Put 1 mL of bacteriostatic water into the 5 mg SS-31 vial. That makes 5.00 mg/mL. A 5 mg dose is then 100.0 units on a U-100 syringe.
That volume is the one that lands the draw on a syringe line, so the reading can be checked by eye. More water makes a weaker mix and a bigger draw. Less water makes a stronger mix and a smaller one. The amount of SS-31 in the glass never changes. Only the number of marks it takes does.
What matters first
Water to add
1 mL
Resulting strength
5.00 mg/mL
Example 5 mg dose
100.0 U-100 units
What is SS-31?
SS-31 is a peptide four amino acids long. It gathers inside mitochondria, the parts of a cell that make energy, and sticks to a fat there.
Medically reviewed by Jennifer Montecillo, MD · non-practicing medical reviewer·Reviewed 2026-08-13·open the primary sources
How much bacteriostatic water for a 5 mg SS-31 vial?
◆ Unique to the 5 mg vialU-100 example draws
Water added
Concentration
Per U-100 unit
Example: 5 mg =
1 mL
5.00 mg/mL
50 mcg
100.0 units
2 mL
2.50 mg/mL
25 mcg
200.0 unitswon’t fit
Straight arithmetic: concentration = 5 mg ÷ water, and 1 U-100 unit = 0.01 mL. The example column shows the math at 5 mg; it is not a dose recommendation.
Which volume to use is a practical choice rather than a dose. Pick the one that puts your draw somewhere you can actually read it on the syringe. The flags in the last column mark where that fails. “Hard to measure” means the draw is too small to judge by eye. “Won’t fit” means it is bigger than one U-100 syringe holds.
The 5 mg vial at 1 mL on a U-100 barrel. 5 mg fills to 100.0 units, at 5.00 mg/mL.
How many units is a documented dose from this vial?
The table above uses one worked example. These are the published quantities, converted into marks on a U-100 barrel at each water volume for a 5 mg vial. Where a quantity was never studied by injection, the row says so.
40 mg — FDA-approved label
40 mg once a day, for people with Barth syndrome weighing at least 30 kg, under the skin. The same 40 mg was used in every registered subcutaneous study of this molecule, from the 12-person crossover behind the approval to the 218-person phase 3 that was stopped.
Water added
Concentration
Draw
1 mL
5.00 mg/mL
800.0 unitswon’t fit
2 mL
2.50 mg/mL
1600.0 unitswon’t fit
FDA labelFORZINITY (elamipretide) injection, for subcutaneous use — FDA prescribing information, Stealth BioTherapeutics Inc., initial U.S. approval 2025 (NDA 215244). Source for the accelerated approval, the Barth syndrome indication, the 40 mg once-daily dose, the 20 mg renal reduction, the 280 mg/3.5 mL solution, and the reaction rates against placebo · retrieved 2026-08-13
20 mg — FDA-approved label
20 mg once a day, where kidney filtration is under 30 mL per minute and the person is not on dialysis, under the skin. It is the only reduction the label describes.
Water added
Concentration
Draw
1 mL
5.00 mg/mL
400.0 unitswon’t fit
2 mL
2.50 mg/mL
800.0 unitswon’t fit
FDA labelFORZINITY (elamipretide) injection, for subcutaneous use — FDA prescribing information, Stealth BioTherapeutics Inc., initial U.S. approval 2025 (NDA 215244). Source for the accelerated approval, the Barth syndrome indication, the 40 mg once-daily dose, the 20 mg renal reduction, the 280 mg/3.5 mL solution, and the reaction rates against placebo · retrieved 2026-08-13
One vial, one day’s worth of nothing like the published amount
This is the only strength this powder is sold in, and the published amount for the molecule inside it is many times larger than the whole vial. The table below is therefore a demonstration as much as a calculation.
3Read the full vial record — 3 notes
The whole vial is one draw
At the worked amount, the full vial is one draw. No smaller published human quantity was found for this molecule.
So there is no schedule to plan and no wastage to price. There is one preparation, one draw, and a decision the literature does not help with.
The larger volume cannot be drawn
Spread this powder through the greater of the two listed volumes and one draw needs twice what a U-100 barrel holds. The row is kept and flagged rather than hidden.
The smaller volume fills the barrel exactly to its top mark. That is a full syringe, and it is worth seeing before it is prepared rather than after.
No window is published for the mixed liquid
No published source says how long this keeps after water is added. The approved version arrives already mixed, so its label does not answer that question.
No published guidance answers the storage question, so no number from a different product is substituted.
How do you mix it, step by step?
Wipe both stoppers with an alcohol swab and let them dry.
Draw up the water volume you picked from the table.
Let the water run slowly down the inside wall of the SS-31 vial, rather than jetting it onto the powder.
Swirl gently until it dissolves. Shaking damages peptides.
Store it as the dispensing label directs. What happens after mixing differs by product — some labels direct against refrigerating the mixed solution at all.
What if your water volume is not on the table?
The table shows the offered water volumes. The calculator does the same arithmetic for any volume and any syringe, and shows its working line by line.
