Growth Hormone Peptides Compared (2026)

Last updated 15 October 2026 · SARMs Store editorial team. Products on this site are supplied strictly for laboratory research and are not for human consumption. This guide summarises published research; it is not medical advice and contains no instructions for use. 18+ only.

CJC-1295, ipamorelin, sermorelin and tesamorelin are the four growth hormone peptides UK researchers ask about most. They are often grouped together, but they belong to two families that act on two different pituitary receptors. This guide compares their mechanism, half-life, research history and UK regulatory status, and links to the full research guide for each one.

Growth hormone peptides at a glance

Three of the four (sermorelin, CJC-1295 and tesamorelin) copy growth hormone releasing hormone (GHRH), and one (ipamorelin) copies the stomach hormone ghrelin. Only tesamorelin holds a current licence anywhere, and none is licensed in the UK.

Peptide	Family	Receptor	Length	Published half-life	Licence history	In our range
Sermorelin	GHRH analogue	GHRH receptor	29 amino acids	Minutes	Licensed in the US as Geref, later withdrawn	Sermorelin 5mg
CJC-1295	GHRH analogue	GHRH receptor	29 amino acids, modified	5.8 to 8.1 days for the DAC form; short for the no-DAC form	Never licensed	CJC-1295 + Ipamorelin 10mg
Tesamorelin	GHRH analogue	GHRH receptor	44 amino acids, stabilised	About 11 minutes (US label)	Licensed in the US since 2010 for one indication	Tesamorelin 10mg
Ipamorelin	Ghrelin mimetic	Ghrelin receptor (GHS-R1a)	5 amino acids	About 2 hours	Never licensed	Ipamorelin 5mg

Research this compound

Origin Peptides CJC-1295 + Ipamorelin 10mg Vial£49.99

10 mg · vial.

Two pathways to growth hormone release

The pituitary releases growth hormone in response to two separate signals: GHRH from the hypothalamus and ghrelin, which is made mainly in the stomach. GHRH analogues act on the first pathway and ghrelin mimetics act on the second, while somatostatin acts as the brake on both.

The GHRH receptor

GHRH was isolated in 1982 by Roger Guillemin's group from a pancreatic tumour that had caused acromegaly; the peptide they sequenced was 44 amino acids long. GHRH binds its own receptor on the somatotroph cells of the pituitary and prompts them to release growth hormone in pulses, which remain subject to the body's normal feedback through IGF-1 and somatostatin. Sermorelin, CJC-1295 and tesamorelin are all built on the GHRH sequence and all act at this receptor.

The ghrelin receptor

The second pathway was found the other way round. In 1984 Cyril Bowers and colleagues described a synthetic hexapeptide, later called GHRP-6, that released growth hormone through a receptor nobody had yet identified. That receptor, the growth hormone secretagogue receptor (GHS-R1a), was cloned in the 1990s, and in 1999 Kojima and colleagues reported in Nature that its natural partner is ghrelin, a 28 amino acid peptide from the stomach. Ipamorelin, GHRP-6, GHRP-2 and the non-peptide MK-677 all act at this receptor.

Why the two families are often discussed together

Because the two receptors are separate, growth hormone research has long studied a GHRH analogue and a ghrelin mimetic side by side, which is the background to blends such as CJC-1295 with ipamorelin. No published human trial has tested that pairing; it is a research-market convention.

Sermorelin: the original GHRH fragment

Sermorelin is the first 29 amino acids of human GHRH, the shortest fragment that keeps the full activity of the parent hormone. It is the only one of the four with a history as a licensed medicine for children.

Under the brand name Geref it was approved in the United States as a diagnostic test for growth hormone deficiency and as a treatment for some children with idiopathic growth hormone deficiency. A 1999 review by Prakash and Goa in BioDrugs summarised that work, reporting sustained increases in height velocity over 12 months in prepubertal children, with facial flushing and local site reactions the commonest adverse events. Geref was later withdrawn from the US market for commercial reasons, and it has never held a UK licence.

In adults, small pilot studies at the US National Institute on Aging (Corpas and colleagues in 1992, Vittone and colleagues in 1997) gave sermorelin to healthy older men for weeks to months and measured raised growth hormone and IGF-1. Native GHRH and sermorelin are cleared from the blood within minutes, which is the short duration of action that later analogues were designed to overcome. The Sermorelin research guide covers the compound in more depth.

CJC-1295: with DAC and without

CJC-1295 is a modified version of the GHRH 1-29 sequence, and it exists in two forms that behave very differently. The original form carries a drug affinity complex (DAC) that lasts for days; the form usually sold for research has no DAC and acts for a much shorter time.

