Function hub
Growth-hormone-releasing peptides (UK research overview)
Growth-hormone-secretagogue peptides stimulate the pituitary to release endogenous growth hormone, rather than supplying GH directly. Class splits into GHRH analogues (Sermorelin, CJC-1295, Tesamorelin) and ghrelin mimetics (Ipamorelin, GHRP-2, GHRP-6, Hexarelin).
Growth hormone has two major peptide release pathways in the human body. GHRH (Growth Hormone Releasing Hormone) acts on the pituitary to release GH. Ghrelin acts on a separate receptor (the GHSR) and also stimulates GH release, with appetite as a side effect. Secretagogue peptides imitate one or the other.
GHRH analogues are the older lane. Sermorelin is a 29-amino-acid GHRH fragment with FDA approval for paediatric GH deficiency, withdrawn from US market in 2008 for commercial reasons but still synthesised and sold globally for research. Tesamorelin is a longer-acting GHRH analogue FDA-approved for HIV-associated lipodystrophy. CJC-1295 is a research-only GHRH analogue, available with or without the DAC (Drug Affinity Complex) modification that extends half-life from minutes to days.
Ghrelin mimetics are the newer lane. Ipamorelin is a pentapeptide with selective GH-release action and minimal appetite or cortisol side effects in the published preclinical work. GHRP-2 and GHRP-6 are older mimetics with broader off-target effects (GHRP-6 stimulates appetite strongly). Hexarelin is a stronger ghrelin mimetic with more pronounced cortisol side effects.
Stack pricing is significant in this category. Many UK retailers sell Sermorelin or CJC-1295 alongside Ipamorelin as a single named bundle (commonly referred to as a GH stack or by retailer-specific branding). The logic is that a GHRH analogue and a ghrelin mimetic act on different receptors and the combined GH release is larger than either alone.
Tesamorelin sits slightly apart from the rest of this list. It is a UK-prescribable medicine via private GLP-1-adjacent clinics for specific lipodystrophy indications. Other GH secretagogues on this page are research compounds and not part of UK clinical practice.
The CoA Trust Index is particularly relevant in this category. GH secretagogues are commonly counterfeited, blended incorrectly, or substituted with inactive peptides. Per-batch third-party CoA documentation is the only credible signal for purity.
Compounds in this category
Ipamorelin
Selective ghrelin-receptor mimetic pentapeptide. Animal-model evidence for GH release with minimal cortisol or appetite side effects.
Read the encyclopedia entrySermorelin
29-residue GHRH fragment. Historically FDA-approved for paediatric GH deficiency. Now research-tier in the UK.
Read the encyclopedia entryTesamorelin
Long-acting GHRH analogue. FDA-approved for HIV lipodystrophy. UK availability is private-clinic only for that indication.
Read the encyclopedia entryGHRP-2 and GHRP-6
Older-generation ghrelin mimetics. Stronger off-target appetite (especially GHRP-6) and modest cortisol effects vs Ipamorelin.
Read the encyclopedia entryCJC-1295 (with and without DAC)
Encyclopedia buildingGHRH analogue with optional Drug Affinity Complex modification that extends half-life from minutes to days. Encyclopedia entry building.
UK retailers stocking this category
See CoA Trust Index →Ranked by CoA Trust tier (strong, partial, weak). Editorial commentary based on publicly available information. We earn a referral fee when readers click through and convert.
Researchers wanting named-stack bundles (Wolverine, KLOW, Glow) and CoAs that can be QR-verified to a named third-party lab.
Research peptide retailer · Wolverine Stack £29.99, BPC-157 single from £14.99
Nottingham-based research peptide retailer (Bio Research Ltd, since 2024). Bundles and stacks are the hero SKU (Wolverine BPC-157 + TB-500, Tesamorelin + Ipamorelin 3:1, KLOW, Glow). Janoshik third-party CoAs published per batch with QR-code verification. 10-vial bulk packs alongside singles. Wholesale tier above 11 vials.
Best for per-batch CoA library
Research peptide retailer · BPC-157 5mg £13.99, TB-500 5mg £36
Long-established UK research peptide supplier. 12 years trading, 15,000+ customers. Operates a public CoA subdomain (coa.purepeptidesuk.com) with downloadable per-batch certificates linked from every PDP. Dual-tier purity (Standard vs Premium with endotoxin LAL + heavy-metal testing on Premium).
Researchers who want transparent third-party HPLC batch documents and a less hyped brand voice.
Research peptide retailer · Per peptide, varies
UK research peptide retailer with third-party HPLC plus transparent batch documentation. Plays the credibility lane alongside Pure Peptides UK and Tide Labs.
Researchers who weight UKAS lab accreditation specifically and want the loudest external-verification claim in the segment.
Research peptide retailer · Per peptide, varies
UK research peptide retailer leaning on UKAS-verified HPLC as the sole-in-UK trust claim. Narrower catalogue than UKPeptides or Pure Peptides UK but the lab-verification angle is the loudest in the segment.
Best for classic peptides catalogue
Research peptide retailer · Per peptide, varies
Long-trading UK research peptide retailer (2012). Heavy on classic compounds (BPC-157, TB-500, GHK-Cu, CJC-1295, Ipamorelin, MOTS-c). No GLP-1, no cosmetic line. CoA gated via on-site contact form (request lab report per product). On-site CusRev reviews 5.0 average, not Trustpilot. Reconstitution calculator on-site.
Frequently asked questions
What is the difference between Ipamorelin and Sermorelin?
They act on different receptors. Sermorelin is a GHRH analogue (works on the pituitary GHRH receptor). Ipamorelin is a ghrelin mimetic (works on the GHSR receptor). Many retailers sell them together as a stack because the dual-pathway action produces larger GH release than either alone in the preclinical work.
Is Tesamorelin available on the NHS?
No. Tesamorelin is private-prescription only in the UK for HIV-associated lipodystrophy. Some private GLP-1-adjacent clinics offer it. It is not used in non-HIV contexts in UK clinical practice.
What is CJC-1295 with DAC vs without DAC?
The Drug Affinity Complex (DAC) is a maleimidopropionic acid modification that binds CJC-1295 to serum albumin, extending half-life from minutes to roughly a week. Without DAC, CJC-1295 is short-acting. With DAC, it is long-acting. Research peptide retailers sell both forms separately.
How do I verify a GH secretagogue is real?
A per-batch Certificate of Analysis from a named third-party laboratory is the only credible purity signal. See our CoA Trust Index for which UK retailers publish these openly versus on email request.
Related on PeptideClear
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