Informational only. Not medical advice.INFORMATIONAL PLATFORM ONLY — NOT MEDICAL ADVICE, DIAGNOSIS, OR TREATMENT
Informational only. Not medical advice.INFORMATIONAL PLATFORM ONLY — NOT MEDICAL ADVICE, DIAGNOSIS, OR TREATMENT
Head-to-head comparison of MK-677 and Semaglutide — mechanism, side effects, legal status, and pricing.
MK-677 (ibutamoren, MK-0677, L-163,191) is an orally active, non-peptide small-molecule growth hormone secretagogue developed by Merck in the 1990s. It is a spiropiperidine ghrelin-receptor (GHSR-1a) agonist — not a peptide and not a SARM, though it is commonly misclassified as both in grey-market retail. Merck discontinued development after mixed efficacy and adverse metabolic / cardiovascular findings; it is not FDA-approved.
Semaglutide is an FDA-approved GLP-1 receptor agonist marketed as Ozempic (SubQ, type 2 diabetes), Wegovy (SubQ, chronic weight management and cardiovascular risk reduction in obesity), and Rybelsus (oral, type 2 diabetes). It is a synthetic analog of native GLP-1 with a fatty-acid (C18 diacid) side chain that enables albumin binding, giving it a ~165-hour half-life suitable for once-weekly injection.
MK-677
Semaglutide
Category
Legal Status
Mechanism
Half-life
Side Effects
COA-verified vendors · trust score ≥70 required · single-vial price — bulk/bundle deals may be lower
MK-677
No pricing data yet.
Check MK-677 prices →Semaglutide
COA corpus from Disclosed Labs — independently tested batches only.
MK-677
5
COAs
98.3%
Avg purity
3
Labs
Semaglutide
128
COAs
99.6%
Avg purity
13
Labs
MK-677 has meaningful human data from Merck-sponsored Phase I/II trials. Murphy et al. (JCEM 1998, PMID 9467534) showed 25 mg MK-677 reversed nitrogen wasting during caloric restriction in healthy adults. Svensson et al. (JCEM 1998, PMID 9467542) reported ~40% IGF-1 elevation, increased fat-free mass, and higher energy expenditure over 8 weeks in obese men. Copinschi et al. (Neuroendocrinology 1997, PMID 9349662) documented improved slow-wave and REM sleep in young and older adults. Nass et al. (Ann Intern Med 2008, PMID 18981485) — the pivotal 2-year randomized trial in 65 healthy older adults — restored GH and IGF-1 to young-adult levels and increased fat-free mass, but produced modest fasting glucose elevation and insulin resistance. The Adunsky et al. Phase IIb hip-fracture trial (Arch Gerontol Geriatr 2011, PMID 21067829) was stopped early after a congestive-heart-failure safety signal (4/62 ibutamoren vs 1/60 placebo). Merck discontinued development. MK-677 is commonly mislabeled as a 'SARM' in grey-market retail — it is not; it is a ghrelin-receptor agonist and oral GH secretagogue. It has never been FDA-approved.
Key references
The STEP program (STEP 1–8) showed average weight loss of roughly 15% of body weight over 68 weeks with weekly 2.4 mg semaglutide (STEP 1: Wilding et al., NEJM 2021, PMID 33567185). The SUSTAIN program established A1c and cardiovascular benefit in type 2 diabetes. The PIONEER program established efficacy of oral semaglutide (Rybelsus) versus placebo, sitagliptin, empagliflozin, and liraglutide (PIONEER 4, PMID 31186120). The SELECT trial (Lincoff et al., NEJM 2023, PMID 37952131) showed a 20% relative reduction in major adverse cardiovascular events in adults with overweight/obesity and established cardiovascular disease but without diabetes, leading to an expanded Wegovy indication.
MK-677 (Performance) and Semaglutide (Metabolic) are in different categories and target different biological pathways. This is a common pattern in multi-compound research protocols. Researchers should monitor the biomarkers from both profiles and watch for interactions listed in each compound’s contraindications. Consult a licensed healthcare provider before combining any research compounds.
This platform provides informational tools only, not medical advice. This comparison is for educational purposes only. Consult a licensed provider.
Contraindications
Lab Testing
Disclosed Labs