Growth Hormone Secretagogues
GHRP-6
5mg
Ghrelin receptor agonist hexapeptide. Growth hormone secretagogue research.
98.8% purity · Third-party tested · Batch UKPL-782 · View certificate
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- Add £57.01 more for free UK delivery
- Cold-chain shipping. Always. Dry-cold pack, Royal Mail Tracked 24
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- Research use only. For in-vitro laboratory research. Not for use in humans or animals, or in food, drugs or diagnostics. Not evaluated by the MHRA or FDA. The buyer is responsible for handling and regulatory compliance.
Bulk Pricing
Counted across your basket, any mix of products.
| Vials in basket | Discount | Per vial |
|---|---|---|
| 1 | None | £11.99 |
| 3-4 | 5% | £11.39 |
| 5-9 | 8% | £11.03 |
| 10-50 | 12% | £10.55 |
Bacteriostatic Water 10ml
Required to reconstitute lyophilised peptides.
What is GHRP-6?
GHRP-6, also written GHRP6, is growth hormone releasing hexapeptide: the first synthetic peptide shown to release growth hormone by acting directly on the pituitary. It activates the ghrelin receptor, GHS-R1a. Each GHRP-6 5mg vial holds white lyophilised powder.
Full description
Bowers and colleagues (Endocrinology, 1984) described the hexapeptide His-D-Trp-Ala-Trp-D-Phe-Lys-NH₂. It released growth hormone in isolated pituitary tissue and in rats, monkeys, lambs and calves. It did not release LH, FSH, TSH or prolactin, and somatostatin blocked its effect.
The peptide resembled no known hypothalamic hormone, so its receptor stayed unknown for twelve years. Howard and colleagues (Science, 1996) then cloned GHS-R1a and showed it was the target of the synthetic secretagogues. Its natural ligand, ghrelin, was identified three years later.
GHRP-6 Research Applications
GHRP-6 is the founding reference compound in growth hormone secretagogue and ghrelin-receptor research. The Bowers paper set up methods still in use: direct secretagogue activity in isolated pituitary preparations, growth hormone measurement in vivo, and specificity checked against other pituitary hormones. It remains a standard GHS-R1a agonist in receptor-expression systems and binding studies. It is also the usual comparator when newer analogues such as GHRP-2 or ipamorelin are benchmarked. Controlled human data on GHRP-6 are sparse, and it is not an approved therapeutic agent anywhere.
GHRP-6 vs GHRP-2 vs Ipamorelin
All three act at GHS-R1a and come from the same structure-activity lineage. GHRP-6 is the founding hexapeptide at 873.0 g/mol. GHRP-2 keeps the Ala-Trp-D-Phe-Lys-NH₂ end but swaps His-D-Trp for D-Ala-D-2-Nal, giving 818.0 g/mol. Ipamorelin is a later, shorter pentapeptide designed for more selective growth hormone release. The hunger effect is usually linked to GHRP-6, but the controlled human food-intake study in this class used GHRP-2 (Laferrère et al., 2005). Most comparative claims about the three come from early in-vitro and animal work.
Research Overview
GHRP-6, also written GHRP 6, carries two D-amino acids and two tryptophans within six residues. The D-residues slow enzymatic breakdown. The tryptophans at positions 2 and 4 make it more light-sensitive than most peptides of its size.
The 1984 Bowers result raised an obvious question. A small synthetic peptide unrelated to any known hypothalamic hormone was releasing growth hormone directly from the pituitary, so it had to be acting on an unidentified receptor. Howard and colleagues answered that in 1996 by cloning the growth hormone secretagogue receptor from pituitary and hypothalamus. Their paper proposed that the synthetic secretagogues mimic an undiscovered hormone. Ghrelin turned out to be that hormone.
GHRP-2, ipamorelin, hexarelin and the small-molecule secretagogues all descend from this line of work. GHRP-6 is not a licensed medicine anywhere.
Product Specifications
- Molecular Formula
- C₄₆H₅₆N₁₂O₆
- Molecular Weight
- 873.0 g/mol
- CAS Number
- 87616-84-0
- Sequence
- His-D-Trp-Ala-Trp-D-Phe-Lys-NH₂
- Purity
- 98.8% (RP-HPLC)
- Batch
- UKPL-782
- Storage
- -20°C lyophilised, 2-8°C reconstituted
- Appearance
- White lyophilised powder
- Form
- Lyophilised powder
Certificate of Analysis
Third-party tested
- Batch
- UKPL-782
- Purity
- 98.8%
- Specification
- ≥98.0%
- Method
- RP-HPLC
- Tested
- Jul 2026
Need the certificate for an earlier batch? Request an older CoA
Storage and Reconstitution
Keep sealed vials at -20°C, dry and in the dark. After reconstitution, keep the solution at 2-8°C and use it within 4 weeks, or freeze single-use aliquots at -20°C. Light protection matters more for GHRP-6 than for most peptides of its size. Oxidation of the tryptophans at positions 2 and 4 is the likeliest degradation route, so keep vials and solutions foil-wrapped.
