Sermorelin + MK-677 (Ibutamoren) Stack: Complete Protocol

Is there a tested protocol for the pair?

Sermorelin stimulates the pituitary GHRH receptor to release growth hormone [4], and MK-677 stimulates the ghrelin (growth hormone secretagogue) receptor [2]. The two drugs act through different receptors. FDA's review of MK-677 reports no formal drug-interaction studies [2]. What is known about each drug comes from separate trials.

Sermorelin

Sermorelin is a 29-amino-acid analogue of human growth hormone-releasing hormone, not growth hormone itself [4]. Its only approvals were as Geref, for testing the pituitary's ability to secrete growth hormone (0.05 mg ampule, approved December 28, 1990) and for idiopathic growth hormone deficiency in children (0.5 mg and 1 mg vials, approved September 26, 1997) [1]. The maker discontinued both in 2008, FDA withdrew the approvals effective June 18, 2009, and in March 2013 FDA determined Geref was not withdrawn for safety or effectiveness reasons [1].

In a 1-year open-label trial, 110 previously untreated prepubertal children received 30 micrograms per kg subcutaneously at bedtime. Among the 86 included in the efficacy analysis, average height velocity rose from 4.1 cm/yr at baseline to 8.0 cm/yr at 6 months and 7.2 cm/yr at 12 months, and fasting glucose did not change [8]. In 10 healthy men with a mean age of 68, 1 mg of GHRH(1-29) twice daily for 14 days raised 24-hour growth hormone and IGF-1 to levels not significantly different from 9 young men [9]. Those are trial doses, not recommended doses. No sermorelin product is currently FDA-approved, so there is no current approved dose [1][8][9].

For information about sermorelin, see the sermorelin product page.

MK-677

MK-677 (ibutamoren mesylate) is an oral small molecule, not a peptide, and not a SARM [2]. It has never been approved, so there is no approved dose; FDA's review notes that trials used 2 to 50 mg a day, with 25 mg a day in most adult trials [2]. In 65 healthy adults aged 60 to 81, 25 mg daily for 12 months raised fat-free mass by 1.1 kg against a 0.5 kg fall on placebo and body weight by 2.7 vs 0.8 kg, while fasting glucose rose about 5 mg/dL; strength and function did not improve [5]. In 563 people with mild to moderate Alzheimer's disease, 12 months raised IGF-1 by 72.9% without slowing progression, with drug-related adverse events in 35.5% vs 23.9% on placebo [10].

Safety signals

FDA placed ibutamoren in category 2 for the potential for congestive heart failure in certain patients, citing a hip-fracture trial terminated early for that signal: per FDA's summary, 4 patients (6.5%) on MK-677 vs 1 (1.7%) on placebo [3][6][2]. FDA lists hyperglycemia, liver enzyme elevations, edema and fluid overload, musculoskeletal pain, increased appetite and raised prolactin among reported events, and notes there are no long-term safety data in the older adults the drug is marketed to [2].

Legal status

FDA's December 12, 2025 warning letter states that ibutamoren is excluded from the dietary supplement definition and that products marketed with drug claims are unapproved new drugs [11]. Sermorelin is not on the category 2 list [3]. Neither drug is one of the six peptides in HHS's draft enforcement-discretion policy for compounding [12]. Compounded drugs are not FDA-approved: FDA does not review their safety, effectiveness or quality before they are marketed [12]. Both drugs are named in WADA section S2.2.4 and prohibited at all times, in and out of competition [7][13].