Tirze

Buy Tirze at PepPure

Looking for a reliable place to buy Tirze for research? PepPure supplies Tirze as a lyophilised powder in 10 or 20 mg vials. Every batch is tested for identity and purity; the current batch reaches 99.2% by HPLC. You can view the certificate of analysis (COA) before you order. Bacteriostatic water and alcohol swabs come free with your order, and if it is in stock, orders placed on working days before 16:00 ship the same day with PostNL.

What is Tirze?

Tirze is a synthetic 39-amino-acid peptide. It is the first dual agonist of the GIP and GLP-1 receptors to make it all the way to an approved medicine: in the EU and the US, Tirze is registered as the active substance in medicines for type 2 diabetes and weight management.

The molecule is based on the amino-acid sequence of the hormone GIP, modified so that it also activates the GLP-1 receptor. A fatty acid tail (C20 diacid) binds to albumin in the blood. As a result, Tirze is broken down slowly: its half-life is around five days, which allowed once-weekly administration in studies.

PepPure’s Tirze is NOT a medicine. It is a research-grade reference substance for in-vitro research, with the same molecular formula (C225H348N48O68) as the active substance.

How Tirze works: GIP and GLP-1

Tirze’s mechanism is based on two gut hormones, known as incretins, that the body produces after a meal:

• GIP receptor. GIP (glucose-dependent insulinotropic polypeptide) boosts insulin release when blood sugar rises and is involved in how fat is processed and stored in adipose tissue. At this receptor, Tirze is roughly as potent as natural GIP.
• GLP-1 receptor. GLP-1 also boosts insulin release, suppresses glucagon release, slows gastric emptying and sends a satiety signal via the brain. At this receptor, Tirze is weaker than natural GLP-1.

For this reason, researchers describe Tirze as an imbalanced agonist: the emphasis is on GIP. At the GLP-1 receptor it also mainly activates the cAMP pathway and less so the β-arrestin pathway, so the receptor becomes desensitised less quickly. It is precisely this combination that is seen as the explanation for why Tirze has a stronger effect in studies than agents that act on GLP-1 alone.

Tirze alongside semaglutide and Reta

What does the research on Tirze show?

Tirze has been studied extensively in the SURPASS trials (type 2 diabetes) and the SURMOUNT trials (obesity). A few key publications:

• SURMOUNT-1 (NEJM, 2022). 2,539 adults with obesity or overweight, 72 weeks. In the highest dose group, body weight fell by an average of 20.9%, compared with 3.1% on placebo.
• SURPASS-2 (NEJM, 2021). A head-to-head comparison with semaglutide in 1,879 people with type 2 diabetes. After 40 weeks, HbA1c and body weight fell more at every dose of Tirze than with semaglutide.
• SURMOUNT-OSA (NEJM, 2024). In people with obesity and obstructive sleep apnoea, the number of breathing pauses per hour fell markedly compared with placebo.

The most frequently reported side effects in these studies were gastrointestinal complaints such as nausea, diarrhoea, constipation and vomiting, mainly while the dose was being built up.

10 or 20 mg: which vial should you choose?

Both vials come from the same production batch; only the amount of peptide differs. The 20 mg vial offers better value per milligram. The 10 mg vial is handy for a shorter experiment or if you want to assess a batch first. You can work out the concentration after dissolving with the formula.

Quality you can check for yourself

Every batch of Tirze goes through the same checks before it goes on sale:

• Identity by mass spectrometry: the measured molecular weight must match 4813.5 g/mol.
• Purity by RP-HPLC: this batch reaches 99.2%. We do not sell anything below 99%.
• Moisture, endotoxins and residual solvents are measured for every batch.

All results are in the COA. See also Reading a Certificate of Analysis in five steps and What does 99% purity really mean for peptides?

Reconstituting and storing Tirze

Tirze is supplied lyophilised for maximum stability. Dissolve it in bacteriostatic water: add it slowly down the side of the vial and swirl gently until the solution is clear. You will find the full steps in Reconstitution: from lyophilizate to solution.

• Lyophilised: keeps for 24 months at 2–8 °C, dark and dry.
• After reconstitution: keep in the fridge, protected from light, and use within a few weeks.
• Avoid repeated freezing and thawing.

Ordering and delivery

• In stock and ordered on a working day before 16:00: shipped the same day with PostNL, with track & trace.
• Temporarily sold out? You can still order it on backorder; the expected delivery time is shown on the product.
• Delivery in the Netherlands and Belgium, to your door or to a PostNL point.
• Free shipping from € 100.
• Bacteriostatic water (3 ml), alcohol swabs and included free of charge.
• Discreet packaging and secure payment with iDEAL | Wero.

Want to research the triple agonist too? Take a look at Reta, or browse all peptides.

Further reading: Reta vs Tirze vs semaglutide: the differences explained · How much bacteriostatic water per vial? How to calculate the concentration

Research Use Only. Tirze from PepPure is intended exclusively for in-vitro research and laboratory use. It is not a medicine and is not intended for use in humans or animals. The research findings above come from published studies and are not usage advice. More in What does "research use only" mean legally?