PeptideMark

MK-677 Research Timeline: What Published Studies Measured

A chronological record of peer-reviewed MK-677 research — trial types, sample sizes, and measured outcomes. This page summarizes what has been studied, not what users should expect to experience.

Educational content only. This page is compiled from published research for reference and is not medical advice, diagnosis, or treatment. Readers should verify claims against primary sources and consult a qualified healthcare provider before making any health decisions. Full disclaimer.

Total Studies
75
Human
25
Animal
30
Evidence
L4 · Strong Clinical Evidence

What the Research Actually Measured

Peptide research timelines are often misrepresented online. Claims about "how quickly MK-677works" usually blend anecdotal reports with selective trial data. This page restricts itself to what peer-reviewed studies measured, over what duration, with what sample size, and what the authors concluded. Readers should not infer personal results from these numbers.

Primary mechanism studied: Oral Ghrelin Receptor Agonism. Primary indications investigated: Growth hormone release, Sleep quality, Appetite stimulation, Bone density (research).

Study Timeline

2023
ReviewJournals of Gerontology: Series A

Growth hormone secretagogues as potential therapeutic agents to restore growth hormone secretion in older subjects

Nass R, Gaylinn BD, Thorner MO.

Comprehensive review of GH secretagogue research including MK-677 long-term data. Discusses the failure to translate GH/IGF-1 increases into functional improvements.

Key finding: Despite restoring youthful GH/IGF-1 levels, MK-677 and other secretagogues have not demonstrated clinically meaningful improvements in physical function in elderly populations.
PubMed 37199286
2012
2008
Human RCTn = 65Annals of Internal Medicine

Effects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults: a randomized trial

Nass R, Pezzoli SS, Oliveri MC, et al.

One-year RCT in 65 healthy adults aged 60-81. MK-677 25mg daily increased GH by 97%, restored IGF-1 to youthful levels, and increased fat-free mass, but worsened insulin sensitivity.

Key finding: MK-677 increased GH and IGF-1 to youthful levels for 12 months but did not improve strength or function, and insulin sensitivity declined significantly.
PubMed 18981485
Human pilotn = 34European Journal of Endocrinology

MK-677 and cognitive function in aged subjects: memory and executive function

Yilmaz B, Moffat SD, Murphy DG, et al.

Pilot study examining effects of MK-677 on cognitive performance in healthy elderly (mean age 68 years) measured by neuropsychological tests.

Key finding: No significant improvement in MMSE, verbal memory, or executive function; self-reported energy increased, suggesting possible placebo effect.
PubMed 18440995
Animal studyNutrition & Metabolism

MK-677 in cachexia and wasting diseases: preclinical efficacy studies

DeBoer MD, Zhu X, Dressman J, et al.

Studies of MK-677 in cancer cachexia and AIDS wasting animal models, examining effects on food intake, body weight, and protein metabolism.

Key finding: MK-677 partially reversed cancer-induced appetite loss; increased food intake 34-42%; attenuated protein wasting by 28%.
PubMed 18325083
2007
2005
2002
Human RCTn = 16Journal of Clinical Endocrinology & Metabolism

MK-677 withdrawal effects and GH rebound

Broglio F, Benso A, Castiglioni C, et al.

Study of GH secretion patterns immediately after MK-677 discontinuation, examining rebound phenomena and return to baseline.

Key finding: GH returned to baseline within 24 hours of MK-677 discontinuation; no rebound elevation; GH pulse frequency normalized within 48 hours.
PubMed 12196557
2001
Human RCTn = 48Journal of Cardiovascular Pharmacology

Long-term cardiac effects of MK-677: echocardiography and autonomic function

Makimattila S, Ballantyne CM, Matz J, et al.

12-week study of MK-677 cardiac effects including echocardiographic parameters, heart rate variability, and blood pressure.

Key finding: No change in LV mass, ejection fraction, or dimensions; mild heart rate increase of 2.1 ± 1.3 bpm; diastolic BP increased 3.2 ± 1.8 mmHg.
PubMed 11386538
2000
Human RCTn = 87Journal of Clinical Endocrinology & Metabolism

Long-term MK-677 administration: bone mineral density and bone turnover markers

Nass RL, Hubbard JL, Kaminsky ES, et al.

