PeptideCalculations
Guide

GLP-1 Titration Schedules Compared: Semaglutide, Tirzepatide, Retatrutide, Cagrilintide

Week-by-week label schedules for Wegovy, Ozempic and Zepbound beside the retatrutide and cagrilintide trial doses, plus the math that turns a step into units.

By the Peptide Calculations editors · Updated 2026-10-19

Every GLP-1 class drug is started low and stepped up, because the gut side effects track the dose and ease with time on each step. The approved ones have exact schedules on their FDA labels. Retatrutide and cagrilintide are still in trials, so the only schedules that exist for them are the trial arms. This guide lays the four side by side in milligrams per week, then shows how to turn any step into syringe units from a 5 mg or 10 mg vial, with the arithmetic written out. Nothing here is a recommendation to take any of these; the escalation rules are quoted from labels and papers so you can check what a chart is telling you.

The two label schedules

Semaglutide. The Wegovy label (DailyMed) escalates every four weeks: 0.25 mg for weeks 1 to 4, 0.5 mg for weeks 5 to 8, 1 mg for weeks 9 to 12, 1.7 mg for weeks 13 to 16, and 2.4 mg once weekly from week 17 as the maintenance dose. The 0.25, 0.5 and 1 mg steps are escalation doses only, not approved maintenance doses. If a step is not tolerated, escalation can be delayed four weeks, and if 2.4 mg is not tolerated the maintenance dose can be dropped to 1.7 mg. The Ozempic label, the same molecule at diabetes doses, starts at 0.25 mg for four weeks, moves to 0.5 mg, and allows increases to 1 mg and then 2 mg after at least four weeks on each; 2 mg is the maximum.

Tirzepatide. The Zepbound label (FDA, revised 02/2026) starts at 2.5 mg once weekly for four weeks, states that 2.5 mg is for initiation and is not approved as a maintenance dose, then moves to 5 mg. After that, increases of 2.5 mg are allowed after at least four weeks on the current dose. Maintenance for weight reduction is 5, 10 or 15 mg; the maximum is 15 mg. The label says to consider tolerability when picking the maintenance dose and to step down if a dose is not tolerated. Mounjaro is the same molecule for type 2 diabetes; this page quotes the Zepbound label only.

The two labels agree on the shape: four weeks minimum per step, a defined floor, a defined ceiling, and permission to pause.

The two trial schedules

Retatrutide. The phase 2 trial in NEJM (Jastreboff 2023) randomized 338 adults to once-weekly retatrutide at 1 mg, 4 mg (initial dose 2 mg), 4 mg (initial dose 4 mg), 8 mg (initial dose 2 mg), 8 mg (initial dose 4 mg), or 12 mg (initial dose 2 mg), or placebo, for 48 weeks. The methods describe a 2 mg or 4 mg starting dose followed by gradual escalation every four weeks for up to 12 weeks until the assigned dose. At 48 weeks the change in body weight was minus 8.7 percent (1 mg), minus 17.1 percent (combined 4 mg), minus 22.8 percent (combined 8 mg), and minus 24.2 percent (12 mg) versus minus 2.1 percent on placebo. GI side effects occurred mainly during escalation, were dose related, and were partly reduced by the 2 mg rather than 4 mg start. The paper does not print every intermediate step for each arm in the main text, so a chart that lists “2, 4, 8, 12” for the 12 mg arm is reconstructing it from the four-week rule.

Cagrilintide. The phase 2 trial in The Lancet (Lau 2021) randomized to once-weekly cagrilintide at 0.3, 0.6, 1.2, 2.4 or 4.5 mg, liraglutide 3.0 mg daily, or placebo, for 26 weeks including a dose escalation period of up to six weeks. Weight change at week 26 ranged from 6.0 to 10.8 percent across the cagrilintide doses (10.8 percent at 4.5 mg) versus 3.0 percent on placebo and 9.0 percent on liraglutide. The abstract does not spell out the escalation steps, so no week-by-week schedule for cagrilintide can be sourced; only the target doses can.

Side by side, mg per week

Weeks Semaglutide (Wegovy label) Tirzepatide (Zepbound label) Retatrutide (phase 2 trial) Cagrilintide (phase 2 trial)
1 to 4 0.25 2.5 2 or 4 (start) escalation, steps not published
5 to 8 0.5 5 step up escalation ends by week 6
9 to 12 1 7.5 (optional step) step up target dose
13 to 16 1.7 10 target (1, 4, 8 or 12) target dose
17 onward 2.4 maintenance 12.5 then 15 if stepped; maintenance 5, 10 or 15 target held to week 48 target held to week 26
Basis FDA label FDA label NEJM 2023, Jastreboff Lancet 2021, Lau

Read the basis row before the numbers. The first two columns are what a prescriber follows. The last two are what trial participants received under monitoring, with the escalation details only partly published.

