MK-677 (Ibutamoren)

MK-677 (Ibutamoren) at a Glance

MK-677 (ibutamoren) is the odd one out in this group: an orally active, non-peptide ghrelin-receptor agonist, so it survives digestion and is taken as a capsule rather than injected. It raises growth hormone and IGF-1 reliably and durably, and unlike the injectable secretagogues it has been through substantial clinical development, including long-term trials in older adults. Development was not completed and it remains unapproved, sold as a research chemical. Its most consistent effects in those trials were increased appetite and fluid retention alongside the hormonal changes.

History & Development

MK-677 was a Merck drug, and Merck stopped it for a specific and instructive reason: it worked, but not as well as the treatment it was meant to replace.

First described	Reported as an orally active growth-hormone secretagogue in the 1990s 6Reference 6Murphy MG et al. · 1998RCTMK-677, an orally active growth hormone secretagogue, reverses diet-induced catabolism — human (randomised crossover)View study →
Discovered / synthesised by	Merck Research Laboratories 6,9Reference 6Murphy MG et al. · 1998RCTMK-677, an orally active growth hormone secretagogue, reverses diet-induced catabolism — human (randomised crossover)View study →Reference 9Murphy MG et al. · 1999Oral administration of the growth hormone secretagogue MK-677 increases markers of bone turnover in healthy and functionally impaired elderly adults — human (pooled RCTs)View study →
Institution	Merck Research Laboratories
Origin	De-novo non-peptide small molecule; ghrelin-receptor (GHS-R1a) agonist
Key patent	Not established in the sources consulted for this section
Assignee	Merck
Development status	Discontinued - deemed less effective than standard growth-hormone therapy; never approved

Discovery

Growth-hormone secretagogues before MK-677 were peptides, which meant injection. MK-677 - ibutamoren mesylate, development code MK-0677 - is not a peptide at all: it is an orally active small molecule that activates the same ghrelin receptor, and that oral activity was the entire point of the programme.

It appears on this hub as an honorary member. Every other compound here is a peptide; MK-677 is grouped with them because it does the same job through the same receptor, and because it is sold through the same channels.

Merck’s published work established the pharmacology: it reversed diet-induced catabolism in humans ^{6Reference 6Murphy MG et al. · 1998RCTMK-677, an orally active growth hormone secretagogue, reverses diet-induced catabolism — human (randomised crossover)View study →} and raised markers of bone turnover in healthy and functionally impaired elderly adults ^{9Reference 9Murphy MG et al. · 1999Oral administration of the growth hormone secretagogue MK-677 increases markers of bone turnover in healthy and functionally impaired elderly adults — human (pooled RCTs)View study →}. The endocrine effect is real and it is sustained - which distinguishes it from the injectable secretagogues, where tolerance is a recurring question.

Development & ownership

Merck Research Laboratories developed MK-677 and ran a Phase 2b trial in children with short stature and growth-hormone deficiency between 1996 and 1998.

The programme was discontinued, and the reason is the useful part of this history: height-velocity improvements were significantly lower than with standard growth-hormone treatment, so the compound was judged not competitive with existing therapy. It was not stopped for toxicity and not stopped for lack of effect - it was stopped for being worse than what already existed.

That framing matters when reading its retail claims. Merck’s own conclusion was that raising growth hormone this way is a weaker intervention than giving growth hormone.

How it reached the market

MK-677 has never been approved for any indication, anywhere. It reached consumers through the research-chemical market, where it is sold for muscle gain, appetite and sleep - and it is banned in sport. Its most consistent effects, appetite stimulation and fluid retention, are the ones users most often report as unwanted.

What It's Used For

MK-677 (ibutamoren; also written MK-0677 or ibutamoren mesylate) is not a peptide at all — it is a small-molecule spiroindoline that agonizes the ghrelin receptor (GHSR-1a), the same receptor the stomach hormone ghrelin acts on, prompting the pituitary to release more of the body’s own growth hormone (GH). It sits alongside the injectable GH secretagogues (the GHRPs) because it drives the same axis, but it differs in the way that matters most to anyone deciding whether to use it: it works by mouth, once a day. Every other compound in this corner — GHRP-2, GHRP-6, ipamorelin, hexarelin, CJC-1295 — is a peptide destroyed by digestion and therefore injected. MK-677 was purpose-engineered to survive the gut, and that single property is why it dominates gray-market GH stacks. Unusually for this hub, it also has a genuine base of published, placebo-controlled human trials: several small studies in the 1990s and two large multi-year randomized trials in the 2000s. The honest read of that evidence is that it reliably moves the biomarker but not the outcome — MK-677 dependably raises GH and IGF-1 by roughly 40–90%, but the two large trials designed to show that this helps (a 2-year body-composition study in healthy older adults and a 12-month trial in Alzheimer’s disease) both hit their biochemical target and then failed to deliver any clinical benefit. It was never approved for any indication, in any country: it is an investigational drug, sold gray-market as a research chemical and banned in sport.

