# Switching From Semaglutide to Tirzepatide: What to Track

Source: https://www.trackpep.com/blog/switching-semaglutide-to-tirzepatide-tracking

> Educational information only. Not medical advice, and not a dosing recommendation. TrackPep records what you enter; it never calculates, converts or decides a dose for you. Talk to a licensed clinician.

Moving between semaglutide and tirzepatide? Here is what to log for the first 8 weeks, how to compare before and after fairly, and what to ask your prescriber, with no dose conversion.

## Short answer

When you switch between semaglutide and tirzepatide, log the date of your last old dose and your first new dose, then track appetite, nausea, other GI effects, energy, injection sites, supply details and a weight trend for about eight weeks. Your prescriber alone decides the new dose; no app or table can.

<Disclaimer />

If you are moving from semaglutide to tirzepatide (or the other way round), the most useful thing you can do is keep a clean record of the changeover: the date of the last old dose, the date of the first new dose, and what your body and your supply chain do over the next eight weeks. That record lets you and your prescriber judge the switch on evidence instead of memory.

This article is about tracking. It does not tell you what dose to use, and it does not convert one drug into the other. Those are prescriber decisions, and there is no safe table you can look up yourself.

## Why people switch

There is rarely one reason. The common ones are:

- **Access.** A pharmacy runs out of one product, or a plan stops covering it.
- **Cost.** Insurance formularies, savings programs and cash prices change, and a different drug may come out cheaper for you this quarter. See our [semaglutide cost guide](/blog/semaglutide-cost-2026) and [tirzepatide cost guide](/blog/tirzepatide-cost-2026).
- **A plateau.** Weight or glucose results stall and you and your clinician want to try something else.
- **Side effects.** Nausea, constipation or other effects that did not settle on the first medicine.
- **A new prescription or a new prescriber.** A change of clinic, country or insurer often changes what is on the script.

Whatever your reason, write it down on day one. Three months later it is surprisingly easy to forget why you switched, and the reason tells you what to measure.

## Semaglutide and tirzepatide at a high level

Both medicines are weekly injections used for type 2 diabetes and weight management, depending on the brand and the country. The difference that matters for understanding them is mechanism:

| | Semaglutide | Tirzepatide |
|---|---|---|
| Drug class | GLP-1 receptor agonist | Dual GIP and GLP-1 receptor agonist |
| What it acts on | The GLP-1 receptor | Both the GIP and the GLP-1 receptors |
| Typical form | Weekly injection (an oral form of semaglutide also exists) | Weekly injection |
| Common brand names | Ozempic, Wegovy | Mounjaro, Zepbound |

That is the extent of what we will claim here. How the two compare in effect size, tolerability or cost for you is a question for your prescriber, who knows your history. For a broader comparison, including newer agents, see [retatrutide vs tirzepatide vs semaglutide](/blog/retatrutide-vs-tirzepatide-vs-semaglutide).

One practical consequence of "different drug, different label": your experience on the old medicine is not a reliable forecast for the new one. Nausea you never had may appear, and the reverse can happen too. That is exactly why a structured log helps.

## What not to do

- **Do not self-convert doses.** Any "X of one equals Y of the other" you find online is not a substitute for your prescriber's instructions.
- **Do not overlap injections on your own.** Whether and when to stop the old medicine and start the new one is part of the plan your prescriber gives you.
- **Do not treat a single bad day as a verdict.** Judge the switch on a window, not on one morning.

## The first 8 weeks: what to log

You do not need a complicated system. You need the same few fields, every time. Our [GLP-1 tracker](/glp-1-tracker), [semaglutide tracker](/semaglutide-tracker) and [tirzepatide tracker](/tirzepatide-tracker) pages show how this looks in TrackPep, but a notebook works too.

