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MK-677 (Ibutamoren)Small moleculeNo amino acid sequence. Icon reflects category theme only.Also known as: MK-677, MK-0677, Ibutamoren
A two-year randomized controlled trial in healthy adults aged 60 to 81. That is what separates MK-677 from most research compounds in the GH space. MK-677 (Ibutamoren, CAS 159634-47-6) is an oral ghrelin receptor agonist that raises IGF-1 levels 40 to 60 percent within weeks of daily dosing. The Nass 2008 trial [1] confirmed fat-free mass gains of roughly 1.1 kg over 12 months at 25 mg/day with no pituitary suppression. Sleep quality improvements often show up within the first week. The tradeoff: appetite increases are near-universal, and fasting glucose trends upward with prolonged use.
Forty to 60 percent IGF-1 elevation from a capsule you take at bedtime. That is the consistent finding across five peer-reviewed RCTs spanning 1996 to 2008, and it is why MK-677 (Ibutamoren, MK-0677, CAS 159634-47-6) remains the most studied oral GH secretagogue on the market. MK-677 is a non-peptide small molecule (C27H36N4O5S, 528.67 Da) that activates the GHSR-1a receptor, the same receptor targeted by endogenous ghrelin. Unlike injectable GH peptides, it bypasses needles entirely. A single oral dose triggers pulsatile GH release from the pituitary that persists for roughly 24 hours, despite a plasma half-life of only 4 to 6 hours. Community adoption runs deep. The dedicated r/MK677 subreddit has over 1,400 members, and thousands of posts across r/peptides, r/steroids, and r/Nootropics describe consistent patterns: better sleep within days, visible body recomposition by weeks 8 to 12, and appetite increases that range from manageable to overwhelming depending on dose. The standard community protocol (25 mg oral at bedtime, 8 to 16 weeks on, 4 to 8 weeks off) maps almost exactly to the Nass 2008 RCT dose. The safety record is mixed. Nass 2008 showed no pituitary suppression after 24 months of continuous dosing. But a separate hip fracture trial in elderly patients (Adunsky 2011)[2] was terminated early after the MK-677 arm showed a 6.5 percent congestive heart failure rate versus 1.7 percent in placebo. That signal restricts confident use in older adults with cardiac risk factors. MK-677 has no FDA approval and remains classified as a research compound.
MK-677 binds to the growth hormone secretagogue receptor type 1a (GHSR-1a) in the pituitary gland and hypothalamus. This is the same receptor that endogenous ghrelin activates to signal hunger and trigger GH release. The binding event triggers a calcium-dependent signaling cascade inside somatotroph cells, producing pulsatile growth hormone secretion that mimics the body's natural pattern. The liver responds to circulating GH by synthesizing IGF-1 (insulin-like growth factor 1). IGF-1 mediates most of the downstream anabolic effects: protein synthesis in skeletal muscle, cell proliferation, and inhibition of programmed cell death. Chapman 1996 [3] confirmed that 25 mg/day for two weeks increased GH pulse amplitude in healthy elderly subjects. Unlike exogenous GH injection, MK-677 does not bypass or suppress the hypothalamic-pituitary axis. The pituitary still receives negative feedback from circulating GH and IGF-1, which limits excessive spikes. Nass 2008 documented no pituitary suppression after 24 months of continuous 25 mg/day dosing. This is a meaningful distinction from recombinant somatropin, which replaces natural GH entirely. The ghrelin receptor activation also drives appetite stimulation. This is not a side effect that varies by individual; it is the mechanism itself. GHSR-1a receptors in the hypothalamus directly increase hunger signaling. At 25 mg, this effect is near-universal. GH also antagonizes insulin action on glucose uptake, which explains the fasting glucose elevation documented in long-term trials.
Oral GH secretagogue with strong RCT evidence for GH/IGF-1 elevation, lean mass gain, and sleep improvement at 10–25 mg/day. No FDA approval. CHF signal in elderly warrants caution.
Nass et al. 2008 (PMID 18981485): 2-year RCT, healthy adults 60–81 yrs, 25 mg/day; increased fat-free mass ~1.1 kg vs. placebo, improved sleep, no pituitary suppression at 24 months. Also: Murphy 1998 (PMID 9467534), Chapman 1996 (PMID 8954023), Copinschi 1997 (PMID 9349662), Svensson 1998 (PMID 9661080).
No RCTs in healthy adults under 40 for body composition. CHF signal from Adunsky hip-fracture trial in elderly (terminated early, 6.5% vs. 1.7% CHF rate). Insulin resistance is dose- and duration-dependent. Half-life data extrapolated from preclinical (canine) models: human PK not formally reported. LUM-201 Phase 3 (Lumos Pharma) targets pediatric GHD only; no adult approval path active.