Evidence by IndicationStrength of support · Beta

Support is an experimental score I’m building — a composite weighted by study type (human > animal > in vitro > review) and study volume. It’s a beta: a fast way to rank strength of evidence at a glance, not a validated metric. Each application links down to its write-up.

01Raising the GH / IGF-1 axisPromising72%Multiple human RCTs, dose–response, receptor mechanism proven by cryo-EM — but this is a biomarker, not an outcome ^{1,2,7,8,11Reference 1Chapman IM et al. · 1996RCTStimulation of the growth hormone (GH)-insulin-like growth factor I axis by daily oral administration of a GH secretagogue (MK-677) in healthy elderly subjects — human (RCT)View study →Reference 2Sevigny JJ et al. · 2008RCTGrowth hormone secretagogue MK-677: no clinical effect on AD progression in a randomized trial — human (RCT, n=563)View study →Reference 7Copinschi G et al. · 1996RCTEffects of a 7-day treatment with a novel, orally active GH secretagogue, MK-677, on 24-hour GH profiles, IGF-I, and adrenocortical function in normal young men — human (RCT)View study →Reference 8Svensson J et al. · 1998RCTTwo-month treatment of obese subjects with the oral growth hormone secretagogue MK-677 increases GH secretion, fat-free mass, and energy expenditure — human (RCT)View study →Reference 11Liu H et al. · 2021In vitroStructural basis of human ghrelin receptor signaling by ghrelin and the synthetic agonist ibutamoren — in vitro (cryo-EM structure)View study →}

02Lean (fat-free) mass in older adultsPromising52%2-year human RCT (n=65): lean mass ↑, but no gain in strength or function ^{3Reference 3Nass R et al. · 2008RCTEffects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults — human (RCT, 2-year)View study →}; 8-week obese-male RCT ^{8Reference 8Svensson J et al. · 1998RCTTwo-month treatment of obese subjects with the oral growth hormone secretagogue MK-677 increases GH secretion, fat-free mass, and energy expenditure — human (RCT)View study →}

03Pediatric growth-hormone deficiency (as LUM-201)Promising48%Human Phase 2 complete, Phase 3 recruiting; oral GH response exceeded standard secretagogues in a responder subset ^{10Reference 10Bright GM · 2022Clinical trialA GH secretagogue receptor agonist (LUM-201) elicits greater GH responses than standard GH secretagogues in subjects with pediatric growth hormone deficiency — human (clinical trial)View study →}

04Sleep qualityShaky40%One human crossover trial (n=8 young, 6 older): ↑ stage-IV and REM sleep ^{5Reference 5Copinschi G et al. · 1997Prolonged oral treatment with MK-677, a novel growth hormone secretagogue, improves sleep quality in man — human (crossover trial)View study →}

05Reversing diet-induced catabolismShaky38%One human crossover trial (n=8): nitrogen balance restored under caloric restriction ^{6Reference 6Murphy MG et al. · 1998RCTMK-677, an orally active growth hormone secretagogue, reverses diet-induced catabolism — human (randomised crossover)View study →}

06Bone turnoverShaky35%Pooled human elderly RCTs: bone-formation markers ↑ — turnover markers, not BMD or fracture outcomes ^{9Reference 9Murphy MG et al. · 1999Oral administration of the growth hormone secretagogue MK-677 increases markers of bone turnover in healthy and functionally impaired elderly adults — human (pooled RCTs)View study →}

07Functional recovery after hip fractureShaky30%Human Phase IIb RCT (n=123): gait speed ↑ but most measures null; terminated early for a CHF signal ^{4Reference 4Adunsky A et al. · 2011RCTMK-0677 (ibutamoren mesylate) for the treatment of patients recovering from hip fracture: a multicenter, randomized, placebo-controlled Phase IIb study — human (RCT, terminated early)View study →}

