Every UK Peptides lot is independently tested to ≥98% HPLC-UV purity and confirmed by ESI mass spectrometry at an accredited independent laboratory 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
Accredited independent labs
Per-lot CoA
Signed, dated, published in our lab reports library
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 independent 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
Retatrutide peptide (LY3437943) — a synthetic 39-residue triple agonist at the GLP-1, GIP and glucagon receptors. Lyophilised powder, signed batch CoA on the page.
Metabolic Research
≥98% (HPLC-UV)Retatrutide 10mg
Retatrutide peptide (LY3437943) — a synthetic 39-residue triple agonist at the GLP-1, GIP and glucagon receptors. Lyophilised powder, signed batch CoA on the page.
Metabolic Research
≥98% (HPLC-UV)Retatrutide 10mg
Retatrutide peptide (LY3437943) — a synthetic 39-residue triple agonist at the GLP-1, GIP and glucagon receptors. Lyophilised powder, signed batch CoA on the page.
Metabolic Research
≥98% (HPLC-UV)Retatrutide 10mg
Retatrutide peptide (LY3437943) — a synthetic 39-residue triple agonist at the GLP-1, GIP and glucagon receptors. Lyophilised powder, signed batch CoA on the page.
Metabolic Research
≥98% (HPLC-UV)Retatrutide 20mg
The same retatrutide (LY3437943) as our 10mg vial — twice the payload from one lot, at a lower cost per milligram. Signed batch CoA on the page.
Metabolic Research
≥98% (HPLC-UV)Retatrutide 20mg
The same retatrutide (LY3437943) as our 10mg vial — twice the payload from one lot, at a lower cost per milligram. Signed batch CoA on the page.
Metabolic Research
≥98% (HPLC-UV)Retatrutide 20mg
The same retatrutide (LY3437943) as our 10mg vial — twice the payload from one lot, at a lower cost per milligram. Signed batch CoA on the page.
Metabolic Research
≥98% (HPLC-UV)Retatrutide 20mg
The same retatrutide (LY3437943) as our 10mg vial — twice the payload from one lot, at a lower cost per milligram. Signed batch CoA on the page.
Metabolic Research
≥98% (HPLC-UV)Retatrutide 30mg
Retatrutide 30mg UK — 30mg of LY3437943 from a single synthesis, so a long study runs start to finish without a lot change. Our lowest cost per milligram.
Metabolic Research
≥98% (HPLC-UV)Retatrutide 30mg
Retatrutide 30mg UK — 30mg of LY3437943 from a single synthesis, so a long study runs start to finish without a lot change. Our lowest cost per milligram.
Metabolic Research
≥98% (HPLC-UV)Retatrutide 30mg
Retatrutide 30mg UK — 30mg of LY3437943 from a single synthesis, so a long study runs start to finish without a lot change. Our lowest cost per milligram.
Metabolic Research
≥98% (HPLC-UV)Retatrutide 30mg
Retatrutide 30mg UK — 30mg of LY3437943 from a single synthesis, so a long study runs start to finish without a lot change. Our lowest cost per milligram.
Skin Health / Anti-Ageing
≥98% HPLCGHK-Cu 100mg
GHK-Cu peptide (copper tripeptide-1), lyophilised. Studied for collagen synthesis, matrix remodelling and wound-repair signalling.
Skin Health / Anti-Ageing
≥98% HPLCGHK-Cu 50mg
GHK-Cu peptide (copper tripeptide-1), lyophilised. Studied for collagen synthesis, matrix remodelling and wound-repair signalling.
Skin Health / Anti-Ageing
≥98% HPLCGHK-Cu 50mg
GHK-Cu peptide (copper tripeptide-1), lyophilised. Studied for collagen synthesis, matrix remodelling and wound-repair signalling.
Skin Health / Anti-Ageing
≥98% HPLCGHK-Cu 50mg
GHK-Cu peptide (copper tripeptide-1), lyophilised. Studied for collagen synthesis, matrix remodelling and wound-repair signalling.
Skin Health / Anti-Ageing
≥98% HPLCGHK-Cu 50mg
GHK-Cu peptide (copper tripeptide-1), lyophilised. Studied for collagen synthesis, matrix remodelling and wound-repair signalling.
Skin Health / Anti-Ageing
≥98% HPLCGHK-Cu 100mg
GHK-Cu peptide (copper tripeptide-1), lyophilised. Studied for collagen synthesis, matrix remodelling and wound-repair signalling.
Skin Health / Anti-Ageing
≥98% HPLCGHK-Cu 100mg
GHK-Cu peptide (copper tripeptide-1), lyophilised. Studied for collagen synthesis, matrix remodelling and wound-repair signalling.
Skin Health / Anti-Ageing
≥98% HPLCGHK-Cu 100mg
GHK-Cu peptide (copper tripeptide-1), lyophilised. Studied for collagen synthesis, matrix remodelling and wound-repair signalling.
Recovery / Healing
≥98% HPLCBPC-157 5mg
BPC-157 peptide — a synthetic pentadecapeptide, lyophilised. Studied in models of tendon, ligament, gut-lining and vascular repair.
