MK-677 (Ibutamoren) + AOD-9604 Stack: Complete Protocol, Dosing, and Evidence Review

Does anything support stacking MK-677 with AOD-9604?

The idea rests on two different mechanisms. MK-677 is an oral, non-peptide ghrelin-receptor agonist that stimulates growth hormone release and raises IGF-1 [1]. AOD-9604 is a modified fragment of growth hormone (hGH amino acids 177 to 191 with an extra tyrosine at the N-terminus) that in obese rodents increased fat-tissue lipolytic activity [8][9].

No study of the two compounds given together is available, so nothing tells you whether the combination does more than either alone, or whether the risks add up.

MK-677 (ibutamoren): what the trials measured

MK-677 is not a peptide. It is a small oral molecule that acts on the ghrelin receptor. Merck synthesised it in 1995 and stopped development in 1999. It is also being studied under the name LUM-201 in pediatric growth hormone deficiency, including a 6-month randomized trial in 68 prepubertal children [1][10].

In 65 healthy adults aged 60 to 81, 25 mg daily for 12 months raised fat-free mass by 1.1 kg versus a 0.5 kg fall on placebo, with body weight up 2.7 kg versus 0.8 kg. Strength and function did not improve. Fasting glucose rose about 5 mg/dL and insulin sensitivity fell; the most frequent side effects were increased appetite, transient mild leg edema and muscle pain [11][1].

In 24 obese men given 25 mg daily for 8 weeks, IGF-1 rose about 40% and fat-free mass increased, but total and visceral fat did not change and an oral glucose tolerance test showed impaired glucose handling at 2 and 8 weeks [12].

In 563 people with mild to moderate Alzheimer's disease, 12 months of 25 mg raised IGF-1 by 72.9% with no effect on disease progression. Drug-related adverse events occurred in 35.5% versus 23.9% on placebo, with blood glucose increases in 15.4% versus 4.6% [13].

AOD-9604 (hGH fragment 176-191): what exists

The animal data are real. In obese Zucker rats, oral AOD-9604 at 500 microgram/kg/day for 19 days cut body-weight gain to 15.8 g versus 35.6 g in controls, increased fat-tissue lipolytic activity, and did not harm insulin sensitivity on euglycemic clamp [9]. In obese mice, 14 days of intraperitoneal AOD-9604 reduced body weight and fat, and the long-term effect was absent in mice lacking the beta-3 adrenergic receptor [14]. Preclinical work also found no binding to the growth hormone receptor [2].

The human record is much thinner. A 2026 review describes a 24-week study of oral AOD9604 as an anti-obesity drug candidate (534 enrolled, 502 randomized) that failed to show a significant benefit on the primary weight-loss endpoint, after which the sponsor dropped the obesity programme [2][15]. The review notes that this conclusion rests on sponsor-reported phase 2 results rather than a peer-reviewed efficacy trial, and that there are no robust human data for visceral fat or other metabolic benefit [2]. That trial tested an oral candidate; no efficacy trial of injected products is cited [2].

The cartilage and joint-repair claims come from a rabbit knee osteoarthritis study of intra-articular AOD9604 with or without hyaluronic acid; there is no convincing human osteoarthritis trial [16][2].

What dose is a 'protocol' based on?

Neither compound has an approved dose [1][2].

MK-677 trials used fixed oral doses of 2 mg to 50 mg per day, most often 25 mg once daily in adults, or 0.2 to 0.8 mg/kg/day in children, for up to two years [1]. Reports cited by FDA describe a single dose as long-acting, roughly 24 hours [1].

For AOD-9604, the only human obesity study described in the 2026 review tested an oral drug candidate, not an injection [2].

Side effects and safety

FDA placed ibutamoren mesylate in its category of bulk substances that may present significant safety risks, citing 'the potential for congestive heart failure in certain patients' and a hip-fracture trial 'terminated early due to a potential safety signal of congestive heart failure' [3][17].