08Alzheimer’s disease progressionShaky12%Large 12-month human RCT (n=563): null despite +73% IGF-1 ^{2Reference 2Sevigny JJ et al. · 2008RCTGrowth hormone secretagogue MK-677: no clinical effect on AD progression in a randomized trial — human (RCT, n=563)View study →} — a well-evidenced negative

Mechanisms

Pharmacokinetics

Oral activity is the whole point of this molecule — and the single fact that reframes everything else on the page. The GH secretagogues it is grouped with are peptides with negligible oral bioavailability: swallow them and they are digested, which is why GHRP-2, GHRP-6, ipamorelin and hexarelin are injected. MK-677 is not a peptide, and it was deliberately designed as an orally bioavailable non-peptide mimic of the GH-releasing peptides, so that constraint simply doesn’t apply. A single oral dose produces a measurable plasma time-course (characterized by a validated picogram-level LC-MS assay) ^{13Reference 13Constanzer ML et al. · 1997Determination of a novel growth hormone secretagogue (MK-677) in human plasma at picogram levels by liquid chromatography–tandem mass spectrometry — human (analytical/PK method)View study →}, and a once-daily 25 mg schedule is what every major trial used ^{1,3Reference 1Chapman IM et al. · 1996RCTStimulation of the growth hormone (GH)-insulin-like growth factor I axis by daily oral administration of a GH secretagogue (MK-677) in healthy elderly subjects — human (RCT)View study →Reference 3Nass R et al. · 2008RCTEffects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults — human (RCT, 2-year)View study →} — implying a duration of action long enough to sustain elevated 24-hour GH and IGF-1 on one dose per day. The IGF-1 rise builds over weeks to a plateau and reflects amplification of the body’s own pulsatile GH secretion, not a continuous “GH clamp.” Metabolism is hepatic; the published metabolite profiling was performed in equine liver microsomes for anti-doping purposes rather than in humans ^{14Reference 14Philip M et al. · 2021In vitroCharacterization of equine liver microsome-generated metabolites of the growth hormone secretagogue small molecule ibutamoren — in vitro (equine microsomes)View study →}. A precisely reported human elimination half-life and oral bioavailability figure are not documented in the primary literature checked here, and none is invented. As a small molecule it needs no reconstitution, sterile technique or cold chain — which removes the injection-specific hazards of the peptide stack but does nothing about the identity and purity problem described below.

Clinical & regulatory status

MK-677 is an investigational drug that was never approved by the FDA, EMA, TGA or any other major regulator, for any indication, despite an extensive Merck development program in the 1990s–2000s and two large randomized trials. It is not a dietary supplement and not a peptide; internationally it circulates as a “research chemical” labeled not for human consumption, and analytical surveys have found ibutamoren present as an undeclared ingredient in products sold online as something else ^{15Reference 15Van Wagoner RM et al. · 2017Chemical composition and labeling of substances marketed as selective androgen receptor modulators and sold via the internet — analytical study (ibutamoren found as an undeclared adulterant)View study →}. It is prohibited in sport by WADA (class S2, hormone and metabolic modulators / growth-hormone secretagogues). The one active approval pathway is the pediatric-GHD program run by Lumos Pharma as LUM-201, now in Phase 3 (NCT06948214, recruiting; long-term safety extension NCT07129759 not yet recruiting). Registered adult trials cluster around body composition (NCT00474279, completed), Alzheimer’s disease (NCT00074529, completed), post-hip-fracture sarcopenia (NCT00128115, terminated), fibromyalgia (NCT00116129, completed), end-stage renal disease (NCT00395291, completed) and non-alcoholic fatty liver disease (NCT05364684, completed, n=12) — nearly all complete, none leading to approval. Registry statuses below were checked directly against the ClinicalTrials.gov API.

Last checked: July 2026.

Sourcing, Route & Legal Status

Regulatory status. MK-677 has never been approved by the FDA or any major regulator for any indication. Merck ran a large clinical program in the 1990s–2000s and, despite completed trials in body composition, Alzheimer’s disease, fibromyalgia and renal wasting, none led to approval. It is therefore an unapproved investigational drug — not a dietary supplement, not a medicine, and not legally marketable for human use in the US, UK, EU or Australia. The only active regulatory pathway is the pediatric growth-hormone-deficiency program under the name LUM-201 (Lumos Pharma), now in Phase 3; that program does not make adult gray-market use legal or safe. MK-677 is on the WADA Prohibited List (S2, growth-hormone secretagogues) and is therefore banned for competitive athletes both in and out of competition. It is not a scheduled/controlled substance in the US — but “not scheduled” is not “approved.”

