Questions, answered plainly

A chain of amino acids joined end to end by peptide bonds. The chain is written from its N-terminus to its C-terminus, and that written sequence is what names the compound. Because every residue has a known mass, the sequence also predicts the mass of the whole chain, which is the figure mass spectrometry is checked against.

The line between a peptide and a protein is convention rather than chemistry, at roughly fifty residues. Below it the chain is called a peptide; above it, a protein. Everything we list sits well below.

Almost all of them are assembled on a solid support, one residue at a time, then cleaved off and purified by preparative HPLC. That last step is the one that decides quality: crude synthesis product also holds chains that stopped short and reagents left over from the process, and purification is what removes them. Purity & testing covers how the result is measured and reported.

What arrives is a dry powder, freeze-dried (lyophilised) in a sealed vial, because a solid keeps far better than a solution. A counter-ion is present alongside the peptide, commonly acetate or trifluoroacetate depending on how it was purified, and a little water is usually held by the solid as well. Neither is a contaminant in the way an unidentified peak is: both are expected, both are measured, and both appear on the certificate.

No. Everything on this site is supplied for laboratory research use only. Not for human or veterinary consumption, not for diagnostic or therapeutic use, and not a medicine or a food.

We supply researchers. What we do not supply is an order intended for a person or an animal, and where an order makes that clear we cancel it and refund it. Buyers must be 18 or over and are responsible for compliance with the law where they are.

That is the whole answer, and it does not change on request.

No. We can tell you what is in the vial, what the certificate of analysis reports about that batch, and the conditions the material should be kept in. We cannot give a quantity, a method or a schedule, and we will not.

Method belongs to the researcher and to whoever is responsible for the work in their institution. A supplier who offers it is advising on the use of a material that is not licensed for use in anything.

Peptides are supplied as a lyophilised (freeze-dried) powder in a sealed vial. The vial contents in milligrams, the physical form, the purity figure and the storage conditions are stated on every listing.

Vials are labelled with the product name, the batch number and the research-use statement.

It is the figure on the certificate of analysis for the batch you are supplied, established by high-performance liquid chromatography. Identity is confirmed separately by mass spectrometry.

Where a listing carries a purity figure, that is what the certificate for that batch reports, not a target, and not a house average. Purity and testing sets out both procedures and what a certificate contains.

Storage conditions are a property of the material. They are printed on the vial, stated on the listing and repeated on the certificate of analysis. Lyophilised peptides are supplied to be held at −20 °C and protected from light.

Once a parcel is delivered, storage is the buyer's responsibility. We cannot advise on handling beyond the conditions on the label, and material that has been outside those conditions cannot be returned, because we could not certify it to anyone else afterwards.

Bacteriostatic water and empty sterile vials, listed as laboratory consumables and described as nothing else. They are sold as ordinary laboratory stock, and no listing on this site pairs a consumable with a peptide or suggests what either is for.

Put what you need in the basket and go to the checkout. It asks for your details, a delivery address, and a confirmation that you are 18 or over and ordering for laboratory research. Stock and the final price are settled before you pay.

Payment is by bank transfer, approved in your own banking app. Purchase orders are welcome. Send yours to support@pxppeptides.co.uk and we will quote against it.

By bank transfer, made through your own bank at the checkout. You approve it the way you approve any other payment in your banking app, and the money moves straight from your account to ours.

There are no card fields anywhere on this site: no card number, no expiry date and no security code, at any point. Goods are despatched once payment has cleared. [Whether account terms are offered to institutional customers is to be confirmed.]

Orders confirmed and paid before 15:00 are despatched the same working day, Monday to Friday, excluding Scottish bank holidays. We despatch from Glasgow by Royal Mail Tracked 24, and send a tracking reference when the parcel leaves us.

Delivery times after that are the carrier's rather than ours. If an order is going to be held up at our end (a batch out of stock, a certificate we are still waiting on), we tell you before we take payment, not after.

Plainly. The outer box carries the delivery address and the carrier's label and nothing else: no product name, no contents printed on the outside. The paperwork goes inside.

Vials are packed to survive a courier.

We are set up to supply within the United Kingdom. We ship within the United Kingdom only.

Where we do supply outside the UK, import rules, duties and any licence requirement are the buyer's responsibility in their own jurisdiction. We describe a shipment on the customs paperwork as exactly what it is.

If you are buying as a consumer, you have fourteen days from delivery to cancel under the Consumer Contracts Regulations, and nothing on this page affects that. Business purchasers: returns are by prior written agreement. Either way, email us first so we can give you a returns reference — goods sent back without one are difficult to match to an order.

We cannot accept the return of an opened vial, of anything whose seal is broken, or of anything that has been outside its stated storage conditions. That is not a policy preference: we could not certify such material to the next customer, so it has no value to us and we will not resell it.

Refunds go back by the method used to pay. If something arrives damaged, or is not what you ordered, tell us as soon as you can and it is ours to put right. The full terms are on the returns page, and none of this affects your statutory rights.