Comparison tool
MK-677 vs Ipamorelin side-by-side
Stack up to four peptides by evidence status, mechanisms, study dosing, side effects, and references.
Comparison tool
Stack up to four peptides by evidence status, mechanisms, study dosing, side effects, and references.
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| Property | MK-677 | Ipamorelin |
|---|---|---|
| Category | Growth Hormone | Growth Hormone |
| Also known as | Ibutamoren, Nutrobal, L-163,191 | IPAM, NNC 26-0161 |
| FDA approved | No | No |
| Clinical status | Investigational; Phase II trials reported halted for safety concerns, with source-noted FDA enforcement activity in 2025-2026.
| Investigational; Phase II trials discontinued. Listed as FDA Category 2 pending possible reclassification, with formal status not changed in the source.
|
| What to expect | Muscle building, sleep improvement, appetite increase | Anti-aging, muscle building, sleep quality, recovery |
| How it works | MK-677 is described as a selective GHS-R1a agonist. By engaging this ghrelin-associated receptor in growth-hormone regulatory pathways, it can increase growth-hormone signaling and raise IGF-1. The source also links its ghrelin-like activity to appetite effects and notes possible cortisol changes. | Ipamorelin is reported to activate GHS-R1a, the ghrelin or growth hormone secretagogue receptor, on somatotroph cells in the anterior pituitary. The source links this receptor activity to Gq/phospholipase C signaling, IP3 generation, intracellular calcium release, and pulsatile release of stored growth hormone. It also describes ipamorelin as relatively selective in early characterization, with GH-releasing doses not meaningfully increasing ACTH, cortisol, prolactin, FSH, LH, or TSH. Because the mechanism relies on pituitary GH stores, the source indicates that pituitary function and normal feedback biology remain relevant to the response. |
| Typical dosing | 10-25 mg daily · Once daily, often before bed · Oral | 200-300 mcg 2-3x daily · 2-3x daily |
| Research dosing | 10-25 mg daily · 8-12 weeks or longer · Oral | 100-300 mcg per injection · 8-12 weeks typical · Subcutaneous injection |
| Typical duration | 8-12 weeks or longer | 8-12 weeks typical |
| Administration | Oral | Subcutaneous injection |
| Timing | Before bed With or without food | Before bed or morning, fasted Fasted timing reported |
| Evidence level | Clinical Trials | Clinical Trials |
| Possible side effects |
+8 more
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| Research summary | The source describes a mixed human-research picture. In older healthy adults, a one-year randomized study using 25 mg daily was reported to raise IGF-1 and increase fat-free mass, while strength or functional outcomes were not characterized as strong and early weight change was partly attributed to water. In an Alzheimer's disease trial with 563 participants over 12 months, IGF-1 increased but cognitive decline was not slowed. The source consistently flags appetite increase, fluid retention, and reduced insulin sensitivity as recurring tolerability concerns, and notes that the compound remains unapproved. | The source identifies Raun et al. 1998 as early foundational work and describes characterization across rats, pigs, and isolated pituitary cells. It reports that ipamorelin released GH without corresponding ACTH or cortisol increases at doses above the GH-release threshold. The source also notes that human development reached Phase II for postoperative ileus before being discontinued for insufficient efficacy. For popular wellness uses such as anti-aging, fat loss, muscle gain, or recovery, the source states that large peer-reviewed human randomized trials are not available and that these claims are extrapolated from mechanism rather than established outcomes. |
| References | ||
| Full profile | View Details | View Details |
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Track your peptide journeyEducational use only. This information is aggregated from public research and community reports. It is not medical advice, and dosing details are descriptive, not recommendations. Always consult a qualified healthcare professional.