Side-by-Side Comparison
AOD-9604 vs MK-677: Mechanism, Evidence & Safety Compared
An evidence-based side-by-side look at how AOD-9604 and MK-677 differ in mechanism, regulatory status, strength of the research base, and clinical application — compiled from the published literature and the FDA regulatory record.
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.
AOD-9604
L2Also: Advanced Obesity Drug 9604, Anti-Obesity Drug 9604, Tyr-hGH Fragment 177-191
A modified fragment of human growth hormone studied for fat metabolism without the growth-promoting effects of full GH.
MK-677
L4Also: Ibutamoren, Nutrobal, L-163,191
An oral ghrelin mimetic (not a peptide) that stimulates growth hormone release. Has extensive human data but has not achieved FDA approval.
Side-by-side comparison
| Attribute | AOD-9604 | MK-677 |
|---|---|---|
| Primary mechanism | Lipolytic GH Fragment Activity | Oral Ghrelin Receptor Agonism |
| FDA status | Research Only | Research Only |
| Evidence level | Preclinical Evidence | Strong Clinical Evidence |
| Human trials | Yes (1+ indexed) | Yes (15+ indexed) |
| Studies indexed | 23 total (2 human, 14 animal) | 75 total (25 human, 30 animal) |
| Primary uses researched | Fat metabolism, Weight loss | Growth hormone release, Sleep quality, Appetite stimulation, Bone density (research) |
| Administration routes | oral, subcutaneous | oral |
| Molecular weight | 1815.08 Da | 528.67 Da |
| Amino acids | 16 | — |
| Category | weight loss | growth hormone |
| WADA status | Prohibited | Prohibited |
Key differences
Mechanism. AOD-9604 acts primarily through lipolytic gh fragment activity, while MK-677 acts primarily through oral ghrelin receptor agonism. This means they address different biological pathways even when targeting overlapping clinical goals.
Regulatory status. Both compounds share the same FDA status (Research Only), which means the practical pathway to access is similar for each.
Evidence base. MK-677 sits at a higher evidence level (L4) than AOD-9604 (L2) under PeptideMark's L1–L5 methodology.
Research focus. Published research on AOD-9604 has concentrated on fat metabolism, weight loss. Research on MK-677 has concentrated on growth hormone release, sleep quality, appetite stimulation. These research programs have limited overlap, and comparisons are most useful when readers are evaluating adjacent therapeutic goals.
Safety snapshot
| Attribute | AOD-9604 | MK-677 |
|---|---|---|
| Documented effects | 4 total | 9 total |
| Serious events | 0 | 0 |
| Common events | 1 | 4 |
| Black box warning | No | No |
| Contraindications | 3 listed | 4 listed |
| Drug interactions | 2 flagged | 2 flagged |
| Most common event | Injection site reactions | Increased appetite |
Strengths & limitations
AOD-9604
Strengths
- Represents an area of active research interest with growing study volume
Limitations
- Not FDA-approved for any indication — research use only
- Limited evidence base (L2)
- Few human trials — most data is preclinical
- Prohibited in competitive sport under WADA
MK-677
Strengths
- Strong evidence base (L4)
- Multiple human clinical trials (15+ indexed)
Limitations
- Not FDA-approved for any indication — research use only
- Prohibited in competitive sport under WADA
Representative studies
AOD-9604
A double blind placebo controlled study of the effects of AOD9604 in overweight and obese subjects
Stier H, et al. · Journal of Obesity & Weight Loss Therapy (2013)
AOD-9604 failed to produce statistically significant weight loss compared to placebo in a clinical trial.
AOD 9604 Promotes Cartilage Proliferation and Type II Collagen Synthesis in Osteoarthritic Chondrocytes
Wu X, Brown L, Kasran A, et al. · International Journal of Obesity (2007)
AOD 9604 increased type II collagen synthesis by 180% and cartilage proteoglycan content by 156% in human OA chondrocytes.
PubMed 17387518MK-677
MK-677, an orally active growth hormone secretagogue, reverses diet-induced catabolism
Murphy MG, Plunkett LM, Gertz BJ, et al. · Journal of Clinical Endocrinology & Metabolism (1998)
MK-677 25mg daily reversed diet-induced nitrogen wasting by increasing GH pulse amplitude and IGF-1 levels.
PubMed 9467534Effects 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. · Annals of Internal Medicine (2008)
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 18981485Frequently asked
What is the main difference between AOD-9604 and MK-677?
AOD-9604 is a modified fragment of human growth hormone studied for fat metabolism without the growth-promoting effects of full gh. Its primary mechanism is lipolytic gh fragment activity. MK-677 is an oral ghrelin mimetic (not a peptide) that stimulates growth hormone release. has extensive human data but has not achieved fda approval. Its primary mechanism is oral ghrelin receptor agonism. The two differ in regulatory status (Research Only vs Research Only), strength of evidence (L2 vs L4), and the primary conditions for which each is researched.
Is AOD-9604 or MK-677 FDA approved?
AOD-9604: Not FDA-approved. Has GRAS (Generally Recognized as Safe) status as a food additive only. Not approved as a drug. MK-677: Not FDA-approved. Non-peptide ghrelin mimetic (not technically a peptide, but commonly grouped with peptides). Has failed in clinical trials for growth hormone deficiency.
How does the evidence base compare?
AOD-9604 has 23 indexed studies (2 human, 14 animal) and is rated Preclinical Evidence. MK-677 has 75 indexed studies (25 human, 30 animal) and is rated Strong Clinical Evidence. Evidence ratings reflect PeptideMark's L1–L5 methodology based on study type, sample size, and replication.
Can AOD-9604 and MK-677 be compared directly?
AOD-9604 and MK-677 come from different therapeutic categories (weight loss vs growth hormone), so direct clinical comparison is limited. Readers often compare them because of overlapping research interest, shared patient populations, or adjacent mechanisms — not because head-to-head trial data exists.
Are AOD-9604 and MK-677 commonly stacked together?
There is no widely documented stacking protocol combining AOD-9604 and MK-677 in the peer-reviewed literature. Any combination use should be supervised by a qualified clinician familiar with both compounds' pharmacology and contraindications.
Which has a better-documented safety profile, AOD-9604 or MK-677?
AOD-9604 has 4 documented side effects (0 serious). MK-677 has 9 documented side effects (0 serious). Better documentation does not necessarily mean safer — FDA-approved drugs have more rigorous adverse-event reporting, while research-only compounds may appear "cleaner" simply because fewer controlled trials have captured events systematically.
How are AOD-9604 and MK-677 administered?
AOD-9604 is typically administered via oral or subcutaneous. MK-677 is typically administered via oral. Route differences affect onset, peak levels, and patient convenience.
Which is better, AOD-9604 or MK-677?
"Better" depends on the therapeutic goal, regulatory context, and individual response. AOD-9604 is most researched for fat metabolism and weight loss; MK-677 is most researched for growth hormone release and sleep quality. FDA status also matters: Research Only for AOD-9604 vs Research Only for MK-677. This page is educational — any decision to use either compound should be made with a qualified clinician who has reviewed your medical history.
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