MK-677 And Cancer: How Strong Is The Evidence?

MK-677, or Ibutamoren, can mimic the hunger hormone Ghrelin and stimulate Growth Hormone and IGF-1 release. In some reports, growth and IGF-1 hormones can also promote tumour growth and cancer. So can MK-677, the anabolic steroid supplement, cause cancer as a severe side effect?
Klara Hatinova

Klara Hatinova

Klara is postgraduate researcher in experimental psychology at the
University of Oxford.

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What is MK-677?

MK-677 is the popular name for the synthetic drug Ibutamoren. MK-677 mimics the effects of the peptide for weight loss, hunger hormone ghrelin. This, in turn, stimulates the release of growth hormone (GH), similar to the natural role of ghrelin, which in turn stimulates the release of insulin-like growth factor I (IGF-I) [1, 2, 3].

So MK-677 leads to GH release, which leads to IGF-1 release.

GH is essential for several functions of the human body, including tendon growth in adolescence, tissue repair, muscle building, growth, and cell specialisation [4]. GH can further inhibit cell death, which may make cancer a side effect of MK-677. This is because stopping cell death in damaged cells can cause them to divide uncontrollably and form tumours. Similarly, IGF-1 is critical for anabolic growth, promoting cell growth and division and inhibiting cell death [4].

In the following sections, we will cover the scientific evidence about MK-677 and GH tumour genesis and the possibility of cancer being a side effect of MK-677.

People Also Ask

MK-677, an oral ghrelin mimetic, significantly increases growth hormone and insulin-like growth factor I levels. Studies have shown that daily administration of MK-677 can increase these levels to those of healthy young adults. For instance, a 2-week treatment with 25 mg/day MK-677 increased mean serum IGF-I concentrations into the normal range for young adults, and a 60.1% increase in serum IGF-I levels was observed at 6 weeks with a 72.9% increase at 12 months [1,2,3,4].

GH secretagogues like ghrelin can interfere with neoplastic growth in different cancers. In lung cancers, ghrelin can inhibit cell proliferation and enhance apoptosis, despite the absence of its primary receptor GHS-R1a [1]. GH secretagogues can also inhibit the proliferation of non-small cell lung carcinoma, demonstrated by a significant decrease in tumor volume and weight [2]. However, the effects of GH secretagogues can be dependent on the presence of certain proteins, such as p21, where the loss of p21 expression abolished the anti-proliferative effects of a GH secretagogue [3].

MK-677 Stimulates Growth Hormone Which Stimulates Cancer?

GH is the critical hormone that facilitates the anabolic properties that MK-677 is known for.

The scientific evidence for whether HG and thereby mk-677, can cause cancer as a side effect is mixed. One study found that patients medicated with growth hormone supplements had a mildly higher incidence of specific cancers, such as colon cancer. On the other hand, patients who died of cancer have no significant history of taking growth hormone supplements, including MK-677 [5]. Similarly, GH treatment in childhood, for example, for Growth Hormone Deficiency Syndrome, was associated with an increased risk of multiple cancer types in eight European countries [6]. More specifically, GH can enhance the growth of existing tumours through its widespread effects on cell growth and division.

Nonetheless, a review highlighted a bias in cancer incidence after GH therapy. This is because through the cellular effects of GH, you would expect to find cancer, and so many asymptomatic tumour-like structures may be marked as cancer [7].

So Is Cancer a Side Effect of MK-677?

Yes, cancer can be a side effect of taking MK-677, but taking MK-677 does not mean you will get cancer.

One review analysed the effects of GH secretagogues, meaning synthetic elements that act similarly to GH, on breast cancer carcinoma growth. Surprisingly, the review found MK-677 reduced carcinoma growth by acting on ghrelin-like receptors. This direct investigation of cancer as a side effect of MK-677 demonstrates that there is not yet sufficient evidence to infer that MK-677, through the action of GH and IGF-1, can cause cancer.

There is also some evidence linking MK-677 and brain damage, but the relationship is more complex. There have also been some reports of MK-677 causing erectile dysfunction, and MK-677 may influence testosterone levels.

Reversing the Roles: MK-677 to Aid Cancer Recovery?

Although the literature on MK-677 causing cancer or leading to cancer as a side effect is scarce, the scientific literature on MK-677 improving catabolism after cancer therapy is much stronger. Chemotherapy influences an individual’s ability to eat, digest, exercise and maintain muscle mass. Therefore, supplementing chemotherapy patients with MK-677 after chemotherapy treatment improved muscle recovery and maintenance in one study [9]. However, MK-677 is still not an approved therapy. Whether it is safe and sustainable in the long term needs to be clearly defined before administering it after chemotherapy since the body is most susceptible after chemotherapy.

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Klara Hatinova

Klara Hatinova

Klara is a postgraduate researcher in experimental psychology at the University of Oxford. She has worked across a spectrum of hot topics in neuroscience, including her current project measuring reinforcement learning strategies in Parkinson’s disease. Previously, she studied the efficacy of psilocybin as a therapy for critical mental health conditions and examined molecular circadian rhythms of migraine disorders. She completed her undergraduate degree in Neuroscience at the University of Glasgow and participated in a year abroad at the University of California, where she worked on a clinical trial for spinal cord injury.