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Head-to-head evidence comparison — which supplement is right for you?
L-Citrulline wins 2 of 3 categories. Both are solid choices — the best pick depends on your specific goals.
Verdict
Probably helps
6 of 10 studies with measurable effects showed benefit.
Top outcomes
Verdict
Likely helps
8 of 10 studies with measurable effects showed benefit.
Top outcomes
Shared outcomes (1)
Outcomes where both HMB and L-Citrulline have evidence — compare verdict strength side-by-side.
3g daily
Split into 1g doses 3x daily, Or all at once with a meal
HMB-Ca (calcium salt) capsules or powder
3-6g (or 6-8g citrulline malate)
30-60 minutes before exercise, Or split doses throughout day
L-Citrulline powder (pure form)
2-4 weeks
1-2 weeks
1-2 weeks
24-48 hours post-exercise
30-60 minutes
With doses >10g
Nutritional interventions for treating foot ulcers in people with diabetes
The Cochrane database of systematic reviews (2020) · Meta analysis · n=629
It is also uncertain whether arginine, glutamine and β-hydroxy-β-methylbutyrate supplement increases the proportion of ulcers healed at 16 weeks compared with placebo (RR 1.09, 95% CI 0.85 to 1.40).
β-Hydroxy-β-methylbutyrate and its impact on skeletal muscle mass and physical function in clinical practice: a systematic review and meta-analysis
The American journal of clinical nutrition (2019) · Meta analysis · n=2137
Effect sizes were small.
Dietary Supplementation on Physical Performance and Recovery in Active-Duty Military Personnel: A Systematic Review of Randomized and Quasi-Experimental Controlled Trials
Nutrients (2024) · Systematic review
Nutrition supplementation may have small benefits on muscle performance and recovery in warfighters.
Absence of Effects of L-Arginine and L-Citrulline on Inflammatory Biomarkers and Oxidative Stress in Response to Physical Exercise: A Systematic Review with Meta-Analysis
Nutrients (2023) · Meta analysis · n=1080
We observed no difference between pre- vs. post-exercise for oxidative stress (subtotal = -0.21 [CI: -0.56, 0.14], p = 0.24, and heterogeneity = 0%.
Effects of Citrulline or Watermelon Supplementation on Body Composition: A Systematic Review and Dose-Response Meta-Analysis
Nutrients (2025) · Meta analysis
Overall, CIT supplementation had no substantial effects on body mass index (BMI), body weight, fat mass (FM), waist circumference (WC), body fat percentage (BFP), and fat-free mass (FFM).
Effect of food sources of nitrate, polyphenols, L-arginine and L-citrulline on endurance exercise performance: a systematic review and meta-analysis of randomised controlled trials
Journal of the International Society of Sports Nutrition (2021) · Meta analysis
No effect on exercise performance following consumption of foods rich in L-citrulline was identified (SMD=-0.03, p=0.24).
Meta-analyses show small but significant effects on total body mass and fat-free mass. Effect sizes are consistently reported as 'small' (ES ~0.21-0.22). Multiple studies show no significant effects in older adults or sarcopenia patients. HMB-FA form may have superior bioavailability to HMB-Ca.
Meta-analysis showed significant reduction in muscle soreness 24h post-exercise but effect size was modest. Studies primarily used citrulline malate form.
AI-estimated from published studies. Interpret as directional guidance.
L-Citrulline has a higher evidence score (9/10 vs 8/10) and wins in 2 of 3 categories.
For improve endurance, L-Citrulline has a higher relevance score (85 vs 45).
No known interactions between HMB and L-Citrulline have been documented in our database. However, always consult a healthcare provider before combining supplements.