Modified GRF (1-29)

tl;dr xxxx

Names: mod GRF (1-29), tetrasubstitued GRF (1-29), GHRH (1-29)NH2, GRF(1-29), CJC-1288, CJC-1293, CJC-1295 w/o DAC


Despite the confusing names (everyone wants to call this peptide something different) they are all pointing to the same thing.

This is a modified version of the body’s natural Growth Hormone Releasing Hormone: GHRH(1-44). The 1-44 at the end is only used in this case to show it’s the full 44 amino acid base. In all other uses, you will see this base hormone just called GHRH.

By removing 15 amino acids, and also changing 1, 2, 3, or 4 of the remaining amino acids, we get a modified GHRH with 29 amino acids. This gives the reasoning behind Mod GRF 1-29. In fact, GRF 1-29 has many different forms and there are several ways to modify the structure. One study has tested 30 of these analogs.1 Some of these versions are more effective than others. I’ll skip over most of the forms in the article and just show you modified GRF 1-29 in general.

No matter what you call it though, it is close enough to full GHRH to make your pituitary glad release hGH as natural pulses. In fact the remaining 29 amino acids in this peptide the critical part of full GHRH(1-44) required by the human body to work. Anything smaller will not work.

Mod GRF Medical Studies

Since there are several names for this peptide study results are varied. Mod GRF(1-29) is the most popular name and has the most results. It is the safest way to refer to this peptide in general because some of the common names thrown around are actually proprietary.

Unfortunately, like CJC-1295, medical studies have been lagging behind with the CJC names. “CJC-1293” is only mentioned twice. And both times have only been called out for doping detection. and

Muscle Growth

Being a GHRH analog, Mod GRF(1-29) biggest use is in raising hGH levels. And it does exactly that. Across the board Mod GRF(1-29) is proven to effective at raising hGH and IGF-1 levels in the body. hGH and IGF-1 are the main growth hormones used to build muscle, repair injuries, and support all around health.

It is well proven as a GHRH replacement in animals and humans2 and works as an injection or intranasally.3

Alzheimer’s/Brain Aging also finds use of GRF(1-29) to increase short term memory. Long term use and testing would be interesting to see if people with cognitive problems, TBI, or Alzheimers would be helped.

Neuroprotective Effects

Nerve Regrowth




This is an interesting study. They gave GRF (1-29) at a rate of 1mcg/kg/hour and tested it with clonidine. Clonidine is a blood pressure medicine that is sometimes used for PTSD treatment. It would make me extremely slow and often cause me to nap, but was useful in returning to a long-term calmer state. In any case - clonidine was found to be useful in also stopping the hGH inhibiting actions of the hypothalamus. This suggests that patients using clonidine would need to watch out for any long term peptide use that mimics GHRH.



Not much to report about this peptide and TBI. One sudy finds that hGH replacement improved the Quality Of Life in TBI patients.4 Both adults and children were helped. If hGH therapy is not available, and the pituitary still is ok, GRF 1-29 could in theory produce a similar effect. It would be an interesting trial at least

Naming Controversy

(This is optional.)

Serious - why all the names? Is CJC-1295 the same as mod GRF(1-29)? Or is CJC-1295 w/o DAC actually CJC-1293?

In 2005 x, x,x, and published a paper about CJC-1295 - a tetrasubstitued GRF (1-29) form with extra lysine derivitive. “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”

It’s a very cool paper to read if you’re interested in biochemical engineering.

Their work describe 3 peptides they made. All are proprietary peptides and somewhat similar but with slight changes to the base molecule:

  • CJC-1288
  • CJC-1293
  • CJC-1295

CJC-1295 ended up being the most promising and you can read about it xxxlink mere XXX herexxx because it is unique enough to deserve it’s own page. All 3 had a smiliar addition at the end of the peptide making it CJC-1295 with DAC. The extra additive is a DAC - drug affinity complex - and made these peptides last longer in the human body.

In any case, CJC-1293 was also effective in it’s own regards as a truncated GHRH analog. But because CJC-1295 spun off and got it’s own reputation, CJC-1293 became a bastard child of the peptide world. It’s name is often used on commercial peptides that may or may not actually be (hGRF)1–29 with the exact specific two amino acid modifications and DAC added at the end as described by x, x, x.

