# MK-677 MK-677 is on FDA's Category 2 list, so no pharmacy may lawfully make it. It is in no approved drug. The evidence grade is moderate-human: trials show it raises growth hormone, but it did not build strength or slow Alzheimer's disease. Status checked: 2026-10-26. Last verified: 2026-10-26. Primary source: https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks This page has not been individually reviewed by a clinician. Information, not medical advice. | Fact | Value | Tier | Checked | Source | |---|---|---|---|---| | Also called | ibutamoren, ibutamoren mesylate, MK-0677, LUM-201 | primary | 2026-10-26 | [source](https://www.fda.gov/media/182087/download) | | Class | non-peptide | primary | 2026-10-26 | [source](https://www.fda.gov/media/182087/download) | | Regulatory status | category-2 | primary | 2026-10-26 | [source](https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks) | | Status source read | 2026-10-26 | primary | 2026-10-26 | [source](https://www.fda.gov/media/94155/download) | | Evidence grade | moderate-human | our assessment | 2026-10-26 | [source](https://peptideindex.ai/methodology#evidence-grade) | ## Name MK-677 Source: https://www.fda.gov/media/182087/download ## Summary A lab-made small molecule, not a peptide, that makes the body release growth hormone. It is in no FDA-approved drug and is sold online for muscle. Source: https://www.fda.gov/media/182087/download ## Short answer MK-677 is on FDA's Category 2 list, so no pharmacy may lawfully make it. It is in no approved drug. The evidence grade is moderate-human: trials show it raises growth hormone, but it did not build strength or slow Alzheimer's disease. Source: https://peptideindex.ai/methodology#short-answer ## Advisory committee record vote no 13, yes 1, abstain 0, outcome The committee recommended against adding ibutamoren mesylate to the 503A bulks list, as FDA had proposed, meeting date 2024-10-29, indication reviewed Growth hormone shortage, weak bones, hip fracture, muscle loss with age, obesity and Alzheimer's disease Source: https://www.fda.gov/media/185412/download ## Known risks - FDA put MK-677 on Category 2 because it may cause congestive heart failure in some patients. That is when the heart cannot pump enough blood [^1]. - A trial in older people recovering from a broken hip was stopped early after some had heart failure [^14]. - In a trial in healthy older adults, MK-677 raised blood sugar and made the body respond less to insulin [^13]. - The most common problems in that trial were more hunger, mild leg swelling and muscle pain [^13]. - FDA's review lists high blood sugar, raised liver enzymes and fluid build-up in people who took MK-677 in trials [^6]. - In 2025, FDA lab tests found MK-677 hidden in a growth product sold for children. Its label did not list it [^10] [^11]. Source: https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks ## What nobody knows yet - Nobody knows what years of use do. FDA says its long-term effects are unknown [^10]. - A rise in growth hormone or IGF-1 on a blood test is a lab marker. In older adults, more lean mass did not bring more strength or better function [^13]. - High IGF-1 in older people has been tied to disease, death and cancer. FDA says safety data on that risk for MK-677 are lacking [^6]. - A 2018 review says few long-term, well-controlled studies exist. Cancer and death rates with long use still need study [^16]. - Nobody knows if the brain results in mice apply to people. A year-long trial in Alzheimer's disease found no slowing [^18] [^15]. - A phase 3 trial in children short of growth hormone is still recruiting, so its results are not known [^19]. Source: https://www.fda.gov/media/182087/download ## What it is MK-677 is a lab-made small molecule, not a peptide [^6] [^16]. Its drug name is ibutamoren. It also goes by MK-0677 and LUM-201 [^6]. It copies ghrelin, a hormone made mostly in the stomach. It makes the pituitary gland release growth hormone [^6] [^11] [^18]. The pituitary is a small gland at the base of the brain. MK-677 is made to be taken by mouth [^6] [^17]. A drug company made it in 1995 and stopped work on it in 1999 [^6]. Another company now studies it as LUM-201 in children short of growth hormone [^6] [^19]. Online, it is sold to build muscle, lose fat, sleep better and slow aging [^6]. Some sellers call it a SARM. A SARM is a different kind of drug that acts on male hormone receptors. FDA says MK-677 is not a SARM [^6]. Source: https://www.fda.gov/media/182087/download ## Where it stands legally MK-677 is on Category 2, FDA's list of substances that may