What is AOD-9604? A plain-English explainer
A lab-made, stabilized copy of a small fragment from the tail end of human growth hormone.
AOD-9604 is a synthetic peptide — a chain of 16 amino acids built from a small fragment near the tail end of human growth hormone (hGH), with one extra amino acid, tyrosine, stitched onto the front for stability. It is sold and studied as a research chemical, not an approved medicine.
That one paragraph is the whole definition. The rest of this page unpacks it at two levels — plain English, then a little deeper — and shows how the reconstitution math works, because AOD-9604 ships as a dried powder that has to be mixed and measured before anything else.
AOD-9604 in plain English
A peptide is a short chain of amino acids — often one cut from or modeled on a much bigger protein. Human growth hormone, for instance, is a full protein 191 amino acids long.
AOD-9604 corresponds to the region near the very end of the hGH chain — amino acids 177 through 191, a 15-amino-acid stretch. Researchers in Australia identified that region in the late 1990s and added one more amino acid, tyrosine, to the front to make the fragment more stable outside the body. That brings the total to 16 amino acids, and gives the compound its full technical name: Tyr-hGH(177-191).
It usually arrives as a small glass vial of white powder. The powder is the peptide with the water removed (freeze-dried, or “lyophilised”) so it stays stable in storage. On its own the powder can’t be measured into a syringe — there’s no volume to draw. That’s why the next step, reconstitution, exists.
The science, a little deeper
A few specifics that the plain-English version glosses over:
- It’s a defined sequence, not a mixture. AOD-9604 is a single, known 16-amino-acid sequence: Tyr-Leu-Arg-Ile-Val-Gln-Cys-Arg-Ser-Val-Glu-Gly-Ser-Cys-Gly-Phe. That’s what makes it a peptide in the chemical sense rather than an extract.
- It’s cyclic, not a straight chain. Two cysteine residues within the sequence form a disulfide bond, folding the peptide into a loop shape that resembles the same region within full-length hGH.
- It’s supplied lyophilised. Removing the water gives the powder a long shelf life; adding a measured liquid back (reconstitution) is what turns it into an injectable solution with a known strength.
- “Research chemical” is a regulatory status, not a marketing word. AOD-9604 has not been approved as a drug anywhere. The U.S. FDA lists it on its Category 2 bulk drug substances list, meaning FDA-registered compounding facilities are prohibited from preparing it. Most of what’s published about it is preclinical — laboratory and animal studies — and this page makes no claim about what it does in people.
If you want the classification in one line: AOD-9604 is a synthetic research peptide, 16 amino acids, built from a fragment of human growth hormone and supplied as a freeze-dried powder for reconstitution.
How reconstitution works for AOD-9604
Reconstitution is just dissolving the powder in a known volume of liquid so you have a concentration — milligrams of peptide per millilitre of solution. Once the concentration is fixed, the volume you draw for any target dose is simple arithmetic:
- Concentration = vial amount (mg) ÷ diluent volume (mL)
- Draw volume = target dose ÷ concentration
- Syringe units = draw volume (mL) × the units-per-mL of your syringe
The numbers all come from your own vial label and your prescription — the peptide amount printed on the vial, the volume of bacteriostatic water you add, and the dose you were told to use. The separate Amidra web calculator runs exactly those three steps and shows the formula at each one, so you can check it by hand. It never fills in a dose for you.
What Amidra does — and doesn’t — do here
Amidra is a tracking and education tool. It converts the values you enter and helps you keep a protocol organised; it does not recommend a dose, a compound, or a schedule, and it takes no position on whether anyone should use AOD-9604. Those decisions belong with a qualified healthcare professional. The information above is definitional — what the compound is — not medical advice.