Peptide Works
Research-Grade Peptides
Peptide Works
Research-Grade Peptides
We supply high-purity peptides to laboratories, universities, research organisations and independent researchers around the world with the analytical evidence to show exactly what is in every vial.
Peptide Works supplies high-purity peptides to labs, universities, independent researchers and research organisations across the globe. That is the crux of it, spoken plainly.
We do not manufacture pharmaceuticals. We do not provide clinical services. We do not sell anything designed or intended for human or animal use. We source, qualify, store and ship research-grade peptide compounds to the people who need to know precisely what their vial contains.
It is a narrower job than it might seem at first, and a more difficult one. For a peptide to be useful to any researcher, its identity and purity must be trusted. If a compound is labelled 99% and an experiment is in fact running on 87%, the outcome is not simply milder. It is wrong. That turns into days of a researcher's life spent chasing an anomaly that only exists because a supplier took a shortcut, or never checked in the first place. We hear that story so often from customers who found us after being burned elsewhere that it has shaped almost every decision we have made about how to do business.
The promise Peptide Works makes is deliberately modest in ambition and demanding in delivery. We tell you what a compound is. We tell you how pure it is, and we share the analytical evidence so you can see for yourself rather than take our word for it. We pack it so that it survives the journey. We send it to you wherever you are, within the limits of customs and carriers. And when something is unclear, or something goes wrong, we respond.
We serve academic labs working through structure-activity studies. We serve biotech teams screening candidate sequences. We serve contract research organisations running client protocols, and independent investigators with a straightforward question and a limited budget. The scale of those needs varies enormously, but they all circle the same requirement: material that can be trusted, documentation that holds up, and a supplier that behaves like a professional counterparty rather than a retail storefront.
We ship worldwide. We keep a broad catalogue across many formats, including a dedicated Peptide Works TB-500 research peptide range for researchers reviewing compounds within that category. And we test every batch to a minimum of 99% purity, with a defined exception at 98% for sequences complex enough that a higher ceiling is not chemically realistic. Every batch is tested, and that testing is verified by laboratories that are entirely independent of us and have no commercial interest in the result.
What follows explains how we arrived here, and how the work is actually done.
Peptide Works did not start with a business plan. It started with frustration.
The people who founded this company came from the buy side of the research supply chain, not the sell side. They had spent years ordering compounds for lab work, and they had collected the particular grievances that only come from being on the receiving end of a delivery — opening a package and finding that the contents did not behave as advertised.
The complaints were consistent. Certificates of analysis that arrived weeks late, or never arrived at all. Certificates that were clearly copied from a previous batch, with the dates changed and nothing else. Peptides left sitting warm for four days in a customs queue, in packaging that had plainly never been designed for temperature-sensitive material. Attentive, eager communication right up until payment cleared, and silence afterwards.
None of this was exotic. It was ordinary, and that is exactly what made it unacceptable. It was science held to unusually relaxed standards. The research-supply industry had normalised a tolerance for unreliability that would not survive in any other technical field. A researcher would never accept a reagent-grade solvent of unknown origin. They would refuse an unlabelled antibody. Yet on the peptide side, a surprising volume of business ran on faith rather than data — and buyers had simply adapted, building failure into their planning. They ordered in excess. They budgeted for waste. They treated the first batch as a trial run.
Peptide Works was founded to refuse that adaptation.
The earliest decisions were the unglamorous ones, and in hindsight they were the most important. We agreed that no batch would go on sale until analytical data for it existed and had been reviewed. Not "would exist shortly." Existed. Third-party verification would not be an optional extra for customers who thought to ask; it would be built into the process as a matter of course, applied to everything, whether or not anyone requested it. And we agreed that support staff would be paid to solve problems rather than close sales, and that they would still be there after delivery rather than disappearing at dispatch.
We also decided what we would not do. We would never make claims about what a peptide does inside a living body. We would not provide dosing instructions. No nodding at benefits, no winking at applications, and none of the coded language that several suppliers in this industry use to say things they are not permitted to say outright. Our material is intended for laboratory research use. That is not a disclaimer bolted to the bottom of a page because a lawyer insisted on it. It is the line the business is drawn around, and we hold it because a supplier who blurs that boundary cannot be trusted on anything else either.
Growth came slowly, mostly by word of mouth — the only kind of growth worth much in a field this small. A postdoc who received a clean batch mentioned it to a colleague. A lab manager who got a reasonable, honest explanation of a two-week delay — rather than a fabricated tracking number — remembered that the next time a purchase order crossed their desk. Reputation in research supply is earned rather than inherited, through incremental and fairly unglamorous behaviour. It can also be lost with a single bad shipment.