### The changeover itself

Record these once, on the day it happens:

- Date of your **last dose of the old medicine** and the product name
- Date of your **first dose of the new medicine** and the product name
- The **dose as written on your prescription**, copied exactly, not calculated by you
- Who prescribed it and the reason for the switch

The gap between the two dates matters. Your prescriber may want to know exactly how many days it was.

### Every injection day

- Date, time and which injection number this is on the new medicine
- Injection site (for example left abdomen, right thigh), so you can rotate and spot local reactions
- Any notes: missed or late dose, travel, illness

### Daily or near-daily

- **Appetite and fullness**, on a simple 1 to 5 scale
- **Nausea**, 0 to 3 (none, mild, moderate, severe)
- **Other GI effects**: reflux, constipation, diarrhoea, bloating, vomiting
- **Energy** on a 1 to 5 scale
- **Food and fluids**, only as much as you can sustain; a quick note such as "small meals, low appetite" is enough
- **Anything unusual**, in free text

### Weekly

- **Weight**, ideally same scale, same time, same conditions
- Injection-site check: redness, lumps, bruising or pain at recent sites
- A short "how did this week feel compared with last week" note

### Supply and cost

- **Pharmacy and fill date** for each pen or vial
- **Lot number and expiry date**, from the box or pen label
- **Price paid, plus insurance or coupon applied**
- How the product was stored since you picked it up

Lot numbers sound fussy until the day a pharmacy recalls a batch or a pen behaves oddly. Then they are the first thing anyone asks for. If you are using any product that is not a pharmacy-dispensed, labelled, FDA-approved pen, read [what actually changed with compounded vs brand GLP-1](/blog/compounded-vs-brand-glp-1-what-changed-2026) first and ask your prescriber or pharmacist about what you are being given.

### A quick checklist for week one

- [ ] Wrote down the reason for the switch
- [ ] Logged last old dose date and first new dose date
- [ ] Copied the prescribed dose exactly from the label or script
- [ ] Took a baseline weight and a baseline appetite and energy score
- [ ] Noted pharmacy, lot number and price
- [ ] Booked a follow-up with the prescriber for around week four

## How to compare before and after fairly

The tempting comparison is "what I weighed the day before I switched versus what I weigh today." It is also the least reliable one, because one weigh-in can swing by a kilogram or more for reasons that have nothing to do with fat: water, salt, a large meal, a bowel movement, hormones, or a different scale.

A fairer approach:

1. **Collect a baseline.** Use the 2 to 4 weeks before the switch, if you have them.
2. **Use weekly averages or a rolling trend.** Average all weigh-ins in a week, then compare week with week.
3. **Compare like with like.** Same scale, similar time of day, similar clothing.
4. **Expect the early weeks to be noisy.** Appetite and food volume can change quickly after a switch, which moves scale weight for reasons that are not the same as the longer trend.
5. **Look at more than weight.** Appetite, nausea days, energy and, if relevant, glucose readings or waist measurement tell you whether the switch is working for you.
6. **Do not compare against someone else's curve.** Forum timelines are survivor stories, not forecasts.

Here is a simple table you can copy to review your own data at weeks 4 and 8:

| Measure | Before switch (avg of last 2 to 4 weeks) | Weeks 1 to 4 on new | Weeks 5 to 8 on new |
|---|---|---|---|
| Weekly average weight | | | |
| Appetite score (1 to 5) | | | |
| Nausea days per week | | | |
| Other GI days per week | | | |
| Energy score (1 to 5) | | | |
| Injection-site reactions | | | |

For more on reading weight data without over-reacting to it, see [weight tracking on GLP-1](/blog/weight-tracking-on-glp-1).

## Side effects after a switch

Many people notice gastrointestinal effects around the time of a new medicine, and both drugs are known to cause them. What helps your prescriber is pattern, not adjectives. Instead of "I felt sick all week," log "nausea 2 out of 3 on the day after injection, gone by day three, vomiting once on day two."

