AOD-9604 Reconstitution Ratio: Water-to-Vial Math

An AOD-9604 reconstitution ratio is the amount of bacteriostatic water added relative to the AOD-9604 mass in the vial. That ratio, once fixed, sets the concentration — and the concentration is what determines how many units a target dose draws to on a syringe. There's no single mandated ratio for AOD-9604; different water volumes are all arithmetically valid, and the right one usually comes down to which resulting unit reading is easiest to draw and double-check. It is written for research and educational purposes only and is not medical advice.

What the ratio actually describes

Reconstitution ratio and concentration describe the same relationship from two directions. Concentration is mass divided by volume — vial mg ÷ mL of bacteriostatic water added. A ratio states that same relationship as a comparison: "2 mL of water per 5 mg of AOD-9604" is another way of saying 2.5 mg/mL. Once the ratio is fixed, every other figure in the calculation — draw volume, syringe units — follows from it.

This matters because AOD-9604 ships as lyophilized powder with no volume of its own to speak of. The mg figure on the vial label is fixed at manufacture. The ratio is the one variable a researcher actually chooses, and it's the lever that decides whether a given dose reads as 5 units or 20.

AOD-9604 at a glance

AOD-9604 is a modified synthetic fragment corresponding to the C-terminal region of human growth hormone, commonly referenced as hGH fragment 176-191. It was developed to isolate the region of the hGH molecule associated with fat metabolism from the region associated with growth and blood-sugar effects, and it has been studied in that context rather than as a growth-hormone replacement.

AOD-9604 is not FDA-approved for any use. It is sold as a lyophilized research compound, not as a drug or supplement, and nothing here describes a use recommendation. It describes reconstitution arithmetic, which is identical regardless of a compound's regulatory status or how far along its research is.

Common AOD-9604 reconstitution ratios

There is no single required ratio. The table below shows how different water volumes change the concentration for a 5 mg vial, one of the sizes AOD-9604 is most commonly supplied in alongside 2 mg and 10 mg:

Water added	Concentration	mcg/mL
1 mL	5 mg/mL	5000 mcg/mL
2 mL	2.5 mg/mL	2500 mcg/mL
2.5 mL	2 mg/mL	2000 mcg/mL
4 mL	1.25 mg/mL	1250 mcg/mL

A commonly referenced starting point for a 5 mg vial is 2 mL of bacteriostatic water, landing at 2.5 mg/mL. It's a reference point rather than a rule — any row above is arithmetically sound, and the right choice depends on which draw volume reads most clearly on a given syringe.

Worked example: holding the ratio constant across vial sizes

Take a 2.5 mg/mL ratio — 2 mL of water per 5 mg of AOD-9604 — and apply it across the three vial sizes AOD-9604 is most often supplied in.

2 mg vial + 0.8 mL water. Concentration: 2 ÷ 0.8 = 2.5 mg/mL. For a 250 mcg (0.25 mg) target dose: 0.25 ÷ 2.5 = 0.1 mL. On a U-100 insulin syringe, 1 mL equals 100 units, so 0.1 × 100 = 10 units.

5 mg vial + 2 mL water. Concentration: 5 ÷ 2 = 2.5 mg/mL — the same concentration, because the ratio of water to mass didn't change. Same 250 mcg dose: 0.25 ÷ 2.5 = 0.1 mL = 10 units.

10 mg vial + 4 mL water. Concentration: 10 ÷ 4 = 2.5 mg/mL. Same dose, same draw: 10 units.

Three different vial sizes, three different water volumes, and the identical 10-unit draw for the identical 250 mcg dose — because the ratio, not the vial size, is what sets the draw. Scaling the water with the mass is what makes a ratio portable between vial sizes. Adding a flat 1 mL to the 5 mg vial instead of 2 mL would push the concentration up to 5 mg/mL and pull that same dose down to just 5 units.

Comparing ratios against the same target dose

Switching the ratio itself — rather than scaling it across vial sizes — changes the draw for a fixed dose. Using a 5 mg vial and a 250 mcg target as the reference:

Water added	Concentration	mcg per unit	Units for 250 mcg
1 mL	5000 mcg/mL	50 mcg/unit	5 units
2 mL	2500 mcg/mL	25 mcg/unit	10 units
4 mL	1250 mcg/mL	12.5 mcg/unit	20 units

None of these rows is wrong — 250 mcg is 250 mcg in every one of them. What changes is how large the draw looks on the barrel. A one-unit misread is a bigger proportional error at the low end, so the 5-unit row leaves less margin than the 20-unit row, even though both land on whole numbers. Checking a candidate ratio against a usual target dose with the peptide calculator beats mixing first and hoping the draw lands somewhere legible.

Ratio sets the draw, not the total doses

A reconstitution ratio doesn't answer how many total doses a vial provides. That comes from vial mass divided by target dose, independent of the ratio chosen. A 5 mg vial dosed at 250 mcg (0.25 mg) provides 5 ÷ 0.25 = 20 doses, whether it's reconstituted at 1250 mcg/mL, 2500 mcg/mL, or any other concentration on the table above. The ratio only changes what each of those draws looks like on the syringe, not how many are in the vial. See the AOD-9604 dosage calculator guide for the full per-dose arithmetic.

Reconstitution process

1. Gather the AOD-9604 vial, bacteriostatic water, a U-100 insulin syringe, and alcohol swabs.
2. Swab both vial stoppers with alcohol.
3. Draw the water volume your chosen ratio calls for.
4. Inject it slowly down the inside wall of the vial, not directly onto the powder.
5. Swirl gently until fully dissolved — don't shake.
6. Confirm the resulting concentration matches what was entered into the calculator before drawing a dose.

For the general steps that apply to any peptide vial, see how to reconstitute peptides.

Storage

Reconstituted AOD-9604 is generally kept refrigerated and protected from light. Unreconstituted lyophilized powder is far more stable than the mixed solution, which is why vials ship dry. Track the date each vial was reconstituted, particularly if more than one vial is in use at a different concentration at the same time.

Common mistakes

• Holding water volume constant instead of the ratio when moving between vial sizes. 2 mL in a 2 mg vial and 2 mL in a 10 mg vial produce very different concentrations, not the same ratio.
• Confusing mg and mcg. AOD-9604 vial labels are in milligrams; research doses are usually written in micrograms. 1 mg equals 1000 mcg, and misreading one for the other produces a 1000x error.
• Assuming a higher-concentration ratio delivers "more" peptide. A 250 mcg dose is 250 mcg at any ratio — concentration changes the draw volume, not the amount delivered.
• Shaking the vial. Swirl gently instead — shaking can degrade the peptide.
• Using a syringe that isn't U-100. Every unit conversion here assumes 100 units equal 1 mL. A different syringe scale changes the math entirely.

Use the calculator

Working out an AOD-9604 reconstitution ratio by hand is a couple of divisions, but checking it against an actual target dose is where a tool saves time. Enter a vial size, the water volume for a chosen ratio, and a target dose into the peptide reconstitution calculator to get concentration, draw volume, and syringe units in one pass. Reverse mode runs it backward — enter a dose and the unit reading to land on, and it returns the water volume that gets there.

For the per-dose arithmetic in more depth, see the AOD-9604 dosage calculator guide, or enter your own numbers into the peptide calculator directly.