Abstract
BACKGROUND: Despite ongoing interest in anabolic therapies for sarcopenia and cachexia, pharmacological interventions are being developed to counteract age- and condition-related losses of muscle mass and strength. This systematic review and meta-analysis evaluated the effect of nandrolone decanoate on lean soft tissue (LST), fat mass, handgrip strength, knee extension strength and bone mineral density (BMD) in adults. METHODS: Following PRISMA guidelines, we searched PubMed, Scopus, Web of Science and Cochrane Library (inception to April 2025) for randomised controlled trials (RCTs) comparing nandrolone decanoate to placebo in adults ≥ 18 years. Data were analysed using a random-effects meta-analysis, and risk of bias was assessed using the RoB2 tool. Mean differences (MD) alongside 95% confidence intervals (95% CI) were applied, whereas standardised MD (SMD) was used when methods or/and units of measurement were not identical (i.e., body fat mass/percentage). RESULTS: Twenty RCTs were included in this study. Nandrolone decanoate significantly increased LST (k = 11; MD: 1.59 kg, 95% CI 1.06-2.13, p < 0.01, I(2) = 0%) but had no effect on fat mass (k = 11; SMD: -0.04, p = 0.65), handgrip strength (k = 12; SMD: 0.39, p = 0.10) or knee extension strength (k = 1; p = 0.99). BMD outcomes were inconsistent, with only total proximal femur BMD showing improvement (p < 0.05). No publication bias was detected. Most studies showed a low risk of bias, whereas GRADE assessment displayed a low certainty of evidence. CONCLUSION: Although nandrolone decanoate modestly increases LST, this was not accompanied by improvements in handgrip strength or consistently observed improvements in BMD, and functional outcomes were informed by limited trial data. Taken together, these findings do not support routine clinical use of nandrolone decanoate for improving musculoskeletal health. Given its limited benefit and known safety concerns, non-pharmacological approaches such as resistance training and nutritional support should remain the preferred strategy for preserving musculoskeletal health.