A first-in-class dual GIP and GLP-1 receptor agonist developed by Eli Lilly. The dual mechanism produces larger weight-loss effects than any GLP-1-only agonist tested to date.

Is Tirzepatide stronger than Semaglutide?

In direct head-to-head trials (SURPASS-2), tirzepatide produced larger HbA1c reductions and greater weight loss than semaglutide 1 mg at all doses tested. The 15 mg dose in SURMOUNT-1 achieved −20.9% body weight versus semaglutide's −14.9% in STEP-1.

Is Tirzepatide authorised in the EU?

Yes — EMA-authorised since 2022 under Mounjaro for type 2 diabetes and chronic weight management.

What is the difference between Mounjaro and Zepbound?

Same active ingredient, different brand names per indication in the US (Mounjaro for diabetes, Zepbound for obesity). In the EU, both indications are marketed under Mounjaro.

Who makes Tirzepatide?

Eli Lilly is the originator. The compound is under patent through the late 2020s; no authorised generics yet.

Tirzepatide — Peptidepedia

MOLECULAR INFORMATION

Molecular information

Weight: 4,813.5 Da
Type: Dual GIP / GLP-1 receptor agonist · once-weekly subcutaneous
Formula: C₂₂₅H₃₄₈N₄₈O₆₈

Tirzepatide is a first-in-class dual GIP and GLP-1 receptor agonist developed by Eli Lilly. Authorised by the EMA under Mounjaro (type 2 diabetes) and Zepbound (chronic weight management). The dual incretin mechanism produces larger weight-loss effects than any GLP-1-only agonist tested to date.

Indications (EU authorisation)

Type 2 diabetes mellitus — Mounjaro
Chronic weight management — Zepbound (BMI ≥ 30 or ≥ 27 with comorbidity)

Why we grade it S

The SURPASS programme (T2DM) and SURMOUNT-1 (obesity) demonstrated −20.9% mean weight loss at the 15 mg dose — exceeding semaglutide head-to-head. Replicated across independent populations, with regulatory authorisation in the EU, US, UK and JP. No major contradictory data.

Regulatory authorisations

US	2022	as Mounjaro
EU	2022	as Mounjaro
US	2023	as Zepbound

RECONSTITUTION

How to reconstitute

YOU WILL NEED

Bacteriostatic water (BAC water)
Insulin syringes (0.5–1 mL)
Alcohol swabs
Vial of lyophilized peptide
Sterile work surface

PROCEDURE

01Clean the work area and hands thoroughly.
02Calculate the required bacteriostatic-water volume for the desired concentration.
03Draw the calculated BAC water into the syringe.
04Inject the water slowly down the inside wall of the vial — not directly onto the powder cake.
05Gently swirl until fully dissolved. Never shake.
06Store the reconstituted vial refrigerated at 2–8 °C and use within 28 days.

Standard biotech reconstitution procedure. Always use sterile technique. This is research-protocol guidance, not medical advice.

References

SURPASS-2 2021

1,879 participants

Head-to-head vs semaglutide 1 mg in T2DM — superior HbA1c + weight reduction at all doses
SURMOUNT-1 2022

2,539 participants

Weight management in obesity — −20.9% body weight at 72 weeks (15 mg dose)
SURMOUNT-4 2023

670 participants

Maintenance of weight loss after lifestyle lead-in — sustained −18% body weight

Frequently asked questions

What is Tirzepatide?: A first-in-class dual GIP and GLP-1 receptor agonist developed by Eli Lilly. The dual mechanism produces larger weight-loss effects than any GLP-1-only agonist tested to date.
Is Tirzepatide stronger than Semaglutide?: In direct head-to-head trials (SURPASS-2), tirzepatide produced larger HbA1c reductions and greater weight loss than semaglutide 1 mg at all doses tested. The 15 mg dose in SURMOUNT-1 achieved −20.9% body weight versus semaglutide's −14.9% in STEP-1.
Is Tirzepatide authorised in the EU?: Yes — EMA-authorised since 2022 under Mounjaro for type 2 diabetes and chronic weight management.
What is the difference between Mounjaro and Zepbound?: Same active ingredient, different brand names per indication in the US (Mounjaro for diabetes, Zepbound for obesity). In the EU, both indications are marketed under Mounjaro.
Who makes Tirzepatide?: Eli Lilly is the originator. The compound is under patent through the late 2020s; no authorised generics yet.