At a glance
Effects
- Elevated GH & IGF-1: A single 25 mg dose can maintain serum GH and IGF-1 significantly above baseline for a full 24-hour period; IGF-1 rises were consistent across multiple clinical trials [1][7].
- Lean-mass preservation: In a two-year Merck study, placebo subjects lost ~0.5 kg of lean mass while ibutamoren-treated subjects gained 1–2 kg, reversing age-related catabolism [6].
- Improved slow-wave sleep: Ghrelin-receptor agonism profoundly deepens sleep; EEG data suggest meaningful increases in stage IV slow-wave and REM sleep duration [4].
- Bone mineral density: Long-term use (12+ months) increased bone-building markers (osteocalcin) in elderly adults and bone mineral density in post-menopausal women in multiple studies [4][5].
- Anti-catabolic / muscle wasting: In a PubMed-indexed RCT, MK-677 reversed diet-induced nitrogen wasting, maintaining positive nitrogen balance even during caloric restriction [7].
- Increased appetite: As a ghrelin mimetic, hunger stimulation is a direct, pharmacologically expected and very consistent effect [3][4].
Growth hormone secretagogue (GHS) — NOT a SARM
~4–6 h (molecular); pharmacodynamic IGF-1 effect lasts ~24 h [1]
Oral (tablet / liquid); ~60–70% bioavailability [1]
GH rises within 30–60 min; body-composition changes take 2–8 weeks [8]
Unapproved / investigational — banned by WADA and DoD; illegal in dietary supplements [2]
About Ibutamoren
Every point here is drawn from public medical and harm-reduction sources. A bracketed number after a claim — like [1]— is a reference: tap it to open the exact source it's based on (numbered list at the bottom). It is not a rating or score. Educational information, not medical advice.
Product specifics
- Est. delivery
- 3–7 business days · EU tracked
Product details as stated by the vendor (claims, not independently verified). Delivery is our standard EU estimate.
What it is
Ibutamoren (MK-677) is a non-peptide, orally active growth hormone secretagogue (GHS) — not a SARM — investigated for muscle wasting, age-related GH decline, and bone density [1][2]. It stimulates the body's own pituitary to release growth hormone and IGF-1 without directly administering exogenous hormones [3].
How it works
MK-677 acts as a potent agonist of the ghrelin receptor (GHSR-1a) in the hypothalamus and anterior pituitary, mimicking the endogenous hunger hormone ghrelin [1][3]. Receptor activation amplifies both the frequency and amplitude of the body's natural pulsatile GH release by reinforcing GHRH signalling and simultaneously suppressing somatostatin's braking effect [3][5]. The resulting GH surge then drives the liver to produce IGF-1, the primary downstream anabolic mediator [3]. Unlike exogenous HGH injections, this mechanism acts upstream so that natural pituitary pulsatility is broadly preserved rather than shut down [1].
Risks & side effects
Most important: A clinical trial in elderly adults was stopped at 24 weeks because participants in the MK-677 arm showed an increased rate of congestive heart failure — a signal serious enough for the FDA to flag it as posing "significant safety risks due to the potential for congestive heart failure in certain patients" [2][8]. Separately, MK-677 consistently raises fasting blood glucose, blunts insulin sensitivity, and elevates HbA1c, meaning metabolic and cardiovascular harm are the dominant concerns, especially with long-term use [4][9].
