Tirzepatide Dosage: FDA-Labeled Doses and the Clinical-Trial Titration Record
TL;DR
Tirzepatide dosage is set by the FDA-approved prescribing information, which specifies a starting dose and a stepwise titration schedule designed to minimise GI side effects while building toward the effective maintenance doses studied in trials. The approved starting dose is 2.5 mg once weekly for four weeks; from there, it titrates up every four weeks until the patient reaches their maintenance dose — typically 5, 10, or 15 mg once weekly. All doses in this section are drawn from the labeled prescribing information and the SURPASS and SURMOUNT phase 3 trial protocols [12][4][3]. This site does not recommend doses to individuals — that is a clinical decision made between a patient and their prescribing clinician.
Tirzepatide dosage — the labeled titration schedule
The FDA prescribing information establishes the following tirzepatide dose protocol as documented for both approved indications [12]:
Tirzepatide dose titration ladder:
| Week | Dose (once weekly, subcutaneous) | |---|---| | Weeks 1–4 | 2.5 mg | | Weeks 5–8 | 5 mg | | Weeks 9–12 | 7.5 mg | | Weeks 13–16 | 10 mg | | Weeks 17–20 | 12.5 mg | | Week 21+ | 15 mg (maximum dose) |
The label documents that if a patient does not tolerate the 15 mg dose, it may be reduced; the minimum effective maintenance dose in trials was 5 mg.
Tirzepatide dose in the SURPASS programme (type 2 diabetes): phase 3 trials studied maintenance doses of 5, 10, and 15 mg once weekly after a 4-week titration from 2.5 mg [3]. The 15 mg dose produced the largest HbA1c reductions but all three doses met the primary glycaemic endpoints.
Tirzepatide dosage in SURMOUNT-1 (obesity): the same 20-week escalation to the maximum tolerated dose (10 or 15 mg) was used [4]. Mean weight change at 72 weeks: -15.0% (5 mg), -19.5% (10 mg), -20.9% (15 mg), vs -3.1% placebo.
Tirzepatide injection — route and administration
Tirzepatide injection route: subcutaneous — the only route studied in the clinical-trial programme and the only approved administration route [12]. The injection is administered once weekly into the abdomen, thigh, or upper arm. Site rotation is recommended in prescribing guidance.
Elimination half-life: approximately 5 days, consistent with the albumin-binding C20 fatty-diacid modification [1]. Steady-state plasma concentrations are reached after 4 weeks of once-weekly dosing.
The pharmacokinetics of tirzepatide in humans were characterised in a radiolabelled study showing renal excretion as the principal elimination route (~66% urine, ~33% faeces), with metabolic breakdown via proteolytic cleavage, beta-oxidation, and amide hydrolysis.
Tirzepatide side effects during the dose-escalation phase are predominantly gastrointestinal: nausea, vomiting, diarrhoea, constipation, and decreased appetite. These are most common during the titration period and for 1–2 weeks after each dose increase, then attenuate [13][14]. The label advises dose adjustments if GI effects are not tolerated during escalation.
Tirzepatide dose — clamp-study and mechanistic doses
The tirzepatide dose most studied for beta-cell function and insulin sensitivity is 15 mg once weekly — the dose used in the Heise et al. (2022) clamp RCT (n=117, 28 weeks) [8]. At 15 mg, tirzepatide produced a clamp disposition index ETD of +1.92 vs placebo and +0.84 vs comparator — far larger than any other glucose-lowering agent has produced on this endpoint.
The Thomas et al. (2020) mechanistic substudy also used doses up to 15 mg and documented improvements in beta-cell function and insulin sensitivity markers [10].
The Yamaguchi et al. (2025) Japanese clamp study used an open-label titration up to the maximum tolerated dose in patients with obesity and type 2 diabetes (n=16), finding glucose infusion rate rose from 3.21 to 5.16 mg/min/kg (P<0.001) — an improvement not significantly predicted by weight loss alone.
For older adults (≥65 years with BMI <30 kg/m²), a post hoc analysis of pooled SURPASS-1 to -5 data found HbA1c reductions of -1.97% to -2.10% across all doses with no increase in hypoglycaemia risk [22]. Dose-proportional weight reduction was numerically lower than in the overall cohort.
Tirzepatide cost — a note on access
This site does not track, list, or quote prices for tirzepatide. Approved formulations are prescription-only and the cost in the United States varies by insurance coverage, prescription-assistance programmes, manufacturer coupon eligibility, and pharmacy. Compounded versions have existed during shortage periods, but regulators have raised specific concerns about the quality, purity, and identity of compounded tirzepatide preparations. Any questions about access, cost, coverage, or prescriptions are for a licensed prescriber or pharmacist.
Tirzepatide vs semaglutide — dose comparison in head-to-head trials
The head-to-head dosing comparison was tested directly in two trials:
SURPASS-2 (glycaemia, n=1,879, 40 weeks): tirzepatide 5/10/15 mg versus semaglutide 1 mg. At the maximum tirzepatide dose, HbA1c fell 2.30 pp versus 1.86 pp with 1 mg comparator dose; body weight fell an additional -5.5 kg with tirzepatide 15 mg [3].
SURMOUNT-5 (obesity, n=751, 72 weeks): tirzepatide maximum tolerated dose (10 or 15 mg) versus comparator maximum tolerated dose (1.7 or 2.4 mg) — the most rigorous dose-equivalent comparison. Body-weight reduction: -20.2% (tirzepatide) vs -13.7% (comparator), P<0.001 [5].
The difference in maximum approved doses matters for interpretation: the SURPASS-2 comparator dose was 1 mg (below the maximum 2.4 mg dose), while SURMOUNT-5 used maximum tolerated doses for both drugs.