How do I model twelve months of orforglipron across supply routes?

I am comparing three suppliers on documentation rather than on price.

I have worked this out and I would like someone to find the error, because I suspect there is one.

My working so far, for the record, is below, and I am fairly sure the error is in the unit conversion rather than the algebra.

Is my approach right even if my number is wrong?

Twelve months is 52 weekly administrations across 365 days, and on a four-week ladder from the bottom of the range about 5 steps — so roughly 20 of the 52 doses are escalation doses and 32 are at maintenance. Model it in that order and the routes become comparable: doses per year first, milligrams per dose second, cost per milligram third. Anything quoted per vial hides the second of those, which is the one that changes most between the first 20 doses and the last 32. Then add what each route charges that the other does not. A prescription route carries consultation and dispensing fees, spread across the 52 doses rather than paid once. A research route carries testing, shipping, and the material lost between them. Testing is the line most sheets omit. At one lot a quarter, a test-every-lot policy is 4 assays a year; at one lot a month it is 12. That difference is usually larger than any difference in price per milligram, and it is a policy you choose rather than a cost you are quoted. Put doses per year in the top row and derive everything under it, and the twelve-month totals compare on arithmetic instead of on presentation.

More usefully, this is a spreadsheet question and doing it properly changes conclusions more often than people expect.

Cost per milligram is the wrong metric entirely if you are optimising for confidence rather than price, and it is worth saying which one you are doing before you build the spreadsheet.

Certificate red flags and what each implies

The full calculation: (unit price + carriage share + testing share) ÷ (nominal mg × measured content fraction × (1 − dead-space and wastage fraction)). Every term after the first is routinely omitted.

Nothing here is medical advice, and research-use compounds are not approved for human use.

Include carriage and testing as per-milligram terms. They dominate small orders.

edited 14 Jul 2025 by Dr_Otto_Lindqvist — updated for the 2026 guidance change

Specifically, wastage from expired reconstituted vials is a real line item and nobody includes it.

Independent testing costs roughly the price of one to two vials at the services this community uses. On a two-vial order that is a fifty to a hundred per cent surcharge; on a twenty-vial order it is five per cent.

Dead-space loss is small with fixed-needle insulin syringes — a few microlitres per draw — and substantial with detachable-needle luer syringes at 35 to 100 microlitres. Across twenty draws that is up to two millilitres of solution.

The caveat is that optimising cost per milligram optimises for the wrong thing if documentation and consistency are what you actually need.

Larger orders are cheaper per milligram and concentrate lot risk. Price both.

Start by listing every cost in the chain, since carriage, testing and wastage frequently exceed the difference in headline price.

Worked example. Supplier A: £60 for a 10 mg vial, content 96 per cent, so 9.6 mg for £60, or £6.25/mg before carriage. Supplier B: £52 for the same nominal vial, content 88 per cent, so 8.8 mg for £52, or £5.91/mg. B still wins here, but the gap has narrowed from thirteen per cent on the label to five per cent in reality.

Change one number and it reverses: if B assays at 82 per cent, that is 8.2 mg for £52, or £6.34/mg, and the cheaper vial is now the more expensive peptide.

Carriage on international consignments scales sub-linearly with weight, which is the quantitative basis for order consolidation.

Fixed-needle syringes save more peptide than most price differences do.

Testing cost per milligram falls sharply with order size, which is the main argument against very small repeat orders.

Carriage amortises across the order. Twenty-five pounds of carriage on one vial is £2.50/mg on a 10 mg vial; on ten vials it is £0.25/mg. That single term explains most of the case for larger, less frequent orders.

Divide by measured content, not by label claim. That is the whole correction.

The honest answer is that the cheapest headline price is frequently not the cheapest outcome.

Wastage from a reconstituted vial discarded at the end of its in-use period is a genuine cost, and it is a function of the diluent volume chosen at reconstitution rather than of anything the supplier did.

Larger orders reduce cost per milligram and increase exposure to a single lot, which is a real trade rather than a free win.

Decide whether you are optimising cost or confidence before you build the model.