Fresh off the newest synthesis window

How new compounds enter the catalogue

A compound is only listed once finished, vialled material exists in our own facility and its release testing has come back within specification. Nothing is listed against a forecast synthesis or an inbound shipment. That is deliberately conservative and it means the new arrivals page moves slowly, but it also means a listed item is an item that can actually be picked, packed and dispatched.

New listings usually fall into three groups: additional fill weights of compounds already catalogued, variants that separate meaningfully different molecules that are often conflated, and genuinely new peptides added because researchers have asked for them. The second group matters more than it sounds — supplying a modified analogue and its parent compound as clearly distinct listings prevents the documentation ambiguity that makes results hard to reproduce.

• Listed only after finished vials exist and release testing is complete.
• Each new fill weight carries its own monograph and certificate record.
• Requests for compounds not currently catalogued are welcome through laboratory support.

Evaluating a sequence that is new to your laboratory

Working with an unfamiliar peptide is mostly a question of characterising its handling before it enters an assay. Start with the physical properties on the monograph: molecular weight, sequence length, isoelectric behaviour and the presence of residues that drive known instability — methionine and cysteine for oxidation, asparagine and glutamine for deamidation, aspartate-glycine motifs for chain cleavage. Those features predict most of what will go wrong in storage far better than the compound's popularity does.

Solubility is the next practical question and it is sequence dependent rather than universal. Highly hydrophobic sequences may need a small volume of an organic co-solvent before aqueous dilution; strongly basic or acidic peptides behave differently near their isoelectric point; some sequences will appear to dissolve and then form aggregates over hours. Preparing a small trial reconstitution before committing a full vial is the cheapest possible experiment.

Finally, establish a baseline. Running your own analytical check on a new sequence — even a simple chromatographic confirmation against the supplied certificate — gives a reference point for every later lot, and makes it obvious whether a change in results months down the line came from the material or from the method. New arrivals are the easiest place to build that baseline, because the lot is fresh and the certificate is recent.

How a new listing is priced and stocked

A newly released presentation enters the catalogue at a price derived from landed cost — synthesis, purification, independent analysis, fill and finish, packaging and domestic fulfilment — rather than from whatever the surrounding market happens to be charging that month. That is why some new arrivals appear below comparable listings elsewhere and others above them: the input costs of a difficult 40-mer with multiple protected residues bear no relation to those of a short, well-behaved sequence, even when both sell in the same 10 mg vial format.

Initial stock depth is intentionally conservative. First releases are filled in smaller quantities so that any analytical or handling issue surfaces before a large volume of material is committed, and the presentation is only scaled up once a second synthesis cycle has been released against the same specification. This is also why a compound can appear here, sell through, and return several weeks later with a new lot code and a new certificate.

If a sequence or fill weight you need is not listed, it is worth asking. A meaningful share of the catalogue began as a request from a laboratory that needed a strength we did not yet vial, and lead times for a new presentation are driven mainly by the synthesis and independent testing cycle rather than by fulfilment.

How a new lot reaches this page

A sequence appears here only after its lot has cleared release testing. Material is produced by solid-phase peptide synthesis, purified by preparative reverse-phase chromatography and lyophilized under vacuum to a stable powder cake. It is then assayed in house by RP-HPLC and submitted to an independent analytical laboratory for confirmatory HPLC and mass spectrometry.

Only when the independent report confirms both purity — area percent at the primary peak — and identity — observed mass against theoretical mass — is the lot released to the catalog and listed as a new arrival. Nothing is listed on the strength of a supplier's own paperwork.

Why newly released lots are worth tracking

Peptide degradation is cumulative and begins the day a lot is filled. A recently released, correctly stored lyophilized lot gives a laboratory the longest usable stability window before hydrolysis, deamidation and oxidation start to shift the purity figure away from the certificate.

Fresh lots also matter for reproducibility. Where a study runs over months, starting from a single recent release avoids introducing a second batch — with its own salt content, residual solvent profile and purity figure — part way through an assay series.

Handling a vial on arrival

Lyophilized peptide is ambient-stable across normal domestic transit, so a vial that arrives at room temperature has not been compromised. Record the receipt date, confirm the seal and crimp are intact, and move the vial to -20 °C freezer storage, desiccated and protected from light.

Reconstitute only what a run consumes. Add diluent slowly against the vial wall, swirl rather than shake, hold solution at 2–8 °C, and avoid repeated freeze-thaw cycling — it is the single most common avoidable cause of drift between replicates.

All material listed here is supplied for in vitro laboratory research by qualified professionals. It is not a drug, supplement, food or cosmetic, and it is not approved for human or veterinary use.