Custom peptide synthesis vs catalog research peptide: cost and documentation

The decision in one paragraph

A catalog research peptide is bought by name: you get whatever specification and documents the supplier publishes. Custom synthesis is bought by specification: you supply the sequence, modifications, purity tier and quantity, and the manufacturer quotes against it. The price gap is real, but so is the documentation gap. This guide puts published numbers on both, using pages fetched on the date shown.

All prices below are list prices quoted on vendor pages, in the vendors' own currencies. They are not quotes, and they change. Nothing here concerns how any peptide is used.

How custom synthesis is priced

Boster Bio publishes per-residue prices at a 5 mg scale with a purity ladder and turnaround for each tier. [2] The page also says standard peptides start at $4.50 per residue, which conflicts with its $3.50 crude figure, and offers 10-25% volume discounts above 100 mg; confirm in a written quote. [2]

LifeTein states that prices start from $2 per residue with a $100 minimum order and publishes 20-mer examples at 1-4 mg: $85 crude, $160 at >85% and $200 at >95%. Other purities and quantities are quote-only. LifeTein gives turnaround as 1-2 weeks for unpurified and 2-3 weeks for purified peptides. Modification examples for a 20-mer include $200 for one disulfide bridge, $500 for amide cyclization and $100 for one phosphorylation site. [1]

What QC the custom price includes

Boster Bio lists analytical HPLC, mass spectrometry, peptide content (net peptide weight), a certificate of analysis with HPLC chromatogram and MS spectrum, and a synthesis report as standard, with endotoxin testing, counter-ion analysis, Karl Fischer water content and optical rotation as optional add-ons without published prices. [2] LifeTein states that MS, HPLC and certificate reports are provided for all synthetic peptides. [1]

Peptide content and counter-ion analysis matter for budgeting, because a vial's gross weight includes counter-ions and water. The site's purity-versus-content guide explains why a 95% HPLC purity does not mean 95% of the weighed powder is peptide.

What a catalog listing showed

Peptides EU lists Kisspeptin-10, a 10-residue peptide, at EUR 33.49 for 5 mg (with 5-15% multi-vial discounts) and EUR 48.49 for 10 mg, states purity of at least 99%, and gives storage of -20 C long term. The product page did not state the sequence, salt form, molecular formula or weight, or a CAS number, and did not show a lot-specific certificate; the site refers generally to independent testing by Janoshik using HPLC and mass spectrometry. [3]

OMNI Peptides' public home page states that products are for in-vitro research only and not for human or veterinary use, and that the catalog opens only after a research-access eligibility step, so its prices could not be captured for this comparison. [4] Record catalog prices only from a page you can see, with the date.

When custom is worth the lead time

Custom tends to fit when the sequence, modification or salt form must be exactly defined; when you need peptide content, counter-ion or water results to calculate how much peptide you actually have; when the material will feed a study whose methods section must describe it; or when no catalog listing states a sequence at all. A 10-residue peptide at >95% for $115 and about 15-18 days can be cheaper overall than buying catalog vials, testing them yourself and then finding the specification is not what you needed.

Catalog tends to fit when speed matters more than specification, the peptide is a common sequence the supplier documents with a lot-specific certificate, and you can verify identity cheaply. If the catalog page omits sequence and salt form, budget the time to ask before ordering; the identity-check guide shows how.

A fictional budget comparison

An invented lab needs 10 mg of a 10-residue peptide with documented salt form and content. Option A: two catalog vials at 5 mg, plus an outside identity and content test it must arrange itself, plus two weeks of email to confirm the sequence. Option B: a custom 10 mg order at >95%, quoted in writing with peptide content and counter-ion analysis listed as line items. The comparison sheet should total each option including testing and staff time, and record which documentation gaps remain in each. Do not convert currencies from a guess; use the rate on your invoice date.