The DAC version was developed by ConjuChem. Teichman and colleagues reported in the Journal of Clinical Endocrinology and Metabolism in 2006 on two randomised, placebo controlled studies in healthy adults aged 21 to 61. A single administration raised mean growth hormone two to tenfold for six days or more and IGF-1 1.5 to threefold for 9 to 11 days, with an estimated half-life of 5.8 to 8.1 days because the DAC binds the peptide to albumin in the blood. A follow-up study by Ionescu and Frohman later that year found that growth hormone pulses continued during this sustained stimulation, with the rise coming mainly from higher trough levels. Development stopped after 2006.

CJC-1295 without DAC, also sold as Modified GRF 1-29 or Mod GRF 1-29, keeps four amino acid substitutions that slow its breakdown compared with sermorelin but lacks the albumin binding group. Far less human pharmacology has been published on this form, so the multi-day figures from the DAC studies do not apply to it. The Origin Peptides CJC-1295 + Ipamorelin 10mg blend uses the no-DAC form, and the CJC-1295 and Ipamorelin research guide explains the difference in detail.

Tesamorelin: the most clinical data

Tesamorelin is the full 44 amino acid GHRH sequence with a trans-3-hexenoyl group added to its first amino acid, which protects it from the enzyme that breaks native GHRH down. It has the largest human trial record of the four and is the only one with a current licence anywhere.

Developed by Theratechnologies as TH9507, it was tested in people with HIV who had built up excess abdominal fat while on antiretroviral therapy. Falutz and colleagues reported the first phase III trial in the New England Journal of Medicine in 2007, and a pooled analysis of two phase III trials covering 806 patients in the Journal of Clinical Endocrinology and Metabolism in 2010. Visceral fat measured by CT fell in the tesamorelin groups compared with placebo over 26 weeks, while fat under the skin was largely unchanged. On that evidence the US Food and Drug Administration approved it in 2010, under the brand Egrifta, for the reduction of excess abdominal fat in HIV infected adults with lipodystrophy.

Despite the stabilising group, tesamorelin is still short lived in the blood: the current US label for EGRIFTA WR gives a mean elimination half-life of 11 minutes in healthy subjects. Its effect on growth hormone and IGF-1 outlasts the peptide itself. Tesamorelin has no UK or EU marketing authorisation. The Tesamorelin research guide covers the trials, including the later liver fat studies.

Ipamorelin: the selective ghrelin mimetic

Ipamorelin is a five amino acid peptide that acts on the ghrelin receptor rather than the GHRH receptor. Its distinguishing feature in the research is selectivity: it releases growth hormone without the cortisol and prolactin rises seen with older ghrelin mimetics.

Raun and colleagues at Novo Nordisk described it in the European Journal of Endocrinology in 1998 as the first selective growth hormone secretagogue. In rats and pigs it released growth hormone with a potency similar to GHRP-6, but unlike GHRP-6 and GHRP-2 it did not raise ACTH or cortisol, even well above the levels needed for growth hormone release. A human pharmacokinetic study by Gobburu and colleagues in Pharmaceutical Research in 1999 found a single pulse of growth hormone peaking at about 40 minutes and a terminal half-life of about two hours.

Because ghrelin also stimulates gut movement, Beck and colleagues later ran a randomised phase II trial in 114 bowel resection patients with post-operative ileus, reported in the International Journal of Colorectal Disease in 2014. They found no significant difference from placebo on the main measures, and development stopped. The Ipamorelin research guide covers the compound in full.

Half-life and duration compared

Half-life is the clearest practical difference between the four on the bench. The DAC form of CJC-1295 is measured in days; ipamorelin in hours; sermorelin, tesamorelin and the no-DAC form of CJC-1295 in minutes.

The DAC form of CJC-1295 lasted 5.8 to 8.1 days in the 2006 healthy volunteer studies because of albumin binding. Ipamorelin had a terminal half-life of about two hours in the 1999 human study. The current US label gives tesamorelin a mean elimination half-life of about 11 minutes, and sermorelin and the no-DAC form of CJC-1295 are also short acting, with little modern human pharmacokinetic data published for the no-DAC form.

Half-life describes how long the peptide stays in the blood, not how long growth hormone or IGF-1 stay raised afterwards, which is why studies report both.

Research history compared

Tesamorelin has phase III trials and a licence; sermorelin has an old paediatric licence and small adult studies; CJC-1295 and ipamorelin have early phase human pharmacology only. None has a controlled human trial for body composition, performance or ageing in healthy people.

