TL;DR

Weekly injectables linger. Semaglutide half-life ≈ 1 week. Tirzepatide half-life ≈ 5 days. Finish your last weekly dose, then start the new drug about 7 days later at a low dose and re-titrate. Start lower if you had GI issues. Informational only, not medical advice.

Why switch

• Access or cost shifts

• Weight-loss or A1c plateau

• Side effects on the current agent

• Goal-specific optimization; tirzepatide often delivers larger average weight loss

Drug kinetics to respect

• Semaglutide: ~1-week half-life; measurable levels for several weeks

• Tirzepatide: ~5-day half-life

The 7-day handoff rule

Stop the weekly GLP-1 or GIP/GLP-1. Wait 7 days. Start the new weekly agent at a low dose. If switching because of GI symptoms, wait until they resolve and begin at the lowest dose.

How to switch

Semaglutide → Tirzepatide

• Timing: Last semaglutide dose → start tirzepatide ~7 days later

• Starting dose: 2.5 mg weekly ×4 weeks → 5 mg; then increase by 2.5-mg steps every ≥4 weeks as needed (up to 15 mg)

• What to expect: Often stronger weight-loss momentum early; GI effects common during up-titration

Tirzepatide → Semaglutide

• Timing: Last tirzepatide dose → start semaglutide ~7 days later

• Starting dose: Start low and re-titrate

  • Ozempic (T2D): 0.25 mg weekly ×4 weeks → 0.5 mg → 1 mg; consider 2 mg if needed

  • Wegovy (weight mgmt): step-up per label to 2.4 mg

• What to expect: Slower GI ramp; average weight loss may be smaller vs tirzepatide, but steady progress is common

Quick-look switch table (not dose-equivalence)

ScriptScores™: Switching Directions (0–10)

Higher = better.

Scoring method: Weighted mix of expected weight change, A1c effect, tolerability during switch, operational simplicity, and access variability. Editorial tool, not a medical directive.

Side-effect control on the new drug

• Nausea: Small meals, avoid high-fat meals during titration, pause dose escalations if symptomatic

• Constipation: Fluids, fiber, stool softener if needed

• Oral meds: Delayed gastric emptying can alter absorption; monitor narrow-therapeutic-index drugs with your prescriber

Red-flag timing

• Procedures with anesthesia or deep sedation: Class delays gastric emptying; follow hold instructions from your care team

• Pregnancy planning: For semaglutide, many programs advise stopping at least 2 months before trying to conceive

Monitoring

• Track weight, waist, and symptoms weekly during titration

• For T2D: review glucose patterns; reduce insulin or sulfonylurea if hypoglycemia risk

• Program add-ons: resistance training, adequate protein, sleep targets, and periodic check-ins improve adherence

Safe switch checklist

1. Confirm last dose date

2. Plan Day 7 start

3. Start low; extend each step ≥4 weeks if symptomatic

4. Flag anesthesia and pregnancy timing in advance
   
   
   Not medical advice. This article is for general information. It does not diagnose, treat, or replace care from a licensed clinician who knows your history.