Can Creatine Supplementation Improve Body Composition and Objective Physical Function in Rheumatoid Arthritis Patients? A Randomized Controlled Trial

Wilkinson TJ, et al. · Arthritis Care & Research

Mixed: creatine increased appendicular lean mass (+0.52 kg, P=0.004 vs placebo) but did not improve knee extensor strength (P=0.41), grip strength (P=0.83) or any objective physical function measure (P=0.34-0.76) — muscle mass gain does not automatically translate to function.

Population

Adults with rheumatoid arthritis, 12 weeks

Intervention

Creatine monohydrate 20 g/day for 5 days, then 3 g/day to week 12

Comparator

Placebo

Limitations

Inflammatory arthritis, not OA, and the endpoints are body composition rather than the joint. The lean-mass gain arrived with 1.08 L more total body water, two-thirds of it intracellular, and receded as that water did once supplementation stopped — so how much of it is contractile tissue is unsettled. Creatine was given without a resistance-training co-intervention; the authors attribute the equal function gains in both arms to a learning effect on the tests.