How it’s supplied & administered. Unlike the injectable GH-releasing peptides, MK-677 is a small molecule that is orally active, and it is sold as capsules, tablets, or (most commonly on the gray market) an oral liquid or bulk powder. The trial dose is 25 mg once daily by mouth. Because it is not a peptide it requires no reconstitution, no sterile injection and no cold-chain storage — which removes the injection-specific hazards of the rest of this hub but does not remove the identity and purity problem below. If anything, the ease of oral dosing lowers the barrier to casual use.

Sourcing reality (this is a safety issue, not a footnote). MK-677 is sold by unregulated vendors as a “research chemical” labeled not for human consumption — a labeling fiction that provides no quality assurance whatsoever. There is no manufacturing oversight, and products in this channel are frequently mislabeled: an analytical study of 44 products sold online as SARMs found only about half contained what the label claimed, roughly a quarter contained substances not listed on the label, and ibutamoren specifically was detected as an undeclared adulterant in products sold as something else ^{15Reference 15Van Wagoner RM et al. · 2017Chemical composition and labeling of substances marketed as selective androgen receptor modulators and sold via the internet — analytical study (ibutamoren found as an undeclared adulterant)View study →}. The risk runs in both directions — a product sold as MK-677 may contain little, none, or a different drug entirely, and a product sold as a SARM or “supplement” may contain MK-677 the buyer never intended to take. Without an independent third-party certificate of analysis (identity, purity and quantification), a buyer cannot know the dose or even the molecule. This page does not recommend or link vendors.

Safety

Unusually for a research chemical, MK-677’s adverse effects come from real human trials rather than inference — and the metabolic cost is the dose-limiter, with reduced insulin sensitivity and raised fasting glucose. One trial was stopped early for heart failure in treated patients.

Safety at a Glance

⚠️ Moderate toxicityCardiac riskCardiac cautionDrug interactions

• Reduced insulin sensitivity and raised fasting glucose. The dose-limiting effect, seen in the 2-year trial and consistent with GH physiology.
• A Phase IIb trial was terminated early for congestive heart failure. It occurred in exactly the frail, older group the anti-aging framing targets.
• Not assessed in pregnancy or breastfeeding. No human or animal reproductive data — see the box below.
• Fluid retention and edema. Transient mild lower-extremity swelling, alongside muscle and joint pain.
• Sustained IGF-1 elevation. A theoretical neoplasia concern that no trial was long enough to exclude.
• Glycemic control can drift on anti-diabetic or insulin therapy. No formal interaction program exists — this is mechanistic caution.

Full Safety & Interactions Detail

Overall posture. Unusually for this hub, the adverse-effect profile comes from real human trials rather than inference, and it is consistent across them. The most common effects are increased appetite (a direct ghrelin-receptor effect, often sustained rather than transient, and the reason weight gain is near-universal), fluid retention with transient mild lower-extremity edema, and muscle and joint pain ^{3Reference 3Nass R et al. · 2008RCTEffects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults — human (RCT, 2-year)View study →}. The metabolically important — and effectively dose-limiting — effect is reduced insulin sensitivity with raised fasting blood glucose, seen in the 2-year body-composition trial and entirely consistent with GH physiology ^{3Reference 3Nass R et al. · 2008RCTEffects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults — human (RCT, 2-year)View study →}. Because MK-677 sustains an elevation in IGF-1, there is a theoretical concern around any IGF-1-sensitive process, neoplasia included; no cancer signal was demonstrated in the trials, but none was designed or long enough to exclude one, and long-term safety is not established.

The most serious documented signal. The Phase IIb hip-fracture trial was terminated early because of cases of congestive heart failure in treated patients ^{4Reference 4Adunsky A et al. · 2011RCTMK-0677 (ibutamoren mesylate) for the treatment of patients recovering from hip fracture: a multicenter, randomized, placebo-controlled Phase IIb study — human (RCT, terminated early)View study →}. That is a real, registry-confirmed termination in exactly the frail, older demographic the anti-aging framing targets — and it carries particular weight for anyone with existing cardiac risk, given the drug’s fluid-retention effect.