The catalogue grew as customers asked for things. The range of formats grew for the same reason: researchers work differently, and a lyophilised vial that suits one workflow is an obstacle in another. International shipping turned out to be far more complicated than anyone had expected, and the only way to get it right was to stop treating it as an afterthought and start treating it as a discipline of its own. That is how the logistics operation began.
Peptide Works today is larger than it was, but the shape of the thing has not changed. We remain a supply house whose competitive edge, such as it is, is doing the basic parts of the job well and repeatedly. There is no secret to it. There is only not stopping when stopping would be easier. A concise overview of our background, standards and operating principles is also available on the Peptide Works about us page.
Our mission is to support scientific discovery by giving researchers high-quality peptides, dependable support and a reliable international supply.
That is the sentence. It is easy to write and easy to hang on a wall. What it commits us to is specific, and worth stating plainly, because a mission that does not translate into daily action is decoration.
A peptide is not high quality because a supplier said so, or because it looked right, or because the same sequence ran cleanly before. Quality is a property of an individual lot. It is established by testing that lot and recording the result on a certificate tied to that lot number. Anything else is guesswork in a lab coat. A purity standard exists to be measured against, and it is the measurement that makes the standard real.
Our support function is not measured on how many enquiries turn into orders. What matters is whether the researcher who wrote in about storage conditions, reconstitution, batch documentation or a discrepancy in their paperwork receives a correct and useful answer from someone who understands the subject. Sometimes the right answer is that we do not have what they need, or that they should look outside the range of questions they have asked, or that their enquiry goes beyond what we are competent to advise on. We would rather say so.
When you ship temperature-sensitive material internationally, some things are within our control and some are not. Reliability, in that context, does not mean pretending to know the unknowable. It means packing correctly, documenting properly, routing sensibly, tracking proactively, and telling customers honestly when something has gone wrong — because sometimes it will — and then putting it right.
Our contribution to science is not that we do science. It is that we remove one category of obstacle for the people who do. An hour a researcher spends re-running an experiment because the starting material was not what the label claimed is an hour taken away from the actual work. If Peptide Works does its job well, our customers barely think about us at all. The compound arrives, it is what the label says it is, the paperwork is there, and they tick the task off and get on with their day.
We consider that the highest form of success available to a supply company, and we make no apology for how unglamorous it is.
We want Peptide Works to be the first name a researcher thinks of, and the one they use without second-guessing themselves.
Default trust is a strange thing to aim for, because you cannot demand it. A company that announces itself as trustworthy has said nothing at all, and has probably raised a question it would rather not have raised. Trust in a research-supply relationship is a residue. It is what remains after a long enough run of transactions in which nothing went badly wrong, and in which the things that did go wrong were handled the way a professional would handle them.
That residue is not mysterious. It is built out of a few specific things.
Consistency is harder than excellence, and it matters more. From a planning point of view, a supplier who is excellent four times out of five and disastrous on the fifth is worse news than one who is reliably adequate. Researchers build protocols and timelines on the assumption that their inputs will behave as expected. Variance is the enemy. A supplier who introduces variance at the front of a workflow contaminates everything downstream from it.
Any supplier will happily hand you a certificate showing 99.4% purity. The real question is what they do when a batch comes back at 96%. We reject it. That decision costs us money every time we make it, and it is the clearest available signal of whether a purity standard is an actual policy or simply a slogan.
Research groups do not make one-off purchases. They come back, sometimes for decades, and they talk to each other. This is a small industry, and reputation travels through it. Any supplier who treats each order as a purely transactional event will be found out eventually.
So our ambition is not to be the biggest peptide supplier, or the loudest, or the most aggressive in expanding the catalogue. It is to be the one a lab manager names when someone asks who they use — without having to think about it, and preferably without adding a caveat.
This is the most important part of the page, so it is where we spend the most time.
Peptide Works qualifies every peptide in the catalogue at 99% purity. The defined exception is 98%, reserved for sequences that are long enough or structurally awkward enough that reaching a higher figure is not chemically realistic.
We want to be exact about that exception rather than hide it and hope it never surfaces, because how a supplier handles the awkward cases tells you far more than how they handle the easy ones. Complex sequences — longer chains, multiple disulphide bridges, cyclic constructions, residues prone to side reactions during synthesis — are much harder to purify to the same level as a short, simple linear peptide. Any supplier claiming a uniform 99.9% across every product, regardless of structure, is either not testing properly or not being honest. We would rather quote a lower number and have it be true.