present significant safety risks in compounding [^1] [^2]. That means no pharmacy may lawfully make it [^3]. It is also in no FDA-approved drug [^6]. Being on the list does not mean FDA has finished its review [^3]. Checked 26 October 2026. FDA keeps lists for two kinds of compounders. A pharmacy is covered by section 503A of the law. An outsourcing facility is covered by section 503B [^3] [^4]. FDA put ibutamoren mesylate on the outsourcing Category 2 list on 29 December 2022. It added it to the pharmacy list on 29 September 2023 [^1]. FDA gave the reason as possible heart failure in some patients [^1]. FDA's pharmacy list of 14 May 2026 still names it in Category 2 [^2]. So does its outsourcing list of 21 March 2025 [^4]. A law firm notes that pharmacies are strictly limited in making any Category 2 substance [^12]. On 29 October 2024, FDA's Pharmacy Compounding Advisory Committee reviewed it for six uses [^5] [^7]. These included growth hormone shortage, weak bones and Alzheimer's disease [^7]. FDA proposed leaving it off the list of substances pharmacies may use. The committee voted 13 to 1 against adding it [^7]. A vote is a recommendation. The final decision is FDA's, made through rulemaking [^3]. MK-677 is not a lawful dietary supplement either. FDA says it was studied as a new drug before anyone sold it as a supplement. That rules it out as a supplement ingredient [^10]. FDA treats products sold for muscle or growth as unapproved new drugs [^8] [^10]. It was reviewed for growth hormone shortage and diseases of aging. It is sold online for muscle and anti-aging [^6] [^7]. Source: https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks ## What the evidence shows The evidence grade is moderate-human: controlled trials show MK-677 raises growth hormone and lean mass [^13] [^14] [^15]. None showed a gain in strength or health, and most measures of function did not change [^13] [^14]. In 65 healthy adults aged 60 to 81, a year of MK-677 raised growth hormone to young-adult levels [^13]. Lean mass rose by about 1 kilogram, but strength and function did not change [^13]. Body weight rose by 2.7 kilograms, against 0.8 on placebo, a dummy pill [^13] [^22]. In 123 older people after a broken hip, MK-677 raised IGF-1 but did not improve most measures of function [^14]. That trial stopped early over heart failure [^14] [^21]. In 563 people with mild to moderate Alzheimer's disease, a year of MK-677 did not slow the disease [^15]. A small US study tested it in adults with fatty liver disease. It is complete, and this page holds no result from it [^20]. In beagles, one dose by mouth raised growth hormone for up to six hours [^17]. In mice bred to model Alzheimer's disease, it reduced plaque in the brain [^18]. These are animal results, not results in people. A rise in growth hormone or IGF-1 is a lab marker. It does not by itself show a benefit [^15] [^16]. FDA's 2024 review found too little evidence that it helps any of the six uses it reviewed [^6]. Source: https://www.fda.gov/media/182087/download ## Legitimate ways to get it No approved drug in the US contains MK-677, and no pharmacy may lawfully make it [^6] [^1]. It cannot be sold as a dietary supplement [^10]. The only legal route is a clinical trial. A phase 3 trial of LUM-201, another name for MK-677, is recruiting children short of growth hormone at US sites [^19]. Open trials are listed in the trials block below, with the date the official registry was last checked. Source: https://clinicaltrials.gov/study/NCT06948214 ## How people are getting it anyway This section describes what happens and is not a recommendation. Three ways of getting MK-677 show up in FDA's records [^6] [^8] [^10]. The first is online sellers that list it beside SARMs, often as a research product. FDA sent warning letters to such sellers in June 2023 and December 2025 [^8] [^9]. FDA said their products are unapproved new drugs, whatever the label says [^8] [^9]. The second is products sold as supplements with MK-677 hidden inside. In 2025, FDA lab tests found it in a growth product for children whose label did not list it [^10] [^11]. The third is pharmacies. FDA found websites that say a compounding pharmacy supplies their MK-677. FDA could not tell if any pharmacy still sells it [^6]. A pharmacy that makes it now is outside the rules, because it is on Category 2 [^1] [^2]. FDA warns that MK-677 may cause heart failure in some people. FDA also says its long-term effects are unknown [^1] [^10]. Source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/dynamic-health-group-dba-sarms-america-719257-12122025 ## Access routes Source: https://www.fda.gov/media/182087/download ### Clinical trial Detail: A phase 3 trial of LUM-201 is recruiting children with growth hormone deficiency at US sites. Open trials are listed in the trials block below, with the date the official registry was last checked. Source: https://clinicaltrials.gov/study/NCT06948214 ## Unofficial channels Source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/dynamic-health-group-dba-sarms-america-719257-12122025 ### Research use seller What it is: Sold online, often labeled for research only and listed beside SARMs, to people seeking muscle or anti-aging. Legal position: FDA says these products are new drugs that need its approval, and none is approved. A research-only label does not change that. (source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/dynamic-health-group-dba-sarms-america-719257-12122025) Documented risks: - FDA says MK-677 may cause congestive heart failure in some patients. (source: https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks) - FDA says use may raise hunger, cause water retention and muscle pain, and change blood sugar control. (source: https://www.fda.gov/drugs/medication-health-fraud-notifications/agebox-ikids-growth-day-formula-may-be-harmful-due-hidden-ingredient) Enforcement: - 2023-06-12: FDA warning letter to an online seller of products sold as SARMs, including MK-677. (source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/warrior-labz-sarms-655280-06122023) - 2025-12-12: FDA warning letter to an online seller of products sold as SARMs, including MK-677. (source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/dynamic-health-group-dba-sarms-america-719257-12122025) Source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/dynamic-health-group-dba-sarms-america-719257-12122025 ### Counterfeit or diverted What it is: Sold as a dietary supplement with MK-677 hidden inside and not listed on the label. Legal position: FDA says ibutamoren is excluded from the definition of a dietary supplement, so a product holding it is an unapproved new drug. (source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/agebox-inc-718252-12192025) Documented risks: - FDA says parents may give such a product to children without knowing it holds an ingredient that may cause serious harm. (source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/agebox-inc-718252-12192025) Enforcement: - 2025-09-23: FDA health fraud notice on a children's growth product found by FDA testing to hold hidden ibutamoren. (source: https://www.fda.gov/drugs/medication-health-fraud-notifications/agebox-ikids-growth-day-formula-may-be-harmful-due-hidden-ingredient) - 2025-12-19: FDA warning letter to the seller of a children's growth product that held undeclared ibutamoren mesylate. (source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/agebox-inc-718252-12192025) Source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/agebox-inc-718252-12192025 ### Compounding outside the rules What it is: Made by a pharmacy from bulk MK-677 powder, which its Category 2 listing does not allow. Legal position: FDA says its interim policy for pharmacies does not cover Category 2 substances. It may act against a compounder who uses one. (source: https://www.fda.gov/drugs/human-drug-compounding/bulk-drug-substances-used-compounding-under-section-503a-fdc-act) Documented risks: - FDA says MK-677 may cause congestive heart failure in some patients. (source: https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks) - FDA found the bulk powder is not well characterized, with no data on its purity or impurities. (source: https://www.fda.gov/media/182087/download) Source: https://www.fda.gov/drugs/human-drug-compounding/bulk-drug-substances-used-compounding-under-section-503a-fdc-act ## Recruiting trials Snapshot date: 2026-10-26. A listing is not a recommendation. Trials have strict eligibility rules. Talk to your doctor and read the official record. - nct NCT07754045, url https://clinicaltrials.gov/study/NCT07754045, phase Phase 2, title Evaluating the Efficacy and Safety of LUM-201 Plus Semaglutide Versus Semaglutide Plus Placebo in Older Obese Adults, status not-yet-recruiting, sponsor Lumos Pharma, countries none listed, us states none listed - nct NCT07129759, url https://clinicaltrials.gov/study/NCT07129759, phase Phase 3, title Phase 3 Long Term Safety Extension Study of LUM-201 in Children With Growth Hormone Deficiency, status not-yet-recruiting, sponsor Lumos Pharma, countries none listed, us states none listed - nct NCT06948214, url