# Tirzepatide Dosage: Labeled Doses, Titration Schedule, and Trial Protocols > Tirzepatide dosage as documented in the FDA label and clinical trials: 2.5 mg starting dose, weekly escalation, 15 mg maximum. Half-life ~5 days. Subcutaneous injection only. Starting dose, titration ladder, pharmacokinetics, and dose-response from SURPASS and SURMOUNT — cited to the source. ## The short version Tirzepatide is given as a once-weekly subcutaneous injection (an injection under the skin). The FDA label documents a starting dose of 2.5 mg once weekly for 4 weeks, then an increase to 5 mg, with further optional increases every 4 weeks in 2.5 mg steps up to a maximum of 15 mg. The three maintenance doses tested in the large SURPASS and SURMOUNT trials are 5 mg, 10 mg, and 15 mg. The drug stays in the body for about 5 days on average (the elimination half-life), which is what allows once-weekly dosing to maintain steady blood levels. Injections go into the thigh, abdomen, or upper arm. The biggest thing to know about tirzepatide dosage: the escalation is slow by design. Jumping doses too quickly is the main driver of nausea and GI side effects. ## Tirzepatide dosage The tirzepatide dosage schedule as documented in the FDA prescribing information [16]: - **Starting dose:** 2.5 mg once weekly subcutaneously (4 weeks) - **First increase:** 5 mg once weekly (4 weeks) - **Optional further increases** in 2.5 mg increments every 4 weeks as tolerated: - 7.5 mg → 10 mg → 12.5 mg → 15 mg - **Maximum maintenance dose:** 15 mg once weekly The three doses used across the SURPASS and SURMOUNT phase 3 programmes were 5 mg, 10 mg, and 15 mg once weekly. The 20-week escalation schedule used in SURMOUNT trials (2.5 mg → 5 mg → 7.5 mg → 10 mg → 12.5 mg → maintenance at 10 or 15 mg) is the schedule most commonly referenced in trial publications [4, 5]. Doses are described here as documented in the FDA label and clinical-trial literature. Prescribing decisions, dose selection, and titration are the province of the treating physician. ## Tirzepatide dose **Dose-response relationship.** In SURPASS-1 through -5, higher doses produced larger HbA1c and body weight reductions in a dose-dependent pattern [8, 3, 10, 11]. In SURMOUNT-1, mean weight change at 72 weeks was -15.0% at 5 mg, -19.5% at 10 mg, and -20.9% at 15 mg versus -3.1% with placebo [4]. This dose-response relationship was consistent across the trial programme. **Maximum tolerated dose in obesity trials.** SURMOUNT-5 compared maximum tolerated doses of tirzepatide (10 or 15 mg) versus maximum tolerated doses of semaglutide (1.7 or 2.4 mg). Tirzepatide produced -20.2% weight loss versus -13.7% [5]. **Why the slow escalation.** The stepwise escalation schedule is designed to manage gastrointestinal tolerability. Nausea, vomiting, and diarrhoea are dose-related and most frequent during escalation. Clinical trial data showed these effects were mostly mild to moderate and typically eased with continued exposure at each dose level [4, 14]. ## Pharmacokinetics: half-life and absorption The elimination half-life of tirzepatide is approximately 5 days in humans [1]. This long half-life is the consequence of the C20 fatty-diacid modification (the eicosanedioic acid arm attached to the GIP-backbone peptide via a glutamic acid linker), which confers high albumin affinity. Once bound to albumin in the blood, the drug is protected from rapid clearance, producing a long-acting profile consistent with once-weekly dosing. A Phase 1 programme in 142 subjects (healthy volunteers and people with type 2 diabetes) characterised the pharmacokinetics supporting once-weekly administration [1]. The fatty-diacid modification also delays gastric emptying — a property that peaks in the first weeks of treatment and attenuates with continued dosing [23]. For the perioperative setting: the ~5-day half-life means the drug is still active for approximately five half-lives (roughly 25 days) after the last dose. Because of slowed gastric motility, clinicians have raised the question of prolonged fasting or point-of-care gastric assessment around procedures — an active area of guidance development [22]. ## Administration: route and injection sites Subcutaneous injection is the only route studied and approved in the clinical trial programme [1, 16]. Injections are administered in the thigh, abdomen, or upper arm. Marketed formulations are refrigerated; specific storage parameters are formulation-dependent and outside the scope of the published efficacy literature. The [tirzepatide injection](/injection) page covers what the research shows about the subcutaneous route, absorption characteristics, and the injection schedule from the label and trial protocols. No oral formulation of tirzepatide has been approved; the once-weekly subcutaneous route is the product of the PK programme that established the albumin-binding design. --- The trial record, read straight — two receptors, one cited page, no white coat and nothing prescribed.