- Also known as
- Tirz · LY3298176 · GIP/GLP-1 dual agonist
- Class
- Dual receptor agonist (GIP, GLP-1)
- Form
- Lyophilised powder (20, 40 mg vials)
- Sizes
- 20 mg · 40 mg
- Storage, dry
- −20 °C, dry and dark
- Storage, mixed
- 2–8 °C, use within 28 days of mixing (as generally reported for reconstituted peptides)
- BAC water per size
- 20 mg: 3 mL · 40 mg: 3 mL
What is Tirzepatide?
Tirzepatide is a synthetic peptide that activates two gut-hormone receptors: glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1). Both hormones are released after eating and act on insulin secretion, glucagon, stomach emptying and appetite; tirzepatide is built to be long acting, so the trials gave it once a week by subcutaneous injection. It was developed by Eli Lilly and has the largest trial record of the metabolic peptides on this site, with phase 3 programmes in type 2 diabetes (SURPASS) and obesity (SURMOUNT), plus trials in sleep apnoea, heart failure with preserved ejection fraction and fatty liver disease. In Australia it is registered on the ARTG as the prescription medicine Mounjaro. The material sold here is a research chemical, not that medicine.
What the research shows
| Study | Model | Dose used | Duration | Finding |
|---|---|---|---|---|
| Jastreboff AM et al.2022 · N Engl J Med · PMID 35658024 | Human, phase 3 randomised controlled trial in adults with obesity, without diabetes (n=2539) — SURMOUNT-1 | 5, 10 or 15 mg once weekly, subcutaneous, vs placebo | 72 weeks, including a 20-week dose-escalation period | Mean weight change at week 72 was −15.0% (5 mg), −19.5% (10 mg) and −20.9% (15 mg) vs −3.1% with placebo. Adverse events, mostly gastrointestinal, led to discontinuation in 4.3% to 7.1% on tirzepatide vs 2.6% on placebo. |
| Jastreboff AM et al.2025 · N Engl J Med · PMID 39536238 | Human, phase 3 randomised controlled trial, obesity with prediabetes (n=1032 of 2539) — SURMOUNT-1, 3-year analysis | 5, 10 or 15 mg once weekly, vs placebo | 176 weeks, then 17 weeks off treatment | Weight change at 176 weeks was −12.3% to −19.7% vs −1.3% with placebo, and type 2 diabetes was diagnosed in 1.3% vs 13.3% (hazard ratio 0.07). No new safety signals were identified. |
| Rosenstock J et al.2021 · Lancet · PMID 34186022 | Human, phase 3 randomised controlled trial in type 2 diabetes on diet and exercise alone (n=478) — SURPASS-1 | 5, 10 or 15 mg once weekly, vs placebo | 40 weeks | HbA1c fell by 1.87%, 1.89% and 2.07% with 5, 10 and 15 mg vs a rise of 0.04% with placebo. An HbA1c below 7.0% was reached by 87–92% on tirzepatide vs 20% on placebo. |
| Frías JP et al.2021 · N Engl J Med · PMID 34170647 | Human, phase 3 open-label randomised trial vs semaglutide 1 mg in type 2 diabetes (n=1879) — SURPASS-2 | 5, 10 or 15 mg once weekly, vs semaglutide 1 mg once weekly | 40 weeks | HbA1c fell by 2.01 to 2.30 percentage points with tirzepatide vs 1.86 with semaglutide, and weight loss was 1.9 to 5.5 kg greater. Nausea was reported by 17–22% on tirzepatide and 18% on semaglutide. |
| Aronne LJ et al.2024 · JAMA · PMID 38078870 | Human, phase 3 randomised withdrawal trial in obesity, without diabetes (n=670 randomised) — SURMOUNT-4 | Maximum tolerated dose of 10 or 15 mg once weekly, subcutaneous, then continued or switched to placebo | 36-week open-label lead-in plus 52 weeks double-blind | After a mean 20.9% reduction in the lead-in, weight changed by −5.5% with continued tirzepatide vs +14.0% after switching to placebo from week 36 to 88. Withdrawal led to substantial regain of lost weight. |
| Malhotra A et al.2024 · N Engl J Med · PMID 38912654 | Human, two phase 3 randomised controlled trials in moderate-to-severe obstructive sleep apnoea with obesity — SURMOUNT-OSA | Maximum tolerated dose of 10 or 15 mg, vs placebo | 52 weeks | The apnoea-hypopnoea index fell by 25.3 and 29.3 events per hour with tirzepatide vs 5.3 and 5.5 with placebo in the two trials. Adverse events were mostly gastrointestinal and mild to moderate. |
| Packer M et al.2025 · N Engl J Med · PMID 39555826 | Human, randomised controlled trial in heart failure with preserved ejection fraction and obesity (n=731) — SUMMIT | Up to 15 mg once weekly, subcutaneous, vs placebo | At least 52 weeks (median follow-up 104 weeks) | Cardiovascular death or worsening heart failure occurred in 9.9% on tirzepatide vs 15.3% on placebo (hazard ratio 0.62). Adverse events leading to discontinuation were 6.3% vs 1.4%. |
| Loomba R et al.2024 · N Engl J Med · PMID 38856224 | Human, phase 2 randomised controlled trial in biopsy-confirmed MASH with F2–F3 fibrosis (n=190) — SYNERGY-NASH | 5, 10 or 15 mg once weekly, subcutaneous, vs placebo | 52 weeks | Resolution of MASH without worsening of fibrosis was seen in 44%, 56% and 62% on 5, 10 and 15 mg vs 10% on placebo. The authors state that larger and longer trials are needed. |
What these studies don't show: Tirzepatide has a far larger human evidence base than most peptides, but these trials were run by the developer with its own pharmaceutical product, not research-grade material. Most ran for 40 to 72 weeks; the 3-year SURMOUNT-1 analysis covers only the prediabetes subgroup. SURMOUNT-4 shows that weight returned when treatment stopped, and in SUMMIT, cardiovascular death on its own occurred in 8 patients on tirzepatide and 5 on placebo, so the benefit came from fewer worsening heart-failure events.