Vials are sold on their own, without bacteriostatic water for mixing or other supplies.
How to reconstitute and handle
Bring the vial to room temperature and swab both stoppers with alcohol. Add bacteriostatic water slowly down the inside wall of the vial and swirl gently until dissolved. Do not shake or vortex. Work away from strong direct light, because both tryptophan residues are light-sensitive. The solution should be clear and colourless. Label the vial with the reconstitution date.
- Protect from light at every stage, including weighing, reconstitution and storage.
- Work aseptically with sterile syringes and alcohol-swabbed stoppers. Split reconstituted stock into single-use, light-protected aliquots and avoid repeated freeze-thaw cycles.
For the full method, see the peptide reconstitution guide and the reconstitution calculator.
Research References
- On the in vitro and in vivo activity of a new synthetic hexapeptide that acts on the pituitary to specifically release growth hormone (Bowers et al., Endocrinology, 1984)
- A receptor in pituitary and hypothalamus that functions in growth hormone release (Howard et al., Science, 1996)
Published research on GHRP-6 is indexed on PubMed.
GHRP-6 Price (UK)
GHRP-6 5mg is for sale at £11.99 per vial, supplied from stock in the UK with a published third-party HPLC certificate. UK delivery is £4.50 by Royal Mail Tracked 24, free over £69.
| Vial | Price | Cost per mg | Availability |
|---|---|---|---|
| GHRP-6 5mgThis page | £11.99 | £2.40 | In stock |
Prices are in GBP per vial and match the basket. See the FAQ for delivery and payment options, and quality & testing for how each batch is checked.
Frequently Asked Questions
How does GHRP-6 work?
GHRP-6 activates GHS-R1a, the ghrelin receptor, on pituitary cells. Bowers and colleagues (Endocrinology, 1984) showed it released growth hormone from isolated pituitary tissue without releasing LH, FSH, TSH or prolactin. Howard and colleagues (Science, 1996) later cloned the receptor it acts on. These are receptor and secretion findings, not evidence of any effect in humans.
Why is GHRP-6 historically important?
The growth hormone secretagogue field descends from it. In 1984 it showed that a small synthetic peptide could release growth hormone directly from the pituitary, which implied an unknown receptor. That receptor, GHS-R1a, was cloned in 1996, and its natural ligand, ghrelin, three years after that. The synthetic tool came before both the receptor and the hormone.
What is the difference between GHRP-6, GHRP-2 and ipamorelin?
All three activate GHS-R1a. GHRP-6 is the original hexapeptide, His-D-Trp-Ala-Trp-D-Phe-Lys-NH₂, at 873.0 g/mol. GHRP-2 replaces His-D-Trp with D-Ala-D-2-Nal and weighs 818.0 g/mol. Ipamorelin is a later pentapeptide designed for more selective growth hormone release. Most comparisons between them come from early in-vitro and animal studies.
Is GHRP-6 banned in sport?
Yes. Section S2 of the WADA Prohibited List names GHRP-6 among the growth hormone secretagogues. It is prohibited at all times, in and out of competition, and athletes subject to anti-doping testing should treat GHRP6 accordingly.
Is GHRP-6 legal to buy in the UK?
Yes, as a research chemical for in-vitro laboratory use only. It is not an approved or licensed medicine and is not supplied for human consumption, veterinary use or any therapeutic purpose. Buyers must be 18 or over and confirm research-only use at checkout.
Where can I buy GHRP-6 in the UK?
UK Peptide Lab has GHRP-6 5mg for sale from UK stock, batch UKPL-782. Orders placed before 3pm UK time on a working day go out the same day. UK delivery by Royal Mail Tracked is free over £69.
Is your GHRP-6 independently tested?
Yes. The certificate for batch UKPL-782 is third-party verified and reports 98.8% purity by RP-HPLC. It is published in full on the product page.
What is GHRP-6 used for in research?
GHRP-6 is used in growth hormone secretagogue and ghrelin-receptor (GHS-R1a) research. Typical systems are isolated pituitary preparations, receptor-expression assays and binding studies. It is also the historical reference agonist for benchmarking newer analogues such as GHRP-2 and ipamorelin.
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