Interactions. No formal drug-interaction program exists. On mechanism, caution is warranted with anti-diabetic and insulin therapy (MK-677 opposes insulin sensitivity and raises glucose, so glycemic control can drift), and with any drug or condition where GH/IGF-1 elevation is undesirable. These are mechanistic cautions, not tested findings.

Who should avoid it. Anyone with diabetes or impaired glucose tolerance; anyone with heart failure or significant cardiac risk; anyone with active or prior malignancy; and anyone pregnant, breastfeeding or trying to conceive. Children should only ever receive this molecule inside the supervised LUM-201 clinical program, never from the gray market. Competitive athletes are subject to a WADA ban.

Scope disclosure (honesty, not a claim):

• Human data? Yes — multiple RCTs, including two large multi-year trials. That is unusual for this hub. But the outcome trials were null on the endpoints that matter, and no approval resulted anywhere.
• Interactions assessed? No formal interaction program — only mechanism-based cautions (anti-diabetic agents, GH-axis drugs).
• Pregnancy/lactation assessed? No — no human or animal reproductive data located.
• Long-term safety established? No. The longest trial ran 2 years, and a separate trial was stopped early for a heart-failure signal. Multi-year cardiac and cancer outcomes are unstudied.

Never imply safety from silence. Where MK-677 has not been studied — interactions, pregnancy, long-term cardiac and neoplasia risk, gray-market product purity — the correct statement is “not assessed,” not “safe.”

Pregnancy & Lactation

? Not established in pregnancy? Not established in lactation

Not assessed / not established. There are no human pregnancy or lactation data for MK-677. A GH/IGF-1-raising investigational drug should be treated as contraindicated by default in pregnancy and breastfeeding.

Dosage

There is no approved human dose for MK-677, and none is recommended here. It is not an approved medicine or dietary supplement in any jurisdiction, and the figure below is data reported for context, not a personal recommendation.

Essentially every human trial used 25 mg orally once daily ^{1,3,4,5,6Reference 1Chapman IM et al. · 1996RCTStimulation of the growth hormone (GH)-insulin-like growth factor I axis by daily oral administration of a GH secretagogue (MK-677) in healthy elderly subjects — human (RCT)View study →Reference 3Nass R et al. · 2008RCTEffects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults — human (RCT, 2-year)View study →Reference 4Adunsky A et al. · 2011RCTMK-0677 (ibutamoren mesylate) for the treatment of patients recovering from hip fracture: a multicenter, randomized, placebo-controlled Phase IIb study — human (RCT, terminated early)View study →Reference 5Copinschi G et al. · 1997Prolonged oral treatment with MK-677, a novel growth hormone secretagogue, improves sleep quality in man — human (crossover trial)View study →Reference 6Murphy MG et al. · 1998RCTMK-677, an orally active growth hormone secretagogue, reverses diet-induced catabolism — human (randomised crossover)View study →} — a single daily oral dose sufficient to sustain elevated 24-hour GH and IGF-1, which is precisely what distinguishes MK-677 from the injected GH secretagogues. Dose-ranging work in the 1990s established that the effect is dose-dependent ^{1Reference 1Chapman IM et al. · 1996RCTStimulation of the growth hormone (GH)-insulin-like growth factor I axis by daily oral administration of a GH secretagogue (MK-677) in healthy elderly subjects — human (RCT)View study →}, and no trial established a safe long-term dose or duration; the 2-year body-composition study is the longest exposure on record, and it is also the study that documented the fall in insulin sensitivity ^{3Reference 3Nass R et al. · 2008RCTEffects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults — human (RCT, 2-year)View study →}. Because the compound is orally active, gray-market products are swallowed rather than injected — which makes casual and prolonged use easier, not safer, and does nothing to address the finding that products in this channel are routinely mislabeled ^{15Reference 15Van Wagoner RM et al. · 2017Chemical composition and labeling of substances marketed as selective androgen receptor modulators and sold via the internet — analytical study (ibutamoren found as an undeclared adulterant)View study →}. This entry is informational only.