A batch that does not meet the relevant standard does not enter the catalogue. It is not quietly downgraded, written off, or blended into a compliant lot. It is rejected.
"Purity" in peptide chemistry is a precise and somewhat limited claim, and it is worth understanding what it does and does not cover.
Chromatographic purity — the number on most certificates of analysis — describes the proportion of peptide-related material in a sample that corresponds to the target sequence, as resolved by a separation technique. It is expressed as a percentage of total detected peak area. What it tells you is that the great majority of the peptide material in the vial is the peptide you ordered, rather than truncated sequences, deletion products or synthesis by-products.
What it does not tell you, on its own, is how much peptide the vial contains by absolute mass. A lyophilised peptide is not pure peptide by weight. It still carries residual water and, usually, counter-ions left over from purification. That is expected and unavoidable, not an error. But it is something researchers have to account for in their concentration calculations, and a supplier who does not mention it is setting customers up for a slow accumulation of systematic noise across every experiment they run.
We raise this because it is probably the single most common source of confusion we encounter, and because we would much rather customers ask us about it than discover it at an inconvenient moment.
For any batch, there are two questions to answer. Is this the right molecule? And how much of what is in the vial is that molecule?
Identity is established primarily by mass spectrometry. The peptide is ionised and its mass-to-charge ratio is measured, then compared against the theoretical molecular weight calculated from the expected sequence. A match indicates that the intended molecule is present at the predicted mass. It is a clear sign of successful synthesis and it is the accepted standard across the field.
Purity is established primarily by high-performance liquid chromatography (HPLC), usually under reversed-phase conditions. The sample is passed through a column that separates its components according to how strongly each interacts with the stationary phase. Different molecules emerge at different times and register as distinct peaks. The dominant peak corresponds to the target peptide; the smaller peaks correspond to impurities, truncations and by-products. Integrating the area under those peaks yields the purity percentage.
Read together, the two methods complement each other. Mass spectrometry confirms what the molecule is. Chromatography establishes what proportion of the sample it makes up. Neither is sufficient alone. A sample can carry the correct mass and still be heavily contaminated, and a sample can be chromatographically clean while containing entirely the wrong peptide. That is why we treat a certificate of analysis showing only one of the two as an incomplete document.
We test. Our suppliers test. Neither fact is worth a great deal on its own, because in both cases the party doing the testing has a financial stake in the outcome.
That is why every batch is also sent to independent third-party laboratories with no interest in the result. This is not a formality or a marketing line. It is what makes our purity claims verifiable rather than merely assertable, and it is why we publish a specific number instead of a comfortable vagueness like "high purity" or "research grade".
Where a third-party result differs materially from an in-house result, the third-party result prevails. That is the entire point of having one.
Every batch has a certificate of analysis tied to its lot number. The certificate is generated for that specific batch. It is not a date-shifted template, and it is not rolled forward from a previous production run of the same sequence.
We labour this point because certificate recycling is a real and widespread problem in this industry, and one a buyer cannot easily detect. A recycled certificate looks entirely genuine. The only defences are a supplier's own discipline and a buyer's willingness to ask for lot-level data — which we recommend you do at all times, including with suppliers who are not us.
Lot traceability matters for another reason that has nothing to do with catching bad actors. Being able to trace a researcher's material back to the batch it came from, and pull the analytical record for that batch, is what turns an unexpected observation into something diagnosable rather than something to shrug at.
A peptide that was 99% pure at the time of testing is often not 99% pure by the time it reaches the bench. Purity is a moment in time, and peptides degrade.
Lyophilisation makes peptides considerably more stable than they would otherwise be, but it does not make them indestructible. Moisture, heat, light and repeated temperature cycling are their principal enemies. Stability falls sharply after reconstitution, and from that point the clock is running. Individual sequences have their own vulnerabilities: residues that oxidise, positions that deamidate, bonds that hydrolyse when the pH is not right.
What that means is that a supplier's responsibility for quality does not end with the analytical result. It extends to how material is stored at our own facility, how it is packed for transit, and what we tell customers about handling what they receive.
So we store material under conditions appropriate to its stability profile. We design our packaging to hold those conditions through transit. And we are plain with customers about how to store what arrives, because a well-synthesised, thoroughly verified peptide left on a bench in direct sunlight over a hot weekend is not, in any practical sense, the product we sold.
