Week 4: Last Week at 2.5mg
Your fourth and final dose at the starter level. This is the calibration week — what 2.5mg does at full steady state is exactly what you feel now, and it is the baseline for everything that follows.
The standard titration schedule moves you to 5mg next week — but standard does not mean mandatory. Tirzepatide's labeling specifically allows clinicians to leave patients at a lower dose longer when tolerability is borderline. Week 4 is when you and your prescriber decide which version of "next week" applies to you.
The honest question to ask yourself before week 5: are side effects fully manageable on a normal day? Not zero — manageable. If yes, the step up is appropriate. If no, an extra month at 2.5mg is a real, supported option.
Appetite Suppression
Roughly two-thirds of users describe consistent appetite control by end of the starter month — without the sharp peaks of weeks 1 and 2.
Cumulative loss through the 2.5mg phase tends to be 2 to 4 percent of starting body weight, though individual variation is wide.
The Week 4 Timeline
The Week 4 Timeline
Day 22 (Injection 4)
Fourth and Final at 2.5mg
The last starter-dose injection. The injection-day experience should be familiar and gentle at this point.
Days 24-26
Calibration Window
This is when you have the clearest signal of what 2.5mg does for you. Notice your hunger, fullness, energy, mood, digestion — these are your reference points for the 5mg step.
Day 28
Decision Point
Talk with your prescriber: step up, or hold steady? Both are valid answers. Many people benefit from one extra month at 2.5mg if anything still feels rough.
Navigating Symptoms
Track what is still bothering you — even mild but persistent symptoms. Those baseline patterns matter when you compare to week 5 after the dose doubles.
A small reframing that helps people: the 2.5mg phase is not the "real" treatment. It is the on-ramp. Most of the weight loss in tirzepatide trials happens at higher doses over longer periods of time — SURMOUNT-1 ran 72 weeks at maintenance doses. Four weeks of modest progress at 2.5mg is exactly what the curve predicts.
What Users Report
“I was nervous about moving up, so I asked to stay at 2.5 for another month. My doctor said that was totally fine. Glad I did — the second 5mg jump went so much smoother.”
— Maya O.
“By the end of week 4 I had lost about 6 pounds and felt completely steady. Stepping up to 5mg felt earned, not rushed.”
— Tom L.
Looking ahead
Week 5 takes you to 5mg — a dose increase of 100 percent in a single jump. This is the largest relative step in the entire tirzepatide schedule, and the side-effect rebound is real. The good news: you have already shown your body can tolerate the drug. The next stretch is about climbing without overshooting.