CJC-1295 Complete Guide: Mechanism, Trial Doses and Safety

What is CJC-1295 and why is the standard story incomplete?

CJC-1295 is a long-acting GHRH analogue: a lab-made copy of the hormone that tells your pituitary to make growth hormone (GH). In a trial in healthy adults, one shot raised GH 2- to 10-fold. It raised IGF-1, a hormone the body makes in response to GH, up to 3-fold. It is not FDA-approved, and the 6-to-14-day window is oversold.

Online, the pitch is simple. FDA's review of websites found them telling people to inject CJC-1295 at night, with one saying once a week. The version in the published studies carries a DAC, short for drug affinity complex, a chemical tail that makes it last. Its half-life, the time the body takes to clear half a dose, is roughly a week.

I think that pitch misses three things. First, most people in the published studies got a single dose. They were healthy adults, and no published trial ran longer than seven weeks. Second, a steady GHRH signal may blunt the response, a risk no trial has tested. Third, sites also offer a no-DAC form, and it has no published human data at all.

So I wrote this from the studies outward.

With CJC-1295, the supplier matters as much as the dose. We only list sources that publish an independent, per-batch certificate of analysis. See the ones that clear it.

Why the 6-to-14-day elevation window is oversold

The half-life data is real. In 2006, Teichman and colleagues published the landmark study. In its first trial, healthy adults got one shot under the skin. The estimated half-life was 5.8 to 8.1 days. GH rose 2- to 10-fold and stayed up for 6 days or more. IGF-1 rose about 1.5- to 3-fold and stayed up for 9 to 11 days. At the two highest doses it stayed up for at least 2 weeks. For a peptide you inject, those numbers are strong. Teichman et al. 2006

Here is what that design cannot tell you: whether days-long GHRH signalling beats the short bursts the body uses.

Natural GHRH comes in pulses. Its half-life in the blood is only 3.0 to 4.8 minutes, per figures cited in a 2013 study by Norman and colleagues. An enzyme called DPP-IV (dipeptidyl peptidase IV) is the main one that breaks down GHRH(1-29) in the blood. Norman's team notes that somatostatin, the brake hormone, decreases the size of each GH burst. So each natural signal is short and separate.

A steady signal may blunt the response. In a rodent (rat) study by Jetté and colleagues, GH fell back to baseline within 2 hours of one CJC-1295 shot. The drug itself stayed in the blood for up to 72 hours. The authors suggested the GHRH receptors may have been turned down, among other causes, per FDA's 2024 review. Teichman's two trials ran 28 and 49 days, and Ionescu and Frohman's study followed people for a week after one shot. None could test this over months, and that gap is the real unknown.

None of this makes DAC useless, but the long window comes with an open question.

What is the CJC-1295 mechanism of action?

The hypothalamus releases GHRH, a 44-amino-acid hormone, in pulses. The night's main GH pulse comes from a GHRH surge soon after you fall into deep sleep. That is per a 1998 review by Van Cauter and colleagues. GHRH then reaches the front of the pituitary. There it binds the GHRH receptor (GHRHR). It is a G-protein-coupled receptor (GPCR), a type that relays signals across the cell's outer membrane. It sits on somatotroph cells, the cells that make GH.

The receptor couples to a G protein called Gs. That raises cyclic AMP (cAMP), a messenger inside the cell. cAMP switches on protein kinase A (PKA). PKA activates a factor called CREB. CREB turns on Pit-1, which controls the GH gene. Release of stored GH probably also involves ion channels, per a 1995 review by Mayo and colleagues.

CJC-1295 uses the same door as native GHRH, but it lasts for days. It is the first 29 amino acids of GHRH with swaps at positions 2, 8, 15, and 27, meant to make it more stable. The swap at position 2 is the kind that resists DPP-IV. An added lysine at the tail end carries the DAC (Drug Affinity Complex), a maleimide group. That is a chemical hook that reacts with the amino acid cysteine. It bonds to cysteine 34 on your own serum albumin, a blood protein.

Its makers credited that albumin bond for the long life. FDA notes that direct proof is lacking, since the swaps may help too. In a rodent (rat) study, the drug was found bound to albumin in the blood. The bound form still triggered GH release from rodent (rat) pituitary cells in a dish, per FDA's summary of Jetté 2005.

Pulse shape still survives, at least early on. Ionescu and Frohman sampled 12 healthy men overnight, before one shot and a week after. The pulses kept coming, with the same number and size. What rose was the floor between pulses. Trough GH went up 7.5-fold and mean GH 46%. IGF-1 rose 45%.

One question stays open: how long that effect lasts before it fades.

How CJC 1295 with DAC and CJC 1295 no DAC compare

FDA's review found sites offering both forms. One has the DAC, and one without it is also sold as MOD-GRF 1-29. The obvious difference is how long each lasts. The bigger difference is the evidence behind each.

MOD-GRF 1-29 is the same 29-amino-acid chain with the same four swaps, just without the DAC. FDA's review found no study showing how it acts as a drug, and no human safety data. It warned that the DAC form's profile cannot be carried over to it. Its half-life in people has not been published.

