MK-677 (lbutamoren Mesylate)
- First described in 1995.
- It is a growth hormone secretagogue which essentially means it stimulates growth hormone secretion.
- It is part of a class of drugs called it belongs to the GHRP (Growth Hormone Releasing Peptides).
- MK-677 is a third generation GHRP because it can be taken orally.
- MK-677 mimics ghrelin (the hunger hormone).
- In many studies on children and the elderly it has shown to increase growth hormone and IGF-1 (Insulin like growth factor 1 – more on this to come) significantly. Furthermore, it was shown to increase lean body tissue, increase energy expenditure (metabolic rates increase) and improved sleep quality.
- MK-677 closely resembles GHRP-6.
- The issue with MK-677 is that it is not selective for growth hormone stimulation. It increases prolactin serum levels, cortisol and ACTH (adrenocorticotropic hormone).
- The postulated theory behind this is the fact that MK-677 works in the anterior pituitary gland Growth Hormone Cells and there is spill over onto other closely related cells like prolactin and ACTH cells.
- The above spill over effects are unlikely to be significant.
- It is banned by WADA.
- Increased appetite. This appetite might be of benefit to those looking to gain weight.
- Fatigue, although MK-677 does improve sleep, day time sleepiness is a common side effect.
- Increased fasted blood sugar levels are common and this must be looked out for by self-testing or visiting your doctor/pharmacy/clinic. This is secondary to impaired insulin sensitivity. The damaging effects of raised blood sugar levels will be discussed in a separate post.
- Oral Hypoglycaemics may be necessary (e.g., Metformin 500mg taken in the evening after dinner).
- Water retention is very common which may result in high blood pressure. Possible ways to avoid this involve the use of anti-hypertensives (specifically low dose diuretics – you must consult with your doctor first).
- Joint pain and carpal tunnel syndrome do occur, possibly secondary to the oedema or overgrowth of connective tissue.
- Paraesthesia (pins and needles) have also been reported. Could be secondary to nerve compression by the oedema or uncontrolled/elevated blood sugar levels.
- The side effects noted above are not as commonly seen as they are in though using pure Growth Hormone since MK-677 alone does not increase growth hormone above the normal range.
- The half life of this drug in dogs is 4 to 6 hours.
- 10 mg daily has been compared to 25mg daily in a multitude of studies. 25 mg in elderly patients seemed to greatly increase growth hormone and IGF-1 levels to that of young adults.
- Therefore, doses range from 10 to 25 mg orally daily.
- Individuals prefer to take the drug in the evening in order to avoid the hunger and fatigue that may occur if taken in the morning.
- This drug is used by bodybuilders to increase appetite.
- This drug also can aid in fat loss if calories are controlled.
- Cycles tend to range from 3 to 6 months in duration.
- Combination cycles are popular. CJC-1295 or Sermorelin are used to compliment actions of MK-677 and enhances release of growth hormone.