ATENEA Study: Adherence to Creatine-Based Nutritional Supplementation in Estrogen-Depleted Women

Inclusion Criteria: * Biological female sex. * Age ≥40 years. * Estrogen-depleted status, defined as at least one of the following: natural menopause, defined as amenorrhea for ≥12 consecutive months; surgically induced menopause; late perimenopause with elevated FSH according to clinical judgment. * Absence of major comorbidities that would contraindicate use of the nutritional supplement or the recommended physical activity. * No relevant changes in usual treatment during the previous 3 months. * Ability to understand the study information and provide written informed consent. * Willingness to take the nutritional supplement according to the study instructions. * Willingness to follow general physical activity recommendations provided by the investigator. * Willingness and ability to attend the planned visits and complete study assessments through Week 12. Exclusion Criteria: * Initiation or modification of treatment with GLP-1 receptor agonists within the previous 12 weeks. * Presence of musculoskeletal or joint conditions that significantly limit the ability to perform regular physical activity or study-related functional assessments. * Clinically relevant renal or hepatic disease. * Current use of diuretics or potentially nephrotoxic medications. * Known allergy or intolerance to any component of the nutritional supplement. * Participation in another clinical study (nutritional, pharmacological, or interventional) within the previous 3 months. * Any medical condition or social circumstance that, in the investigator's judgment, could interfere with study participation, adherence, or data validity.