Mod GRF 1-29

What is Mod GRF 1-29?

Mod GRF 1-29 is a lab-made version of growth hormone-releasing hormone (GHRH), the brain signal that tells the pituitary gland to release growth hormone. The name means modified growth hormone-releasing factor, amino acids 1 to 29. It is the same molecule that research-chemical sellers label CJC-1295 without DAC.

The name causes real confusion. The Canadian company ConjuChem developed CJC-1295 in the early 2000s. Its version carried a chemical add-on called a Drug Affinity Complex, or DAC, that binds to albumin in the blood and makes the drug last for days. The modified peptide without that add-on became known in the gray market as Mod GRF 1-29, or CJC-1295 no-DAC. Some vendors and clinics still use the names loosely.

Mod GRF 1-29 is not approved for any medical use. It is sold as a research chemical and popular in anti-aging and bodybuilding circles, usually combined with a growth hormone-releasing peptide such as ipamorelin.

How Mod GRF 1-29 works

Your hypothalamus releases GHRH in bursts. Each burst tells the pituitary to release a pulse of growth hormone, which then raises IGF-1 in the liver and other tissues. Mod GRF 1-29 copies the active front part of GHRH, so an injection triggers a pulse of growth hormone. Because natural feedback still works, the pituitary will not keep releasing hormone indefinitely.

The natural first 29 amino acids of GHRH are broken down in a few minutes. Mod GRF 1-29 has four amino acid swaps that slow that breakdown, so each dose lasts somewhat longer, though still well under an hour. Because each dose produces only a short pulse, people who use it inject one to three times a day, which is very different from the weekly DAC version.

In precise terms, Mod GRF 1-29 is GHRH(1-29)-NH2 with substitutions at positions 2 (D-alanine), 8 (glutamine), 15 (alanine) and 27 (leucine). These changes resist dipeptidyl peptidase-4 cleavage, reduce rearrangement at position 8, and remove an oxidation-prone methionine. It binds the GHRH receptor on pituitary somatotroph cells, raising cyclic AMP and growth hormone release. Researchers have long noted that GHRH analogs and ghrelin-receptor agonists act together to produce a larger growth hormone pulse, which is the basis for the common pairing with ipamorelin.

What the research shows on Mod GRF 1-29

Most published human data concerns the DAC version, not Mod GRF 1-29. In two randomized, placebo-controlled trials in healthy adults, a single injection of CJC-1295 with DAC raised growth hormone 2- to 10-fold for six days or more and IGF-1 1.5- to 3-fold for 9 to 11 days. Its estimated half-life was 5.8 to 8.1 days.² Those results describe a long-acting drug with very different kinetics. They should not be applied to the short-acting no-DAC peptide.

Published human pharmacokinetic and outcome data specific to Mod GRF 1-29 are sparse. Recent reviews written for orthopedic and sports medicine doctors found that the evidence for CJC-1295 combined with ipamorelin comes from animal work, such as better muscle function in mice with steroid-induced muscle loss.¹ Another review noted that growth hormone secretagogues including CJC-1295 are promoted for repair through IGF-1 signaling, but that clinical trials are lacking.³

A 2026 review of unapproved peptides in sports medicine reached a similar conclusion. Many show favorable effects in animal models, but rigorous human safety data are scarce.⁴ No trial has shown that Mod GRF 1-29 improves body composition, recovery, sleep or aging outcomes in healthy adults.

Studied for: Growth hormone elevation, Stacking with GHRPs.

Mod GRF 1-29 reference data

Mod GRF 1-29 dosage in published research

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How Mod GRF 1-29 is used in practice

Some US anti-aging and wellness clinics have offered CJC-1295 and ipamorelin injections, often through compounding pharmacies, but CJC-1295 is not an FDA-approved drug and its status as a compounding ingredient has been restricted. Many users buy freeze-dried vials from research-chemical sites, mix them with bacteriostatic water and inject under the skin, often before bed or after training, to line up with natural growth hormone pulses.

An online study of forum posts found that women using CJC-1295 cited weight loss, muscle, younger-looking skin, sleep and injury healing, and expressed uncertainty about dosing and long-term effects.⁷ A 2026 review of peptide doping warned that the supply chain is largely unregulated and products are often mislabeled or contaminated.⁶

The labeling mix-up matters in practice. A vial sold as CJC-1295 may contain the DAC version, intended for weekly dosing, or Mod GRF 1-29, intended for multiple doses per day. Confusing the two can mean a large overdose or no meaningful effect. Clinics that sell peptide programs often present CJC-1295 with ipamorelin as a gentler alternative to growth hormone. Outcome trials do not support that framing, and ongoing programs can be expensive.

Mod GRF 1-29 risks and side effects

Reported side effects include flushing and warmth shortly after injection, headache, dizziness, injection-site redness and water retention. Over time, raised growth hormone and IGF-1 can cause joint aches, tingling in the hands and reduced insulin sensitivity. The peptide doping review lists insulin resistance and cardiovascular strain among emerging risks of this class.⁶

Long-term safety has not been studied. Raising IGF-1 is a concern for anyone with active cancer or a history of it, and it should not be used in pregnancy. Glucocorticoids blunt the growth hormone response.

GHRH analogs, including CJC-1295, are on the World Anti-Doping Agency prohibited list, and anti-doping labs have methods to detect them in urine.⁸

Reported side effects

Alternatives to Mod GRF 1-29

For diagnosed growth hormone deficiency, FDA-approved somatropin and long-acting growth hormone products are the standard. Tesamorelin (Egrifta) is an approved GHRH analog for reducing excess abdominal fat in adults with HIV. Sermorelin, an earlier GHRH(1-29) drug, was once FDA approved and is still compounded by some pharmacies.

For the goals people usually have in mind, such as more muscle, less fat and better sleep, resistance training, adequate protein, weight management and treatment of sleep problems have much stronger evidence.

Questions for a clinician

• What evidence applies to my situation, and at what level?
• What established alternatives should I consider first?
• What monitoring would be necessary, and how often?
• Can this be prescribed at all where I live, or only sold for research?