This randomized, double-blind, placebo-controlled clinical trial will investigate the effects of creatine supplementation combined with a 12-week supervised resistance training program on muscle mass, muscle strength, physical performance (e.g., parameters of sarcopenia), and muscle density in men with prostate cancer undergoing androgen deprivation therapy (ADT). ADT often causes loss of lean mass, reduced muscle strength, functional impairment, and increased fat mass. Eligible male patients will be randomly assigned to receive either creatine monohydrate or a placebo (maltodextrin) in a double-blind manner, in addition to participating in the resistance exercise program. Assessments will be performed at baseline and after the 12-week intervention period and will include:

• Muscle density and architecture assessed by ultrasound
• Body composition (lean mass and fat mass)
• Muscle strength
• Physical performance (functional performance tests)
• Inflammatory biomarkers
• Vascular function parameters

The primary goal is to assess whether creatine supplementation combined with resistance training can safely improve muscle quality and quantity, strength, and physical function in these patients. If effective and safe, the intervention could help reduce muscle loss and improve quality of life in men undergoing ADT.

Men receiving androgen-deprivation therapy (ADT) for prostate cancer often experience significant loss of muscle mass, reduction in muscle strength, and increased fat mass. These changes can lead to sarcopenia, poorer physical function, and lower quality of life. Resistance training is known to improve muscle mass and strength in this population, but it is not clear whether adding creatine supplementation can further enhance these benefits. This study will investigate whether combining creatine monohydrate supplementation with a 12-week supervised resistance training program leads to greater improvements in muscle health compared to resistance training alone. Creatine is a nutritional supplement that may help increase muscle energy availability and support muscle growth and function, but its effects in men undergoing ADT have not been fully established. Participants will be randomly assigned to receive either creatine monohydrate or a placebo (maltodextrin) once daily throughout the 12-week resistance training program. All patients will follow the same structured resistance exercise protocol, supervised by trained professionals. The study will evaluate changes in muscle mass, muscle strength, physical performance, muscle density measured by ultrasound, inflammatory markers, vascular function, and other indicators of muscle health. The goal of this study is to determine whether creatine supplementation is a safe and effective strategy to improve muscle quality, physical function, and overall health for men receiving ADT. Findings from this trial may help guide future recommendations for exercise and nutritional support in this population.

Inclusion Criteria:

• Men aged ≥ 40 years;
• Patients with histologically or cytologically confirmed localized prostate cancer;
• Patients who have undergone surgical castration or pharmacological castration with gonadotropin-releasing hormone (GnRH/LHRH) agonists or antagonists for at least six months prior to the start of the intervention;
• Patients receiving continuous or intermittent androgen deprivation therapy;
• Patients with an Eastern Cooperative Oncology Group (ECOG) performance status ≤ 2;
• Not engaged in resistance training in the three months prior to the intervention;
• Not using creatine supplementation in the three months prior to the intervention;
• Willing to participate in a 12-week intervention consisting of resistance training performed three times per week and daily supplementation with creatine monohydrate or maltodextrin.

Exclusion Criteria:

• Patients with insulin-dependent diabetes mellitus;
• Patients with dialysis-dependent renal failure;
• Patients with severe chronic liver disease;
• Estimated glomerular filtration rate (eGFR) < 30 mL/min/1.73 m²;
• Any hormonal treatment outside that established by the medical team;
• Patients planning to undergo chemotherapy within the next six months.

Decision has not been made yet

Both participants and investigators are blinded to group assignment, managed by an external researcher. The supplements are identical in appearance, taste, and caloric content.