Phosphocreatine (also known as creatine phosphate) is primarily recognized for its role in the rapid regeneration of adenosine triphosphate (ATP) in muscle cells during periods of high energy demand. Its supplementation, often in the form of creatine monohydrate, has been extensively studied in the context of muscle wasting conditions, such as sarcopenia (age-related muscle loss), cachexia (muscle wasting due to chronic illness), and muscular dystrophies. Clinical studies and meta-analyses suggest that creatine supplementation can modestly improve muscle mass, strength, and physical performance in individuals experiencing muscle wasting, especially when combined with resistance training. The mechanism is thought to involve increased phosphocreatine stores in muscle, which augment ATP availability during muscle contraction, potentially reducing protein breakdown and supporting muscle protein synthesis.

While there is scientific validation for creatine (and by extension, phosphocreatine) as a supportive therapy in muscle wasting, the strength of evidence varies by condition and population. Benefits appear more pronounced in elderly populations and in certain neuromuscular disorders, with mixed results in cancer cachexia. Safety profiles are generally favorable for short- to moderate-term use. However, phosphocreatine itself is less commonly used as a supplement compared to creatine, due to differences in absorption and cost. Nevertheless, the overall scientific consensus supports the use of creatine supplementation as an adjunctive measure to help counteract muscle wasting, particularly when paired with exercise interventions.