Retatrutide: the complete research guide
By the OzPeptides lab team · Updated 28 Sep 2026 · 1,655 wordsRead the Retatrutide research guide →Why Retatrutide 15MG specifically
Retatrutide 15MG is one of five Retatrutide strengths: a 15mg vial of lyophilised powder at $160, or $10.67 per mg. Triple-agonist GIP, GLP-1 & glucagon research, synthesised and tested in our own Australian lab. It is also the best value per milligram in the range.
What is in a 15MG vial
A Retatrutide 15MG vial contains 15mg — 15,000 micrograms — of lyophilised powder.
Reconstituted with 1ML of bacteriostatic water it gives 15mg/ML, so a 0.1ML draw holds 1.50mg. With 2ML that becomes 7.50mg/ML and 750mcg per 0.1ML; with 3ML, 5mg/ML and 500mcg. The powder is the same either way — the volume only changes the concentration.
Bacteriostatic water is sold separately. Pre-mixed vials and pen cartridges arrive reconstituted, so this arithmetic only applies to the plain vial.
How many draws a 15MG vial holds
A 15MG vial is 15,000 micrograms, so at 250mcg per draw it holds 60 draws, at 500mcg it holds 30, and at 1mg it holds 15. That count does not change with how much bacteriostatic water is added — the water sets the concentration, not the quantity.
At $160 the vial, that works out to $2.67 per 250mcg draw, $5.33 per 500mcg draw, or $10.67 per 1mg. Cost per draw is usually a more useful comparison than cost per vial, because it is the figure that survives a change of strength.
15MG on a 100-unit syringe
A standard U-100 insulin syringe holds 1ML in 100 marked units, so one unit is 0.01ML. Reconstitute this 15MG vial with 1ML and 250mcg sits at 1.67 units; with 2ML it is 3.33 units; with 3ML, 5 units.
For a 500mcg draw the same three volumes give 3.33, 6.67 and 10 units. Choosing the volume that puts a typical draw on a whole number rather than an awkward fraction removes a whole category of measuring error, which is the practical reason to do this arithmetic before mixing rather than after.
Plain, pre-mixed or pen cartridge
Retatrutide 15MG is $160 as a plain lyophilised vial, and the same as a mixed vial or pen cartridge: we reconstitute it here at no extra cost, and it arrives as a solution.
The plain vial keeps longest, because a lyophilised peptide stored cold and dry outlasts the same peptide in solution by a wide margin. Pre-mixed suits anyone who would rather not handle the reconstitution step, and the cartridge suits a pen. Bacteriostatic water is sold separately and is only needed for the plain vial.
Buying Retatrutide 15MG in Australia
Retatrutide 15MG is $160. Sydney delivery is free on orders over $100, so a single 15MG vial clears that threshold on its own. Everywhere else in Australia is $15 express post, free on orders of $200 or more. Orders placed before the daily cut-off dispatch the same day from Sydney.
The peptide itself is synthesised and tested in our own lab in Blacktown, NSW — not imported in bulk and relabelled here, which is how most research peptides reach the Australian market. That matters for a practical reason rather than a patriotic one: an imported peptide has a longer chain between synthesis and vial, the testing that matters happened somewhere else if it happened at all, and the certificate is one the buyer cannot trace.
Every batch is confirmed by mass spectrometry, measured at ≥99% purity by HPLC and screened at 0 ppm heavy metals, and the batch number printed on the vial resolves to that batch's own certificate. Supplied for in-vitro and laboratory research only, to buyers aged 18 and over.
Retatrutide strengths compared
We make Retatrutide in five strengths: 5MG at $80 ($16.00 per mg), 10MG at $130 ($13.00 per mg), 15MG at $160 ($10.67 per mg), 20MG at $220 ($11.00 per mg), 30MG at $320 ($10.67 per mg).
Each strength has its own page, its own batch and its own price per milligram. Larger vials are usually better value per milligram, which is why the arithmetic is on every page rather than left to the reader.
What is retatrutide?
Retatrutide (research code LY3437943) is an investigational peptide developed by Eli Lilly and Company. It is a single molecule engineered to activate three hormone receptors at the same time: the glucose-dependent insulinotropic polypeptide receptor (GIP-R), the glucagon-like peptide-1 receptor (GLP-1-R) and the glucagon receptor (GCG-R). Because it engages three receptors, it is commonly described as a "triple agonist" or "triple-G" compound.
