MK-677 (Ibutamoren) + GHK-Cu Stack: Evidence, Mechanisms, and Protocol

Is there any study of MK-677 plus GHK-Cu together?

No human study of the two used together is cited on this page; the evidence below concerns each substance separately. The two are not alike. MK-677 is a small oral molecule that raises growth hormone and IGF-1 [3]. GHK-Cu is a copper-binding tripeptide [4]. Any argument that they complement each other is reasoning about mechanisms, not a finding.

What MK-677 is and what the trials showed

MK-677 (ibutamoren mesylate) is an oral, non-peptide molecule that stimulates growth hormone release through the ghrelin receptor. Merck synthesized it in 1995 and development was discontinued in 1999; it has no USP or National Formulary monograph and is not part of any FDA-approved drug [3]. It is often sold alongside SARMs but is not one [3]. A single oral dose is long-acting, about 24 hours [3].

The cleanest test in healthy older adults was Nass 2008, a 2-year double-blind trial in 65 adults aged 60 to 81 taking 25 mg daily or placebo. At 12 months, fat-free mass rose 1.1 kg against a 0.5 kg fall on placebo, body weight rose 2.7 kg versus 0.8 kg, fasting glucose rose about 5 mg/dL, insulin sensitivity fell, and strength and function did not improve [9].

Shorter studies in other groups reached the same place from different directions. Chapman 1996 gave 32 healthy adults aged 64 to 81 doses of 2, 10 or 25 mg daily; at 25 mg, mean 24-hour GH concentration rose 97% and mean IGF-1 went from 141 to 265 micrograms/L at 4 weeks, while fasting glucose rose from 5.4 to 6.8 mmol/L [10]. Bach 2004, in 161 hip-fracture patients over 6 months, raised IGF-1 by 84% versus 17% on placebo without a significant functional benefit [11]. Sevigny 2008, in 563 people with mild to moderate Alzheimer's disease over 12 months, raised IGF-1 by 72.9% with no effect on any progression measure [7].

In these trials MK-677 consistently raised IGF-1, but they did not show consistent improvements in strength, function, cognition or other clinical outcomes [9][11][7].

What MK-677's safety record shows

FDA lists ibutamoren mesylate in category 2 — bulk substances that may present significant safety risks when compounded — citing "the potential for congestive heart failure in certain patients" [1]. It was added to that category on December 29, 2022 for outsourcing facilities and September 29, 2023 for state-licensed pharmacies and physicians, and it is still there on FDA's page dated 04/22/2026 [1].

The trial behind that concern was Adunsky 2011: 123 hip-fracture patients, 25 mg daily for 24 weeks, stopped early for a safety signal of congestive heart failure. Per FDA's summary, 4 patients (6.5%) on MK-677 developed heart failure versus 1 (1.7%) on placebo; systolic blood pressure rose 11.9 to 16.4 mmHg against 2.3 to -2.3 on placebo; serious adverse events occurred in 24% versus 13% [12][3]. The authors concluded that MK-0677 "has an unfavorable safety profile" in that population [12].

Other trials add detail. In Bach 2004, serious adverse events were 24% versus 18%, thrombosis occurred in 4 versus 0 patients, glucose rose 8.0 mg/dL versus a 1.6 mg/dL fall, HbA1c rose 0.7% versus 0.3%, 12% versus 2.6% stopped for adverse events, and edema or fluid overload affected 16 versus 10 patients [11][3]. In the Alzheimer's trial, drug-related adverse events were 35.5% versus 23.9% on placebo, blood glucose increases 15.4% versus 4.6%, and HbA1c increases 11.1% versus 1.4% [7][3].

FDA's wider concern is class-wide: by raising GH and IGF-1, MK-677 may carry the risks listed on approved growth hormone labels, including increased risk of neoplasm, glucose intolerance and diabetes, intracranial hypertension, fluid retention, hypoadrenalism, hypothyroidism and pancreatitis, plus slipped capital femoral epiphysis and scoliosis progression in children [3]. FDA also notes there are no long-term safety data in the older adults the drug is marketed to [3].

Legally, FDA's December 12, 2025 warning letter stated that ibutamoren is excluded from the dietary supplement definition and that products marketed with drug claims are unapproved new drugs [13]. WADA names ibutamoren (MK-677) in S2.2.4, prohibited at all times, in and out of competition [8].

