Both Semaglutide and Tirzepatide are FDA-approved prescription medications. The dosing schedules below are summarized from the official prescribing information. Switching between them, adjusting a dose, or starting either should be done with your prescribing provider — not based on a blog post.
If you've used Semaglutide and you're considering Tirzepatide (or vice versa), the first thing you'll notice is that the numbers don't match. Semaglutide tops out at 2.4 mg per week. Tirzepatide goes to 15 mg per week. That's roughly 6× difference — but it absolutely does not mean Tirzepatide is "6× stronger." This post explains what the math actually represents, where the differences come from, and what changes on the syringe when you switch.
The two compounds, briefly
| Compound | Receptors | FDA-approved brand names | Approved indications |
|---|---|---|---|
| Semaglutide | GLP-1 | Ozempic®, Wegovy®, Rybelsus® | Type-2 diabetes, chronic weight management |
| Tirzepatide | GLP-1 + GIP | Mounjaro®, Zepbound® | Type-2 diabetes, chronic weight management, OSA |
Tirzepatide is a dual agonist — it activates GLP-1 (the same target as Semaglutide) plus GIP (a second incretin receptor). The GIP component changes the dose-response curve, which is the main reason the mg numbers differ.
The titration schedules — side by side
These are the schedules from the FDA-approved labels for each compound's weight-management indication:
| Phase | Weeks | Dose |
|---|---|---|
| Semaglutide (Wegovy®)16-week ramp to maintenance | 1–4 / 5–8 / 9–12 / 13–16 / 17+ | 0.25 → 0.5 → 1.0 → 1.7 → 2.4 mg |
| Tirzepatide (Zepbound®)20-week ramp to maintenance; 5.0 mg and 10.0 mg are also approved maintenance options | 1–4 / 5–8 / 9–12 / 13–16 / 17–20 / 21+ | 2.5 → 5.0 → 7.5 → 10.0 → 12.5 → 15.0 mg |
A few things to notice:
- Tirzepatide takes longer to titrate (20 weeks vs 16). The label is more conservative about how fast you escalate.
- The starting doses differ by 10× (0.25 mg vs 2.5 mg). Despite that, the side-effect intensity at the starting dose is roughly comparable, because the receptor occupancy is what matters, not the milligram number.
- Tirzepatide has multiple approved maintenance options (5, 10, or 15 mg). Semaglutide is more binary: 1.0 mg for diabetes, 2.4 mg for weight management.
Why the mg numbers are different
Two compounds that produce broadly similar appetite-and-glucose effects have wildly different mg doses for one core reason: affinity. The amount of any drug needed to fill the relevant receptors depends on how strongly the molecule binds. Different binding profiles → different mg ranges. There is no clinical interpretation of "more mg = stronger drug" across compounds.
Comparing across drugs is like comparing the brightness of two flashlights by measuring the diameter of the bulb. Different physical quantity, different scale.
What changes on the syringe
Both compounds ship as multi-dose vials that you reconstitute and draw yourself. The math is the same formula, but the typical vial sizes differ:
| Compound | Common vial size | Typical BAC water | Concentration |
|---|---|---|---|
| Semaglutide | 10 mg | 2 ml | 5.0 mg/ml |
| Tirzepatide | 30 mg | 2 ml | 15.0 mg/ml |
For the same week's dose-step:
Semaglutide week 1 (0.25 mg @ 5 mg/ml):
0.25 ÷ 5 = 0.05 ml = 5 units U-100
Tirzepatide week 1 (2.5 mg @ 15 mg/ml):
2.5 ÷ 15 = 0.167 ml = 17 units U-100
Tirzepatide draws are roughly 3× the volume of comparable-week Semaglutide draws. That's purely a function of the higher mg number and slightly higher vial concentration; it has no clinical meaning, but it does affect how the syringe looks at draw time. Verify against your specific vial:
Inputs
Tirzepatide common vial sizes: 10 mg, 15 mg, 30 mg, 60 mg. Typical dose range: 2.5–15 mg. Public clinical dosing guidance. Not medical advice.
for a 2.5 mg dose
- Concentration
- 10.0 mg/ml
- Volume
- 0.250 ml
- Per ml
- 100 u
Not medical advice. Always verify against your vial label and your provider's instructions. Re-check before drawing.
Side effects — broadly similar profile
Both compounds produce a similar adverse-event pattern in trials, with gastrointestinal symptoms dominating:
- Nausea (most common, dose-dependent, worst in the first weeks of each step)
- Vomiting
- Diarrhea
- Constipation
- Reduced appetite (the intended effect)
- Fatigue, headache, dizziness early in titration
Some users tolerate one better than the other. There's no reliable predictor of which — you find out by trying. Switching is something your prescribing provider supervises; it usually isn't a 1:1 dose match because of the affinity differences described above.
Severe abdominal pain, persistent vomiting, signs of dehydration, or allergic-reaction symptoms with either drug are reasons to stop and contact your provider. The serious adverse events listed on each label (pancreatitis, gallbladder disease, severe dehydration, allergic reactions) are rare but real for both compounds.
Switching between them
The label-directed approach: stop one, wait the appropriate clearance window, start the other at its starting dose, and re-titrate from the bottom of the schedule. The reasoning:
- There's no validated 1:1 mg conversion between the two
- Your tolerance to one compound doesn't transfer to the other — gastric-emptying side effects re-emerge at the new compound's starting dose for most users
- Re-titrating gives the prescriber a clean baseline to assess response
This is not the same as "switching from 2.4 mg Semaglutide directly to 15 mg Tirzepatide" — that's a high-side-effect-risk approach not supported by either label.
Cost, availability, and other practical differences
Outside the scope of this post, but worth flagging:
- Insurance coverage differs between the two
- Compounded versions of both exist; legal status and quality vary and are governed by the FDA compounding rules
- Brand-name vs generic: there are no FDA-approved generics for either compound as of April 2026
Tracking either one in the iOS app
The iOS app handles both protocols:
- 16-week Semaglutide ramp or the 12-week aggressive variant
- 20-week Tirzepatide ramp or a fast-12-week alternate
- Reconstitution math against any vial size
- Body-map injection-site rotation across abdomen / thigh / upper arm
- Side-effect timeline keyed to each dose-escalation step
- Doctor-ready PDF for endocrinology or weight-management appointments
Related reading
- Semaglutide reference page
- Tirzepatide reference page
- How to titrate Semaglutide safely — detailed walkthrough of the 16-week ramp
- Retatrutide explained — the next GLP-class compound in development
References
- DailyMed: Ozempic — Semaglutide for type-2 diabetes
- DailyMed: Wegovy — Semaglutide for weight management
- DailyMed: Mounjaro — Tirzepatide for type-2 diabetes
- DailyMed: Zepbound — Tirzepatide for weight management