What is a reverse peptide calculator?

A reverse calculator works backwards from syringe units to dose. Enter how many units you drew, your vial size, and BAC water amount. It tells you the exact mcg or mg you're injecting.

When would you need to reverse-calculate a dose?

It's useful when someone tells you to "draw 10 units" without explaining the mcg dose. It also helps when switching syringe types or verifying your dose matches the right dosing tier.

Does syringe type affect the dose?

No. A U-100 and U-30 syringe drawing the same number of units deliver the same volume of liquid. The difference is tick mark spacing. U-30 syringes are easier to read for small doses.

Can you use this calculator for insulin too?

This tool is designed for reconstituted peptides, not pre-filled insulin pens. Insulin concentration is standardized at U-100 (100 IU/mL), so the math is different. Use your insulin pen's built-in dosing.

How do you convert units to mcg?

Divide your vial size (in mcg) by the BAC water (in mL) to get mcg per mL. Then multiply by the units drawn divided by 100. For example: 10,000 mcg vial + 2 mL water = 5,000 mcg/mL. Drawing 10 units = 500 mcg.

Not medical advice. Talk to your provider before using any peptide.

Full disclaimer

Reverse Peptide Calculator

Peptide Schedule Research Team

Already drew your dose? Enter the units on your syringe to find out how many mcg/mg you actually injected. Select a peptide to see which dosing tier it matches.

Peptide — optional, auto-fills vial & water

Vial Size (mg)

BAC Water (mL)

Syringe Type

Units Drawn on Syringe

0100 units

10.0 units

100 units (1mL)

Actual Dose

250mcg

0.250 mg

Volume

0.100 mL

Concentration

2,500 mcg/mL

When to Use the Reverse Calculator

The reverse calculator is useful when you know how many units you drew on your syringe but need to verify the actual dose in mcg or mg. Common scenarios:

You followed someone else's protocol that says "draw 10 units" but you want to know the actual mcg dose
You're switching syringe types (e.g., U-100 to U-30) and need to recalculate
You're verifying your dose against a dosing tier (beginner/moderate/aggressive)
You reconstituted with a different amount of BAC water and need to check your new dose per unit

Need to calculate a dose from scratch? Try the forward dosage calculator. New to reconstitution? Read the reconstitution guide.

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Frequently Asked Questions

Frequently Asked Questions