At a Glance
Quickcomparison
Dose Range
MK-677 (Ibutamoren)
10–25 mg
Ipamorelin
100–300 mcg
Frequency
Once daily
Multiple times daily
Administration
Oral (capsule or liquid)
Subcutaneous injection
Cycle Length
8-12 weeks
Onset Speed
Moderate (1-2 weeks)
Evidence Level
Moderate human trials (Phase 1-2)
Efficacy
Benefitratings
Muscle and body composition
Recovery and athletic performance
Sleep quality and metabolic health
GH Selectivity
Recovery Support
Safety Profile
Technical Data
Compoundspecifications
Molecular Formula
C27H36N4O5S
Molecular Weight
528.7 g/mol
Half-Life
4-6 hours (IGF-1 elevation persists ~24 hours)
Bioavailability
High oral bioavailability
CAS Number
159634-47-6
C38H49N9O5
711.85 g/mol
2 hours
High when injected subcutaneously
170851-70-4
Protocols
Dosingtiers
starting
10 mg
2-4 weeks initial
Lower entry dose used in practice to limit water retention and appetite surge before titrating up.
standard
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].
100 mcg per injection
2-3 times daily
4-8 weeks
Conservative entry dose; Ipamorelin is a selective GH secretagogue with a ~2 hour half-life, so doses are split through the day [1][2]. Used in research and practice to assess tolerance before titrating up.
200 mcg per injection
Most commonly cited research/practice dose; gives a meaningful pulsatile GH release without raising cortisol or prolactin at standard doses [1][2].
advanced
300 mcg per injection
3 times daily
Upper end of the commonly used range; total daily exposure split across three injections. Used in practice by experienced users [1].
Applications
Bestsuited for
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.
Clean GH Boost Seekers
If you want the benefits of increased growth hormone without spiking cortisol or other stress hormones, Ipamorelin is uniquely selective. Unlike GHRP-2 or GHRP-6, it won't raise your cortisol levels even at doses 200 times higher than needed for GH release.
Recovery-Focused Athletes
Ipamorelin shines for athletes who want better recovery between training sessions. The GH boost helps repair muscle tissue faster, and since it doesn't mess with other hormones, you can use it consistently without the rollercoaster effects.
Anti-Aging Enthusiasts
Growth hormone naturally declines as we age, contributing to muscle loss, fat gain, and reduced vitality. Ipamorelin offers a gentle way to restore more youthful GH levels without the risks of actual HGH therapy.
Those Recovering from Steroid Use
Research shows Ipamorelin can help counteract the muscle and bone-weakening effects of glucocorticoid medications. If you've been on steroids for medical reasons, this peptide may help you rebuild what you've lost.
Sideeffects
Common
Increased appetite
Mild water retention or edema
Elevated fasting glucose
Uncommon
Joint or muscle pain
Carpal tunnel syndrome or nerve compression symptoms
Mild nausea or digestive upset
Serious
Glucose dysregulation and diabetes risk
Mild headache
Injection site reactions
Water retention
Tingling in hands or feet
Joint stiffness
Allergic reaction
Research Status
Safety& evidence
FDA Status
Research compound
Safety Overview
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.
Contraindications
xUncontrolled diabetes or severe glucose dysregulation
xActive cancer or high cancer risk requiring caution with IGF-1 elevation
xPregnancy or breastfeeding
Ipamorelin has shown a favorable safety profile in both animal and human studies. What makes it stand out is its remarkable selectivity—it releases growth hormone without significantly affecting cortisol, ACTH, or other hormones. In clinical trials, it was well-tolerated with mostly mild, temporary side effects. Phase 2 trials in patients recovering from surgery showed no significant safety concerns compared to placebo.
xActive cancer or history of cancer
xPituitary disorders or tumors
xKnown allergy to peptide components
xChildren and adolescents (growth plates still open)
Decision Guide
Which isright for you?
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
Choose Ipamorelin if...
Muscle recovery and growth
Anti-aging and vitality
Body composition improvement
Sleep quality enhancement