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Topical Peptide Cream Calculator

Lyophilized peptide is usually reconstituted with bacteriostatic water first, then a measured volume of that solution is stirred into a cream, gel or serum. The number that matters is the concentration of the finished mix — how much peptide sits in each gram, once the added liquid is counted.

The formula

Solution concentration = peptide ÷ bacteriostatic water
Peptide added = solution concentration × volume added
Finished amount = base + volume added
Concentration = peptide added ÷ finished amount

Worked example

Illustrative numbers only — not a strength recommendation.

Example
Peptide in vial10 mg
Bacteriostatic water into vial1 mL → 10 mg/mL
Solution added to base1 mL (10 mg)
Carrier / base30 g → 31 g finished
Per gram0.32 mg/g (323 mcg/g)
Concentration0.032% w/w

Add only part of the solution for a weaker mix, or use less base for a stronger one. Note the 1 mL you add becomes part of the 31 g finished amount — ignoring it would overstate the concentration.

How to use the calculator

  1. Leave the mode on Reconstitute, then add to base (the default).
  2. Enter the peptide in the vial and the bacteriostatic water you dissolve it in — that sets the solution's mg/mL.
  3. Enter the volume of solution you add to the base, then the carrier / base amount (grams for % w/w, millilitres for % w/v).
  4. Read off the concentration as a percent and as mg per gram; optionally add an application size to see the peptide per use.

Adding dry powder straight into the base instead? Switch to the Dry powder into base mode, which skips the water and puts the whole vial into the base.

Open the topical calculator

Starting from a lyophilized vial? See what reconstitution does first →

Frequently asked questions

How do I calculate the concentration of a peptide cream?
If you reconstitute first, divide the vial by the bacteriostatic water to get the solution's mg/mL, multiply that by the volume you add to find the peptide that goes in, then divide by the finished amount (base plus the liquid you added). For example, 10 mg in 1 mL is 10 mg/mL; adding 1 mL moves 10 mg into 30 g of base, giving 31 g finished and about 0.32 mg/g, or 0.032% w/w.
Why does the added bacteriostatic water change the result?
Because the liquid you stir in becomes part of the finished product. If you add 2 mL of solution to 30 g of base, the mix weighs about 32 g, not 30 g, so the concentration is the peptide divided by 32. Leaving the added water out would overstate the strength — the more solution you add, the bigger that effect.
What is the difference between percent and mg per gram?
They describe the same concentration two ways. Percent by weight (% w/w) is the fraction of the finished mix that is peptide; mg/g is the milligrams of peptide in each gram. The two are locked together: 1% w/w is 10 mg/g, 0.5% is 5 mg/g, 0.1% is 1 mg/g, and so on.
Does the calculator recommend a strength to use?
No. It only performs arithmetic on the amounts you enter to report the resulting concentration. It does not suggest a target percentage, a carrier, or how any preparation should be applied.

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