Sermorelin, Mod GRF 1-29, CJC-1295 and tesamorelin belong to one group: they are GHRH analogues, copies of the hormone the hypothalamus uses to tell the pituitary to release growth hormone. They differ in chain length, resistance to enzymes and duration of action. CJC-1295 with DAC stayed in the blood for 5.8 to 8.1 days, while tesamorelin is gone after about 11 minutes. Below you will find all four molecules in one table, the key studies on each and the prices of the vials in the shop.
What is a GHRH analogue?
A GHRH analogue is a peptide that mimics the natural growth hormone releasing hormone. Natural GHRH is made by the hypothalamus, and its receptor sits in the front part of the pituitary. When it binds to the receptor, the pituitary releases a pulse of growth hormone, and the liver responds by producing IGF-1. The analogues switch on the same pathway, so the growth hormone comes from your own pituitary, not from an injection.
Natural GHRH has a serious drawback as a drug. The authors of a 2006 study on CJC-1295 write plainly that its use is limited by its short duration of action. It is broken down by, among others, the enzyme DPP-IV, which is present in the blood. Each of the four analogues solves this problem in a different way, and that is what sets them apart most. The second group of growth hormone peptides, which act through the ghrelin receptor, is covered in the guide on GHRH, GHRP and ghrelin.
How do the four GHRH analogues differ?
In short, sermorelin is the simplest, Mod GRF 1-29 more resistant, CJC-1295 with DAC the longest acting, and tesamorelin the only one approved as a drug today. The table collects what can be stated with a source.
| Feature | Sermorelin | Mod GRF 1-29 | CJC-1295 with DAC | Tesamorelin |
|---|---|---|---|---|
| Chain length | 29 amino acids | 29 amino acids with 4 substitutions | 29 amino acids with 4 substitutions and an albumin-binding group | 44 amino acids with a hexenoyl chain |
| What the structure changes | shortest segment with full GHRH activity | D-alanine at position 2 protects against the enzyme DPP-4 | binds to albumin in the blood | full GHRH chain with an addition at the start |
| Time in the blood | short, like natural GHRH | longer than sermorelin | half-life 5.8-8.1 days | half-life about 11 minutes |
| Drug status | formerly the drug Geref in the US, withdrawn for commercial reasons | not approved | not approved | the drug Egrifta in the US since 2010 |
| Price in the shop | from 40 EUR for 5 mg | from 35 EUR for 10 mg | from 35 EUR for 5 mg | 50 EUR for 10 mg |
What makes sermorelin stand out?
Sermorelin is the shortest synthetic peptide that keeps the full biological activity of GHRH. It has 29 amino acids, the opening segment of the natural hormone. A 1999 review in BioDrugs describes two uses. The first is a diagnostic test: an intravenous dose of 1 microgram per kilogram checks whether the pituitary can release growth hormone. The second is the treatment of children with idiopathic growth hormone deficiency.
Children received 30 micrograms per kilogram under the skin once a day, at bedtime. Growth rate rose significantly over 12 months, and in some children the effect lasted for 36 months. The most common side effects were brief facial flushing and pain at the injection site. In the United States sermorelin was approved as the drug Geref. In 2013 the FDA determined that Geref was not withdrawn from sale for reasons of safety or effectiveness.
What is Mod GRF 1-29?
Mod GRF 1-29 is the same 29 amino acid segment as sermorelin, but with four amino acids swapped. The most important swap is D-alanine at position two, which protects the chain from the enzyme DPP-4. This same tetrasubstituted chain is the backbone of CJC-1295. A 2005 paper in Endocrinology describes CJC-1295 precisely as a tetrasubstituted form of GRF 1-29 with an added albumin-binding group.
That is why Mod GRF 1-29 is sometimes called CJC-1295 without DAC. It lasts longer than sermorelin but is still short acting, because it does not bind to albumin. A detailed comparison with sermorelin is in the guide sermorelin vs Mod GRF 1-29.
Why does CJC-1295 with DAC last the longest?
CJC-1295 with DAC binds to albumin, the most abundant protein in the blood, and so it circulates for many days. DAC stands for a chemical group that attaches the peptide to albumin after injection. In a 2005 study in rats this complex was more resistant to the enzyme DPP-IV. CJC-1295 was present in plasma for more than 72 hours.
A 2006 study in healthy adults, published in the Journal of Clinical Endocrinology and Metabolism, confirmed this in humans. After a single injection, mean growth hormone levels rose 2 to 10 times and stayed raised for 6 days or more. IGF-1 rose 1.5 to 3 times and stayed raised for 9 to 11 days. After several doses, IGF-1 remained above baseline for up to 28 days. The difference between the versions with and without DAC is covered in the guide CJC-1295 with or without DAC.
What did studies of tesamorelin confirm?
In a study published in the New England Journal of Medicine in 2007, tesamorelin reduced visceral fat by 15.2 percent over 26 weeks. It included 412 patients with HIV and excess abdominal fat. Half received 2 mg of tesamorelin under the skin daily, and half received placebo. In the placebo group, visceral fat rose by 5.0 percent over the same period.