Retatrutide sits within the incretin family of metabolic research compounds. The earliest compounds in this family were designed around a single receptor. Later compounds combined two. Retatrutide is one of the first to combine three in one peptide, which is why it has become one of the most closely watched compounds in metabolic research.
At OzPeptides, retatrutide is synthesised and tested in our own Australian lab and sold strictly for research and laboratory use.
How retatrutide works: three receptors, one peptide
GLP-1 receptor. GLP-1 is an incretin hormone released after eating. In research models, GLP-1 receptor activation is associated with glucose-dependent insulin secretion, slowed gastric emptying and satiety signalling. It is the receptor targeted by semaglutide.
GIP receptor. GIP is the other major incretin. It is studied for its role in insulin secretion and fat metabolism, and for how it may complement GLP-1 signalling. Tirzepatide combines GIP and GLP-1 receptor activity.
Glucagon receptor. Glucagon is usually associated with raising blood glucose, but in research it is also studied for its effects on energy expenditure and liver fat metabolism. Adding glucagon receptor activity is what separates retatrutide from dual agonists.
The research interest in retatrutide comes from how these three signals interact when they are triggered together by one molecule, rather than by combining separate compounds.
Retatrutide vs tirzepatide vs semaglutide
The simplest way to compare the three is by receptor count. Semaglutide is a single agonist (GLP-1). Tirzepatide is a dual agonist (GIP and GLP-1). Retatrutide is a triple agonist (GIP, GLP-1 and glucagon).
All three are peptides studied in metabolic, appetite and glucose-regulation research. Researchers often run them side by side to compare single, dual and triple receptor activity. OzPeptides stocks all three, each made and batch-tested in Australia.
What the published research shows
Retatrutide has been evaluated in human clinical trials run by its developer. A Phase 2 obesity trial published in the New England Journal of Medicine in 2023 (Jastreboff et al.) reported mean body-weight reductions of up to 24.2% at 48 weeks in the highest-dose group, compared with placebo. A separate Phase 2 trial in type 2 diabetes, published in The Lancet in 2023 (Rosenstock et al.), reported improvements in glycaemic markers and body weight.
Larger Phase 3 studies have followed under Eli Lilly's TRIUMPH programme. These results are summarised here for educational context only. They relate to regulated clinical trials, not to research-grade material, and they are not a claim about any OzPeptides product.
Choosing a strength and format
OzPeptides supplies retatrutide in five strengths: 5MG, 10MG, 15MG, 20MG and 30MG. Each strength has its own product page so researchers can find and reorder the exact vial they need. Every strength is available as a standard vial, a mixed vial or a pen cartridge for our reusable metal pen. Mixing is free, or $5 a vial while a sale is running.
The standard vial contains lyophilised (freeze-dried) powder. Pre-mixed and cartridge formats are prepared in our lab for convenience. Buy 3 Get 1 Free applies to every strength.
What makes research-grade retatrutide trustworthy
Quality varies enormously between suppliers. Much of the peptide stock sold in Australia is manufactured overseas, shipped in bulk and relabelled locally, with little visibility over how it was made or tested. That is the problem OzPeptides was set up to solve.
Every batch of OzPeptides retatrutide is synthesised in our Australian lab and tested in-house before release. Purity is measured by HPLC (high-performance liquid chromatography) and must be at least 99%. Identity is confirmed by mass spectrometry, so the compound in the vial matches the label. Every batch is screened for heavy metals (lead, mercury, arsenic and cadmium), with results of 0 ppm. The batch number printed on your vial links to its certificate of analysis.
No nasties, no fillers, no heavy metals and no guess work from China.
Retatrutide in Australia
Retatrutide is not approved for therapeutic use in Australia. It is available only as a research compound. OzPeptides sells retatrutide strictly for in-vitro research and laboratory use, to buyers aged 18 and over. It is not for human consumption.
Because it is made here, OzPeptides retatrutide does not pass through international customs. Orders confirmed before 1PM AEST are dispatched the same day. Sydney orders are hand-delivered by our own team, and orders everywhere else in Australia travel by tracked express post.
Laboratory handling and storage
Like most research peptides, lyophilised retatrutide is typically stored cold and away from light, and reconstituted with bacteriostatic water when needed. Reconstituted material is generally kept refrigerated and used within the timeframe set by the laboratory's own protocols. Our lab team can answer handling questions on WhatsApp.
Retatrutide glossary
Agonist: a compound that binds to and activates a receptor. Retatrutide is an agonist at three receptors.
