Show HN: Peptide calculators ask the wrong question. I built a better one
silviogutierrez Sunday, February 01, 2026
Most peptide calculators ask the wrong question.
They ask: How much water are you adding?
But in practice, what you actually know is your vial size and your target dose.
The water amount should be the output, not the input.
It should also make your dose land on a real syringe tick mark. Not something like 17.3 units.
I built a peptide calculator that works this way: https://www.joyapp.com/peptides/
What’s different:
- You pick vial size and target dose → reconstitution is calculated for you
- Doses align to actual syringe markings
- Common dose presets per peptide
- Works well on mobile (where this is usually done)
- Supports blends and compounds (e.g. GLOW or CJC-1295 + Ipamorelin)
- You can save your vials. No account required.
Happy to hear feedback or edge cases worth supporting.