How does ecnoglutide at 1 mg weekly compare on cost per milligram across routes?

The case in front of me: ecnoglutide · 1 mg.

Please show the division. I want to check my own against yours.

I would like the general form as well as the specific number, so I can apply it again.

Is my approach right even if my number is wrong?

1 mg a week is 52 mg a year and 4.3 mg in an average month — put every route on that denominator before comparing anything. Cost per milligram is the only figure that survives the comparison, because the presentations differ: a licensed pen prices a dose, a compounding pharmacy prices a vial, and a research supplier prices a mass. Divide each one's twelve-month cost by 52 mg and the three become the same number in the same unit. Then add what the cheapest route does not include — independent purity and content testing, the vials you discard, and the postage — because a route that needs testing to be trustworthy has that testing in its cost per milligram whether you account for it or not.

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.

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

edited 16 Jul 2025 by mala_venkatesh — added the method parameters

This is a spreadsheet question and doing it properly changes conclusions more often than people expect.

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.

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.

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

Answer first: compare cost per milligram of measured peptide, not per milligram of label claim, because content varies enough to reverse a comparison.

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.

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.

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

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

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.

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

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.

Independent testing prices at the services this community uses are published and are stable enough to model.

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

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