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Water Retention and Edema: Subcutaneous vs Intramuscular Effects
Bodybuilders researching MK-677 frequently report water retention as a primary concern. And for good reason. Elevated growth hormone and IGF-1 both increase sodium retention at the renal tubule level, leading to extracellular fluid accumulation. Clinical trial
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- Bodybuilders researching MK-677 frequently report water retention as a primary concern. And for good reason. Elevated growth hormone and IGF-1 both increase sodium retention at the renal tubule level, leading to extracellular fluid accumulation. Clinical trials document an average 1.5–3kg weight gain in the first 2–4 weeks of MK-677 use, with most of that attributable to water rather than lean tissue.
- The water gain has two components: subcutaneous edema (the soft, smooth appearance bodybuilders try to avoid) and intramuscular glycogen-associated water (which contributes to muscle fullness). The ratio between these depends on dietary sodium intake, carbohydrate timing, and baseline aldosterone sensitivity. High-sodium diets compound the edema effect. MK-677 users who reduce sodium to 2,000–2,500mg daily report significantly less facial puffiness and ankle swelling than those consuming 4,000mg+ sodium.
- Intramuscular water is mechanistically different: elevated IGF-1 upregulates glucose transporter expression (GLUT4) in skeletal muscle, increasing glycogen storage capacity. Each gram of glycogen binds approximately 3 grams of water intracellularly. This type of water retention is functionally beneficial. It contributes to muscle volume, nutrient partitioning, and the pump effect during training. Subcutaneous edema, by contrast, is cosmetically undesirable and doesn't contribute to performance.
- The distinction matters for contest prep: bodybuilders using MK-677 during a growth phase tolerate the water retention as part of the anabolic package, but those attempting to use it during a cut find the subcutaneous smoothness counterproductive to conditioning goals. Discontinuing MK-677 10–14 days before a competition allows extracellular water to normalize without losing the intramuscular glycogen enhancement.