It matters because of reproducibility — the thing experimental science rests on, and the thing that upstream sloppiness quietly erodes.
When starting material varies in ways nobody has measured, results vary in ways nobody can explain. Controls stop controlling for what they were designed to control for. A dose-response curve shifts, and the shift gets attributed to biology when it was chemistry. Two labs run the same protocol, get different results, and each concludes the other made a mistake — when in fact both executed correctly using materially different inputs.
Nobody publishes a paper about the time their peptide was only 91% pure. The failure is invisible. It is absorbed into the noise and dismissed as variability. That is what makes it dangerous: an obvious failure gets fixed, while an invisible one gets normalised.
Our purity standards, the tests we run, the third-party verification and the batch-level documentation all exist to solve one problem. What we send to a researcher should be something they can be certain of, so that whatever they observe downstream belongs to their experiment and not to ours.
Researchers do not all work the same way, so our catalogue is broad and is structured around offering a wide selection of research peptides in more than one format. Which format is appropriate usually depends less on the compound and more on the work being done with it.
The default, and for good reason. Freeze-drying removes the water responsible for most degradation pathways, which gives the material a long and predictable shelf life and lets it travel without refrigeration. It also leaves reconstitution in the researcher's hands, so solvent, buffer and final concentration can be chosen to suit the protocol rather than inherited from someone else's decision. For most laboratory applications, this is the correct starting point.
These bring several sequences together in a single preparation. Where a protocol calls for a precise ratio of compounds, preparing that mixture once under consistent, controlled conditions removes a source of variability that would otherwise be reintroduced at the bench every time. The trade-off is rigidity: when a researcher needs to vary each component independently, single-compound vials are the better choice.
Some research workflows need the compound in a solid oral dosage form — for oral bioavailability work, formulation stability, or gastrointestinal modelling. That is why capsules exist. In this case the peptide itself is almost beside the point; the delivery system is the subject, and studying a delivery system requires using it.
These exist primarily for research into intranasal delivery, where the question under investigation concerns absorption across the nasal membranes.
Supplied as ready-to-use solutions at a known concentration. They trade some shelf life for immediacy, which suits situations where preparation time is limited, or where the concentration needs to stay identical across repeated use rather than be preserved for the long term.
We are not going to tell you which format you need. You know your protocol and we do not. What we will do, if you write in and ask, is walk through the trade-offs — solubility behaviour, stability characteristics, storage requirements, and what tends to go wrong — with someone who has had that conversation many times before.
The catalogue itself, with detailed specifications for every product, is kept separately from this page. Researchers reviewing individual compounds can consult product-specific listings such as Peptide Works CJC-1295 No DAC for relevant catalogue information and specifications.
Across much of the research-supply world, customer support is classified as a commercial activity. It is not. We treat it as a technical one.
Our support staff work on no commission, and they are not measured against how quickly they can close a ticket. They are expected to give accurate answers, to know the material, and — when they are unsure — to say "I don't know, let me find out" rather than improvise. Improvisation is the worst behaviour anyone in this role can fall into, and it is unpleasantly common across the sector.
The questions we receive are practical, and they tend to cluster.
How should this be kept? How long is it good for? What if it was left out overnight? What does degradation look like? These questions are answerable and they have consequences, so we answer them.
What solvent, at what concentration, and what should the researcher expect to see? Solubility behaviour is highly sequence-dependent, and a peptide that resists dissolving is not, by that fact alone, a defective peptide. Knowing this in advance saves a great deal of unnecessary alarm.
Certificates of analysis, lot numbers, analytical data for a given batch — the records needed to purchase in line with institutional requirements, or to satisfy a grant audit. These requests are routine and we receive them constantly, which is exactly why we treat them professionally. Documentation should never be used as a bargaining chip.
Where is it, when will it arrive, and what happens if it is held up? We pass on what we know, including when the news is unwelcome.
Something arrived damaged. Paperwork went missing. Something behaved unexpectedly. These are the moments that define a supplier, and they are also the moments when the temptation to go quiet is strongest.
We are unambiguous about this last one: support does not stop at delivery. A supplier who loses interest in you the moment the package is signed for has told you precisely what the relationship was worth to them. If a problem originated with us, we will say so and we will fix it. If it did not, we will still help you work out what happened, because that is what a competent counterparty does.