Most popular oral GH secretagogue. Valued for oral convenience, rapid sleep improvement, and body recomposition. Appetite stimulation and water retention are the top complaints.
Clinical trials used 10–25 mg/day; community standard of 25 mg bedtime exactly matches the Nass 2008 2-year RCT dose. Community cycling (8–16 wks on/off) is more conservative than the continuous 2-year supervised trial protocol: rationale is insulin sensitivity management, not GH-axis protection.
| Level | Dose / Injection | Frequency |
|---|---|---|
| Beginner | 10mg | Daily |
| Moderate | 15mg | Daily |
| Aggressive | 25mg | Daily |
MK-677 is not a peptide. It is a non-peptide small molecule taken orally as a capsule or liquid solution. No reconstitution, no syringes, no bacteriostatic water. That simplicity is a big part of its popularity. The most common formats are 25 mg capsules (60 per bottle) and liquid solutions at 25 mg/mL in 30 mL dropper bottles. For capsules, dosing is straightforward. For liquid, 10 mg equals 0.4 mL, 15 mg equals 0.6 mL, and 25 mg equals 1 mL. Use a calibrated oral syringe for accuracy. Take it 30 to 60 minutes before bed on an empty stomach. Food blunts the GH response. Bedtime dosing lets you sleep through the worst of the appetite spike and aligns peak GH release with your natural nocturnal surge. The thing most beginners miss: monitor fasting glucose. Buy a home glucometer. Check before you start and again at weeks 4 and 8. If you're running 25 mg for longer than 8 weeks, add HbA1c at the 12-week mark. This is not optional at 25 mg.
MK-677 does NOT suppress the hypothalamic-pituitary-GH axis (no PCT required) and does NOT cause GHSR-1a desensitization like injectable GHRPs. Cycling at 25 mg/day is recommended primarily for insulin sensitivity recovery and glycemic monitoring, not receptor or axis health. The Nass 2008 2-year RCT demonstrated sustained efficacy without cycling under supervised clinical conditions. At 10 mg/day, continuous use with quarterly glucose monitoring is an accepted community protocol.
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Expected: Improved sleep quality and depth within 1–2 weeks; modest IGF-1 elevation; mild appetite increase; minor body recomposition over 8–12 weeks
Monitor: Fasting glucose at baseline and 8 weeks; IGF-1 at 8 weeks
Capsules (typically 10 or 25 mg) require no preparation. Liquid solution (typically 25 mg/mL) needs a calibrated oral syringe or dropper.
For liquid at 25 mg/mL: 10 mg = 0.4 mL, 15 mg = 0.6 mL, 25 mg = 1.0 mL. Draw with an oral syringe (not an injection syringe) for accuracy.
Do not eat for at least 2 hours prior. Food, especially carbohydrates, blunts the GH release response.
Swallow the capsule or dispense liquid under your tongue and hold for 30 seconds before swallowing. Sublingual absorption is anecdotal, not confirmed by PK data, but commonly practiced.
Store capsules at room temperature in a cool, dry place away from light. Liquid solutions have shorter shelf life once opened; check vendor instructions (usually 60 to 90 days).
Start at 10 mg daily for weeks 1 through 2 to assess appetite and water retention. Advance to 15 mg, then 25 mg only if metabolic monitoring looks clean.
Check HbA1c every 3 months if running 25 mg beyond 8 weeks. Check IGF-1 at baseline and 8 to 12 weeks.
No bioavailability difference vs. liquid solution: both are oral routes
Most common research-chemical format (10–25 mg capsules). Easier to dose accurately than liquid. Shelf-stable. No refrigeration required.
No bioavailability difference from capsule; measure carefully with calibrated dropper or oral syringe
Typically sold as 25 mg/mL in 30–50 mL dropper bottles. Shorter shelf life once opened. Check excipients (PEG-400, ethanol common). More cost-effective per mg than capsule format from most vendors.
Complementary GH secretagogues: Ipamorelin provides pulsatile GH release (GHSR-1a agonist, SC injection) while MK-677 provides sustained tonic GH elevation (oral). Different routes, additive GH output. Community "belt and suspenders" GH stack.
MK-677 25 mg oral bedtime + Ipamorelin 200–300 mcg SC 2–3×/day
Highly synergistic: CJC-1295 is a GHRH analog acting on GHRH-R (amplifies GH pulse amplitude) while MK-677 acts on GHSR-1a (increases pulse frequency). Complementary receptor mechanisms produce additive/synergistic GH output.
MK-677 25 mg oral bedtime + CJC-1295 (No DAC) 100–300 mcg SC 1–3×/day
Recovery stack: MK-677 elevates GH/IGF-1 systemically; BPC-157 acts locally on connective tissue via NO/growth-factor pathway. No pharmacological interaction. Widely used for injury recovery and tissue healing.
