Retatrutide Dosing Guide: 2026 Phase 3 Titration & Results

Important Dosing Info

While Tirzepatide (Zepbound) goes up to 15mg, Retatrutide's maximum studied dose is 12mg. Taking higher amounts is not supported by current Phase 3 clinical trials.

Understanding Retatrutide Dosing in 2026

As of January 2026, Retatrutide remains an investigational drug in Phase 3 trials. While users often search for a "Retatrutide 15mg" dose—likely due to familiarity with Zepbound® (Tirzepatide)—clinical data from the TRIUMPH-4 trial confirms that the maximum studied dose is actually 12mg.

The Standard Titration Schedule

In the latest clinical protocols, Retatrutide is started at a low dose to allow the body's triple receptors (GLP-1, GIP, and Glucagon) to adjust, minimizing gastrointestinal side effects.

Month	Weekly Dose	Phase	Purpose
Month 1	2 mg	Initiation	Receptor Adjustment
Month 2	4 mg	Early Titration	Weight Loss Begins
Month 3	8 mg	Therapeutic	Active Fat Burning
Month 4	12 mg	Maximum	Peak Weight Loss Results

Standard titration protocol for Retatrutide weight loss drug

Why is there no 15mg dose?

Unlike Tirzepatide, which goes up to 15mg, Retatrutide is significantly more potent due to its "triple-agonist" mechanism. The December 2025 Phase 3 results showed that the 12mg dose was sufficient to achieve a record-breaking 28.7% average weight loss. Research indicates that pushing beyond 12mg may increase side effects like dysesthesia (skin sensitivity) without providing meaningful additional weight loss.

Comparing Weight Loss by Dose

Your results will scale significantly based on your maintenance dose. Here is what the latest 2025/2026 data shows for each milestone:

Retatrutide 4mg: Participants saw significant metabolic improvements and steady weight loss (approx. 17% over 48 weeks).
Retatrutide 8mg: Often considered the "sweet spot" for many users, providing a balance of high efficacy with fewer side effects than the maximum dose.
Retatrutide 12mg: The highest tested dose, resulting in the most dramatic outcomes (up to 71.2 lbs lost on average).

Is there a 5mg or 10mg Retatrutide dose?

While these aren't standard titration steps, they may be used as maintenance doses for patients who are sensitive to the 8mg or 12mg levels.

How often is Retatrutide administered?

Retatrutide is administered as a once-weekly subcutaneous injection. Like other GLP-1 medications, it is injected just under the skin of the upper arm, thigh, or stomach area.

What is the starting dose for Retatrutide?

In clinical trials, the most common starting dose is 2 mg once weekly for the first four weeks. A lower starting dose of 1 mg is also being studied to help the body adjust to the "triple-agonist" mechanism and minimize gastrointestinal side effects.

Is there a 15 mg dose of Retatrutide?

No, there is currently no 15 mg dose for Retatrutide. While Tirzepatide (Zepbound) has a maximum dose of 15 mg, Retatrutide’s record-breaking 28.7% weight loss results were achieved at a maximum maintenance dose of 12 mg per week.

What is the titration schedule for Retatrutide?

The titration schedule typically increases the dose every four weeks based on tolerance:
Weeks 1–4: 2 mg weekly
Weeks 5–8: 4 mg weekly
Weeks 9–12: 8 mg weekly
Week 13+: 12 mg weekly (Maximum Maintenance Dose)

What are the maintenance doses for Retatrutide?

The target maintenance doses studied in the TRIUMPH Phase 3 program are 4 mg, 8 mg, and 12 mg. The 12 mg dose has demonstrated the highest efficacy, with an average weight loss of approximately 24.2% to 28.7%.