Every study links to its PubMed record. See all Tirzepatide studies in the research library →
Tirzepatide price in Australia: 20mg and 40mg vials
Buy Tirzepatide in Australia in 2 vial sizes and a starter kit. Prices are in AUD, you pay by PayID or bank transfer, and orders are dispatched from Australian stock.
| Size | Price | Per mg | BAC water (example) |
|---|---|---|---|
| 20 mg | $249.99 | $12.50/mg | 3 mL |
| 40 mg | $279.99 | $7.00/mg | 3 mL |
The BAC water column is an example volume for the maths only. Open the calculator (pre-set for Tirzepatide).
Starter kit
Is Tirzepatide available in Australia?
Yes, tirzepatide is registered on the ARTG as Mounjaro, a prescription medicine. That registration covers the finished Mounjaro product, not research-grade tirzepatide powder. Tasman supplies tirzepatide as a research chemical for laboratory work only, and it is not Mounjaro and not for human consumption. How the TGA treats research peptides →
Side effects reported in studies
Across the tirzepatide trials the most common adverse events were gastrointestinal, chiefly nausea, diarrhoea and vomiting, mostly mild to moderate and concentrated in the dose-escalation period. In SURMOUNT-1, adults with obesity lost a mean 15.0% to 20.9% of body weight over 72 weeks, compared with 3.1% on placebo.
Reconstitution
| Vial | BAC water (example) | Concentration |
|---|---|---|
| 20 mg | 3 mL | 6.67 mg/mL |
| 40 mg | 3 mL | 13.33 mg/mL |
Tirzepatide FAQ
Where can I buy tirzepatide in Australia?
Tasman Peptides supplies research-grade tirzepatide from Australian stock, for laboratory research only. It comes as lyophilised powder in 20 mg and 40 mg vials, and each lot is tested by HPLC before dispatch. This is a research chemical, not the prescription medicine Mounjaro, and it is not for human consumption.
Is tirzepatide legal in Australia?
Tirzepatide is registered on the ARTG as Mounjaro, a prescription medicine, so it is an approved medicine in Australia in that form. Research-grade tirzepatide powder is a separate product: Tasman sells it as a research chemical for laboratory work only. We do not give advice on obtaining tirzepatide as a medicine; the TGA's ARTG search holds the current registration details.
Is research tirzepatide the same as Mounjaro?
No. Mounjaro is a finished prescription medicine registered on the ARTG, made and labelled under that registration. Research tirzepatide is the same named compound supplied as lyophilised powder for laboratory work, tested by HPLC, and it is not a medicine. The published SURPASS and SURMOUNT trials studied the developer's pharmaceutical product, not research-grade material.
How much is tirzepatide per mg?
The price per mg depends on the vial size, and the size table on this page shows the per-mg figure for the 20 mg and 40 mg vials side by side. The larger vial carries a lower cost per mg. Both vials contain the same HPLC-tested lyophilised tirzepatide.
What is the difference between the 20 mg and 40 mg vials?
The 40 mg vial holds twice as much lyophilised tirzepatide as the 20 mg vial; the compound and purity testing are the same. For the site's calculator, the neutral default for both sizes is 3 mL of bacteriostatic water, which is arithmetic only, so the 40 mg vial gives a solution twice as concentrated.
How should tirzepatide be stored?
Unmixed lyophilised tirzepatide is best kept at −20 °C, dry and away from light. Once reconstituted it is generally kept at 2–8 °C and used within 28 days, as reported for reconstituted peptides. Avoid freezing a mixed solution and avoid repeated warming and cooling.
Tirzepatide vs retatrutide: what is the difference?
Tirzepatide acts on two receptors (GIP and GLP-1), while retatrutide adds a third, the glucagon receptor. Tirzepatide has completed phase 3 programmes and is registered on the ARTG as Mounjaro; retatrutide is still investigational and not registered. In SURMOUNT-1, tirzepatide produced a mean weight change of up to −20.9% at 72 weeks in adults with obesity.
Tirzepatide vs semaglutide: what did the head-to-head trial find?
In SURPASS-2, tirzepatide lowered HbA1c more than semaglutide 1 mg over 40 weeks in 1879 people with type 2 diabetes. HbA1c fell by 2.01 to 2.30 percentage points with tirzepatide vs 1.86 with semaglutide, and weight loss was 1.9 to 5.5 kg greater. Gastrointestinal adverse events were similar between the groups.
What is tirzepatide studied for?
Tirzepatide has been studied most in type 2 diabetes and obesity, where the trials measured HbA1c, body weight and body composition. Later trials looked at obstructive sleep apnoea, heart failure with preserved ejection fraction, MASH with liver fibrosis, prevention of type 2 diabetes in prediabetes, and youth-onset type 2 diabetes.
Is there a tirzepatide starter kit?
Yes. The tirzepatide starter kit contains a 20 mg vial, 3 mL of bacteriostatic water, ten 0.5 mL insulin syringes and 20 alcohol swabs. It is sold for laboratory research only.
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