Doctors Warn Against MK-677, Contradicting Fitness Industry Opinions

MK-677, also known as ibutamoren, is an investigational drug initially developed to treat growth hormone deficiencies. Despite lacking regulatory approval for its use in humans and information on its safety, it's gained popularity in the bodybuilding community for its purported benefits such as increased muscle mass, better recovery after workouts, and improved sleep.

The UK-muscle.co.uk forum, for instance, features nearly 500 posts dedicated to the topic. Similarly, the MK-677 subreddit has over 1,400 members who actively share firsthand experiences with the substance.

According to Google Trends, interest in MK-677 has been slowly increasing since 2016, but it significantly surged at the end of 2022 and has remained high ever since.

How does MK-677 work?

• Increase in growth hormone levels. MK-677 binds to growth hormone secretagogue receptor 1a (GHS-R1a) in the brain and stimulates the hypothalamus and pituitary gland to secrete more growth hormone (GH). This mimics the natural pathway through which GH is released.
• Increase in IGF-1 levels. The elevated GH levels stimulate the liver to produce more insulin-like growth factor 1 (IGF-1). IGF-1 mediates many of the growth-promoting effects of GH, including muscle and bone growth and maintaining bone density.

Physiological effects of increased GH and IGF-1 levels from MK-677

So, what are the observed effects of MK-677, according to a multitude of clinical trials?

Not approved for human use

Despite MK-677 rising in popularity among bodybuilders, the U.S. Food and Drug Administration (FDA) has not approved it as a medication for human use. It's still classified as an investigational medication. Therefore, it may be sold only for research purposes.

The World Anti-Doping Agency (WADA) includes ibutamoren on its prohibited list under class s2: peptide hormones, growth factors, related substances, and mimetics, specifically in subclass 2.2.4: growth hormone-releasing factors. This classification means that ibutamoren is banned for athletes both in and out of competition.

Despite marketing claims suggesting otherwise, Sport Integrity Australia warns that ibutamoren (MK-677) is neither safe nor legal. MK-677 is also included in the Australian Poisons Standard, meaning possessing without authority is illegal. The agency cautions fitness enthusiasts to be wary of the risks associated with the use of such substances.

However, hundreds of individuals in the bodybuilding community obtain MK-677 from unregulated sources for personal use, which raises concerns about product quality, purity, and safety.

Users on the MK-677 subreddit have reported receiving counterfeit products. They noticed that after switching suppliers, the effects they experienced with authentic MK-677 disappeared, suggesting that the new products were likely fake.

Doctors disagree with fitness personalities on the safety and use of MK-677

While some enthusiasts promote MK-677 for its purported fitness benefits, many doctors express concern over its safety profile and use. Medical experts note the lack of long-term clinical studies on MK-677 and warn that its use may lead to adverse effects such as insulin resistance and heart complications.

Summary

Licensed doctors, like Dr. Thomas O'Connor (Anabolic Doc), Dr. Nicholas Downey, and Dr. Michael Moeller, generally advise against MK-677 based on their assessment of scientific studies, their medical expertise, and clinical practice experience.

Connor Murphy, Nyle Nayga, Jonni Shreve, KO Podcast, and "Dr." Tony Huge (not a licensed medical doctor) share personal experiences using MK-677. They mention encountering severe side effects, like developing insulin resistance and going into a pre-diabetic stage. However, even after experiencing severe side effects, they tend to advocate for the use of the substance with the caveat of using other supplements to potentially counteract the side effects, such as taking berberine to avoid developing insulin resistance.

What do Healthnews researchers think about MK-677?

Healthnews researcher Linas Černiauskas, PhD candidate at Vilnius University with a background in biochemistry and medical biology, commented on the MK-677.

“MK-677, or ibutamoren, is, first and foremost, an investigational drug not yet approved for human use by the FDA. Currently, it is being evaluated in clinical trials as a potential therapy for children with growth hormone (GH) deficiency.

As the misuse of MK-677 is a huge topic online, especially among fitness enthusiasts, it is important to note that this substance has not been properly evaluated in rigorous clinical trials involving adult participants, and its safety profile and effects on physical exercise are unknown.

According to the available scientific literature at the time this article was published, the adverse effects of MK-677 observed in small clinical trials indicate that it may pose serious risks to human health, both short-term and long-term. One example of the health risks observed in these trials involved reduced insulin sensitivity and increased fasting blood glucose levels, which, over time, may lead to prediabetes and diabetes.

Individuals need to be informed about the potential health risks that come with MK-677 or similar substance misuse, as well as their legal status. The use of such unapproved and understudied substances is highly discouraged based on currently available information.”

Conclusion

Despite the surging interest and anecdotal endorsements within fitness communities, MK-677 remains an unapproved investigational drug that raises significant health and legal concerns.

While some users report benefits like increased muscle mass and improved recovery, medical experts strongly advise against its use due to a lack of available information on its safety, serious risks such as insulin resistance, heart complications, and the potential for counterfeit products from unregulated sources.

Until rigorous clinical trials validate its safety and efficacy, the medical community's consensus is clear: MK-677's potential hazards far outweigh its purported advantages for use in humans without medical necessity.