In the tesamorelin group, triglycerides fell by an average of 50 mg per decilitre and IGF-1 rose by 81 percent. The ratio of total cholesterol to HDL also improved. On this basis tesamorelin was approved in the US in 2010. The current Egrifta label gives the indication: reduction of excess abdominal fat in adults with HIV and lipodystrophy. The label also states that the drug is not meant for weight loss.
Tesamorelin has 44 amino acids, the full chain of human GHRH. A short carbon chain with a double bond is attached to the start of the chain. In the newer form of the drug the recommended dose is 1.28 mg once a day. More on its approval and limits is in the guide on tesamorelin.
Which GHRH analogue to choose for research?
The choice depends on which growth hormone release pattern the study is meant to reproduce. Tesamorelin leaves the blood within minutes, like the other short analogues. CJC-1295 with DAC raises growth hormone and IGF-1 for many days after a single injection. The list below sorts out these differences.
- Sermorelin has a drug approval and clinical studies in children behind it.
- Mod GRF 1-29 is a more resistant version of the short analogue, often combined with a ghrelin secretagogue.
- CJC-1295 with DAC suits work where a long, steady rise in IGF-1 matters.
- Tesamorelin has the best documented effect on visceral fat.
GHRH analogues are often combined with secretagogues that act through the ghrelin receptor, for example ipamorelin. Why this pair is the most popular is explained in the guide on CJC-1295 and ipamorelin.
How much do GHRH analogues cost in the shop?
The shop offers 9 items of the four molecules discussed, from three manufacturers. The prices in the table come from the product pages.
| Product | Contents | Price | Price per mg |
|---|---|---|---|
| Sermorelin Bio-Peptide | 5 mg | 40 EUR | 8.00 EUR |
| Sermorelin Genheal | 5 mg | 40 EUR | 8.00 EUR |
| Sermorelin Nouveaux Ltd. | 10 mg | 75 EUR | 7.50 EUR |
| Mod GRF 1-29 Bio-Peptide | 10 mg | 35 EUR | 3.50 EUR |
| Mod GRF 1-29 Genheal | 10 mg | 35 EUR | 3.50 EUR |
| Mod GRF 1-29 Nouveaux Ltd. | 10 mg | 40 EUR | 4.00 EUR |
| CJC-1295 with DAC Genheal | 5 mg | 35 EUR | 7.00 EUR |
| CJC-1295 with DAC Nouveaux Ltd. | 10 mg | 60 EUR | 6.00 EUR |
| Tesamorelin Genheal | 10 mg | 50 EUR | 5.00 EUR |
The catalogue also has vials of CJC-1295 without DAC in 5 and 10 mg. Descriptions of the molecules, all variants and current availability are on the sermorelin, Mod GRF 1-29, CJC-1295 with DAC and tesamorelin pages.
Frequently asked questions
How does sermorelin differ from tesamorelin?
Sermorelin has 29 amino acids, the opening segment of GHRH. Tesamorelin has the full 44 amino acids with an added carbon chain and is approved as the drug Egrifta.
Which GHRH analogue lasts the longest?
CJC-1295 with DAC. In a 2006 study its half-life was 5.8 to 8.1 days, and IGF-1 stayed raised for 9 to 11 days after a single dose.
Is Mod GRF 1-29 the same as CJC-1295?
Mod GRF 1-29 is the tetrasubstituted GRF 1-29 chain, the backbone of CJC-1295 without the albumin-binding DAC group. That is why it is called CJC-1295 without DAC.
Which GHRH analogue is an approved drug?
Today only tesamorelin, as Egrifta in the US since 2010. Sermorelin was approved as Geref and was withdrawn for reasons other than safety and effectiveness.
How much visceral fat did tesamorelin reduce?
In a 2007 study of 412 patients with HIV, visceral fat fell by 15.2 percent over 26 weeks, while on placebo it rose by 5.0 percent.
This is information about published research, not medical advice. The choice of treatment belongs to a doctor.
Sources
- 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. https://doi.org/10.1210/jc.2005-1536
- Jetté L, Léger R, Thibaudeau K et al. Human growth hormone-releasing factor (hGRF)1-29-albumin bioconjugates activate the GRF receptor on the anterior pituitary in rats: identification of CJC-1295 as a long-lasting GRF analog. Endocrinology, 2005, 146(7): 3052-3058. https://doi.org/10.1210/en.2004-1286
- 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. https://doi.org/10.2165/00063030-199912020-00007
- FDA. Determination That GEREF (Sermorelin Acetate) Injection Were Not Withdrawn From Sale for Reasons of Safety or Effectiveness. Federal Register, 4 March 2013, document 2013-04827. https://www.federalregister.gov/documents/2013/03/04/2013-04827
- 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. https://doi.org/10.1056/NEJMoa072375
- Theratechnologies. EGRIFTA WR (tesamorelin), prescribing information, DailyMed. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=839334d3-8c1d-4c26-9036-2ab524a6ea75