For Research Purposes Only · Not For Human Consumption
Every UK Peptides lot is independently tested to ≥98% HPLC-UV purity and confirmed by ESI mass spectrometry at Janoshik Analytical or Aspen Bioanalytics before release. The signed Certificate of Analysis is linked from the product page — open it, read it, then decide whether to buy.
RP-HPLC-UV
C18, 0.1% TFA / acetonitrile, 214 nm
ESI-MS
Identity match vs theoretical mass
Two labs
Janoshik Analytical · Aspen Bioanalytics
Per-lot CoA
Signed, dated, linked on every product page
When an analyst injects a peptide sample into a reverse-phase HPLC column, the detector records a chromatogram — a graph of UV absorbance against retention time. The intended peptide elutes as a single dominant peak. Synthesis impurities — truncated sequences, deletion peptides, oxidation products, capping artefacts — elute as smaller, distinct peaks. The purity figure is the area under the main peak expressed as a percentage of the area under every detected peak.
A figure of ≥98% means that under 2% of the UV-absorbing material in the vial is anything other than the named compound. For most in-vitro research that is enough signal-to-noise to draw clean conclusions. For analytical work where contaminant peaks would interfere with detection, labs typically request a re-test against a higher-resolution method.
For a full walkthrough of the HPLC and mass spectrometry methods, read the guide to verifying peptide purity.
Case study · in-house re-test
In September 2025, a UK in-vitro research group ran two consecutive lots of UK Peptides BPC-157 5mg through their in-house HPLC against a USP reference standard. The first lot returned 99.1% purity, the second 99.4%, against figures of 98.6% and 98.9% printed on the Janoshik Analytical certificates. ESI-MS identity matched the theoretical 1,419.55 Da mass on both lots within 0.01%.
"Purity came back slightly above the floor on the CoA. Consistently better than I expect from a sub-£60 vial. Will keep ordering."
— Laura H., research scientist, September 2025
View BPC-157 5mg with CoA →Click any product to open the signed third-party Certificate of Analysis for the lot you would receive. No login, no form, no email request.
Metabolic Research
≥98% (HPLC-UV)Retatrutide 10mg
Triple-receptor GLP-1, GIP and glucagon agonist. Retatrutide is the most advanced metabolic research peptide, supplied as lyophilised powder with batch-matched CoA.
Metabolic Research
≥98% (HPLC-UV)Retatrutide 20mg
Higher-dose triple-receptor GLP-1, GIP and glucagon agonist for extended research. Lyophilised powder with batch-matched CoA.
Skin Health / Anti-Ageing
≥98% HPLCGHK-Cu 100mg
Copper peptide tripeptide-1. Researched for collagen synthesis, wound repair and skin rejuvenation.
Recovery / Healing
≥98% HPLCBPC-157 5mg
Body Protection Compound-157. Widely researched for tissue repair, gut health and joint recovery.
Growth Hormone / Recovery
≥98% HPLC (both peptides)CJC-1295 + Ipamorelin 5+5mg
Gold-standard GHRH + GHRP blend. Research-grade dual peptide for GH pulse stimulation.
Skin / Hormonal Research
≥98% HPLCMT-2 10mg
Melanotan II — synthetic melanocortin receptor agonist. Studied for melanogenesis and libido research.
Recovery / Healing
≥98% HPLCTB-500 5mg
Thymosin Beta-4 fragment analogue. Researched for tissue repair, inflammation and cardiovascular recovery.
Nootropic / Cognitive Research
≥98% HPLCSemax 10mg
Synthetic ACTH(4-10) analogue. Researched for BDNF expression, focus, memory and neuroprotection in preclinical models.
Mitochondrial / Metabolic Research
≥98% HPLCMOTS-C 10mg
16-amino-acid mitochondrial-derived peptide. Studied for AMPK activation, insulin sensitivity and metabolic homeostasis.
Longevity / Metabolic Research
≥98% HPLCNAD+ 500mg
Nicotinamide Adenine Dinucleotide. Central coenzyme in cellular energy metabolism, sirtuin activity and DNA repair research.
Nootropic / Anxiolytic Research
≥98% HPLCSelank 10mg
Synthetic tuftsin-derived heptapeptide. Studied for GABAergic modulation, anxiolytic response and BDNF expression without sedation.