MK-677 10–25 mg oral bedtime + BPC-157 200–300 mcg SC near injury site 1–2×/day
"Wolverine" recovery stack: TB-500 promotes systemic tissue repair via actin regulation; MK-677 provides anabolic GH/IGF-1 support. Complementary mechanisms with no known pharmacological interaction.
MK-677 25 mg oral bedtime + TB-500 2–5 mg SC 2×/week loading, then 2 mg SC/week maintenance
Concurrent use stacks two GH-elevating agents; risks supraphysiological IGF-1 levels and compounds insulin resistance and edema. Adding MK-677 to exogenous HGH has diminishing benefit for most users and multiplies metabolic side-effect burden.
Pricing updated 2026-04-09
The hip fracture trial deserves attention first. Adunsky and colleagues [2] studied MK-677 in elderly patients recovering from hip fracture and terminated the trial early. The MK-677 group had a congestive heart failure rate of 6.5 percent versus 1.7 percent in placebo. This population was older and frailer than typical users, but the signal is real. Adults over 60, anyone with a history of heart failure, or people with conditions worsened by fluid retention should treat this data seriously. Appetite stimulation is the most universal complaint in community reports. MK-677 directly activates GHSR-1a, the ghrelin receptor, so hunger is mechanism-driven, not idiosyncratic. At 10 to 15 mg, most users describe it as manageable. At 25 mg, the word "insatiable" appears in forums with notable frequency. Bedtime dosing helps because you sleep through the peak ghrelin window, but it does not eliminate the effect. Water retention is common and dose-dependent, especially during weeks 1 through 4. Users report 1 to 3 kg of water weight gain. Reducing sodium intake helps. Persistent pitting edema at any dose warrants discontinuation and cardiac evaluation, particularly in adults over 60. Insulin resistance is the long-term concern that deserves the most monitoring. Nass 2008 documented an average fasting glucose increase from 95 to 105 mg/dL over two years at 25 mg/day in healthy elderly subjects. At 10 mg in younger adults, the metabolic effect is likely modest and reversible. At 25 mg, or if you carry risk factors for type 2 diabetes (prediabetes, excess weight, family history), fasting glucose and HbA1c every 3 to 6 months is the minimum monitoring standard. Morning grogginess is a common early complaint. Community users call it the "MK hangover." It typically appears in weeks 1 through 3 and resolves by week 4. Taking the dose 60 to 90 minutes before sleep (not at the moment of lying down) and starting at 10 mg both reduce severity. Vivid dreams are frequently reported and are likely connected to increased stage IV and REM sleep duration. Most users consider this neutral or positive. Lethargy, joint discomfort from water retention, and transient numbness or tingling in the hands have all been reported in community forums. These are typically mild and dose-responsive. There is no human safety data for MK-677 during pregnancy or breastfeeding. Active malignancy is an absolute contraindication because sustained GH and IGF-1 elevation may promote tumor growth.
Verify MK-677 (Ibutamoren) dosing and safety with a second opinion
Research chemical sold through unregulated gray-market vendors; no pharmaceutical-grade GMP product available without prescription. Capsule and liquid products have variable purity and dosing accuracy. Multiple FDA warning letters issued 2024–2026 for mislabeled or undeclared ibutamoren in supplement products.
| Test | When | Target |
|---|---|---|
| Fasting glucose | Baseline; every 4–6 weeks while using | <100 mg/dL; consider dose reduction if >100 mg/dL; discontinue or reduce to 10 mg if >110 mg/dL |
| HbA1c | Baseline; every 3 months on protocols ≥8 weeks | <5.7% (normal); discontinue or reduce dose if trending into pre-diabetic range 5.7–6.4% |
| IGF-1 (serum) | Baseline; every 3 months | Age-adjusted normal; generally <300 ng/mL in adults; values >400 ng/mL warrant dose reduction |
| Comprehensive Metabolic Panel (CMP) | Baseline; every 3–6 months | — |
| Fasting insulin / HOMA-IR | Baseline; every 6 months | — |
MK-677 reduces insulin sensitivity; Nass 2008 documented average increase from 95 to 105 mg/dL over 2 years at 25 mg/day
Chronic glycemic trend; more reliable than spot glucose for sustained protocols
Confirm GH secretagogue response is adequate; detect supraphysiological elevation (potential tumor promotion risk)
Liver enzymes, kidney function, electrolytes: fluid retention can affect electrolyte balance
Early insulin resistance detection before fasting glucose becomes abnormal; particularly relevant at 25 mg/day
Appetite increases noticeably within the first few days. Mild water retention and improved sleep quality often reported by end of week one.
IGF-1 levels rise 40-60% above baseline. Sleep deepens with increased stage IV and REM duration. Vivid dreams are common.
Bone turnover markers increase: osteocalcin rises ~29%. Skin and hair quality begin improving. Strength and recovery show early gains.