Common
- Increased appetite / hyperphagia (direct pharmacological effect of ghrelin-receptor agonism) [3]
- Water retention / peripheral oedema [2][9]
- Fatigue, lethargy (especially early in use) [2]
- Muscle or joint aches / transient joint pain [2]
- Mild numbness or tingling (carpal-tunnel-like) [9]
- Elevated fasting blood glucose [2][4]
- Headaches [9]
- Nausea or diarrhoea [2]
Serious
- Insulin resistance and impaired glucose tolerance progressing to hyperglycaemia — confirmed across multiple Phase 2 studies [4][9]
- Elevated blood pressure (systolic and diastolic increases noted in subjects over 60 in clinical trials) [8]
- Risk of congestive heart failure — one trial stopped early due to this signal; FDA has issued formal warnings [2][8]
- Long-term safety entirely unknown — no approved human use; potential organ effects (heart, liver, kidney) remain unstudied at duration [9]
- Anxiety and mood changes reported by users [9]
- Theoretical IGF-1-mediated tumour-growth promotion with long-term sustained elevation [4]
Rare
- Worsening of pre-existing congestive heart failure through fluid retention [3]
- Possible contribution to cancer growth via sustained IGF-1 elevation (unconfirmed in humans but mechanistically plausible) [4]
- No androgenic or oestrogenic effects reported — but hormonal system interactions at prolonged use remain incompletely characterised [1]
Safety & harm reduction
- History of congestive heart failure or cardiac dysfunction — fluid retention risk is severe [2][8]
- Active or prior cancer — sustained IGF-1 elevation may promote tumour growth [4]
- Pre-existing diabetes or significant insulin resistance — glucose control will worsen [4][9]
- Elderly patients (≥60) — highest-risk population per available clinical data; CHF signal was strongest in this group [3]
- Pregnant or breastfeeding individuals — no safety data whatsoever [2]
- Competitive athletes — banned by WADA; presence of MK-677 in urine constitutes a doping violation [2]
- Fasting blood glucose and HbA1c before starting and every 4–8 weeks — glucose elevation is consistent and predictable [4]
- Blood pressure at baseline and regularly throughout use, especially in older users [8]
- Serum IGF-1 — to track GH-axis activation and avoid sustained supra-physiological elevation [1]
- Cardiac function / fluid-retention symptoms (ankle swelling, shortness of breath) — discontinue immediately if present [2]
- Lipid panel — GH axis changes can alter lipid metabolism [9]
- Corticosteroids — additive fluid retention, may increase oedema and CHF risk [3]
- Insulin or oral antidiabetics — MK-677 opposes insulin sensitivity; glucose-lowering drug requirements may change unpredictably [4]
- Other GH-axis compounds (GHRH analogues, recombinant HGH, other GHRPs) — additive/synergistic GH/IGF-1 elevation; combined safety not established [3]
- Antihypertensives — blood pressure effects of MK-677 may blunt therapeutic benefit [8]
- Not an oral androgen — liver support and PCT are not required on this basis; however, metabolic support (blood-glucose monitoring, controlled carbohydrate intake) is essential [1][4]
- Start at the lower end of the research-reported range (10 mg/day) to assess individual glucose and appetite response before any dose increase [7]
- Evening dosing is sometimes preferred to align lethargy/appetite surge with sleep and leverage nocturnal GH pulse, though morning dosing was used in most clinical trials [4]
- Because pharmacodynamic effects outlast the molecular half-life, once-daily dosing is sufficient — more frequent dosing is not supported by evidence and increases side-effect burden [1]
Dosage context
Clinical trials used 10–25 mg orally once daily; the 25 mg/day dose appears in the majority of published human trials showing meaningful IGF-1 and lean-mass outcomes [1][7]. No strong evidence supports doses above 25 mg — side effects including water retention, appetite stimulation, and glucose elevation scale with dose [7]. These are research-reported ranges only, not a prescription or recommendation. Long-term safety data are absent [9].
Sources
- 1.Loti Labs — MK-677 Research Guide 2026 (mechanism & PK)
- 2.OPSS / DoD — MK-677 Performance Enhancing Substance Profile
- 3.Kimerachems — MK-677 Mechanism & GH/IGF-1 Axis Overview
- 4.Bodynutrition.org — MK-677 Clinical Evidence Guide 2026
- 5.TransformYou — MK-677 Explanation, Benefits, Side Effects
- 6.University of Maryland HSHSL — Ibutamoren Mesylate Summary Report (Merck trial data)
- 7.PeptideDeck — MK-677 Dosage Guide 2026
- 8.Besthghdoctor — MK-677 Side Effects & Benefits (cardiovascular trial data)
- 9.Healthy Male (Australia) — MK-677 Side Effects
- 10.Sport Integrity Australia — Ibutamoren MK-677 Information (link unavailable)
- 11.PubMed — Murphy MG et al. (MK-677 reverses diet-induced catabolism, 1998)
- 12.GetSmartAboutDrugs.gov — Beyond the Hype: Potential Health Risks of MK-677
- 13.PeptideProtocolWiki — Ibutamoren Side Effects & Safety Profile
- 14.AAIClinics — What is Ibutamoren MK-677?
This information is provided for educational and harm-reduction purposes only. It is not medical advice. These substances can carry serious health risks; effects and safe use vary by individual. Consult a qualified healthcare professional before use. Legal status varies by country — it is your responsibility to know your local law. We do not encourage misuse.
Other options for Ibutamoren· 3 offers
Same compound from different labs/brands and pack sizes. Tap a row to switch brand — the price and buy button update instantly.
This compound comes in different forms (e.g. injectable vs oral vs topical). Cost per mg is only comparable within the same form.
| Brand | Form | Strength | Pack | Price | Per mg |
|---|---|---|---|---|---|
Intex PharmaSelected | blister-pack | 10 mg/tab | 60 tab | 124,99 € | €0.208/mg |
Generic | oral-liquid | 20 mg/ml | 50 ml | 129,99 € | €0.130/mg |
Generic | oral-liquid | 20 mg/ml | 100 ml | 219,99 € | ★€0.110/mg |