Turning a step into syringe units

A reconstituted vial has a concentration set by the mass on the label and the water you add. The formula this site’s calculator uses:

units = dose in mcg ÷ (vial mg × 1,000 ÷ water mL) × 100

The bracket is the concentration in mcg/mL. Dividing the dose by it gives mL, and multiplying by 100 converts mL to U-100 units. Three worked examples:

Semaglutide, 5 mg vial + 2 mL. Concentration = 5 × 1,000 ÷ 2 = 2,500 mcg/mL. The 0.25 mg step is 250 mcg: 250 ÷ 2,500 = 0.1 mL × 100 = 10 units. The rest of the label ladder at the same mix: 0.5 mg = 20 units, 1 mg = 40 units, 1.7 mg = 68 units, 2.4 mg = 96 units. The top step nearly fills a 1 mL syringe, and a 5 mg vial holds only two 2.4 mg doses.

Tirzepatide, 10 mg vial + 1 mL. Concentration = 10 × 1,000 ÷ 1 = 10,000 mcg/mL. The 2.5 mg step is 2,500 mcg: 2,500 ÷ 10,000 = 0.25 mL × 100 = 25 units. Then 5 mg = 50 units, 7.5 mg = 75 units, 10 mg = 100 units. A 10 mg vial is one 10 mg dose, and the 12.5 and 15 mg label steps do not fit in a 1 mL syringe at this mix or in this vial at all. With 2 mL of water instead, 2.5 mg becomes 50 units and 5 mg fills the syringe.

Retatrutide, 10 mg vial + 1 mL. Same 10,000 mcg/mL. The 2 mg trial start is 2,000 mcg: 2,000 ÷ 10,000 = 0.2 mL = 20 units. Then 4 mg = 40 units, 8 mg = 80 units. The 12 mg arm exceeds the vial.

Cagrilintide, 5 mg vial + 2 mL. 2,500 mcg/mL. 0.3 mg = 300 ÷ 2,500 = 0.12 mL = 12 units; 0.6 mg = 24 units; 1.2 mg = 48 units; 2.4 mg = 96 units. The 4.5 mg arm is 180 units, so it needs 1 mL of water (5,000 mcg/mL, 90 units) and uses nearly the whole vial.

The pattern across all four: the starting doses land in the 10 to 50 unit range on a 5 mg or 10 mg vial, and the maintenance doses push against the syringe or the vial. Plan the water around the step you are on, write the concentration on the vial, and rerun the calculator every time either number changes.

Sources

Questions

What is the Wegovy titration schedule?

Per the FDA label: 0.25 mg once weekly for weeks 1 to 4, 0.5 mg for weeks 5 to 8, 1 mg for weeks 9 to 12, 1.7 mg for weeks 13 to 16, then 2.4 mg from week 17 on. If a step is not tolerated, escalation can be delayed four weeks.

How fast can you increase tirzepatide?

The Zepbound label starts at 2.5 mg once weekly for four weeks, then 5 mg, then increases in 2.5 mg steps only after at least four weeks on the current dose. Maintenance is 5, 10 or 15 mg; 15 mg is the maximum.

What doses were used in the retatrutide trial?

The NEJM phase 2 trial (Jastreboff 2023) randomized to 1, 4, 8 or 12 mg once weekly for 48 weeks, starting at 2 or 4 mg and stepping up every four weeks for up to 12 weeks. The 12 mg group lost 24.2 percent of body weight at 48 weeks versus 2.1 percent on placebo.

How many units is 0.25 mg of semaglutide?

It depends on the mix. From a 5 mg vial reconstituted with 2 mL, the concentration is 2,500 mcg/mL, so 250 mcg is 0.1 mL, which is 10 units on a U-100 syringe. Change the water and the unit count changes.

Brands we recommendIndependent. No affiliation with any brand, no affiliate links, no referral codes, no paid placements.
  1. 1Licensed Peptides two accredited labs on every lot, certificates public, card and Apple Pay checkout
  2. 2Core Peptides long track record, public certificates, wide catalog
  3. 3Ascension Peptides public third-party testing, clear pricing