Peptide price per milligram: how to compare listings fairly

The formula in three steps

Step 1, landed cost: number of vials times price per vial, minus any volume discount, plus shipping and other charges, plus VAT if it is added at checkout, all converted to one currency at a dated exchange rate.

Step 2, cost per labelled milligram: landed cost divided by vials times labelled milligrams per vial. This is the fairest number you can calculate from a product page alone.

Step 3, cost per usable milligram: landed cost divided by labelled milligrams times net peptide content. Use it only when a certificate states net peptide content and its mass basis. If content is not stated, leave this column blank. Entering 100 percent would silently favour the listing that tells you least.

Why a labelled milligram is not a usable milligram

Bachem's quality-control guide defines net peptide content as the percentage of peptide relative to non-peptide material, which is mostly counter-ions and moisture. It notes that most peptides contain trifluoroacetic acid or acetic acid, that water is measured separately by Karl Fischer titration, and that a low net peptide content must be expected for peptides with many basic amino acids. [1]

HPLC purity measures something else. GenScript describes it as the area percent of the target peptide's peak in the chromatogram. [2] A vial can be 99 percent pure by HPLC and still contain substantially less than its labelled mass of peptide, because purity is calculated among the peaks the detector sees, while counter-ions and water also add weight.

The listings we checked rarely give you what you need. The Peptides EU tesamorelin page states purity of at least 99 percent but no salt form or net peptide content. [3] An Evolve Peptides purity report for tesamorelin 5 mg gives a quantity result of 4.97 mg against a 5 mg specification without saying whether that is gross mass or peptide content. [4] [5] Ask the supplier to state the basis before you treat any quantity as usable milligrams.

Some buyers multiply net peptide content by HPLC purity to estimate target peptide mass. Do that only if the certificate defines both figures and your reviewer accepts area percent as a proxy for mass; the two numbers measure different things. [1] [2]

Three worked comparisons where the cheaper sticker costs more

These listings are fictional so that every input is known. The worksheet reproduces them.

Real price ladders, dated 29 October 2026

From listed prices only, per labelled milligram, before shipping and tax. They show why you should calculate every size, not just the headline one. [3] [6] [9]

Comparing across currencies and borders

On 29 October 2026 Evolve Peptides listed "Tesa 5 mg" at USD 65.00, and Peptides EU listed tesamorelin 5 mg at EUR 66.00. [3] [6] At the European Central Bank's reference rate for that day, 1 euro = 1.1130 US dollars, USD 65.00 is EUR 58.40, or EUR 11.68 per labelled mg against EUR 13.20. [7]

Add published shipping and the gap narrows. Evolve's standard US shipping is USD 14.90 below a USD 200 order, making USD 79.90, or EUR 71.79 and EUR 14.36 per mg. Peptides EU's minimum shipping makes EUR 73.99, or EUR 14.80 per mg. [8] [10]

The comparison is mostly academic. Evolve's shipping policy says it ships to the United States and Canada, and Peptides EU describes delivery to EU countries, so few buyers can choose between them. [8] [10] There is a second warning in the documents: the Evolve certificate lists tesamorelin under CAS 218949-48-5, Evolve's own product page lists CAS 901758-09-6, and the Peptides EU page lists CAS 901758-57-6. [3] [4] [5] Different registry numbers can mean different forms of the material, such as a salt versus the free peptide. Ask both suppliers what exactly they ship before treating the two as the same product.

Using the worksheet

The CSV has one row per listing, with the three fictional examples filled in and blank rows for your own. Record the source URL and the date you checked each price, keep currency and exchange rate in their own columns, and leave net peptide content blank until a lot certificate supplies it. The formula notes in the last row match the steps above.

• Compare only listings of the same material: same name, same salt form, same identifier.
• Use one currency and one dated exchange rate for the whole sheet.
• Keep unknown shipping and VAT visible as unknowns rather than zeros.
• Recalculate when you receive the lot certificate; the ranking can change.