App, spreadsheet, notes or paper?
All four can work. They fail in different places. Here's an honest comparison.
| Koyomi | Spreadsheet | Notes app | Paper | |
|---|---|---|---|---|
| Units to draw, worked out for you | ✓ Every dose | If you build the formula | ✗ | ✗ |
| Reminders at dose times | ✓ | ✗ | Separate app | ✗ |
| Doses left in each vial | ✓ Automatic | Manual | ✗ | Manual |
| Use-by date warnings | ✓ | ✗ | ✗ | ✗ |
| Injection site rotation | ✓ Suggests the next site | Manual | Manual | Manual |
| Cycles and dose changes | ✓ | Possible, fiddly | ✗ | ✗ |
| Weight, mood and side-effect trends | ✓ Charts | If you build them | ✗ | ✗ |
| Export for your doctor | ✓ CSV | ✓ | Copy and paste | Photocopy |
| Works offline, data stays on your device | ✓ | Depends | Depends | ✓ |
| Cost | Free | Free | Free | Free |
When a spreadsheet is enough
If you take one thing on a simple schedule and you're comfortable with formulas, a spreadsheet works. The usual problems are a formula broken by accident, no reminders, and having to remember to open it.
When notes or paper are enough
For a short course of one medicine with a pre-filled pen, a simple note may be all you need. They struggle once you're mixing vials, rotating sites or running more than one thing.
When an app helps most
When you're mixing your own vials, running more than one peptide, following cycles or dose changes, or want a record you can hand to your doctor without extra work.