MK-677 vs CJC-1295 ipamorelin: both raise growth hormone, but in different ways. MK-677 (ibutamoren) is a pill that mimics ghrelin, the “hunger hormone”;[1] in a two-year trial in older adults, 25 mg a day added about 1.1 kg of lean mass but raised blood sugar and caused swelling.[2] CJC-1295 + ipamorelin is an injected pair: a long-acting version of growth hormone-releasing hormone (GHRH) plus a ghrelin-type peptide.[3][4] The pair has never been tested together in a published human study. None of the three is FDA-approved, and FDA advisers voted against allowing any of them in compounding.[5][6]
See the MK-677, CJC-1295 and ipamorelin profiles, or browse the growth hormone peptides hub.
MK-677 vs CJC-1295 ipamorelin at a glance
| MK-677 (ibutamoren) | CJC-1295 + ipamorelin | |
|---|---|---|
| What it is | Small non-peptide molecule[1] | Two injected peptides[3][4] |
| How it is taken | By mouth, once daily[2] | Injection under the skin |
| Receptor | Ghrelin receptor[1] | GHRH receptor (CJC-1295) plus ghrelin receptor (ipamorelin) |
| How long it lasts | Long enough for once-daily dosing[1] | CJC-1295 with DAC: half-life 5.8 to 8.1 days;[3] ipamorelin: about 2 hours[7] |
| Longest human trial | 2 years in 65 older adults[2] | None for the combination |
| Key risks | Higher blood sugar, swelling, heart failure signal[2][9] | Flushing, headache, fast heart rate (CJC-1295 data)[12] |
| FDA status | Not approved; advisers voted 1 to 13 against compounding[5] | Not approved; advisers voted against both peptides[5][6] |
How they work
Your pituitary gland releases growth hormone when it gets two signals: GHRH from the brain and ghrelin, mostly from the stomach. Growth hormone then raises IGF-1, which carries out many of its effects.
- MK-677 switches on the ghrelin receptor. It works like the older peptide GHRP-6 but survives digestion and lasts all day.[1] In older adults, 25 mg a day raised IGF-1 from 141 to 265 micrograms per liter within four weeks.[8]
- CJC-1295 copies the first 29 amino acids of GHRH with changes for stability. The version with “DAC” binds to albumin in the blood and lasts for days; one dose raised growth hormone 2- to 10-fold for at least 6 days in healthy adults.[3] The version without DAC, often called mod GRF 1-29, is the one usually paired with ipamorelin, and it has no published human studies.[15]
- Ipamorelin is a 5-amino-acid ghrelin-type peptide. In pigs it released growth hormone without raising the stress hormones ACTH and cortisol.[4] In healthy men, one IV dose caused a single growth hormone pulse that peaked about 40 minutes later.[7]
The idea behind the pair is that hitting both receptors releases more growth hormone than either alone. That is plausible, but for this specific pair it has not been measured in a published trial. Our CJC-1295 + ipamorelin guide covers the combination in detail.
Evidence quality: human trials vs none
MK-677 has real human trials, mostly from the 1990s and 2000s:
- Older adults, 2 years: fat-free mass rose 1.1 kg versus a 0.5 kg loss on placebo, but body weight and limb fat also rose, and strength and function did not improve.[2]
- Sleep: in small studies, it increased deep sleep and REM sleep.[16]
- Alzheimer’s disease: a year of treatment in 563 patients did not slow decline.[17]
- Hip fracture recovery: the trial was stopped early because of a congestive heart failure signal in a small number of patients.[9]
CJC-1295 + ipamorelin has much less. CJC-1295 with DAC was tested in healthy adults and raised growth hormone and IGF-1, but FDA found no studies of any CJC-1295 form in people with a disease or condition.[3][12] Ipamorelin’s only published efficacy trial, in 114 patients after bowel surgery, did not beat placebo on its main goal.[10]
Side effects and safety
MK-677 (two-year trial in older adults):[2]
| Side effect | MK-677 | Placebo |
|---|---|---|
| Increased appetite | 67% | 36% |
| Swelling (edema) | 44% | 27% |
| Muscle pain | 33% | 9% |
- Fasting glucose rose about 5 mg/dL, HbA1c rose about 0.2%, and insulin sensitivity fell.[2]
- FDA lists ibutamoren among compounding substances with significant safety risks, citing the heart failure signal.[11]
CJC-1295 + ipamorelin:
- In FDA’s summary of CJC-1295 with DAC studies, injection-site reactions, headache, flushing, a temporary drop in blood pressure and a dose-related rise in heart rate were common.[12]
- Ipamorelin’s human safety data come mostly from hospital patients given it by IV.[10] FDA lists ipamorelin as a possible immune-reaction risk in compounded products.[11]
Product quality affects both. In a JAMA analysis of 44 products sold online as “SARMs,” 39% contained other unapproved drugs, including ibutamoren.[13] Vials sold as “research peptides” have no quality oversight; see research-use-only peptides.
Legal status and access
- Not FDA-approved: no approved drug contains ibutamoren, ipamorelin or CJC-1295.[5][6]
- Compounding: in October 2024, FDA’s Pharmacy Compounding Advisory Committee voted 1 to 13 against ibutamoren and 0 to 12 (one abstention) against ipamorelin.[5] In December 2024 it voted 0 to 13 against each form of CJC-1295.[6]
- Sport: WADA bans all three at all times.[14]
Because none can be legally compounded or prescribed as an approved drug, there is no regulated price to compare. See the FDA peptide compounding crackdown for the wider picture. This is general information, not legal advice.
Who might consider each: questions for a clinician
- If you have prediabetes, diabetes or heart failure, how would MK-677’s effects on blood sugar and fluid retention affect you?[2][9]
- If the goal is low growth hormone, should you be tested for true growth hormone deficiency, which has approved treatments? See peptides vs HGH.
- If you want an approved option for belly fat, is tesamorelin relevant? It is approved only for HIV-associated abdominal fat; see tesamorelin + ipamorelin.
- If you compete in tested sport, all three are prohibited.[14]
The verdict
MK-677 has more human evidence, but that evidence shows modest lean mass gains, no strength benefit, higher blood sugar and a heart failure signal.[2][9] CJC-1295 + ipamorelin raises growth hormone in short studies of each peptide, but the combination has no published human outcome data at all.[12][10] Neither is approved, and both carry real unknowns. For related comparisons, see hexarelin vs ipamorelin and CJC-1295 vs sermorelin.
