Custom Peptide Synthesis — A Practical Guide

Ordering a custom peptide for the first time? Here's what to prepare and what to expect from a competent synthesis partner.

Information To Provide

1. Full sequence — One-letter code, N-to-C direction
2. Modifications — Position and type (acetyl, biotin, FAM, etc.)
3. Quantity — Milligrams or grams
4. Purity requirement — >85%, >95%, or >98%
5. Application — Helps the supplier recommend appropriate grade

Timeline Expectations

Standard linear peptides (10-30 AA): 2-3 weeks. Modified peptides: 3-4 weeks. Long peptides (>50 AA): 4-6 weeks. Cyclic or stapled peptides: 3-5 weeks depending on cyclization chemistry.

What You Should Receive

Peptide product, Certificate of Analysis (HPLC + MS), MSDS, and packing list. Chromatogram and mass spectrum PDFs should be included — request them if not provided automatically.

Common First-Order Mistakes

Specifying the wrong terminal modification (free acid vs. amide changes the C-terminus charge). Not accounting for hydrophobic sequences that may need special solubilization. Ordering too little for pilot studies — always budget for replicates.