CJC-1295 without DAC is a bad name at worst, misleading at best. But people do sometimes refer to it this way. The CJC series are genius and have beautiful engineering behind them. There is no reason to remove the DAC chemistry and end up with Mod GRF 1-29 though. It’s a negative form of a name that somehow sticks around. “CJC-1295 without DAC” directly would name an unstable GRF analog with a short half-life that may or may not actually work.

I don’t consider anything called CJC-1295 without DAC real, and any reports about it are useless. There’s simply no way to know what was tested.

Someone had to start providing clarity to a situation quickly becoming unreadable. A researcher going only by the name “DatBtrue” created the general form of the name “modified GRF (1-29)” on his private forum in 2008. Prior to this, people were referring to this peptide by a laundry list of names. And as people continue to copy and paste articles on forums it kept getting messier.

Why is that?

For general purpose muscle development the GRF(1-29) series behave similar enough. By continuing to refer to all variants as “modified GRF (1-29)” on the DatBtrue forum this became the preferred name for bodybuilders.

This is unlike clinical studies that refer to the exact modifications made or tested to the GRF (1-29) base. Citing the use of a “modified GRF (1-29) peptide” in a clinical study would be useless - there are 30+ variants. The exact modifications must be specified.

For example, PubMed has 0 studies found for “mod GRF (1-29)” or “modified GRF (1-29)”. But there are 166 results as of February 2017 for “GRF (1-29)” though, each with it’s description about the exact modifications.

DatBtrue’s website was taken offline in September, 2016. Archived copies don’t exist publicly. Some say it was for health reasons. Other’s say it was because of legal problems. Whatever the case, in 2017 using any search engine for “modified GRF (1-29)” will return mostly bodybuilding discussions now. The split between medicine and bodybuilding is apparent.

PEG Mod GRF(1-29)

As with many similar peptides, Mod GRF(1-29) can also come in a PEGylated form. This means it has had Polyethylene Glycol added to it’s structure. THis change is proven to increase it’s half life.5 One specific version - Lys21-PEG-GRF(1-29) - that has been altered at the Lys21-amine for a 7 to 24 times longer half-life.6


The downside of using just the (1-29) fragment is faster breakdown in the blood. The extra amino acids that mother nature added act as a protective factor to keep GHRH(1-44) useful in many metabolic scenarios. This is why a PEG version, or the propritary CJC-1295 with DAC, exist - to keep the benefots of the (1-29) fragment active longer.

Published studies of any of the GRF fragments, regardless of name, did not detail any specific side effects unique to this peptide. Primary side effects would be a result of their increased hGH or IGF-1 levels.


Doses: 1 microgram/kg/h 100 micrograms also 150 micrograms, i.v., in children

1 micrograms/kg, iv



Pubchem doesn’t seem to have an entry for Des(1–3)IGF-1. Sigma-Aldrich does not seem to sell it, but some other high end suppliers have it starting anywhere from $50-$250 for 20mcg, with bigger orders being around the same price as peptide sites.

Peptide site pricing is around $110-$120 for 1-1.2mg.

Legality XXXX

This is a good time to point out my standard disclaimer: I am not a doctor or a lawyer. I made this site to help in my own research of the human endocrine system, and to find any new treatments for PTSD and Traumatic Brain Injury. I’m not making any medical or legal claims about any drug here besides what medical studies are showing and what people are self-reporting they use.

Each country and state is free to make their own scheduling on substances so it’s up to you to check. At the time of writing Mod GRF(1-29) didn’t appear on the DEA list.

WADA specifically bans GHRPs by name. They prohibit at all times:

  • GH-Releasing Peptides (GHRPs), e.g. alexamorelin, GHRP-6, hexarelin, and pralmorelin (GHRP-2);

GHRH/GRF isn’t listed directly there, but the end result is the same.

The NCAA bans as a class “Peptide Hormones and Analogues” naming “Growth hormone (hGH); human chorionic gonadotropin (hCG); erythropoietin (EPO); IGF-1; etc.” While a GHRH is not hGH itself, I believe the spirit of their list would include it as it’s main point is to raise hGH levels.


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