We do not offer guidance on human or animal use of a peptide. We do not provide dosing advice. We do not discuss physiological effects or health outcomes. This is not evasiveness. Our products are supplied for laboratory research only, and any conversation of that kind would fall outside both our competence and the terms on which we operate. Rather than sidestep the question, we simply tell you that directly.
We ship to most countries. We describe that carefully, because there is a bright line between the parts of international logistics a supplier controls and the parts it does not — and suppliers who blur that line are simply preparing their customers for disappointment.
The first thing is packaging, and it is where a large share of the damage in this area originates. Peptides are sensitive to heat, moisture and light. A package that will be in transit for days — including, potentially, hours on a warm airport apron — has to be designed for the journey rather than for the shelf. We account for thermal insulation, moisture exclusion and physical damage, and we design against a realistic worst case rather than an optimistic average.
The second is documentation. A great many international shipping failures come down to paperwork. A missing or incorrect customs declaration, an absent commercial invoice, a mismatched value, an inadequate description of contents — packages do not so much get lost as get set aside in a facility where nobody has any particular incentive to resolve the problem. We prepare documentation meticulously, because a package sitting in a queue for three weeks is functionally destroyed no matter how well it was wrapped.
The third is routing and carrier selection. Not all routes are equal, and familiarity comes with experience. Some corridors work well and others do not. We use what we have learned.
Customs authorities are sovereign. They can inspect, delay, levy duties or refuse entry, and they are not required to justify any of it to us or to you. Import rules vary by country and change without notice. We cannot carry that responsibility on a recipient's behalf; researchers need to know what may lawfully be imported into their own jurisdiction.
Carriers sometimes misplace, delay or damage things. Weather closes airports. Public holidays in transit countries can hold shipments for days. None of that is within our reach.
We offer shipping protection, which exists precisely because this uncontrollable stretch of the journey is real and should not rest entirely on the researcher.
We track shipments actively, rather than waiting for a customer to discover that something has gone wrong.
And we tell the truth. If a shipment is stuck, we say it is stuck. If we do not know when it will move, we say that too. Our experience is that customers are far more forgiving of an honestly reported problem than of a falsely promised happy ending — and that the second approach only ever works once.
All products supplied by Peptide Works are for laboratory research and development use only. They are not intended for ingestion by humans or animals of any species, and nothing we supply is intended to diagnose, treat, cure or prevent any disease.
We have placed this near the end of the page deliberately, not as an afterthought. By the time you reach it, you have read everything else and have a reasonable sense of what kind of company this is. This statement follows directly from all of it, rather than sitting apart from it like a piece of well-meaning legal tape.
There is a great deal of coded language in peptide supply. Compounds are described as "research chemicals" with a nudge. Persuasion is implicit at best: benefits hinted at through careful wording, copy that reads like a testimonial while having nothing to do with laboratory work, imagery that has no plausible connection to a research setting. The disclaimer sits at the bottom of the page in grey, doing all of the legal work while the rest of the site quietly does something else entirely.
We do not do that, and it is worth being candid about why. It is a compliance position, but it is not only a compliance position. A company willing to be dishonest about what its products are for has already demonstrated that it will be dishonest when honesty becomes expensive. Honouring purity claims is expensive. Maintaining certificates properly is expensive. Rejecting a batch that fails to meet the standard is expensive. A supplier whose analytical data you can actually trust will not be winking at you from the homepage, because the same instinct that produces the wink also produces the recycled certificate.
Our limits are straightforward and they do not move. We supply research material to researchers. Our products are not for use in humans or animals, so we do not advise on human or animal use. We do not supply dosage information. We do not make claims about physiology. We do not describe outcomes.
Researchers are responsible for complying with the regulations, institutional requirements and import rules that apply to their work. We expect our customers to take that obligation seriously, and in our experience they do.
The work ahead of us is incremental, and we are comfortable with that.
Our analytical documentation is becoming more detailed, on the principle that the customer should have the underlying material in hand. If a researcher wants to interrogate a chromatogram, they should be given the chance to.
We are extending the scope of what independent verification covers, because doing it has only ever strengthened the case for doing more of it.
We are working on lead times — the least interesting and most frequently mentioned friction point in our customers' experience of us, and one that improves only through painstaking logistical gains rather than any clever trick.
And we will carry on rejecting batches that fall short of the standard. It will remain the most expensive thing we do, and the thing we are least willing to stop doing.
Peptide Works is a supplier. Our contribution to science sits far upstream, it is unglamorous, and when it works properly it is largely invisible. We are content with that. The discoveries belong at the bench.