What GHK-Cu is and what the human data show

GHK-Cu is the copper(II) complex of GHK, a tripeptide found in human plasma, saliva and urine whose levels are reported to decline with age [4]. The actions usually cited for it — stimulating collagen and proteoglycan synthesis, modulating metalloproteinases and their inhibitors, attracting immune and endothelial cells to an injury, and speeding wound healing in dogs, rats, mice and pigs — come from laboratory and animal work summarized by the researchers who proposed them [4]. They are proposed mechanisms, not proven human effects [4].

No FDA-approved drug is known to contain GHK-Cu [5]. Topical copper peptide creams are sold as cosmetics and are not FDA-approved before sale [6]. Whether such a product is a cosmetic or a drug depends on its intended use: claims to treat disease or change the body's structure or function make it a drug [6].

The human trial record is small and mixed:

• Miller 2006: 13 patients had circumoral skin resurfaced with a CO2 laser and used post-treatment skin care with or without GHK-Cu. Computer analysis and blinded evaluators found no significant difference in redness resolution, wrinkles or overall skin quality. A patient questionnaire found a significant difference in overall skin quality favoring GHK-Cu (P=.04) [14].
• Bishop 1992: 86 evaluable patients with venous stasis ulcers. A 0.4% tripeptide copper complex cream was no different from an inert vehicle for ulcer size, while silver sulfadiazine 1% reduced ulcer size [2].
• A 2026 systematic review of GHK-Cu microneedle delivery kept 64 records and concluded that despite four decades of preclinical work the human literature is thin and fragmented: most randomized trials are small and run on facial cosmetic creams, and microneedle delivery has not been tested in a registered, adequately powered human randomized controlled trial [15].

Can either one be prescribed or compounded?

FDA places MK-677 in category 2 because of significant safety risks, and its category 1 compounding policy does not apply [1][17]. On October 29, 2024, FDA's Pharmacy Compounding Advisory Committee voted 1 yes, 13 no, 0 abstain against adding ibutamoren mesylate to the list of bulk substances that can be used in compounding, in line with FDA's proposal; members cited fluid retention, congestive heart failure and hyperglycemia [16]. MK-677 is also not one of the six peptides (BPC-157, epitalon, KPV, MOTS-c, Semax, TB-500) in HHS's draft enforcement-discretion policy filed October 28, 2026 [18]. Compounded drugs are not FDA-approved — FDA does not review their safety, effectiveness or quality before they are marketed [19].

GHK-Cu splits by route. Non-injectable GHK-Cu, such as topical, is in category 1, the group FDA is still evaluating, and FDA says it generally does not intend to act against compounders of category 1 substances when the conditions in its guidance are met [5][17]. That entry was removed on April 22, 2026 when the nominations were withdrawn, then added back after a nominator clarified on May 5, 2026 that only the injectable route had been withdrawn, with the list updated May 14, 2026 [5][17]. FDA has said it intends to consult its advisory committee before the end of February 2027 on whether to include GHK-Cu on the list; no vote has happened yet [5].

Injectable GHK-Cu is different. It appears in FDA's "nominated but withdrawn" table, where FDA states that compounded injectable drugs containing GHK-Cu "may pose risk for immunogenicity due to the potential for aggregation and peptide-related impurities" and that there are "limited data in humans to inform safety-related considerations" [1]. It is not in category 1, and not in any category on FDA's current list [5].

What doses were actually studied

MK-677 has no FDA-approved dose [3]. MK-677 trials used fixed oral doses of 2 mg to 50 mg per day — 25 mg once daily in most adult trials, and 0.2 to 0.8 mg/kg/day in children — for up to 2 years; none of these is a recommended dose [3]. For GHK-Cu, the only drug-style human trial found used a 0.4% tripeptide copper complex cream, and topical cosmetic strengths are set by manufacturers and are not FDA-reviewed [2]. For injectable GHK-Cu, FDA's stated position is that human safety data are limited [1].

What to watch for

MK-677 trials reported increased appetite, edema or fluid retention, muscle or musculoskeletal pain, and changes in glucose handling [3][9]. FDA's September 23, 2025 notification about a children's product found to contain hidden ibutamoren listed increased appetite, water retention, fatigue, muscle pain, changes in glucose metabolism and insulin sensitivity, and an increased potential for congestive heart failure in certain individuals [20]. In the healthy older adult trial, the most frequent side effects were increased appetite, transient mild leg edema and muscle pain [9]. Average blood glucose and HbA1c rose more on MK-677 in the hip-fracture trial [11]; increases in both measures were more frequent with MK-677 in the Alzheimer's trial [7].

For GHK-Cu, FDA's stated safety concern is about the injectable route and immunogenicity risk [1].