https://clinicaltrials.gov/study/NCT06948214, phase Phase 3, title Phase 3 Study of LUM-201 in Children With Growth Hormone Deficiency, status recruiting, sponsor Lumos Pharma, countries United States, Argentina, Australia, Chile, India, New Zealand, Thailand, United Kingdom, us states Alabama, California, Colorado, District of Columbia, Florida, Georgia, Indiana, Iowa, Louisiana, Minnesota, Missouri, Nevada, New Jersey, New York, Ohio, Oklahoma, South Carolina, Texas, Virginia, Washington Source: https://clinicaltrials.gov/api/v2/studies?query.intr=ibutamoren+OR+MK-677+OR+MK-0677+OR+LUM-201&filter.overallStatus=RECRUITING%2CNOT_YET_RECRUITING&pageSize=50&sort=StartDate%3Adesc&countTotal=true&fields=NCTId%2CBriefTitle%2COverallStatus%2CPhase%2CLeadSponsorName%2CStartDate%2CLocationCountry%2CLocationState ## Sources Source: https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks ### 1. FDA: bulk drug substances that may present significant safety risks, with ibutamoren mesylate added in 2022 and 2023 Type: regulatory Tier: primary Source: https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks ### 2. FDA: bulk drug substances nominated under section 503A, list updated 14 May 2026 Type: regulatory Tier: primary Source: https://www.fda.gov/media/94155/download ### 3. FDA: bulk drug substances used in compounding under section 503A Type: regulatory Tier: primary Source: https://www.fda.gov/drugs/human-drug-compounding/bulk-drug-substances-used-compounding-under-section-503a-fdc-act ### 4. FDA: bulk drug substances nominated under section 503B, list updated 21 March 2025 Type: regulatory Tier: primary Source: https://www.fda.gov/media/94164/download ### 5. FDA: Pharmacy Compounding Advisory Committee meeting, 29 October 2024 Type: regulatory Tier: primary Source: https://www.fda.gov/advisory-committees/advisory-committee-calendar/october-29-2024-meeting-pharmacy-compounding-advisory-committee-10292024 ### 6. FDA briefing document on ibutamoren mesylate for the committee, 2024 Type: regulatory Tier: primary Source: https://www.fda.gov/media/182087/download ### 7. FDA: final summary minutes of the committee meeting of 29 October 2024 Type: regulatory Tier: primary Source: https://www.fda.gov/media/185412/download ### 8. FDA warning letter to an online seller of SARMs that listed MK-677, 12 June 2023 Type: regulatory Tier: primary Source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/warrior-labz-sarms-655280-06122023 ### 9. FDA warning letter to an online seller of SARMs that listed MK-677, 12 December 2025 Type: regulatory Tier: primary Source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/dynamic-health-group-dba-sarms-america-719257-12122025 ### 10. FDA warning letter on a children's growth product with hidden ibutamoren, 19 December 2025 Type: regulatory Tier: primary Source: https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/agebox-inc-718252-12192025 ### 11. FDA health fraud notice: hidden ibutamoren in a children's growth product, 2025 Type: regulatory Tier: primary Source: https://www.fda.gov/drugs/medication-health-fraud-notifications/agebox-ikids-growth-day-formula-may-be-harmful-due-hidden-ingredient ### 12. Holt Law: the 2026 federal rules on peptides and the risks for prescribers Type: legal-analysis Tier: legal-analysis Source: https://djholtlaw.com/navigating-the-2026-peptide-regulatory-landscape-federal-compliance-state-enforcement-and-the-legal-liabilities-of-healthcare-providers/ ### 13. MK-677 for up to two years in healthy older adults, 2008 Type: rct Tier: peer-reviewed Source: https://pubmed.ncbi.nlm.nih.gov/18981485/ ### 14. MK-0677 in older people recovering from hip fracture, stopped early, 2011 Type: rct Tier: peer-reviewed Source: https://pubmed.ncbi.nlm.nih.gov/21067829/ ### 15. MK-677 for a year in people with Alzheimer's disease, 2008 Type: rct Tier: peer-reviewed Source: https://pubmed.ncbi.nlm.nih.gov/19015485/ ### 16. Review: the safety and efficacy of growth hormone secretagogues, ibutamoren among them, 2018 Type: reference Tier: peer-reviewed Source: https://pubmed.ncbi.nlm.nih.gov/28400207/ ### 17. MK-0677 by mouth and by vein in beagles, 1996 Type: animal Tier: peer-reviewed Source: https://pubmed.ncbi.nlm.nih.gov/8940347/ ### 18. MK-0677 and brain plaque in mice bred to model Alzheimer's disease, 2018 Type: animal Tier: peer-reviewed Source: https://pubmed.ncbi.nlm.nih.gov/29912176/ ### 19. ClinicalTrials.gov: phase 3 trial of LUM-201, a name for ibutamoren, in children short of growth hormone Type: reference Tier: primary Source: https://clinicaltrials.gov/study/NCT06948214 ### 20. ClinicalTrials.gov: ibutamoren in fatty liver disease Type: reference Tier: primary Source: https://clinicaltrials.gov/study/NCT05364684 ### 21. ClinicalTrials.gov: MK-0677 after hip fracture, stopped early Type: reference Tier: primary Source: https://clinicaltrials.gov/study/NCT00128115 ### 22. NBC News: MK-677 and muscle in older adults, 2008 Type: reference Tier: established-news Source: https://www.nbcnews.com/id/wbna27524685 Last verified: 2026-10-26. Sources: - https://clinicaltrials.gov/api/v2/studies?query.intr=ibutamoren+OR+MK-677+OR+MK-0677+OR+LUM-201&filter.overallStatus=RECRUITING%2CNOT_YET_RECRUITING&pageSize=50&sort=StartDate%3Adesc&countTotal=true&fields=NCTId%2CBriefTitle%2COverallStatus%2CPhase%2CLeadSponsorName%2CStartDate%2CLocationCountry%2CLocationState - https://clinicaltrials.gov/study/NCT06948214 - https://peptideindex.ai/methodology#evidence-grade - https://peptideindex.ai/methodology#short-answer - https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks - https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/dynamic-health-group-dba-sarms-america-719257-12122025 - https://www.fda.gov/media/182087/download - https://www.fda.gov/media/185412/download - https://www.fda.gov/media/94155/download [^1]: FDA: bulk drug substances that may present significant safety risks, with ibutamoren mesylate added in 2022 and 2023 https://www.fda.gov/drugs/human-drug-compounding/certain-bulk-drug-substances-use-compounding-may-present-significant-safety-risks [^2]: FDA: bulk drug substances nominated under section 503A, list updated 14 May 2026 https://www.fda.gov/media/94155/download [^3]: FDA: bulk drug substances used in compounding under section 503A https://www.fda.gov/drugs/human-drug-compounding/bulk-drug-substances-used-compounding-under-section-503a-fdc-act [^4]: FDA: bulk drug substances nominated under section 503B, list updated 21 March 2025 https://www.fda.gov/media/94164/download [^5]: FDA: Pharmacy Compounding Advisory Committee meeting, 29 October 2024 https://www.fda.gov/advisory-committees/advisory-committee-calendar/october-29-2024-meeting-pharmacy-compounding-advisory-committee-10292024 [^6]: FDA briefing document on ibutamoren mesylate for the committee, 2024 https://www.fda.gov/media/182087/download [^7]: FDA: final summary minutes of the committee meeting of 29 October 2024 https://www.fda.gov/media/185412/download [^8]: FDA warning letter to an online seller of SARMs that listed MK-677, 12 June 2023 https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/warrior-labz-sarms-655280-06122023 [^9]: FDA warning letter to an online seller of SARMs that listed MK-677, 12 December 2025 https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/dynamic-health-group-dba-sarms-america-719257-12122025 [^10]: FDA warning letter on a children's growth product with hidden ibutamoren, 19 December 2025 https://www.fda.gov/inspections-compliance-enforcement-and-criminal-investigations/warning-letters/agebox-inc-718252-12192025 [^11]: FDA health fraud notice: hidden ibutamoren in a children's growth product, 2025 https://www.fda.gov/drugs/medication-health-fraud-notifications/agebox-ikids-growth-day-formula-may-be-harmful-due-hidden-ingredient [^12]: Holt Law: the 2026 federal rules on peptides and the risks for prescribers https://djholtlaw.com/navigating-the-2026-peptide-regulatory-landscape-federal-compliance-state-enforcement-and-the-legal-liabilities-of-healthcare-providers/ [^13]: MK-677 for up to two years in healthy older adults, 2008 https://pubmed.ncbi.nlm.nih.gov/18981485/ [^14]: MK-0677 in older people recovering from hip fracture, stopped early, 2011 https://pubmed.ncbi.nlm.nih.gov/21067829/ [^15]: MK-677 for a year in people with Alzheimer's disease, 2008 https://pubmed.ncbi.nlm.nih.gov/19015485/ [^16]: Review: the safety and efficacy of growth hormone secretagogues, ibutamoren among them, 2018 https://pubmed.ncbi.nlm.nih.gov/28400207/ [^17]: MK-0677 by mouth and by vein in beagles, 1996 https://pubmed.ncbi.nlm.nih.gov/8940347/ [^18]: MK-0677 and brain plaque in mice bred to model Alzheimer's disease, 2018 https://pubmed.ncbi.nlm.nih.gov/29912176/ [^19]: ClinicalTrials.gov: phase 3 trial of LUM-201, a name for ibutamoren, in children short of growth hormone https://clinicaltrials.gov/study/NCT06948214 [^20]: ClinicalTrials.gov: ibutamoren in fatty liver disease https://clinicaltrials.gov/study/NCT05364684 [^21]: ClinicalTrials.gov: MK-0677 after hip fracture, stopped early https://clinicaltrials.gov/study/NCT00128115 [^22]: NBC News: MK-677 and muscle in older adults, 2008 https://www.nbcnews.com/id/wbna27524685