Recovery / Healing
≥98% HPLCBPC-157 5mg
BPC-157 peptide — a synthetic pentadecapeptide, lyophilised. Studied in models of tendon, ligament, gut-lining and vascular repair.
Recovery / Healing
≥98% HPLCBPC-157 5mg
BPC-157 peptide — a synthetic pentadecapeptide, lyophilised. Studied in models of tendon, ligament, gut-lining and vascular repair.
Recovery / Healing
≥98% HPLCBPC-157 5mg
BPC-157 peptide — a synthetic pentadecapeptide, lyophilised. Studied in models of tendon, ligament, gut-lining and vascular repair.
Recovery / Healing
≥98% HPLCBPC-157 10mg
BPC-157 peptide — a synthetic pentadecapeptide, lyophilised. Studied in models of tendon, ligament, gut-lining and vascular repair.
Recovery / Healing
≥98% HPLCBPC-157 10mg
BPC-157 peptide — a synthetic pentadecapeptide, lyophilised. Studied in models of tendon, ligament, gut-lining and vascular repair.
Recovery / Healing
≥98% HPLCBPC-157 10mg
BPC-157 peptide — a synthetic pentadecapeptide, lyophilised. Studied in models of tendon, ligament, gut-lining and vascular repair.
Recovery / Healing
≥98% HPLCBPC-157 10mg
BPC-157 peptide — a synthetic pentadecapeptide, lyophilised. Studied in models of tendon, ligament, gut-lining and vascular repair.
Recovery / Healing
≥98% HPLCBPC-157 20mg
BPC-157 peptide — a synthetic pentadecapeptide, lyophilised. Studied in models of tendon, ligament, gut-lining and vascular repair.
Recovery / Healing
≥98% HPLCBPC-157 20mg
BPC-157 peptide — a synthetic pentadecapeptide, lyophilised. Studied in models of tendon, ligament, gut-lining and vascular repair.
Recovery / Healing
≥98% HPLCBPC-157 20mg
BPC-157 peptide — a synthetic pentadecapeptide, lyophilised. Studied in models of tendon, ligament, gut-lining and vascular repair.
Recovery / Healing
≥98% HPLCBPC-157 20mg
BPC-157 peptide — a synthetic pentadecapeptide, lyophilised. Studied in models of tendon, ligament, gut-lining and vascular repair.
Growth Hormone / Recovery
≥98% HPLC (both peptides)CJC-1295 + Ipamorelin 5+5mg
CJC-1295 without DAC, co-lyophilised with Ipamorelin at 5mg of each. A short-acting GHRH analogue paired with a selective ghrelin-receptor agonist.
Growth Hormone / Recovery
≥98% HPLC (both peptides)CJC-1295 + Ipamorelin 5+5mg
CJC-1295 without DAC, co-lyophilised with Ipamorelin at 5mg of each. A short-acting GHRH analogue paired with a selective ghrelin-receptor agonist.
Growth Hormone / Recovery
≥98% HPLC (both peptides)CJC-1295 + Ipamorelin 5+5mg
CJC-1295 without DAC, co-lyophilised with Ipamorelin at 5mg of each. A short-acting GHRH analogue paired with a selective ghrelin-receptor agonist.
Growth Hormone / Recovery
≥98% HPLC (both peptides)CJC-1295 + Ipamorelin 5+5mg
CJC-1295 without DAC, co-lyophilised with Ipamorelin at 5mg of each. A short-acting GHRH analogue paired with a selective ghrelin-receptor agonist.
Skin / Hormonal Research
≥98% HPLCMT-2 10mg
Melanotan 2 (MT-2) — a synthetic melanocortin receptor agonist, lyophilised. Studied for melanogenesis and receptor signalling.
Skin / Hormonal Research
≥98% HPLCMT-2 10mg
Melanotan 2 (MT-2) — a synthetic melanocortin receptor agonist, lyophilised. Studied for melanogenesis and receptor signalling.
Skin / Hormonal Research
≥98% HPLCMT-2 10mg
Melanotan 2 (MT-2) — a synthetic melanocortin receptor agonist, lyophilised. Studied for melanogenesis and receptor signalling.
Skin / Hormonal Research
≥98% HPLCMT-2 10mg
Melanotan 2 (MT-2) — a synthetic melanocortin receptor agonist, lyophilised. Studied for melanogenesis and receptor signalling.
Recovery / Healing
≥98% HPLCTB-500 5mg
TB-500 peptide — a Thymosin Beta-4 fragment analogue. Researched for tissue repair, inflammation and cardiovascular recovery.
Recovery / Healing
≥98% HPLCTB-500 5mg
TB-500 peptide — a Thymosin Beta-4 fragment analogue. Researched for tissue repair, inflammation and cardiovascular recovery.
Recovery / Healing
≥98% HPLCTB-500 5mg
TB-500 peptide — a Thymosin Beta-4 fragment analogue. Researched for tissue repair, inflammation and cardiovascular recovery.
Recovery / Healing
≥98% HPLCTB-500 5mg
TB-500 peptide — a Thymosin Beta-4 fragment analogue. Researched for tissue repair, inflammation and cardiovascular recovery.
