Mazdutide

Mazdutide (development names IBI362 and LY3305677) is a dual agonist at GLP-1 and glucagon receptors, just like survodutide. The difference is in the build: mazdutide is derived from oxyntomodulin, a gut hormone the body makes that naturally hits both receptors. It is developed and mainly studied in China.

It is injected once a week. Mazdutide is not broadly approved yet but in late clinical research (a phase 3 programme in China). It ships as a freeze-dried powder you dissolve in bacteriostatic water before the first use.

The GLP-1 part does the familiar work: it boosts the insulin response, slows gastric emptying and dampens appetite, the food noise gets quieter. The glucagon part additionally raises energy expenditure and fat breakdown, especially in the liver.

Because mazdutide is based on oxyntomodulin, the glucagon share is comparatively pronounced. Studies suggest this helps not only with weight but also with metabolism and liver fat. But more is not automatically better here either.

Before you start, have everything ready. The list is short:

• The Mazdutide vial with the freeze-dried powder
• Bacteriostatic water to dissolve it
• U-100 insulin syringes for the injection (they also work for drawing the water, you just draw more often; a larger syringe is faster but not a must)
• Alcohol swabs for the vial cap and the skin
• A sealable sharps container for used needles

With everything clean and in one place, the rest is straightforward.

The powder is dissolved in bacteriostatic water. How much water you add sets the concentration, and with it how many units you later draw on the insulin syringe for your dose.

Use the calculator above for exactly this: pick your vial size and the water volume, and you instantly see the concentration and the units per dose. Roughly: less water means higher concentration and fewer units.

When dissolving, just add the bac water and let the powder dissolve. It does not matter if the water hits the powder directly, and swirling or shaking are both fine.

The injection is subcutaneous, into the fat layer under the skin. Common spots are the abdomen (keep about two finger-widths clear of the navel), the front of the thigh, or the back of the upper arm.

The short version:

• Clean the spot with an alcohol swab and let it dry
• Pinch up a small fold of skin
• Insert the needle at a 45 to 90 degree angle
• Inject slowly, wait a moment, then withdraw
• Put the needle straight into the sharps container

Rotate the site each time so the tissue does not get irritated.

Mazdutide is well documented in phase 2 studies, but mainly in China. In the obesity study (Nature Communications, 2023), weight dropped dose-dependently and clearly over 24 weeks, and several metabolic markers improved. A 2024 meta-analysis summarises efficacy and safety across several studies. The phase 3 programme is ongoing. Large studies outside China are limited so far, and that belongs in the picture honestly.

The individual studies with links are in the source block below.

Like the whole class, gastrointestinal effects come first: nausea, fullness, sometimes diarrhoea or constipation. In the studies this was clearly dose-dependent and manageable through the slow titration. The glucagon share is the reason to ease in slowly.

Mazdutide takes the hunger away, the rest is on you. A few things get more out of the research phase and keep you healthy:

• Enough protein. If you eat little, make the little you eat protein-rich, or you lose muscle along with fat.
• Drink enough. With low appetite you often drink less without noticing, and the risk of dehydration goes up.
• Resistance training. Keeps muscle mass while the weight comes off.
• Eat slowly. With delayed gastric emptying you fill up faster, big portions sit heavy.

Alcohol and very fatty meals make the nausea noticeably worse, especially early on.

The undissolved powder is robust, normal room temperature (around 20 to 25 degrees) is fine, ideally kept in the dark. Once dissolved, the solution goes into the fridge (2 to 8 degrees) and stays stable there for at least 8 to 10 weeks with barely any loss of potency, in practice considerably longer. The bacteriostatic water brings a preservative that keeps the dissolved form stable for longer.