Citrulline malate supplementation does not improve German Volume Training performance or reduce muscle soreness in moderately trained males and females

Design: randomized, double-blind, placebo-controlled cross-over trial. Participants: healthy recreationally active men and women; fifteen completed (11 male, 4 female); mean age 23.7 ± 2.4 years; regular resistance training ≥2 times/week for ≥6 months; non-smokers; no injuries or chronic conditions; maintained usual diet and avoided new supplements.

8 g Citrulline Malate per dose (4.21 g citrulline + 3.79 g malate; ratio 1.11:1), dissolved in 70 ml fruit cordial and 150 ml water, consumed within 5 minutes, 60 minutes before exercise; acute per-session dosing (two sessions).

Acute 8 g CM dose did not significantly improve anaerobic performance in recreationally active adults performing German Volume Training. Across 10 sets, total repetitions: placebo 94.0 ± 7.9 vs CM 90.9 ± 13.9 (P = 0.33). No significant differences in peak force after GVT for isometric, concentric, or eccentric contractions (P = 0.60, 0.38, 0.65). Blood lactate responses were similar (pre: 1.45 ± 0.54 vs 1.69 ± 1.07 mmol/L; post: 4.16 ± 1.34 vs 4.31 ± 1.31 mmol/L; delta: 2.87 ± 1.53 vs 2.51 ± 1.25; P > 0.48). Total muscle soreness over 72 h was higher with CM than placebo (P < 0.01). Conclusion: Acute CM at 8 g does not enhance anaerobic performance and may increase soreness; caution in recommending CM; product composition may differ from manufacturer claims; further trials needed.

Small sample size (n=15 completed); some measurements incomplete due to technical issues (Fmax follow-up in 10 participants); mixed-sex sample with varying training histories; menstrual cycle not controlled; testing not fasting; dietary/supplement controls limited; potential under-dosing due to actual citrulline:malate ratio differing from label; single acute-dose design; isokinetic single-joint protocol may limit generalizability to real-world multi-joint exercises.