Measurable increases in fat-free mass (~1.1 kg over 12 months in clinical data). Body recomposition becomes visible. Bone mineral density trends upward.
Sustained IGF-1 elevation and body composition changes. Monitor fasting glucose closely as insulin sensitivity may decline with prolonged use.
Days 1 through 7: GH pulse amplitude increases from the first dose. IGF-1 begins climbing by days 3 to 5. Copinschi 1997 [5] picked up sleep stage IV improvements in this window. Community users consistently describe deeper sleep and vivid dreams within the first 3 to 7 days. Appetite increase hits by days 2 to 3, especially at 25 mg. Mild water retention is typical. Some morning grogginess is common. Weeks 2 through 4: IGF-1 reaches 40 to 60 percent above baseline per Chapman 1996 and Murphy 1998. Sleep benefits deepen. Workout recovery gets noticeably faster. Water retention usually stabilizes as the body adjusts. Appetite stimulation persists. Vivid or unusual dreams are common. Some users report transient wrist or joint discomfort from fluid. Weeks 4 through 8: Bone turnover markers climb. Svensson 1998 tracked a roughly 29 percent osteocalcin increase. Skin and hair texture begin changing. Lean mass gains show early signs. The "MK hangover" grogginess typically resolves by week 4. Fasting glucose may start trending upward; check it at the 8-week mark. Weeks 8 through 16: This is the peak body recomposition window. Visible composition changes typically appear by weeks 10 to 12. Skin, nail, and hair improvements are consistently reported across community forums. Recovery is at its best. Insulin resistance risk also peaks here. Fasting glucose monitoring is not optional during this phase. Water retention usually plateaus. Off cycle (weeks 1 through 8 post-cessation): GH and IGF-1 return toward baseline within 1 to 2 weeks of stopping. Insulin sensitivity recovers over 4 to 8 weeks. Water retention drops within days. Hunger normalizes within the first week off. Sleep benefits may linger for several weeks. Lean mass gains are largely retained with continued training.
GH pulse amplitude increases within first dose. IGF-1 begins rising by days 3–5. Sleep stage IV begins improving per Copinschi 1997 (PMID 9349662).
Improved sleep depth and vivid dreams within first 3–7 days: most consistent early effect. Hunger increase noticeable by days 2–3, especially at 25 mg.
IGF-1 rises 40–60% above baseline within 2–4 weeks per Chapman 1996 and Murphy 1998. Lean mass accretion begins; fat loss modest at this stage.
Sleep benefits persist and deepen. Workout recovery noticeably faster. Water retention often stabilizes as body adjusts.
Bone turnover markers rise (osteocalcin ~+29% per Svensson 1998). Fat-free mass accumulation continues; fat mass begins declining with maintained training and diet.
Lean mass gains become perceptible. Skin and hair texture improvements begin. Morning grogginess typically resolves by week 4.
Sustained IGF-1 elevation; lean mass accumulation continues. Fasting glucose and insulin resistance risk peak with prolonged use per Nass 2008.
Visible body composition changes typically apparent by weeks 10–12. Skin, nail, and hair improvements consistently reported. Recovery at its best.
GH/IGF-1 return toward baseline within 1–2 weeks of cessation. Insulin sensitivity recovers over 4–8 weeks. Lean mass gains largely retained.
Water retention drops within days of stopping. Hunger normalizes within 1 week. Sleep benefits may persist several weeks post-cycle.
Source: Plasma elimination t½ of 4-6 hours in preclinical models; GH/IGF-1 pharmacodynamic effects persist ~24 hours allowing once-daily dosing
Loading the interactive decay curve.
MK-677 (Ibutamoren) has no FDA approval for any indication. It is classified as a research compound in the United States and most other jurisdictions. Merck developed it through Phase II clinical trials but never pursued a New Drug Application for the adult population. Lumos Pharma is currently running a Phase 3 trial for LUM-201 (oral MK-677 formulation) in pediatric growth hormone deficiency only; no adult approval pathway is active. In the US, MK-677 is sold by research-chemical vendors under the "for research purposes only" designation. The FDA has issued multiple warning letters (2024 through 2026) against companies selling MK-677 as a dietary supplement with undeclared active ingredients. It is not a supplement. Purchasing through compounding pharmacies with a telehealth prescription offers a pharmaceutical-grade alternative at higher cost ($150 to $300 per month). WADA prohibits MK-677 under category S2 (Peptide Hormones, Growth Factors, Related Substances) at all times, both in and out of competition. Hair testing now detects MK-677 months after last use (2025)[7]. Competitive athletes should treat this as a hard disqualification risk. This content is for educational and research purposes only. It is not medical advice. Consult a qualified healthcare provider before using any research compound.
Peptide Schedule Research TeamReviewed Apr 20267 Citations