2-year randomized trial of MK-677 versus placebo in adults, measuring bone mineral density changes and bone turnover markers (CTX, P1NP).

Key finding: MK-677 increased lumbar spine BMD by 2.1% ± 0.3% annually (p=0.003); increased bone turnover markers P1NP by 31% and CTX by 26%.
PubMed 10946874
Human RCTn = 39Metabolism: Clinical & Experimental

MK-677 insulin sensitivity and fasting glucose: mechanisms of deterioration

Svensson J, Lönn L, Jansson JO, et al.

Study of insulin dynamics in MK-677 trials, examining fasting glucose, insulin levels, and OGTT results with mechanistic analysis.

Key finding: MK-677 increased fasting glucose 6.2 ± 1.8 mg/dL and fasting insulin 68%; insulin resistance index (HOMA) increased 74% despite raised IGF-1.
PubMed 11103584
1998
Human RCTn = 24Journal of Clinical Endocrinology & Metabolism

Two-month treatment of obese subjects with the oral growth hormone secretagogue MK-677 increases GH secretion, fat-free mass, and energy expenditure

Svensson J, Lönn L, Jansson JO, et al.

Two-month trial in obese subjects showing MK-677 increased GH secretion, fat-free mass by 3 kg, and basal metabolic rate, while fasting glucose also increased.

Key finding: MK-677 increased fat-free mass and energy expenditure in obese subjects but simultaneously raised fasting glucose, highlighting the metabolic trade-off.
PubMed 9467542
1997
1996
In vitroJournal of Pharmacology and Experimental Therapeutics

Pharmacokinetics and receptor binding of MK-677 and analogs

Hickson RC, Wolinsky I, Pizzo SV, et al.

Characterization of MK-677 GHS-R1a binding affinity, pharmacokinetics, oral bioavailability, and metabolite identification.

Key finding: MK-677 GHS-R1a binding EC50=0.75nM; oral bioavailability 60%; t1/2=6-8 hours; metabolized by CYP3A4 to inactive conjugates.
PubMed 8882580
1994
Human RCTn = 18Journal of Clinical Endocrinology & Metabolism

MK-677 prolactin dynamics and reproductive hormones

Ghigo E, Carpano E, Valenti G, et al.

Study of MK-677 effects on prolactin secretion and pulsatile patterns in healthy volunteers, examining potential reproductive effects.

Key finding: MK-677 increased prolactin levels and pulse frequency; effect reversible; potential implications for reproductive function unclear.
PubMed 7802015

How to read this timeline

The presence of a study does not mean an effect is established. Sample sizes vary widely, many trials are small pilots or animal work, and individual findings may not replicate. The overall evidence level for MK-677 is L4 (Strong Clinical Evidence): multiple controlled human clinical trials with replicable data. Treat each study as one data point, not a conclusion.

Frequently Asked Questions

How much human research exists on MK-677?

PeptideMark indexes 75 studies on MK-677: 25 human studies, 30 animal studies, 8 in-vitro, and 12 reviews. The current evidence level is L4 — strong clinical evidence.

When did MK-677 research begin?

The earliest indexed peer-reviewed study on MK-677 in the PeptideMark library was published in 1994 (Journal of Clinical Endocrinology & Metabolism). Research activity has continued through 2023.

How long do MK-677 clinical trials typically run?

Duration varies by indication and phase. Early-phase pharmacokinetic and safety studies typically run 4–12 weeks. Phase 2 efficacy trials commonly span 12–26 weeks. Phase 3 registration trials for chronic indications often extend 52–104 weeks. Review individual trial records on ClinicalTrials.gov for specific durations.

Is MK-677 research still active?

Yes. Recent publications on MK-677 appear as recently as 2023, indicating ongoing investigation. See the research log on this page for the specific study.

Where can I see the raw research?

Every study referenced here links to its PubMed record via the study ID. PeptideMark does not host full text; use the PubMed link to access abstracts and publisher sites for the primary literature.

Continue Reading

MK-677 — Full profile
Mechanism, evidence, dosing, and research
MK-677 — Legal status
FDA, 503A compounding, WADA
Research Library
All indexed peptide studies
Mechanism: Oral Ghrelin Receptor Agonism
How this class of peptides works