Skin / Anti-Ageing Blend
≥98% HPLC (all components)GLOW 70mg
Proprietary GHK-Cu + BPC-157 + TB-500 co-lyophilised skin & recovery research blend. Advanced collagen and repair pathway modelling.
Skin / Anti-Ageing Blend
≥98% HPLC (all components)KLOW 80mg
High-payload copper peptide + repair blend. KPV + GHK-Cu + BPC-157 + TB-500 co-lyophilised for advanced collagen and connective-tissue research.
Antioxidant / Skin Research
≥98% HPLCGlutathione 1500mg
Reduced L-Glutathione (GSH). Master intracellular antioxidant researched for oxidative stress, detoxification and skin brightening pathways.
Sleep / Neuropeptide Research
≥98% HPLCDSIP 5mg
Delta Sleep-Inducing Peptide. Nonapeptide studied for slow-wave sleep architecture, stress response and neuroendocrine modulation.
Growth Factor Research
≥98% HPLCIGF-1 LR3 1mg
Long R3 Insulin-like Growth Factor 1. Extended half-life IGF-1 analogue researched for myogenesis, hypertrophy and IGF-1R signalling.
Anti-Inflammatory Research
≥98% HPLCKPV 10mg
C-terminal α-MSH tripeptide (Lys-Pro-Val). Researched for NF-κB suppression, gut inflammation and mast-cell modulation.
| Criterion | UK Peptides | Typical grey-market UK source |
|---|---|---|
| HPLC purity floor | ≥98%, every lot, before release | Claimed in marketing, rarely verified |
| CoA source | Independent — Janoshik / Aspen | In-house template, often unsigned |
| CoA lot-matching | Lot on vial = lot on CoA = lot on invoice | Generic CoA recycled across batches |
| Identity confirmation | ESI-MS on every lot | Often omitted entirely |
| UK business address | Registered UK Ltd, Manchester despatch | PO box or no address at all |
| Dispatch cut-off | Same-day before 6pm GMT | 1–3 working day handling |
| Cold chain in transit | Insulated mailer + ice packs | Padded envelope, no cold pack |
In the research-peptide market, 'high purity' is generally accepted to mean ≥98% by HPLC-UV at 214 nm against impurity-resolved peaks. UK Peptides applies a strict ≥98% floor on every lot, verified by an independent analytical laboratory before release. Anything below the threshold is rejected and destroyed — never relabelled, never discounted, never dispatched.
Purity is quantified by reverse-phase High-Performance Liquid Chromatography with UV detection (RP-HPLC-UV). The peptide is separated on a C18 column under a TFA / acetonitrile gradient and the area under the main peak is expressed as a percentage of the total area under all detected peaks. A second method, ESI mass spectrometry, confirms the identity of the main peak matches the theoretical mass of the named peptide.
≥98% is the de facto floor for laboratory-grade research peptides because residual synthesis impurities (truncated sequences, deletion peptides, oxidation products) are extremely difficult to eliminate below 1–2% without further preparative chromatography. Material at ≥99% exists but typically commands a 30–50% price premium without a meaningful effect size in most in-vitro work. ≥98% is the price/quality sweet spot used by serious UK research labs.
Read the CoA. A genuine CoA is signed by a named analyst at a named external laboratory, dated, lot-numbered, and includes the HPLC method (column, mobile phase, gradient) plus a printed chromatogram. If any of those are missing, the purity figure on the front of the document is not verifiable. Every UK Peptides product page links the signed CoA directly.
Yes. Take a small sample of any lot to an external analytical laboratory (Janoshik, Aspen, Anresco) and request HPLC-UV plus ESI-MS. Multiple UK research labs have done exactly this — see the Retatrutide case study below. Independent re-test figures consistently fall within standard analytical tolerance of the figure on the supplied CoA.
Higher purity reduces analytical noise and improves experimental reproducibility, but it is not the same as potency. A 99% lot and a 98% lot of the same peptide will behave identically in most in-vitro assays — the difference appears in highly sensitive analytical work where contaminant peaks would interfere with detection. For routine research, ≥98% is sufficient.
Next step
Browse the catalogue, open a CoA, or read the full methodology behind every UK Peptides lot.