The case for short pulses is a theory. It rests on the rodent (rat) finding above and on how natural GHRH works. No published human trial has tested either form for longer than seven weeks.

With CJC-1295, the supplier matters as much as the dose. We only list sources that publish an independent, per-batch certificate of analysis.

See CJC-1295 dosage: DAC vs. no-DAC for more on the two forms.

What the Teichman trial can and can't tell us

The 2006 study is still the main human evidence. It rewards a close read. Teichman et al. 2006

It ran two randomised, placebo-controlled, double-blind trials in healthy adults aged 21 to 61. In the first, each person got one shot under the skin, at one of four rising doses. In the second, people got two or three shots, a week or two weeks apart.

Key findings:

• Mean GH rose 2- to 10-fold above baseline. Peaks mostly came within an hour.
• IGF-1 rose about 1.5- to 3-fold. It stayed up for 9 to 11 days after one shot.
• After repeat doses, IGF-1 stayed above baseline for up to 28 days.
• The estimated half-life was 5.8 to 8.1 days.
• Injection site reactions were the most common adverse event.
• No serious adverse reactions were reported.

What it cannot tell you:

• Whether weekly dosing for 12 to 24 weeks holds the same GH and IGF-1 rise.
• Whether people with low GH output respond the same way. FDA notes that everyone studied was healthy, with a working pituitary.
• Whether higher IGF-1 delivers the body composition, recovery or longevity results people want.
• Anything about safety past the study window.

The study was built to measure kinetics (how the drug moves through the body) and safety, and it did that. The problem comes later, when people treat short-term, mostly one-dose data as proof for long protocols.

Doses used in the CJC-1295 trials

This part is educational only. It is not approved for any use in the US, and its published human data come only from small trials in healthy adults. Nothing here replaces a qualified clinician's advice. This is not medical advice.

The published human doses were set by body weight. Teichman's first trial gave single doses of 30, 60, 125 or 250 micrograms per kilogram. The second gave two or three shots, weekly or every two weeks, at up to 60 micrograms per kilogram. Ionescu and Frohman gave one shot of 60 or 90 micrograms per kilogram.

The Teichman authors called it safe and relatively well tolerated, particularly at 30 or 60 micrograms per kilogram. Side effects were more common at the two highest doses, per FDA's review.

FDA's review found websites quoting fixed doses in micrograms, given weekly or daily. No published trial used a fixed microgram dose; every one dosed by body weight. No published trial has given MOD-GRF 1-29 to people, so there is no research dose for it. The longest published trial ran 49 days, so there is no published data on cycle length or breaks either.

What the CJC-1295 trials show on side effects

The trial base is small and short. FDA counts 63 healthy adults across three studies, and most got one shot. FDA says the drug works by raising your own GH, so its safety profile may be expected to resemble approved GH products.

Injection site reactions: Irritation, redness, hardening, pain or itching hit about 70% of people in Teichman's first trial. They were worse at higher doses. Hives at the injection site showed up in almost 30%.

Headache and flushing: Headache hit 63% on CJC-1295, against 14% on placebo, in the first trial. Flushing, warmth and brief drops in blood pressure hit 30%. In the second trial, flushing started within 30 minutes and faded within 1 to 2 hours. It was dose dependent.

Gut and heart rate: Diarrhoea hit 43% in the first trial. Loose stools were common at the two highest doses. Ionescu and Frohman saw heart rate rise with dose.

Insulin sensitivity: Teichman's trials found no consistent change in blood glucose, liver tests or ECGs. They were short, though. GH works against insulin, per a 2025 Frontiers in Aging review. So longer use is untested for blood sugar.

Cancer and pituitary concerns: FDA notes that raised GH and IGF-1 carry known risks. The warnings on every approved GH product label include an increased risk of neoplasm (new abnormal growths, such as tumours), and glucose intolerance and diabetes. FDA found no data to suggest CJC-1295 would not carry similar risks. In rodent (mouse) pituitary cells, both in a dish and in live mice, CJC-1295 with DAC caused DNA damage. With no long-term cancer studies, FDA says pituitary gland hyperplasia (overgrowth of its cells) and tumours from overstimulation cannot be ruled out.

Desensitisation, in theory: Published human trials have not shown it, because none ran long enough to look. The rodent (rat) finding above raises the flag.

The trial that stopped: A Phase 2 trial in people with HIV and belly fat, registered on ClinicalTrials.gov, was ended in 2006. Reports FDA cites say a participant had a heart attack two hours after an 11th weekly dose and died. FDA says the attending doctor's "most likely explanation" was coronary artery disease that had caused no symptoms, with a ruptured plaque blocking the artery. The data were never published.

The registry entry shows what that trial planned. It was a phase 2 design that compared a low dose, a high dose and placebo for 12 weeks. It was open to adults aged 18 to 65 with HIV and fat stored around the organs. The ClinicalTrials.gov record lists it as terminated, with no results posted.

Our CJC-1295 side effects article covers safety in more depth.

CJC-1295 with ipamorelin: what has been tested

GH release has two main switches, GHRH and the ghrelin receptor (GHSR), and one brake, somatostatin. CJC-1295 works on the first switch. Ipamorelin works on the second.