Nootropic / Cognitive Research
≥98% HPLCSemax 10mg
Semax peptide — a synthetic ACTH(4-10) analogue. Researched for BDNF expression, focus, memory and neuroprotection in preclinical models.
Nootropic / Cognitive Research
≥98% HPLCSemax 10mg
Semax peptide — a synthetic ACTH(4-10) analogue. Researched for BDNF expression, focus, memory and neuroprotection in preclinical models.
Nootropic / Cognitive Research
≥98% HPLCSemax 10mg
Semax peptide — a synthetic ACTH(4-10) analogue. Researched for BDNF expression, focus, memory and neuroprotection in preclinical models.
Nootropic / Cognitive Research
≥98% HPLCSemax 10mg
Semax peptide — a synthetic ACTH(4-10) analogue. Researched for BDNF expression, focus, memory and neuroprotection in preclinical models.
Mitochondrial / Metabolic Research
≥98% HPLCMOTS-C 10mg
MOTS-c peptide — 16 amino acids, encoded in the mitochondrial genome. Studied for AMPK activation, insulin sensitivity and metabolic homeostasis.
Mitochondrial / Metabolic Research
≥98% HPLCMOTS-C 10mg
MOTS-c peptide — 16 amino acids, encoded in the mitochondrial genome. Studied for AMPK activation, insulin sensitivity and metabolic homeostasis.
Mitochondrial / Metabolic Research
≥98% HPLCMOTS-C 10mg
MOTS-c peptide — 16 amino acids, encoded in the mitochondrial genome. Studied for AMPK activation, insulin sensitivity and metabolic homeostasis.
Mitochondrial / Metabolic Research
≥98% HPLCMOTS-C 10mg
MOTS-c peptide — 16 amino acids, encoded in the mitochondrial genome. 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.
Longevity / Metabolic Research
≥98% HPLCNAD+ 500mg
Nicotinamide Adenine Dinucleotide. Central coenzyme in cellular energy metabolism, sirtuin activity and DNA repair research.
Longevity / Metabolic Research
≥98% HPLCNAD+ 500mg
Nicotinamide Adenine Dinucleotide. Central coenzyme in cellular energy metabolism, sirtuin activity and DNA repair research.
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
Selank peptide — the tuftsin-derived heptapeptide TKPRPGP, lyophilised. Preclinical work on GABA-A, enkephalinase and BDNF expression.
Nootropic / Anxiolytic Research
≥98% HPLCSelank 10mg
Selank peptide — the tuftsin-derived heptapeptide TKPRPGP, lyophilised. Preclinical work on GABA-A, enkephalinase and BDNF expression.
Nootropic / Anxiolytic Research
≥98% HPLCSelank 10mg
Selank peptide — the tuftsin-derived heptapeptide TKPRPGP, lyophilised. Preclinical work on GABA-A, enkephalinase and BDNF expression.
Nootropic / Anxiolytic Research
≥98% HPLCSelank 10mg
Selank peptide — the tuftsin-derived heptapeptide TKPRPGP, lyophilised. Preclinical work on GABA-A, enkephalinase and BDNF expression.
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)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)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)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.
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.
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.
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.
Antioxidant / Skin Research
≥98% HPLCGlutathione 1500mg
Reduced L-Glutathione (GSH). Master intracellular antioxidant researched for oxidative stress, detoxification and skin brightening pathways.
Antioxidant / Skin Research
≥98% HPLCGlutathione 1500mg
Reduced L-Glutathione (GSH). Master intracellular antioxidant researched for oxidative stress, detoxification and skin brightening pathways.
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.
Sleep / Neuropeptide Research
≥98% HPLCDSIP 5mg
Delta Sleep-Inducing Peptide. Nonapeptide studied for slow-wave sleep architecture, stress response and neuroendocrine modulation.
Sleep / Neuropeptide Research
≥98% HPLCDSIP 5mg
Delta Sleep-Inducing Peptide. Nonapeptide studied for slow-wave sleep architecture, stress response and neuroendocrine modulation.
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
An 83-residue recombinant IGF-1 analogue with reduced IGF-binding-protein affinity. Lyophilised cell-culture reagent for IGF-1R signalling work.
Growth Factor Research
≥98% HPLCIGF-1 LR3 1mg
An 83-residue recombinant IGF-1 analogue with reduced IGF-binding-protein affinity. Lyophilised cell-culture reagent for IGF-1R signalling work.
Growth Factor Research
≥98% HPLCIGF-1 LR3 1mg
An 83-residue recombinant IGF-1 analogue with reduced IGF-binding-protein affinity. Lyophilised cell-culture reagent for IGF-1R signalling work.
Growth Factor Research
≥98% HPLCIGF-1 LR3 1mg
An 83-residue recombinant IGF-1 analogue with reduced IGF-binding-protein affinity. Lyophilised cell-culture reagent for IGF-1R signalling work.
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.
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.
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.
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 — Independent lab | 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 | Named UK trader, 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 (an independent laboratory) 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.