Peptide	Highest level of human evidence	What it was studied for	Main gap
Tesamorelin	Two phase III randomised trials	Visceral fat and liver fat in people with HIV	Little data outside defined patient groups
Sermorelin	Licensing studies in children	Diagnosis and treatment of growth hormone deficiency	No modern controlled adult trials
CJC-1295	Phase I and II pharmacology (DAC form)	Growth hormone and IGF-1 release	Almost no published data on the no-DAC form
Ipamorelin	Pharmacokinetic study; phase II in post-operative ileus	Selective growth hormone release; gut motility	The phase II trial did not meet its endpoint

A 2018 review of growth hormone secretagogues by Sigalos and Pastuszak in Sexual Medicine Reviews concluded that few long term, rigorously controlled studies exist, and flagged reduced insulin sensitivity and raised blood glucose as a recurring concern. That caution applies across the whole group.

How they differ from growth hormone itself

None of these peptides is growth hormone. They prompt the pituitary to release its own growth hormone, so the response depends on a working pituitary and stays under the body's feedback control.

Recombinant growth hormone (somatropin) is a 191 amino acid protein that supplies the hormone directly and bypasses pituitary feedback. Releasing peptides amplify the body's own pulses instead, which is why researchers call them secretagogues, and why the peptides and the hormone sit in different places in UK law.

UK regulatory status in 2026

None of the four peptides is a controlled drug in the UK, none holds a UK marketing authorisation, and all four are prohibited in sport. In the UK they can be supplied only as research materials, not sold or advertised for human use.

Misuse of Drugs Act 1971

Sermorelin, CJC-1295, tesamorelin and ipamorelin are not listed under the Misuse of Drugs Act 1971. Growth hormone itself is different: somatropin, somatrem and chorionic gonadotrophin are listed in Part III of Schedule 2 to the Act. Research buyers should not confuse the releasing peptides with the hormone.

Medicines law

Under the Human Medicines Regulations 2012, a product presented for treating or preventing disease, or used to restore, correct or modify physiological functions in people, is treated as a medicine and needs a marketing authorisation. None of these peptides has one in the UK, so the MHRA would treat any of them sold for human use as an unlicensed medicine. Tesamorelin's US licence does not carry over to the UK.

Sport

Section S2 of the World Anti-Doping Agency Prohibited List bans growth hormone releasing factors, including GHRH and its analogues such as CJC-1295, sermorelin and tesamorelin, and growth hormone secretagogues and GHRPs, including ipamorelin, at all times, in and out of competition.

Names you will see on labels

Each of the four is sold under several names, and some names are easily confused. Check the exact compound, and for CJC-1295 check whether the listing says with or without DAC.

Sermorelin: sermorelin acetate, GHRH (1-29), GRF 1-29 NH2, Geref (former US brand).
CJC-1295 without DAC: Modified GRF 1-29, Mod GRF 1-29, tetrasubstituted GRF 1-29.
CJC-1295 with DAC: CJC-1295 DAC, the original ConjuChem molecule.
Tesamorelin: tesamorelin acetate, TH9507, Egrifta (US brand).
Ipamorelin: ipamorelin acetate, NNC 26-0161 (Novo Nordisk code).
Not the same: MK-677 (ibutamoren) is an oral small molecule, not a peptide, although it acts on the ghrelin receptor like ipamorelin. HGH Fragment 176-191 is a piece of the growth hormone molecule itself and does not act through either releasing pathway.

Choosing a peptide for a research question

The right compound depends on the question being asked. A study of the GHRH pathway calls for a GHRH analogue, a study of the ghrelin pathway calls for a ghrelin mimetic, and the half-life of each shapes how a laboratory experiment is designed.

Comparing with licensed medicine data: tesamorelin and sermorelin have a published clinical record.
Studying a short pulse versus sustained exposure: the half-life differences between ipamorelin, the no-DAC and DAC forms of CJC-1295, and sermorelin are the main variable.
Studying receptor selectivity: ipamorelin's lack of effect on cortisol and prolactin in the original animal work is the reason it is the reference ghrelin mimetic.
Studying both pathways together: blends such as CJC-1295 with ipamorelin combine one compound from each family.

All four are supplied as lyophilised powders in sealed vials, best kept cold and away from light. Our What are peptides? guide explains the purity and identity tests to check.

Frequently asked questions

What is the difference between a GHRH analogue and a ghrelin mimetic?

A GHRH analogue (sermorelin, CJC-1295, tesamorelin) copies the hypothalamic hormone GHRH and acts on the GHRH receptor. A ghrelin mimetic (ipamorelin) copies the stomach hormone ghrelin and acts on the separate GHS-R1a receptor. Both lead the pituitary to release growth hormone.

Which growth hormone peptide has the most human research?

Tesamorelin. It completed two phase III trials in people with HIV associated abdominal fat and was licensed in the United States in 2010 for that single indication. It has no UK licence.

