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    Ingredient guide · Ingredient reference

    Creatine in rheumatoid arthritis: lean mass increased without better function

    A rheumatoid arthritis trial found an increase in appendicular lean mass but no improvement in measured strength or physical function. These outcomes should remain separate.

    Read the evidence ↓

    Supplement Science Insights Editorial Team

    Published September 23, 2026

    Body composition and function did not move together

    Forty people with rheumatoid arthritis entered a double-blind trial of creatine or placebo. Supplementation lasted 12 weeks, with body composition, strength and physical function assessed. [1]

    Creatine increased appendicular lean mass, a surrogate for muscle mass, by about half a kilogram relative to the reported analysis. Intracellular water also increased. Knee-extensor strength, handgrip strength and objective physical function did not improve compared with placebo. [1]

    More lean mass does not necessarily mean better daily ability

    The findings do not establish relief of joint inflammation, reduced disease activity or a substitute for rheumatoid arthritis treatment. A body-composition measure includes more than a direct measurement of newly formed contractile muscle. [1]

    No treatment-related adverse effects were reported, but the small sample and short duration limit safety conclusions. Funding and conflicts were not established from the abstract. The practical value of the lean-mass change remains uncertain when function did not improve. [1]

    Check the functional outcome separately

    Imagine a scan reports more lean mass while measured strength stays unchanged. It would overstate the result to promise easier lifting or walking based on the scan alone.

    Evidence summary — Creatine in rheumatoid arthritis
    DetailInterpretation
    Appendicular lean massIncreased
    Intracellular waterAlso increased
    Measured strength and functionNo comparative improvement
    Creatine in rheumatoid arthritis: lean mass increased without better function — original article outline diagram
    Original editorial diagram of this article’s sections; no product photograph or clinical finding is depicted.

    Sources for this article

    1. Can Creatine Supplementation Improve Body Composition and Objective Physical Function in Rheumatoid Arthritis Patients? A Randomized Controlled Trial - PubMed
      Source consulted: 2026-09-19. This is a reference resource, not a claim that we conducted the studies or tested a product.