Our guide to [common GLP-1 side effects and how to track them](/blog/glp-1-side-effects-tracker) gives a fuller structure. Two reminders:

- Severe or persistent vomiting, severe abdominal pain, signs of dehydration, or symptoms of an allergic reaction need prompt medical attention. Do not wait for your next appointment.
- Do not change what you take, or when, to manage side effects without talking to your prescriber.

## Questions to bring to your prescriber

Print or screenshot your log and take these:

- Why this medicine, now? What are we hoping to see, and by when?
- What exactly should I do with the old medicine, and on what dates?
- What dose am I starting on, and what is the plan for reviewing it? (Let them answer; do not assume it matches your old one.)
- Which side effects are expected, and which should make me call you?
- How will we judge whether the switch worked? Weight, glucose, appetite, something else?
- What if the pharmacy cannot fill it or the price changes mid-treatment?
- Are there interactions with my other medicines, or conditions that change the risk?
- When is our follow-up, and what do you want me to bring?

## Tracking the cost of the switch

Switching often changes your monthly cost, sometimes up and sometimes down, and it is easy to lose track when coupons, deductibles and pharmacy changes are involved. Record, for each fill:

- Date, pharmacy and product
- List or cash price, insurance paid, coupon applied, and what you actually paid
- Number of weekly doses in the fill, so you can work out cost per injection
- Any prior-authorization or appeal dates

After two or three fills you will have a real cost per injection for each medicine, based on your own receipts rather than internet averages. Our guide on [how to track GLP-1 cost per dose](/blog/how-to-track-glp-1-cost-per-dose) walks through the method.

## A sensible 8-week rhythm

| Week | Focus |
|---|---|
| 0 (changeover) | Log reason, last old dose, first new dose, prescription details, baseline weight and scores |
| 1 to 2 | Daily appetite, nausea, GI and energy notes; injection-site checks |
| 3 to 4 | Review the first month with your table; message the prescriber if anything worries you |
| 5 to 6 | Watch the weekly weight average, not single days; log supply and cost for the next fill |
| 7 to 8 | Complete the comparison table and bring it to your follow-up |

## Putting it together

A switch between semaglutide and tirzepatide is a change of drug, not just a change of number on a pen. A short, consistent log makes it far easier to see what changed, to compare fairly, and to have a specific conversation with the person who actually decides your treatment.

If you want somewhere to keep all of this in one place, TrackPep lets you log doses, side effects, weight, injection sites and costs privately on your own device. It records what you enter and shows your own history; it never suggests a dose.

## Frequently asked questions

### Can I convert my semaglutide dose to a tirzepatide dose?

No. The two medicines are different molecules with different labels, and there is no safe do-it-yourself equivalence. Which dose you start on, and how it changes, is your prescriber's decision. Bring your log and ask.

### How long should I track after switching GLP-1 medications?

Eight weeks is a practical window. It covers the first several injections of the new medicine, enough for appetite, GI effects and weight trend to show a pattern. Keep logging longer if your prescriber is still adjusting things.

### Why does my weight jump around in the first weeks after a switch?

Day-to-day weight moves with water, salt, food volume and bowel movements. Compare weekly averages or a rolling trend rather than single weigh-ins, especially when appetite or eating patterns change.

### Should I tell my prescriber about nausea after switching?

Yes. Share what you logged: when it started, how severe it was and how it lined up with injection day. Severe or persistent vomiting, severe abdominal pain or signs of dehydration need prompt medical attention.

## Sources

- [Semaglutide Injection: MedlinePlus Drug Information (NIH)](https://medlineplus.gov/druginfo/meds/a618008.html)
- [Tirzepatide injection: MedlinePlus Drug Information (NIH)](https://medlineplus.gov/druginfo/meds/a622044.html)
- [FDA's Concerns with Unapproved GLP-1 Drugs Used for Weight Loss](https://www.fda.gov/drugs/drug-alerts-and-statements/fdas-concerns-unapproved-glp-1-drugs-used-weight-loss)

By TrackPep Team.