Is CJC-1295 the same as sermorelin?

No. Both are based on the first 29 amino acids of GHRH and act on the same receptor, but CJC-1295 carries four amino acid substitutions that slow its breakdown, and the DAC form adds an albumin binding group that extends its half-life to days.

Do these peptides contain growth hormone?

No. They prompt the pituitary to release its own growth hormone. Growth hormone itself is a 191 amino acid protein and is treated differently in UK law.

Are growth hormone peptides legal in the UK?

They are not controlled drugs, so they are legal to buy and possess as research materials. None holds a UK marketing authorisation, so they cannot be sold or advertised for human use.

Are they banned in sport?

Yes. All four fall under section S2 of the WADA Prohibited List and are banned at all times.

Is MK-677 a growth hormone peptide?

No. MK-677 (ibutamoren) is an orally active small molecule. It acts on the same ghrelin receptor as ipamorelin but is not a peptide. See our MK-677 research guide.

Sources

Guillemin R, Brazeau P, Böhlen P, et al. Growth hormone-releasing factor from a human pancreatic tumor that caused acromegaly. Science. 1982;218(4572):585-587.
Bowers CY, Momany FA, Reynolds GA, Hong A. On the in vitro and in vivo activity of a new synthetic hexapeptide that acts on the pituitary to specifically release growth hormone. Endocrinology. 1984;114(5):1537-1545.
Kojima M, Hosoda H, Date Y, et al. Ghrelin is a growth-hormone-releasing acylated peptide from stomach. Nature. 1999;402(6762):656-660.
Prakash A, Goa KL. Sermorelin: a review of its use in the diagnosis and treatment of children with idiopathic growth hormone deficiency. BioDrugs. 1999;12(2):139-157.
Corpas E, Harman SM, Piñeyro MA, et al. Growth hormone (GH)-releasing hormone-(1-29) twice daily reverses the decreased GH and insulin-like growth factor-I levels in old men. Journal of Clinical Endocrinology and Metabolism. 1992;75(2):530-535.
Vittone J, Blackman MR, Busby-Whitehead J, et al. Effects of single nightly injections of growth hormone-releasing hormone (GHRH 1-29) in healthy elderly men. Metabolism. 1997;46(1):89-96.
Teichman SL, Neale A, Lawrence B, et al. Prolonged stimulation of growth hormone (GH) and insulin-like growth factor I secretion by CJC-1295, a long-acting analog of GH-releasing hormone, in healthy adults. Journal of Clinical Endocrinology and Metabolism. 2006;91(3):799-805.
Ionescu M, Frohman LA. Pulsatile secretion of growth hormone (GH) persists during continuous stimulation by CJC-1295, a long-acting GH-releasing hormone analog. Journal of Clinical Endocrinology and Metabolism. 2006;91(12):4792-4797.
Falutz J, Allas S, Blot K, et al. Metabolic effects of a growth hormone-releasing factor in patients with HIV. New England Journal of Medicine. 2007;357(23):2359-2370.
Falutz J, Mamputu JC, Potvin D, et al. Effects of tesamorelin (TH9507), a growth hormone-releasing factor analog, in human immunodeficiency virus-infected patients with excess abdominal fat: a pooled analysis of two multicenter, double-blind placebo-controlled phase 3 trials with safety extension data. Journal of Clinical Endocrinology and Metabolism. 2010;95(9):4291-4304.
US Food and Drug Administration. EGRIFTA WR (tesamorelin) prescribing information. Revised March 2025.
Raun K, Hansen BS, Johansen NL, et al. Ipamorelin, the first selective growth hormone secretagogue. European Journal of Endocrinology. 1998;139(5):552-561.
Gobburu JV, Agersø H, Jusko WJ, Ynddal L. Pharmacokinetic-pharmacodynamic modeling of ipamorelin, a growth hormone releasing peptide, in human volunteers. Pharmaceutical Research. 1999;16(9):1412-1416.
Beck DE, Sweeney WB, McCarter MD; Ipamorelin 201 Study Group. Prospective, randomized, controlled, proof-of-concept study of the ghrelin mimetic ipamorelin for the management of postoperative ileus in bowel resection patients. International Journal of Colorectal Disease. 2014;29(12):1527-1534.
Sigalos JT, Pastuszak AW. The safety and efficacy of growth hormone secretagogues. Sexual Medicine Reviews. 2018;6(1):45-53.
Misuse of Drugs Act 1971, Schedule 2. legislation.gov.uk.
The Human Medicines Regulations 2012. legislation.gov.uk.
World Anti-Doping Agency. Prohibited List, section S2.