Capromorelin vs MK-677 (Ibutamoren) — Peptide Comparison

Capromorelin vs MK-677 (Ibutamoren) — Peptide Comparison Capromorelin vs MK-677 (Ibutamoren) — compare dosing, benefits, safety profiles, side effects, and how they stack. See which peptide is right for you. At a Glance Dose Range Capromorelin 3–30 mg MK-677 (Ibutamoren) 10–25 mg Frequency Once daily Administration Oral (capsule or tablet) Oral (capsule or liquid) Cycle Length 4-6 weeks 8-12 weeks Onset Speed Moderate (1-2 weeks) Evidence Level Moderate human trials (Phase 1-2) Efficacy GH & IGF-1 Stimulation Physical Function Oral Convenience Muscle and body composition Recovery and athletic performance Sleep quality and metabolic health Technical Data Molecular Formula C28H35N5O4 Molecular Weight 505.6 g/mol Half-Life 1-2.4 hours in humans Bioavailability Good oral bioavailability CAS Number 193273-66-4 C27H36N4O5S 528.7 g/mol 4-6 hours (IGF-1 elevation persists ~24 hours) High oral bioavailability 159634-47-6 Protocols starting 3 mg Twice daily Initial weeks One of the lower doses tested in the year-long study in older adults; raised growth hormone and IGF-1 [1]. standard 10 mg Once daily at bedtime Ongoing A simple once-daily bedtime dose used in the human trial that improved lean body mass [1]. advanced Up to 12 months in the trial The highest daily amount studied in older adults, giving the largest gains in muscle mass and physical function [1]. 2-4 weeks initial Lower entry dose used in practice to limit water retention and appetite surge before titrating up. 25 mg Studied up to 1-2 years 25 mg once-daily oral is the dose used in the randomized trial in healthy older adults; increased GH/IGF-1 and fat-free mass [1]. Most-studied dose [2]. Applications Age-Related Muscle Wasting Capromorelin showed significant improvements in physical function — including tandem walk and stair climb — in elderly adults, making it a strong candidate for combating sarcopenia. Appetite Stimulation As an FDA-approved veterinary appetite stimulant, capromorelin has extensive real-world evidence for boosting food intake and body weight in mammals. Growth Hormone Research One of the best-studied oral ghrelin agonists with human Phase 2 data, offering researchers a well-characterized tool for studying GH/IGF-1 pathways. Older Adults (60+) Seeking Body Composition Improvements MK-677 was designed for aging populations. It restores GH and IGF-1 to youthful levels, increases lean mass, and improves physical function in people over 60. A 2-year clinical trial showed a 1.1 kg gain in fat-free mass with only modest fat gain—ideal for maintaining strength in older age. Athletes and Fitness Enthusiasts Wanting Recovery Support Oral dosing makes MK-677 convenient for athletes. It enhances muscle protein synthesis, speeds recovery after intense training, and supports lean mass building without the hassle of injections. People with Chronic Wasting or Protein Deficiency Clinical trials show MK-677 helps treat protein-energy wasting in kidney disease and other conditions. It stimulates appetite (a feature in these populations) and preserves muscle tissue—making it useful for those losing mass despite good nutrition. Safety Profile Common Appetite stimulation Fluid retention and weight gain Uncommon Joint and muscle aches Fatigue or lethargy Peripheral edema (swelling) Serious Hyperglycemia Increased appetite Mild water retention or edema Elevated fasting glucose Joint or muscle pain Carpal tunnel syndrome or nerve compression symptoms Mild nausea or digestive upset Glucose dysregulation and diabetes risk Research Status FDA Status FDA approved for this use Safety Overview Capromorelin was generally well-tolerated in Phase 2 human trials involving nearly 400 elderly participants. Most side effects were mild to moderate. Its FDA-approved veterinary use provides additional long-term safety data in mammalian species. Contraindications xActive cancer or history of cancer (GH may stimulate growth) xUncontrolled diabetes or severe metabolic disorders xSevere liver or kidney disease xPregnancy and lactation Research compound MK-677 has been studied in hundreds of humans over 2+ years and is generally well tolerated. Most side effects are mild and manageable, especially with lower starting doses. The lack of injection requirement makes it safer than injectable GH in terms of infection risk and sterility concerns. However, it is not FDA approved and should be viewed as a research compound. xUncontrolled diabetes or severe glucose dysregulation xActive cancer or high cancer risk requiring caution with IGF-1 elevation xPregnancy or breastfeeding Decision Guide Choose Capromorelin if... Stimulating growth hormone production in elderly adults Supporting appetite and weight gain in wasting conditions Improving muscle mass and physical performance Anti-aging and longevity optimization Choose MK-677 (Ibutamoren) if... Building lean muscle mass and strength Improving overall body composition in aging adults Enhancing athletic recovery and performance Supporting metabolic health and fat loss