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Blog  ›  MK-677 vs CJC-1295 No DAC: Simple Research Comparison

MK-677 vs CJC-1295 No DAC: Simple Research Comparison

Jun 11, 2026 4 min Growth Hormone
TL;DR
MK-677 is a once-daily oral pill that tells the pituitary to release more growth hormone; CJC-1295 (no DAC) is a short-acting injectable peptide that does something similar but wears off faster. Research protocols differ sharply between the two, so reading the right dosing data for each one matters. Neither is approved for human use outside clinical trials.

Two Compounds, One Goal — But Very Different Tools

Both MK-677 and CJC-1295 (no DAC) appear in growth hormone research, yet they are not the same thing. Understanding the difference starts with understanding how each one nudges the body's GH system.

What Is MK-677?

MK-677 (also called ibutamoren) is a small-molecule growth hormone secretagogue. That fancy term just means it mimics a hunger hormone called ghrelin, which signals the pituitary gland — a pea-sized gland at the base of the brain — to release more growth hormone (GH). The big deal: it is taken by mouth, not injected. Early clinical research showed a 25 mg oral daily dose reversed diet-induced protein loss in healthy volunteers, raising IGF-1 (a downstream marker of GH activity) significantly compared to placebo.[1] A rat study later found that long-term dosing may trigger a feedback brake — the brain releases more somatostatin, a GH-suppressing hormone — which blunted the GH response over six weeks.[3]

What Is CJC-1295 (No DAC)?

CJC-1295 without DAC (sometimes called Modified GRF 1-29) is a synthetic peptide — a short chain of amino acids — that mimics GHRH, growth hormone-releasing hormone. It binds to GHRH receptors in the pituitary and prompts a pulse of GH release. The key word is pulse. Without the DAC (Drug Affinity Complex) attachment, this version has a short half-life of roughly 30 minutes, producing a sharp GH spike rather than a prolonged elevation. Researchers often pair it with a GHRP (growth hormone-releasing peptide) to amplify that pulse. Because it is a peptide, it must be injected — it breaks down in the stomach if swallowed.

How Research Dosing Differs

This is where the two compounds diverge most clearly. Always use a calculator to cross-reference any figures you read against published protocols.

  • MK-677 — oral, once daily. Clinical trials have most commonly studied doses of 10–25 mg per day taken by mouth. The 25 mg dose was the benchmark in the nitrogen-balance trial.[1] A case report involving 15 mg daily alongside another compound still noted significant liver enzyme changes.[4]
  • CJC-1295 (no DAC) — subcutaneous injection, multiple times daily. Because its half-life is so short, research protocols typically use 100–200 mcg per injection, administered two to three times daily, often timed around sleep or fasting windows when natural GH pulses occur.
  • Duration differs too. MK-677 studies have run as long as 12 months in Alzheimer's research (where it showed no benefit on disease progression).[6] CJC-1295 (no DAC) protocols are typically shorter and cyclical.

Quick Side-by-Side

  • Route: MK-677 = oral pill | CJC-1295 (no DAC) = injection
  • Mechanism: MK-677 mimics ghrelin | CJC-1295 (no DAC) mimics GHRH
  • Duration of action: MK-677 ~24 hours | CJC-1295 (no DAC) ~30 minutes
  • Typical research frequency: MK-677 = once daily | CJC-1295 (no DAC) = 2–3x daily
  • GH release pattern: MK-677 = sustained elevation | CJC-1295 (no DAC) = sharp pulse
  • Often combined with: MK-677 used alone or with SARMs | CJC-1295 (no DAC) often paired with a GHRP

Safety Signals Researchers Track

No compound in this space is without flags. MK-677 case reports have documented liver enzyme elevations and transaminitis — one otherwise healthy man developed abnormal liver function after two months of use, which resolved after stopping.[2] Hormonal side effects have also appeared; one case linked a supplement containing MK-677 to gynecomastia (breast tissue growth in males) and suppressed natural testosterone, both of which resolved after stopping.[5] These are case reports, not controlled trials, but they are signals worth knowing.

CJC-1295 (no DAC) has a smaller published safety dataset in humans, partly because it is newer and harder to study in oral populations. The short half-life means the GH pulse fades quickly, which some researchers consider a more physiological — and potentially less disruptive — pattern than sustained elevation.

How to Choose What to Read About

The choice between researching one versus the other usually comes down to the question being asked. If you are reading about sustained GH elevation, appetite, nitrogen balance, or long-duration protocols, MK-677 literature is more developed. If you are reading about pulsatile GH release, GHRH receptor biology, or stacked peptide combinations, CJC-1295 (no DAC) literature is the better starting point. Explore the full dosing charts for MK-677 and CJC-1295 (no DAC), and use the calculator to put any numbers in context.

Sources

  1. MK-677, an orally active growth hormone secretagogue, reverses diet-induced catabolism. — The Journal of clinical endocrinology and metabolism, 1998. PMID 9467534.
  2. Hepatotoxicity induced by MK-677. — BMJ case reports, 2025. PMID 40675653.
  3. Effect of the Orally Active Growth Hormone Secretagogue MK-677 on Somatic Growth in Rats. — Yonsei medical journal, 2018. PMID 30450851.
  4. LGD-4033 and MK-677 use impacts body composition, circulating biomarkers, and skeletal muscle androgenic hormone and receptor content: A case report. — Experimental physiology, 2022. PMID 36303408.
  5. Reversible Gynecomastia and Hypogonadism Due to Usage of Commercial Performance-Enhancing Supplement Use. — JCEM case reports, 2024. PMID 39145153.
  6. Growth hormone secretagogue MK-677: no clinical effect on AD progression in a randomized trial. — Neurology, 2008. PMID 19015485.
See the dosage chart — MK-677
An orally active ghrelin-mimetic GH secretagogue.
MK-677

FAQ

Can MK-677 and CJC-1295 (no DAC) be used together in research?
Some researchers combine them because they work on different receptors — MK-677 on ghrelin receptors and CJC-1295 (no DAC) on GHRH receptors — potentially producing a synergistic GH pulse. However, combined protocols are less studied, and combining compounds also stacks safety unknowns. Always review individual compound data first before reading about combination protocols.
Why does MK-677 only need to be taken once a day?
MK-677 is a small non-peptide molecule with a long half-life — roughly 24 hours. That means it stays active in the body all day from a single oral dose, which is why research protocols typically use once-daily dosing. CJC-1295 (no DAC) is a peptide and breaks down much faster, requiring multiple daily injections to maintain its effect.
Did MK-677 show benefits in Alzheimer's disease research?
A randomized controlled trial tested MK-677 in patients with mild-to-moderate Alzheimer's disease and found no meaningful clinical benefit on disease progression despite the compound successfully raising IGF-1 levels in participants.[6] This is an important reminder that raising GH or IGF-1 does not automatically translate into benefit for every condition researchers hoped to address.
What liver risks have been reported with MK-677?
A 2025 BMJ case report documented a healthy man in his 30s who developed transaminitis — elevated liver enzymes signaling liver stress — after two months of MK-677 use. Liver function returned to normal after he stopped taking it.[2] A separate case report also noted elevated liver enzymes during MK-677 co-administration.[4] These are individual cases, not population-level data, but they are documented safety signals.
For research and educational use only. Not medical advice.