Side Effects After Stopping MK-677

In this article, we will closely examine the potential side effects after stopping MK-677, a nonpeptide growth hormone secretagogue. We will discuss the side effects of taking MK-677 and what one may expect after stopping MK-677. We also include a brief discussion on the typical duration of treatment with MK-677.
Klara Hatinova

Klara Hatinova

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

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Side effects after stopping MK-677

After discontinuing MK-677, it is possible to see a temporary decrease in growth hormone and IGF-1 levels, combined with an increased appetite. However, these side effects are typically short-lived and resolve over time. Always consult with a healthcare professional before starting or stopping MK-677, as it is not FDA-approved.

What is MK-677?

MK-677, known as Ibutamoren Mesylate, is an orally active, nonpeptide growth hormone secretagogue developed in the 1990s [1]. It stimulates the secretion of human growth hormone (hGH), harnessing your body’s natural growth hormone release from the pituitary gland. It does this by mimicking the human hunger peptide – ghrelin – and binding to ghrelin receptors throughout the body [2]. This method of increasing hGH levels reduces some of the side effects of synthetic growth hormone [3].

By increasing growth hormone levels, MK-677 also increases IGF-1 levels, enhancing its anabolic effects.


MK-677 is not FDA-approved and is a banned doping substance in competitive sports.

MK-677 is banned in sports and does not significantly enhance strength and power, although it does increase muscle mass. It is widely available online as a 'supplement' product [4, 2]. In clinical applications, MK-677 has been studied for its potential to supplement growth hormone in growth hormone deficiency conditions or muscle wasting.

This encompasses patient populations such as in chemotherapy patients, bed-ridden individuals, elderly people with bone fractures or people with natural ageing [5, 6, 2].

How long should you take MK-677 for?

The duration of MK-677 usage can vary depending on the individual's health status and the intended purpose of the treatment. In the studies provided, the duration of MK-677 administration ranged from 2 weeks to 18 months, although some people may take MK-677 under medical supervision for several years.

A healthcare provider should determine the duration of treatment, taking into account the individual's health status, the intended purpose of the treatment, and the potential side effects. MK-677 should not be taken as a performance-enhancing supplement in recreational sports.

Side effects of taking MK-677

The side effects of stopping MK-677/ibutamoren are unclear, but the side effects of taking MK-677 are fairly well-defined. They can include:

  • Reduced insulin sensitivity / High blood sugar: This can mean that your cells are less likely to respond to insulin by taking in glucose from the blood. This is similar to Type 2 diabetes, leading to elevated blood glucose levels [7, 2]. Over time, MK-677 may increase the risk of insulin resistance.
  • Increased appetite: MK-677 stimulates the ghrelin receptor, responsible for receiving hunger signals [2].
  • Bloating: MK-677 can interfere with digestion  
  • Swelling (edema) or muscle pain [2]
  • Cardiovascular side effects: These can include high blood pressure and increased risk of blood clots. Congestive heart failure was among the most prominent adverse effects leading to a termination of one study [8].

Contrary to the rumours, there is no evidence of MK-677 causing brain damage, lowering testosterone or affecting fertility. Further research is needed to determine whether MK-677 causes cancer as a side effect

What are MK-677 side effects after stopping?

As MK-677 is not FDA-approved for treatment, there is limited scientific evidence about the side effects, if any, one can experience after stopping it.

Most evidence of side effects after stopping comes from case reports, which are biased to only report the occurrence of side effects but do not tell us the number of people who stopped taking MK-677 without any side effects. The following evidence has largely been aggregated from research on growth hormone secretagogues.

Stopping MK-677 does not reduce endogenous Growth Hormone release

The two most feared side effects of stopping MK-677 include muscle loss or weight loss. This could be caused by a reduction in endogenous human Growth Hormone secretion because the body has become sensitized to the constant input signalling, 'Release more growth hormone!’ However, this is unlikely, as MK-677 only stays in the body for 4-6 hours, which is insufficient to greatly impact ghrelin receptor sensitization.

Furthermore, most MK-677 / ibutamoren cases were for acutely facilitating bone fracture healing, supporting bone mineral density, lowering LDL cholesterol [9], or improving body composition [10]. For these purposes, the advantages of taking MK-677 outweighed the unknown side effects [3]. 

Increased hunger after stopping MK-677

One side effect that did not subside immediately after stopping MK-677 was increased hunger. In a study of elderly patients, the individuals reported an increased appetite a few months after stopping the medication [2]. 

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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.