Plus ipamorelin: The pair is sold widely, and FDA found websites calling it synergistic. But no published study has given people both together. The three human studies of CJC-1295 gave it alone. Full detail sits in the CJC-1295 ipamorelin guide. The closest evidence is a related pair. Native GHRH plus the ghrelin-type drug GHRP-2 released more GH together than either alone, in 26 older men (Norman 2013). In pigs, GHRP-2 and GHRP-6 raised ACTH, the pituitary hormone that drives cortisol release, and cortisol itself. Ipamorelin did not. Raun et al. 1998

Plus BPC-157: BPC-157 is a separate peptide with its own evidence base. No study cited here tested it with CJC-1295. See BPC-157 and TB-500 post-surgery recovery.

Plus GHK-Cu: GHK-Cu, the copper peptide, is also separate. No study cited here tested it with CJC-1295 either. The GHK-Cu complete guide covers its evidence.

Where this sits in anti-ageing research

GH output falls with age, a slide some call somatopause. The Frontiers review links that decline to more body fat. It also points to possible links with bone loss, broken sleep and slower thinking in ageing.

The review notes that the GH cells keep their ability to release GH in older people, even as output falls. In a 1992 study the review cites, two weeks of GHRH(1-29), the same chain as sermorelin, raised GH and IGF-1 in healthy older men. The rise was significant only at the higher of the two doses. That is the case for a GHRH analogue. But the published CJC-1295 studies used only healthy adults. The one trial in a disease, HIV with belly fat, was stopped and never published. FDA's cancer and pituitary cautions, in the side-effects section above, concern exactly this kind of long-term use.

One animal study did look at body make-up. In a rodent (mouse) model, young animals born without their own GHRH got 2 micrograms of CJC-1295 a day for 5 weeks. They reached normal body weight and length. Their lean mass and fat under the skin were normal for their size. Shots every 2 or 3 days worked less well. That model tests growth in animals that lack GHRH, not muscle gain or fat loss in adults. Alba et al. 2006

Sellers claim more lean mass, less fat, better sleep, denser bones and faster recovery, per FDA's review of their websites. The published human studies measured hormone levels, not any of these outcomes. For context, see best peptides for anti-ageing and longevity 2026. There is also best peptides for men over 40.

What FDA found about the powder

FDA describes CJC-1295 with DAC as a fine white freeze-dried powder, stored at minus 20 degrees Celsius. One of the two nominations FDA reviewed came with a certificate of analysis (CoA), a lab report on a batch. It was for CJC-1295 acetate, a no-DAC form. It lacked tests for impurities, clumps (aggregates) and bacterial toxins (endotoxins). No CoA came for the DAC form, and most FDA found online listed only purity. FDA judged every form it reviewed not well characterised. It flagged a risk of immune reactions from impurities and clumping when injected under the skin. For general handling of freeze-dried peptides, see the how to reconstitute peptides guide.

The legal picture in 2026

CJC-1295 is not approved for any use in the US. FDA found no approved drug that contains any form of it. It also found no approved product in the 12 countries it checked, or in the EU.

A research use only label does not make selling it for human use lawful. In a December 2024 warning letter to a peptide seller, FDA said such labels did not stop products being unapproved new drugs. The seller's own website showed they were meant for people. That letter concerned other peptides, such as semaglutide.

Pharmacies cannot lawfully compound it either. Under 21 USC 353a, the ingredient needs a USP monograph (an official quality standard), or must be part of an approved drug. Otherwise it must be on FDA's bulks list. FDA found no monograph and no approved drug, and the bulks list does not name it.

FDA once put CJC-1295 in category 2 of its compounding list, for significant safety risks. Its safety page now lists it as a nomination that was withdrawn. The page names serious adverse events, including a faster heart rate and a whole-body flushing reaction. In December 2024, FDA's advisers voted against adding any form of it to the bulks list, 0 to 13 for the DAC form. The guide to FDA's compounding rules explains the category lists.

WADA bans CJC-1295 by name for tested athletes, in and out of competition. The 2026 Prohibited List puts it under S2.2.4, growth hormone releasing factors, among the substances banned at all times. S2 substances are non-Specified. Under the WADA Code, a first positive test for a non-Specified substance carries a standard four-year ban, unless the athlete shows it was not intentional. Our overview, are peptides legal in 2026, has the wider picture.

With CJC-1295, the supplier matters as much as the dose. We only list sources that publish an independent, per-batch certificate of analysis.

My bottom line

The DAC design is clever, and it did what it was built to do. One shot kept GH and IGF-1 up for days in healthy adults.

But the evidence stops there. Three small published studies cover 63 healthy adults, by FDA's count, most given one dose. A Phase 2 trial ended after a death and was never published. No published trial has tested it for ageing, body composition or any disease. Steady signalling is not clearly better than bursts, and the repeat-dose question is still open.

MOD-GRF 1-29 is no way around that gap. It has no published human data at all. The short-term DAC data is firm, and the long-term assumptions built on it are untested.

This content is for educational purposes only. These compounds are intended for research use. Nothing here is medical advice.