References

1. Chapman IM, Bach MA, Van Cauter E, et al. (1996). Stimulation of the growth hormone (GH)-insulin-like growth factor I axis by daily oral administration of a GH secretagogue (MK-677) in healthy elderly subjects — human (RCT). Journal of Clinical Endocrinology & Metabolism. https://pubmed.ncbi.nlm.nih.gov/8954023/
2. Sevigny JJ, Ryan JM, van Dyck CH, et al. (2008). Growth hormone secretagogue MK-677: no clinical effect on AD progression in a randomized trial — human (RCT, n=563). Neurology. https://pubmed.ncbi.nlm.nih.gov/19015485/
3. Nass R, Pezzoli SS, Oliveri MC, et al. (2008). Effects of an oral ghrelin mimetic on body composition and clinical outcomes in healthy older adults — human (RCT, 2-year). Annals of Internal Medicine. https://pubmed.ncbi.nlm.nih.gov/18981485/
4. Adunsky A, Chandler J, Heyden N, et al. (2011). MK-0677 (ibutamoren mesylate) for the treatment of patients recovering from hip fracture: a multicenter, randomized, placebo-controlled Phase IIb study — human (RCT, terminated early). Archives of Gerontology and Geriatrics. https://pubmed.ncbi.nlm.nih.gov/21067829/
5. Copinschi G, Leproult R, Van Onderbergen A, et al. (1997). Prolonged oral treatment with MK-677, a novel growth hormone secretagogue, improves sleep quality in man — human (crossover trial). Neuroendocrinology. https://pubmed.ncbi.nlm.nih.gov/9349662/
6. Murphy MG, Plunkett LM, Gertz BJ, et al. (1998). MK-677, an orally active growth hormone secretagogue, reverses diet-induced catabolism — human (randomised crossover). Journal of Clinical Endocrinology & Metabolism. https://pubmed.ncbi.nlm.nih.gov/9467534/
7. Copinschi G, Van Onderbergen A, L’Hermite-Balériaux M, et al. (1996). Effects of a 7-day treatment with a novel, orally active GH secretagogue, MK-677, on 24-hour GH profiles, IGF-I, and adrenocortical function in normal young men — human (RCT). Journal of Clinical Endocrinology & Metabolism. https://pubmed.ncbi.nlm.nih.gov/8768828/
8. Svensson J, Lönn L, Jansson JO, et al. (1998). Two-month treatment of obese subjects with the oral growth hormone secretagogue MK-677 increases GH secretion, fat-free mass, and energy expenditure — human (RCT). Journal of Clinical Endocrinology & Metabolism. https://pubmed.ncbi.nlm.nih.gov/9467542/
9. Murphy MG, Bach MA, Plotkin D, et al. (1999). Oral administration of the growth hormone secretagogue MK-677 increases markers of bone turnover in healthy and functionally impaired elderly adults — human (pooled RCTs). Journal of Bone and Mineral Research. https://pubmed.ncbi.nlm.nih.gov/10404019/
10. Bright GM, Thorner MO. (2022). A GH secretagogue receptor agonist (LUM-201) elicits greater GH responses than standard GH secretagogues in subjects with pediatric growth hormone deficiency — human (clinical trial). Hormone Research in Paediatrics. https://pubmed.ncbi.nlm.nih.gov/35354138/
11. Liu H, Sun D, Myasnikov A, et al. (2021). Structural basis of human ghrelin receptor signaling by ghrelin and the synthetic agonist ibutamoren — in vitro (cryo-EM structure). Nature Communications. https://pubmed.ncbi.nlm.nih.gov/34737341/
12. Campbell GA, et al. (2018). Oral ghrelin receptor agonist MK-0677 increases serum insulin-like growth factor 1 in hemodialysis patients — human (randomised blinded study). Nephrology Dialysis Transplantation. https://pubmed.ncbi.nlm.nih.gov/28340044/
13. Constanzer ML, Chavez-Eng CM, Matuszewski BK. (1997). Determination of a novel growth hormone secretagogue (MK-677) in human plasma at picogram levels by liquid chromatography–tandem mass spectrometry — human (analytical/PK method). Journal of Chromatography B. https://pubmed.ncbi.nlm.nih.gov/9200526/
14. Philip M, et al. (2021). Characterization of equine liver microsome-generated metabolites of the growth hormone secretagogue small molecule ibutamoren — in vitro (equine microsomes). Rapid Communications in Mass Spectrometry. https://pubmed.ncbi.nlm.nih.gov/34542924/
15. Van Wagoner RM, Eichner A, Bhasin S, et al. (2017). Chemical composition and labeling of substances marketed as selective androgen receptor modulators and sold via the internet — analytical study (ibutamoren found as an undeclared adulterant). JAMA. https://pubmed.ncbi.nlm.nih.gov/29183075/

View all 15 references▾