MK-677 (Ibutamoren) Compounding Pharmacy Quality Red Flags to Avoid

The first red flag: a pharmacy that will compound MK-677

FDA's rules for state-licensed pharmacists and physicians say they may compound only with bulk drug substances that comply with a USP or National Formulary monograph if one exists, are components of FDA-approved drug products if no monograph exists, or appear on FDA's list of bulk substances that can be used in compounding [3]. Ibutamoren mesylate meets none of those: there is no monograph, it is not a component of any FDA-approved drug, and FDA placed it in category 2 rather than on the list [4][1].

Category 2 is FDA's designation for bulk substances it has identified as presenting significant safety risks. For those substances, FDA says it does not intend to apply the no-action policy it applies to category 1 substances [3]. Ibutamoren mesylate was added to category 2 on December 29, 2022 for outsourcing facilities and on September 29, 2023 for state-licensed pharmacies and physicians, and it is still on FDA's category 2 page dated April 22, 2026 [1]. FDA's stated reason: it poses significant safety risks due to the potential for congestive heart failure in certain patients, citing a hip-fracture trial that was terminated early for a potential safety signal of congestive heart failure [1][9].

On October 29, 2024, FDA's Pharmacy Compounding Advisory Committee voted 1 yes, 13 no, 0 abstain against adding ibutamoren mesylate to the pharmacy bulks list, with members citing fluid retention, congestive heart failure and hyperglycemia [2]. FDA also found that one outsourcing facility had reported compounding a 25 mg capsule in 2019 and 2020 and none since [2][4].

Red flag: claiming the new peptide policy covers it

HHS's draft enforcement-discretion policy for compounded peptides names six substances: BPC-157, epitalon, KPV, MOTS-c, Semax and TB-500 [6][7]. MK-677 is not one of them. It is also not a peptide. It is an oral, non-peptide small molecule that stimulates growth hormone release through the ghrelin receptor; Merck first synthesized it in 1995 and stopped development in 1999 [4]. FDA's review notes it is a growth hormone secretagogue, not a SARM, despite being sold alongside SARMs [4].

Red flag: sold as a supplement or a research chemical

In a December 12, 2025 warning letter, FDA stated that ibutamoren is excluded from the dietary supplement definition because it was authorized for investigation as a new drug, substantial clinical investigations were instituted, and it was not marketed as a supplement or food before that. The same letter states that products marketed with drug claims are unapproved new drugs [5].

Then there is the hidden-ingredient problem. On September 23, 2025, FDA warned that Agebox iKids Growth Day Formula, promoted to stimulate growth in children aged 5 and up, contained ibutamoren that was not listed on the label. FDA's notice lists risks including increased appetite, water retention, fatigue, muscle pain, changes in glucose metabolism and insulin sensitivity, and that it may increase the potential for congestive heart failure in certain individuals [8].

Red flag: a certificate of analysis presented as a safety file

Batch testing addresses the contents of one lot. It does not change what FDA concluded about the substance itself [1]. Compounded drugs are not FDA-approved, and FDA does not review their safety, effectiveness or quality before they reach patients [10].

What any seller should be telling you about MK-677 itself

There is no approved dose. Clinical trials used fixed oral doses from 2 mg to 50 mg per day, most often 25 mg once daily in adults, and ran for up to 2 years [4]. None of those is a recommended dose.

The safety record is the part sellers leave out. In the hip-fracture trial of 123 patients, the study was stopped early for a congestive heart failure signal: per FDA's summary, 4 patients (6.5%) on MK-677 versus 1 (1.7%) on placebo, with serious adverse events in 24% versus 13%, and systolic blood pressure rising 11.9 to 16.4 mmHg versus 2.3 to -2.3 mmHg [4][9]. In 65 healthy older adults aged 60 to 81 taking 25 mg daily, fasting glucose rose about 5 mg/dL over 12 months and insulin sensitivity fell, while body weight rose 2.7 kg versus 0.8 kg on placebo; increased appetite, mild leg swelling and muscle pain were the most frequent side effects [11][4]. In a 12-month trial of 563 people with Alzheimer's disease, blood glucose increases occurred in 15.4% on MK-677 versus 4.6% on placebo, and HbA1c increases in 11.1% versus 1.4% [12].

FDA's wider concern is class-wide: by raising growth hormone and IGF-1, MK-677 may carry the risks listed on approved growth hormone labels, including neoplasms, glucose intolerance and diabetes, fluid retention, hypoadrenalism, hypothyroidism and pancreatitis [4]. FDA also notes there are no long-term safety data in the older adults this drug is marketed to [4].

Is MK-677 legal to buy?

There is no FDA-approved MK-677 product [4]. FDA has told at least one seller that its ibutamoren products are unapproved new drugs, and stated that ibutamoren is excluded from the dietary supplement definition [5]. On the compounding side, it sits in FDA's category for substances with significant safety risks [1].

Questions to ask before you trust a source

• Does the page describe MK-677 as a peptide or as a legal compounded medicine? FDA's review describes it as a non-peptide, and FDA lists it in its significant-safety-risk category [4][1].
• Does it claim the new peptide enforcement policy covers MK-677? The draft policy names six other substances [6][7].
• Does it sell MK-677 as a dietary supplement or a research chemical? FDA says ibutamoren is excluded from the supplement definition [5].
• Does it promise muscle, strength or anti-aging results? In older adults, fat-free mass rose 1.1 kg over a year against a 0.5 kg fall on placebo, but strength and function did not improve [11].
• Does it mention blood sugar at all? Fasting glucose and HbA1c rose in multiple trials [11][12].