Peptide verification FAQ

Discard the solution and do not use it for research. Cloudiness after initial clear reconstitution indicates protein aggregation caused by either contamination during handling, storage temperature excursions above 8°C, or an impure starting material that was marginally soluble to begin with. Aggregated peptides lose biological activity and introduce experimental artifacts. Any data generated using cloudy peptide solutions is unreliable. Legitimate suppliers replace batches that develop aggregation within the 28-day stability window when proper storage was maintained.

Request a full refund and source from a different supplier. Inability to trace a specific batch indicates either the lot code was fabricated, the supplier doesn't maintain proper batch records, or the product was sourced from an unknown third party and relabeled. Batch traceability is a fundamental quality control requirement. Without it, you cannot confirm the peptide in your vial matches any analytical testing the supplier claims to have performed. This represents a complete breakdown in quality assurance.

Request a replacement CoA or consider the product suspect. Peptide synthesis via solid-phase methods always produces trace impurities from incomplete coupling reactions, protecting group residues, or deletion sequences. Achieving exactly 100.0% purity is thermodynamically implausible. Authentic HPLC results show purity ranges between 98.0–99.5% with small satellite peaks visible in the chromatogram. A certificate claiming perfect purity either reflects falsified data or indicates the supplier didn't perform actual HPLC analysis and generated a fraudulent certificate instead.

Find a different supplier before placing another order. Refusal to provide batch-specific COAs is the clearest signal of counterfeit or untested products. Legitimate peptide suppliers conduct HPLC-MS testing on every synthesized batch and provide results as standard documentation. Suppliers who offer only generic template COAs, claim "proprietary formulation" prevents disclosure, or provide COAs without matching batch numbers to shipped vials are distributing untested compounds. The regulatory reality: research-grade peptides operate in a gray zone where verification is voluntary, meaning supplier transparency is your only protection. Real Peptides publishes batch-specific HPLC chromatograms and mass spectrometry data with every order because molecular verification is non-negotiable for reproducible research.

Switch to a verified supplier with batch-specific third-party purity testing immediately and rerun your most recent experiments as controls. Inconsistent results despite controlled experimental conditions almost always trace to peptide degradation, incorrect sequencing, or batch-to-batch contamination. Not researcher error. The mechanism: counterfeit or degraded VIP contains variable percentages of deletion sequences, oxidized methionine residues, and aggregated species that change the effective concentration and receptor binding profile in unpredictable ways. Researchers waste 3–6 months troubleshooting methodology when the root cause is molecular inconsistency in the supplied peptide. Real Peptides eliminates this variable through small-batch synthesis with <5% variance in EC50 values across all batches. Your results should replicate within normal experimental error if the peptide is structurally consistent.

Proceed with extreme caution and demand third-party purity testing before use. Artificially low pricing almost always correlates with reduced purity, incorrect sequencing, or complete absence of the target peptide. VIP synthesis involves 28 individual amino-acid coupling steps with purification and lyophilization, establishing a baseline production cost that legitimate suppliers cannot undercut by 60% without compromising quality. Counterfeit operations achieve low pricing by skipping coupling verification, using contaminated starting materials, or substituting cheaper peptides with similar molecular weights. The financial calculus: a $180 vial that contains 95% pure VIP delivers more usable peptide per dollar than a $70 vial containing 40% target compound and 60% deletion sequences. The apparent savings evaporates when your experiments fail.

Discard the vial immediately and do not use it for research. Visible precipitation indicates irreversible aggregation from incorrect sequencing, oxidative damage, or temperature abuse during shipping. Authentic VIP forms reversible aggregates at high concentrations that dissociate upon dilution, but precipitated aggregates cannot redissolve and have zero biological activity. Contact your supplier for replacement and request cold-chain documentation for the original shipment. If the supplier cannot provide temperature data from synthesis through delivery, assume all vials from that batch are compromised. This is why Real Peptides includes temperature data loggers with every shipment. Molecular stability depends on unbroken cold-chain custody, not supplier assurances.