PubMed
MK-677, an orally active growth hormone secretagogue: effects on body composition
Murphy MG, Plunkett LM, Gertz BJ, et al. J Clin Endocrinol Metab. 1998
Compare
MK-677 vs TB-500 Fragment
Side-by-side observational reports from PeptIQ users. This compares self-reported patterns — not clinical head-to-head trials.
Last reviewed . By the PeptIQ team.
Observational reporting only — not medical advice. Does not recommend doses, protocols, or treatments.
MK-677
24 community reports
Overall experience
From check-in ratings — separate from side effects logged below. Side effects are logged separately from overall experience. A favorable check-in can still include nausea, fatigue, or injection-site reactions.
Favorable 98% · Mixed 2% · Unfavorable overall 0%
Most reported benefits
Benefits users selected when logging a favorable or mixed check-in.
Sleep
135
Most logged side effects
Side effects are logged separately from overall experience. A favorable check-in can still include nausea, fatigue, or injection-site reactions.
Water retention
2
Fatigue
1
Self-reported dose per injection
Median bucket: 2+ mg · Most common: 2+ mg
Reports span 2 to ≥ 2 mg (open-ended top bucket)
2+ mg
135
Anonymized self-reports from PeptIQ users — not prescribing guidance. Buckets group similar logged amounts; open-ended top buckets mean “at least” that dose.
Commonly stacked with
How repeat users are trending
Among repeat reporters, 91% said they felt similar to their last entry, 9% more positive, and 0% more negative.
Overall, repeat reporters leaned more positive than their previous entry.
Median gap between entries: 156 days · Based on 22 repeat reporters
TB-500 Fragment
26 community reports
Overall experience
From check-in ratings — separate from side effects logged below. Side effects are logged separately from overall experience. A favorable check-in can still include nausea, fatigue, or injection-site reactions.
Favorable 3% · Mixed 97% · Unfavorable overall 0%
Most reported benefits
Benefits users selected when logging a favorable or mixed check-in.
Recovery
176
Most logged side effects
Side effects are logged separately from overall experience. A favorable check-in can still include nausea, fatigue, or injection-site reactions.
Injection site irritation
171
Self-reported dose per injection
Median bucket: 2+ mg · Most common: 2+ mg
Reports span 1 to ≥ 2 mg (open-ended top bucket)
1–2 mg
59
2+ mg
117
Anonymized self-reports from PeptIQ users — not prescribing guidance. Buckets group similar logged amounts; open-ended top buckets mean “at least” that dose.
Commonly stacked with
How repeat users are trending
Among repeat reporters, 79% said they felt similar to their last entry, 21% more positive, and 0% more negative.
Overall, repeat reporters leaned more positive than their previous entry.
Median gap between entries: 188 days · Based on 24 repeat reporters
Sources (8)
Published sources linked on the MK-677 and TB-500 Fragment wiki pages.
- Wiki study page →Source
- Wiki study page →Source
PubMed
Two-year treatment with ibutamoren increases bone mineral density, body composition, and quality of life
Nass R, Pezzoli SS, Oliveri MC, et al. J Clin Endocrinol Metab. 2008
- Wiki study page →Source
ClinicalTrials.gov
Ibutamoren (MK-677) studies on ClinicalTrials.gov
ClinicalTrials.gov. Clinical trial registry. 2024
- Wiki study page →Source
PubMed
MK-677, an orally active growth hormone secretagogue, reverses diet-induced catabolism
Murphy MG, Plunkett LM, Gertz BJ, et al. The Journal of clinical endocrinology and metabolism. 1998
- Wiki study page →Source
PubMed
Characterization of growth hormone secretagogue small molecule ibutamoren (MK-0677) and its possible metabolites in thoroughbred horses for doping control
Philip M, Karakka Kal AK, Subhahar MB, et al. Rapid communications in mass spectrometry : RCM. 2022
- Wiki study page →Source
PubMed
Thymosin beta4: a multi-functional regenerative peptide (review)
Goldstein AL, Kleinman HK. Ann N Y Acad Sci. 2012
- Wiki study page →Source
PubMed
Thymosin beta 4 and wound healing: a multifunctional peptide
Goldstein AL, Kleinman HK. Expert Opin Biol Ther. 2010
- Wiki study page →Source
PubMed
Safety and Efficacy of Approved and Unapproved Peptide Therapies for Musculoskeletal Injuries and Athletic Performance
Mendias CL, Awan TM. Sports medicine (Auckland, N.Z.). 2026