That trial enrolled 123 patients aged 60 or older, 25 mg daily versus placebo for 24 weeks. Per FDA's summary, heart failure occurred in 4 patients (6.5%) on MK-677 versus 1 (1.7%) on placebo; systolic blood pressure rose 11.9 to 16.4 mmHg versus 2.3 to minus 2.3 mmHg; serious adverse events were 24% versus 13%; IGF-1 rose 51.4 ng/mL more than placebo; gait speed improved but most function measures did not [17][1].

An earlier 6-month hip-fracture trial in 161 patients found IGF-1 up 84% versus 17% on placebo with no significant functional benefit, serious adverse events in 24% (20/84) versus 18% (14/77), thrombosis in 4 versus 0, glucose up 8.0 versus down 1.6 mg/dL, and HbA1c up 0.7% versus 0.3% [18][1].

FDA's review says that by raising GH and IGF-1, MK-677 may carry the risks listed on FDA-approved growth hormone labels: increased risk of neoplasm, glucose intolerance and diabetes, intracranial hypertension, fluid retention, hypoadrenalism, hypothyroidism and pancreatitis, and in children slipped capital femoral epiphysis and scoliosis progression [1]. FDA's consumer notice on a children's product containing undeclared ibutamoren lists increased appetite, water retention, fatigue, muscle pain, changes in glucose metabolism and insulin sensitivity, and a possible increase in congestive heart failure risk in certain people [19].

For AOD-9604, FDA states it 'has also identified serious adverse events that may be associated with AOD-9604, though causality is not clear,' and gives no details [3]. A 2026 review of performance-enhancing peptides concludes human evidence on AOD-9604 is limited and largely short-term [2], and a separate review of gray-market peptides notes that rigorous human safety data are scarce and serious harm is possible [20].

Regulatory status and sport

Neither compound is FDA-approved [15][2][1]. Ibutamoren mesylate was added to FDA's significant-safety-risk category on December 29, 2022 for outsourcing facilities and September 29, 2023 for state-licensed pharmacies and physicians, and is still listed on FDA's page dated 04/22/2026 [3][4][5]. On October 29, 2024 FDA's Pharmacy Compounding Advisory Committee voted 1 yes, 13 no, 0 abstain against adding it to the bulks list, citing fluid retention, heart failure and hyperglycemia [21][1].

In a December 12, 2025 warning letter, FDA stated that 'ibutamoren is excluded from the dietary supplement definition' and that products marketed with drug claims for it are unapproved new drugs [22].

AOD-9604 appears in FDA's 'nominated but withdrawn' table, where FDA lists concerns about immunogenicity risk from peptide impurities and characterization problems, no or limited safety information, and serious adverse events with unclear causality; removal from that category was not a finding of safety [3]. It appears in none of the three categories on FDA's lists for state-licensed pharmacies and physicians or for outsourcing facilities [4][5][6].

Claims that AOD-9604 is GRAS do not hold up: FDA's GRAS Notice Inventory contains no AOD-9604 notice. The claims trace to the developer rather than FDA, and GRAS is a food-ingredient concept that would not make an injectable lawful as a drug [23][24].

Neither substance is among the six peptides in HHS's draft enforcement-discretion policy for compounding, filed October 28, 2026, and neither was on the agenda of FDA's July 2026 advisory committee [25][26][27]. Compounded drugs are not FDA-approved, and FDA does not verify their safety, effectiveness or quality before marketing [28].

Both are also banned in sport. WADA's Prohibited List names AOD-9604 and hGH 176-191 in S2.2.3 and ibutamoren in S2.2.4, prohibited at all times in and out of competition; both are on the 2026 List and remain on the 2027 List [7][29].

Drug interactions

FDA's review of MK-677 reports no formal drug-interaction studies [1]. A randomized trial did test MK-677 with alendronate in 292 postmenopausal women with osteoporosis: 25 mg plus 10 mg alendronate for 12 months partly offset alendronate's drop in osteocalcin (down 40% versus 54% with alendronate alone) and raised femoral neck bone density 4.2% versus 2.5%, with no extra gain at the spine, total hip or total body; 8.6% of women across all four arms stopped for treatment-related adverse events [30][1].

A separate case report of a 25-year-old man taking the SARM LGD-4033 together with MK-677 described unfavorable changes in lipids and liver enzymes, but the effect of MK-677 cannot be separated from the other drug [31].