Never work out a switch dose yourself, and never use a figure from someone else's switch.

1. Tell your care team you want to discuss switching. Say which semaglutide strength you are on, how long you have been on it, and what is prompting the change: a stall, side effects, cost or something else.
2. Your physician reviews it. The review covers your history, how you tolerated semaglutide, your current medications, and anything that changes the picture, such as pregnancy plans or oral contraceptives.
3. A new prescription is written. If the switch is appropriate, your physician sets your tirzepatide dose and writes a new prescription. Your physician may also suggest staying on semaglutide, holding your current strength, or a different plan.
4. The pharmacy sends the tirzepatide vial. It arrives as a new vial with its own label and directions. Until it arrives, your semaglutide directions are the ones that apply.
5. The timing is set for you. The usual approach is to take the last semaglutide dose on its usual day and start tirzepatide the following week. Follow the timing your care team gives you.
6. Step-ups follow from there. Your physician reviews how each tirzepatide step goes before any increase, with at least four weeks on a step before an increase is considered.

If you are moving to Pepti from another provider rather than switching molecule, say the exact medication and strength you are on. The semaglutide vs tirzepatide page covers that case as well.

This is the practical detail that catches people out. Pepti's semaglutide and tirzepatide vials are built differently.

Never carry the units from your semaglutide vial over to tirzepatide, or the reverse. A unit is a volume mark on a U-100 syringe, not a measure of medication, and the same number of units from two different vials can be very different doses. Read the new label, and if anything on it does not match what you were told, message your care team before injecting. The tirzepatide steps are set out in the tirzepatide dosing chart.

Semaglutide has an elimination half-life of about a week, and the approved weight-management label states it is present in the circulation for about five to seven weeks after the last dose. That means semaglutide is still in your system when tirzepatide starts. Both act at the GLP-1 receptor, so taking them together stacks GLP-1 exposure and its side effects with no mechanism gained, and both approved labels state that coadministration with another GLP-1 receptor agonist is not recommended.

That is why the switch is a clean handover on the weekly schedule, not an overlap. Do not use up leftover semaglutide alongside tirzepatide, and do not take an extra dose of either to bridge a gap. How long each stays in the body is set out in how long does tirzepatide stay in your system.

The side effects of the two medications are the same family: nausea, early fullness, reflux, constipation, diarrhea and vomiting, clustered in the days after starting and after each increase. In SURPASS-2, the trial that measured them side by side at diabetes doses, nausea, diarrhea and vomiting rates were within a few percentage points of each other. How fast the dose climbs matters more than which molecule is in the vial.

Birth control pills

This matters at a switch specifically. The approved tirzepatide label advises anyone taking an oral contraceptive to switch to a non-oral method, or add a barrier method, for four weeks after starting tirzepatide and four weeks after each dose increase, because slower stomach emptying reduces absorption. Starting tirzepatide counts as starting, even if you were on semaglutide before. The full side-effect picture is in tirzepatide side effects and managing nausea in GLP-1 nausea.

Tirzepatide is priced from $159 a month and semaglutide from $99 a month at Pepti, both by dose, because a higher strength is a vial with more medication in it. When your physician switches you, the tirzepatide price for the strength on your prescription applies from that fill. Each price covers one vial per 28-day fill, physician review, refill management and refrigerated shipping with ice packs, sterile syringes and alcohol prep pads. Pepti is cash-pay and does not bill insurance. Current prices by strength are on the tirzepatide and semaglutide product pages.

Both medications have large trial programmes behind the branded products, and SURMOUNT-5 compared them directly. What the trials did not test is switching itself: no randomized trial in Pepti's reference pages studied people moved from semaglutide to tirzepatide, and none established a conversion between them. The approach of starting lower and stepping up again comes from how the side effects behave and from the labels' escalation schedules, not from a switching trial. Compounded semaglutide and tirzepatide contain the same active ingredients as the approved products but are not FDA approved, and no trial has been run on either compounded preparation.

1. Complete a free online intake covering your history, medications and what you want help with, including your current semaglutide strength.
2. A physician licensed in your state reviews it, usually within 24 hours.
3. If it is appropriate, a PCAB-accredited, FDA-registered US 503A pharmacy compounds it to that prescription. Lot test results are published at /quality/lab-results.
4. It ships refrigerated with ice packs, sterile syringes and alcohol prep pads, with your directions printed on the vial.
5. Your care team stays reachable for side effects and dose questions. Refills run every 28 days, one vial per fill.

Bloodwork is not required for any Pepti treatment. If your physician wants labs for your care, they'll ask through your account. The step-by-step page is how to get tirzepatide prescribed online.