Cost per milligram (revision 4)
Old revision·19:31, 2 Jan 2025·HarmReductionHen
| Cost per milligram | |
|---|---|
| Purpose | Normalise price across presentations |
| Trap | Nominal milligrams are not peptide milligrams |
| Correction | Divide by content |
| Topic infobox · conventions | |
Cost per milligram normalises price across pack sizes and presentations so that offers can be compared. Its usefulness depends entirely on what the milligram refers to.[1]
A price divided by a nominal label claim is a cost per nominal milligram. The mass of peptide in the vial is the product of fill mass, content and purity, and at typical content values a nominal milligram is appreciably less than a milligram of peptide. See Underfilling and Trifluoroacetate counterion.[1]
The arithmetic
[edit]Suppose two offers of a nominal 5 mg vial, one at a given price with a certificate reporting 82% peptide content and 5% water, the other cheaper with a certificate reporting purity only.[1]
The first contains about 4.1 mg of peptide, so its cost per milligram of peptide is the price divided by 4.1. The second contains an unknown mass, so no such figure exists for it — the comparison cannot be made, rather than being made and won.