• In female patients with knee osteoarthritis (OA), researchers observed reduced inflammatory markers and pain with short-term supplementation of L-carnitine.

• 72 women with mild to moderate knee osteoarthritis started the study and were divided into 2 groups to receive 750 mg/d L-carnitine (n=36) or placebo (n=36) for 8 w.
• Measures of serum levels of Interleukine-1β (IL-1β), high-sensitivity C-reactive protein (hs-CRP), and matrix metalloproteinases (MMPs) -1 and -13.
• Visual analog scale (VAS) for pain was assessed.

• 69 patients (33 in the L-carnitine group and 36 in the placebo group) completed the study.
• L-carnitine supplementation decreased serum IL-1β and MMP-1 levels (P=.001 and .021, respectively).
• In patients taking placebo serum hs-CRP and MMP-13, levels did not change (P>.05); serum IL-1β levels increased significantly (P=.011); other studied biomarkers did not change.
• In the L-carnitine and placebo groups mean VAS score decreased by 52.67% and 21.82%, respectively (P<.001).
• After adjusting for baseline values and covariates, differences were only observed between L-carnitine and placebo groups in serum IL-1β (P<.001), MMP-1 (P=.006), and mean VAS score (P=.002).

• Study was limited to 8 w.
• Inflammatory mediators and metalloproteinase enzymes were only measured in serum, not in the synovial fluids.

Why this matters

• More studies should be done to explore the benefits of L-carnitine, with higher doses of L-carnitine, long-term supplementation, and measures of other inflammatory and anti-inflammatory mediators, including TNF-α, IL-6, IL-10, and MMP-3.