What a dose actually costs
Most people know what their medication costs per box or per vial. Far fewer know what it costs per dose — and the two are related by arithmetic that changes every time your dose step changes. This is the single most commonly miscalculated number in a protocol.
The naive calculation, and why it is wrong
The obvious approach is to divide what you paid by the number of doses on the label. That gives a number, and the number is usually wrong, for three reasons.
- Your dose step determines the yield, not the label. A vial's labeled dose count assumes a particular dose. At a higher step you get fewer doses from the same vial; at a lower step, more.
- Diluent and supplies cost money. Bacteriostatic water, syringes and alcohol wipes are small individually and not small annually.
- Not every dose in a vial gets used. Residual volume, expiry windows and waste during drawing all mean actual yield is usually below theoretical yield.
The calculation that works
Cost per dose = (vial cost + share of supplies) ÷ doses actually obtained from that vial.
The important term is the last one. "Doses actually obtained" is an observed number from your own log, not a figure from the label. Over a few vials it converges on something reliable, and it is often meaningfully different from the theoretical figure.
Why it rises as you titrate
This is the part that surprises people, and it is worth being concrete about.
Take a vial holding 10 mg of medication. At a 2.5 mg weekly step, that vial yields four doses. At a 5 mg step, two doses. At 10 mg, one. The vial costs exactly the same in all three cases — so cost per dose has doubled and then doubled again while nothing about the price changed.
Anyone budgeting from their starting-dose cost per dose will be wrong, in the expensive direction, by the time they reach a maintenance step. Working this out before you escalate rather than after is worth the ten minutes.
Cost per month is the number that matters
Cost per dose is the building block; cost per month is what you actually budget against.
Monthly cost = cost per dose × doses per month. For a weekly injection that is roughly 4.3 doses per month, not 4 — a detail that produces about a 7% underestimate over a year if you use 4.
The Cost Planner handles this, and the Vial Longevity Calculator gives the dose count it depends on.
What else belongs in the real number
If you want a figure you can actually plan against, these belong in it:
- Supplies — diluent, syringes, wipes, sharps disposal.
- Shipping or dispensing fees, amortised across the doses they cover.
- Any consultation or lab costs your protocol requires on a recurring basis.
- Wastage — vials that expired before they emptied.
None of these are large on their own. Together they routinely move the real figure by a noticeable margin from the one people quote.
Frequently asked
Why does my cost per dose go up when I increase my dose?
How many doses are there really in a vial?
Should I include syringes and diluent?
Is 4 doses a month right for a weekly injection?
Does Peptide Plug tell me where to buy anything?
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