Incretin: a gut hormone released after eating that influences insulin secretion. GLP-1 and GIP are the two main incretins.
GLP-1 (glucagon-like peptide-1): an incretin hormone studied for its roles in insulin release, gastric emptying and satiety.
GIP (glucose-dependent insulinotropic polypeptide): the second major incretin, studied for its roles in insulin secretion and fat metabolism.
Glucagon: a pancreatic hormone that raises blood glucose and is studied for its effects on energy expenditure and liver fat.
Lyophilised: freeze-dried. Most research peptides are supplied as a dry powder cake because it is more stable than a solution.
Bacteriostatic water: sterile water containing 0.9% benzyl alcohol, commonly used in laboratories to reconstitute lyophilised peptides.
HPLC: high-performance liquid chromatography, the standard analytical method for measuring peptide purity.
Mass spectrometry: an analytical method that measures molecular mass, used to confirm a peptide's identity.
COA (certificate of analysis): the document that reports a batch's test results, including purity, identity and contaminant screening.
How to read an OzPeptides certificate of analysis
Every OzPeptides vial carries a batch number, and that batch number links to a certificate of analysis. The certificate lists the compound and strength, the batch number and the manufacturing location (Australia). It then reports each test against its specification.
Purity is reported as a percentage from HPLC analysis. OzPeptides releases a batch only if purity is at least 99%. The HPLC chromatogram on the certificate shows a single dominant peak for the target compound; minor peaks represent trace related substances.
Identity is confirmed by mass spectrometry, which checks that the measured molecular mass matches retatrutide (approximately 4731 Da). This is the test that proves the vial contains what the label says.
Heavy metals are reported individually for lead (Pb), mercury (Hg), arsenic (As) and cadmium (Cd). OzPeptides results read 0 ppm for each. A PASS stamp confirms the batch met every specification before release.
If a supplier cannot show you a certificate that matches the batch number on your vial, you have no way of knowing what is inside it.
Why researchers are moving to Australian-made peptides
For years, most research peptides reaching Australia were manufactured overseas, often in large contract facilities, and resold by local sellers who never saw the production line. Researchers had to trust generic certificates, wait weeks for international shipping and accept the risk of consignments being held at the border.
Making retatrutide onshore removes each of those problems. Production and testing happen in the same Australian facility, so every batch can be traced from synthesis to dispatch. There is no customs clearance, so orders confirmed before 1PM AEST leave the lab the same day. Sydney orders are hand-delivered by our own team, and the rest of Australia receives tracked express post.
It also means a real, local team that can answer questions about a specific batch, format or strength on WhatsApp, usually within the hour.
Which retatrutide strength is right for your research?
The right strength depends on the design of your study and how much material each protocol requires. Smaller strengths such as 5MG and 10MG suit pilot work and short protocols. 15MG is our most-ordered strength and a common middle ground. 20MG and 30MG suit larger or longer studies and usually work out cheaper per milligram.
If you are unsure, message our lab team with the scope of your study and we will point you to the most practical option. Remember that Buy 3 Get 1 Free applies per strength, so ordering four of the same strength is often the most economical way to stock a longer project.
Ordering retatrutide from OzPeptides
Ordering is deliberately simple. Every product page has a green WhatsApp button, and tapping it opens a message with your compound, strength, format and quantity already filled in. A member of our Australian lab team confirms stock, applies any current offer, such as Buy 3 Get 1 Free or the October vial discount, and sends secure payment details.
Once payment is confirmed, your order is packed at the lab in a plain, unbranded box. If it is confirmed before 1PM AEST on a business day, it is dispatched the same day. Sydney customers receive a personal hand delivery from our team, and every other Australian address receives tracked express post with the tracking number sent back to you on WhatsApp. Sydney delivery is free over $100 — over $200 while a sale is running — and $10 under that. Express post anywhere else in Australia is $15, free on orders of $200 or more.
There are no accounts to create and no checkout forms to fill in, and you are always talking to a real person who works in the lab that made your vial. If you have a question about a batch number, a strength or a format, you can ask it in the same chat.
Related research compounds
Researchers working with retatrutide often compare it with other compounds in our metabolic range. Semaglutide (single GLP-1 agonist) and tirzepatide (dual GIP/GLP-1 agonist) are the usual reference points. Cagrilintide, a long-acting amylin analogue, is studied in satiety research, and MOTS-c, a mitochondrial-derived peptide, is studied in energy metabolism. All are made and batch-tested in Australia with the same 99% purity and 0 ppm heavy-metal standards.