Finding a reliable contract research organisation (CRO) for peptide synthesis comes down to four checks: capability fit (sequence length, modifications, and scale), documented quality assurance (HPLC purity, mass-spec confirmation, batch-level COAs), regulatory standing where it matters (GLP, GMP, ISO), and watertight intellectual property and confidentiality terms. Skip any of these and project risk multiplies.

CRO vs catalogue supplier: Know what you actually need

Before you start outreach, decide whether you need a custom-synthesis CRO or an off-the-shelf catalogue supplier.

Catalogue suppliers ship pre-made peptide research solutions quickly and at lower cost for known sequences and research-use applications. A CRO, by contrast, synthesises to spec, handles modifications, scales up, and supports regulatory work which is what you want for novel sequences and translational research. Mixing the two up wastes both budget and timeline.

Match capability to your sequence and scale

Not every CRO can make every peptide.

• Sequence length: Confirm the CRO can produce in your range (most cap out at 30–50 residues for routine work; specialists handle 100+).
• Modifications: Cyclic peptides, fluorescent tags, PEGylation, lipidation, D-amino acids. Ask for examples.
• Scale: Milligrams for in-vitro, grams for in-vivo, kilograms for late-stage work; and the CRO should be honest about which they routinely deliver.

Quality assurance: COA, HPLC, and mass spectrometry

Every batch should ship with a Certificate of Analysis containing:

• Reverse-phase HPLC purity with the actual chromatogram, not just a number.
• Mass spectrometry confirmation (ESI-MS or MALDI-TOF).
• Peptide-content correction (net peptide versus salt and water).
• Sequence, batch ID, and synthesis date.

Ask to see a sample COA before signing. If they won’t share one, walk.

Regulatory standing: GLP, GMP, ISO

• Early research: ISO 9001 and an internal QMS are usually sufficient.
• IND-enabling studies: GLP-compliant material is often required.
• Clinical use: GMP synthesis with full regulatory documentation.
• Match the standard to your stage. Paying for GMP at discovery is overkill; assuming a non-GMP CRO will get you to IND is a costly mistake.

IP and confidentiality

This is where peptide projects most often go wrong. Get these in writing before any sequence is shared:

• A signed CDA/NDA before sequence disclosure.
• Explicit ownership of all synthesis IP and improvements.
• No reuse of your sequence for any other client.
• Data destruction or return clause.
• Jurisdiction and dispute terms that work for both sides.

Questions to ask before you sign

• Can we see three example COAs and one redacted past project?
• What is the failure rate on sequences over 40 residues?
• Who is the primary scientific contact, and what is their direct line?
• If a batch fails QC, at whose cost?
• Are there any sequences or modifications you don’t handle?

Optimise for ease of comparison

Once you have a shortlist, send each CRO the same brief, same sequence, same scale, same QC requirements and compare apples to apples. The exercise of writing the brief itself usually surfaces project requirements you hadn’t fully nailed down.

For the parallel exercise of evaluating an off-the-shelf synthesis service, see this practical buyer’s checklist on what to verify before ordering.

Frequently asked questions

• What’s the difference between a peptide CRO and a peptide supplier? A CRO custom-synthesises peptides to your specification, handles modifications, and often supports regulatory work. A supplier ships pre-made catalogue peptides; faster and cheaper, but only for sequences they already stock.
• What certifications should a peptide CRO have? For early research, ISO 9001 and a published QMS are usually enough. GLP is needed for IND-enabling studies; GMP for clinical material. Match the certification to the stage.
• How much does CRO peptide synthesis cost? Costs vary widely by sequence length, modifications, scale, and quality grade. Short research-grade peptides start in the low hundreds; modified or GMP-grade work can run into thousands per gram. Always request itemised quotes.

Adam Mulligan, a psychology graduate from the University of Hertfordshire, has a keen interest in the fields of mental health, wellness, and lifestyle.