Peps
What is MK-677?
MK-677, or ibutamoren, is a small-molecule ghrelin mimetic. A trial in older adults found increased fat-free mass without an improvement in strength or physical function.
Biological role or research focus
Growth-hormone secretagogue research.
More fat-free mass does not establish stronger muscles, improved independence, or a longevity benefit.
Role reference: Effects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults: a randomized trial. · 2008 ↗
Names you may encounter
Ibutamoren · MK677
Search terms can include brands, combinations, or historical names. They are not automatic product equivalents.
- Class / identity
- Small-molecule ghrelin mimetic; not a peptide
- Research focus
- Growth-hormone secretagogue research
- Featured evidence
- Human randomized trial
- Source check
- October 4, 2026
Biology & proposed mechanism
The intervention stimulates the growth-hormone secretagogue pathway. Hormonal and body-composition changes should be separated from patient-important functional outcomes.
Research context & identity
This page covers research in healthy older adults, rather than a validated anti-aging treatment or performance-enhancement regimen.
What does the evidence show?
Selected published evidence, with the population, findings, and limits kept together. These original summaries draw on publication abstracts; they are not a systematic review.
Human randomized trial · 2008
Ibutamoren in healthy older adults
What did this publication test, and what did it find?
- Population / model
- 65 healthy adults aged 60–81.
- Study design
- Randomized double-blind modified-crossover study over two years, with principal comparisons at one year.
- Main finding
- Fat-free mass increased with ibutamoren versus placebo, but strength and function did not improve. Fasting glucose increased and insulin sensitivity decreased.
- Limits & context
- More fat-free mass does not establish stronger muscles, improved independence, or a longevity benefit.
Human phase 2 randomized trial · 2011
Ibutamoren after hip fracture
Did a higher IGF-1 level translate into functional recovery?
- Population / model
- 123 older patients recovering from hip fracture.
- Study design
- Double-blind placebo-controlled trial reporting 24-week functional and IGF-1 outcomes; stopped early.
- Main finding
- IGF-1 increased, but most functional measures did not improve. Gait speed improved while the stair-climbing difference was not statistically significant. A congestive-heart-failure safety signal led to early termination.
- How to read it
- A hormone biomarker increase is not equivalent to improved strength or recovery.
- Limits & context
- Early stopping limits inference. The safety signal concerns this vulnerable population and cannot quantify risk in healthy users. This small molecule is not a peptide, and the study does not establish safe recreational use.
Read the original paper for methods, adverse events, funding, and conflicts of interest. Publisher access may require a subscription.
Search additional PubMed records ↗New editorial updates
New source discoveries
Links appear automatically. Unreviewed discoveries are not verified medical findings.
Safety & precautions
Safety & what remains unknown
Reported effects included increased appetite, edema, and muscle pain. Glucose and insulin-sensitivity changes are material safety considerations.
Evidence boundaries
More fat-free mass does not establish stronger muscles, improved independence, or a longevity benefit.
Hip-fracture trial safety signal
An older-patient trial stopped early after a congestive-heart-failure signal. Increased IGF-1 did not translate into improvement in most functional measures. The signal should remain visible when interpreting body-composition claims.
Source: Ibutamoren after hip fracture · 2011 ↗
This is not a complete list of contraindications, interactions, or adverse effects. Medicine labels apply to specific products and indications; research-use listings are not interchangeable with approved medicines.
What are people discussing?
No editorial transcript note has been reviewed for this profile yet. Below are the matching video records available for exploration; title and caption matches are not verified claims.
Watch the source discussions
7 matching video records · 4 with captions indexed.
Across the full library, 30 caption files are indexed from 20,199 inventoried videos. Most transcripts remain unreviewed. Select a thumbnail or timestamp to watch inside PepsRadar. Thumbnail images load from YouTube.
Fouad Abiad Media
RETATRUTIDE: EVERYTHING YOU NEED TO KNOW | Wes Christensen | Fouad Abiad's Real Bodybuilding Podcast ↗
Captions indexed · Automatic matches need review
Peptide Of The Week
Peptide Q&A #60 – Live from South Carolina, COA Verification, HGH Long Game & SIBO ↗
Captions indexed · Automatic matches need review
Peptide Of The Week
Telehealth vs Research Peptides: The Truth Nobody Tells You | Peptide of the Week Q&A #61 ↗
Captions indexed · Automatic matches need review
Trevor Kruder
Episode 16: The Truth About Peptides: Testing, Manufacturing, Safety & the Future ↗
Captions indexed · Automatic matches need review
Dr. Jones, DC
MK-677: The HARMFUL Peptide?! 😱🧬 #growthhormone #peptides ↗
Title match · Captions not indexed
Dr. Trevor Bachmeyer
Building Muscle & Skyrocketing Performance (Cardarine and MK677) - Unbreakable Podcast 185 ↗
Title match · Captions not indexed
Sources & supplier listings
Listings are grouped by the vendor’s stated identity. Blends and modified derivatives are labeled separately. Inclusion is not a quality assessment or an endorsement.
We have not added a supplier for this profile. Missing products and coded listings are not filled with guesses.
Catalog checked 2026-10-04. Seller listings retain their stated intended use. Shops covered: BioLongevity Labs, BioLongevity Supplements, American Peptides, PSPeptides. This is not a market-wide comparison. Affiliate participation does not determine evidence or editorial coverage.
Questions worth asking
- Is MK-677 a peptide, and did this trial show improved strength?
- What material, population, and route were actually studied?
- More fat-free mass does not establish stronger muscles, improved independence, or a longevity benefit.
- What adverse effects, uncertainty, and conflicts of interest does the original source report?
Frequently asked questions
Is MK-677 a peptide, and did this trial show improved strength?
It is a small molecule rather than a peptide. The featured trial did not show improved strength or physical function.
Does the publication verify a supplier’s product?
No. The tested material and a commercial listing need separate identity and batch checks. A research-use disclaimer does not establish clinical suitability.
References & editorial record
Source notes checked 2026-10-04. Original PepsRadar summaries. Not reviewed by a medical professional. Topic grouping is editorial navigation, not a treatment recommendation. Video notes specify which excerpts were reviewed; no full transcripts are published.