Beta-Alanine vs Citrulline — which performance supplement matches your training?

Updated 2026-05-10 · Reviewed by SupplementScore editors · No sponsorships

Both are in nearly every pre-workout product, and both are well-evidenced — but for completely different exercise demands. Beta-alanine extends the duration of high-intensity efforts in the 1- to 4-minute range by raising muscle carnosine and buffering hydrogen ion accumulation. Citrulline (specifically L-citrulline or citrulline malate) raises plasma arginine, increases nitric oxide availability and modestly improves muscular endurance and post-exercise soreness across a wider variety of efforts. Picking the wrong one for your training type is one of the most common pre-workout mistakes.

Quick verdict

How they compare on the things that matter

Mechanism — buffer vs vasodilator

Beta-alanine is the rate-limiting precursor for muscle carnosine synthesis. Carnosine acts as an intracellular buffer for hydrogen ions produced during high-intensity exercise (the protons that drive the burning sensation and contribute to muscular fatigue in the 1–4 minute effort window). Loading takes weeks — muscle carnosine doesn't change overnight — but the loaded effect is durable.

Citrulline (L-citrulline or citrulline malate, the latter combining citrulline with malic acid) is converted to arginine in the kidneys, raising plasma arginine more reliably than oral arginine itself does. Arginine is the substrate for nitric oxide synthase. The downstream effects are vasodilation, modest blood pressure reduction, improved blood flow to working muscle, and probably enhanced ammonia clearance during exercise.

Evidence base by clinical endpoint

• Performance in 1–4 minute high-intensity efforts: Beta-alanine has a Hobson 2012 meta-analysis and an ISSN position stand confirming modest but reliable improvement (~2.85% improvement in tasks of 60s to 240s).
• Reps to failure in moderate-rep hypertrophy training: Citrulline malate has Pérez-Guisado 2010 and several replications showing increased reps to failure and reduced delayed-onset muscle soreness.
• Strength (1RM): Neither has reliable 1RM-improvement data — that's creatine's domain.
• Endurance > 30 min: Both have modest signals. Citrulline edges beta-alanine in some trials; both lose to caffeine and beetroot nitrate at this duration.
• Soreness / recovery: Citrulline has the better DOMS data (smaller post-exercise soreness scores at 24–48h).
• Time to effect: Beta-alanine requires 2–4 weeks of loading. Citrulline is acute — a single dose 60 minutes pre-exercise has measurable effects.

Dose and form

For beta-alanine, the standard daily dose is 4–6 g/day, often split into 1.5–2 g doses to minimise paraesthesia (the harmless "tingling" at higher single doses). Sustained-release forms (Carnosyn SR) reduce the tingling. Loading takes 2–4 weeks; once muscle carnosine is loaded, the effect is durable for weeks even after cessation. Single-dose pre-workout (the classic pre-workout product format) is mostly placebo and tingles — the carnosine effect doesn't work that way.

For citrulline, two main forms: L-citrulline 6–8 g, or citrulline malate 8–10 g (which is roughly half citrulline by mass plus malic acid). Take 60 minutes pre-exercise on training days. Acute effect; no loading required. Citrulline malate trials have generally used the higher doses (8 g malate ≈ 4 g citrulline) and shown the better hypertrophy-training results.

Safety

Beta-alanine is well-tolerated. The only common adverse effect is paraesthesia (tingling, mostly on the face and hands) at single doses above 2 g — harmless and resolves within an hour. Long-term safety at the loading dose is well-characterised; concerns about taurine depletion in animal studies have not translated to humans at supplemental doses.

Citrulline is well-tolerated. The main caution is additive blood pressure lowering with antihypertensives or PDE5 inhibitors (sildenafil, tadalafil); discuss with prescriber. GI upset can occur at higher doses (10+ g malate).

What the price difference buys you

Beta-alanine bulk powder runs $0.20–0.40/day at the loading dose. Citrulline malate bulk powder runs $0.30–0.60/day at trial doses. Pre-workout products typically include sub-therapeutic doses of both — read the label. If your pre-workout has 1.6 g beta-alanine and 1 g citrulline malate, you're getting tingles and very little real effect.

Who should skip each

Beta-alanine has very few contraindications. Pregnancy and lactation safety data are limited; standard caution applies. People uncomfortable with the paraesthesia can use sustained-release forms.

Citrulline should be approached cautiously in users on antihypertensives or PDE5 inhibitors (additive hypotension), and in pregnancy (limited data). Caution in advanced kidney disease as citrulline-to-arginine conversion occurs in the kidneys.

What we'd actually buy

For CrossFit, middle-distance running, swimming, rowing, or any sport with sustained high-intensity efforts in the 60- to 240-second window: beta-alanine 4–6 g/day, split into smaller doses. Load for 4 weeks before reassessing.

For typical hypertrophy training (bodybuilding-style 8–15 rep sets) and "pump" preferences: citrulline malate 8 g taken 60 minutes pre-workout on training days.

For both: take both at the right doses on training days. They work via independent mechanisms and stack cleanly. But pair both with creatine 5 g/day — creatine outperforms either of them in most strength and power endpoints.

Sources

• Trexler ET, et al. International Society of Sports Nutrition Position Stand: Beta-Alanine. J Int Soc Sports Nutr. 2015;12:30. PMID: 26175657
• Hobson RM, et al. Effects of β-alanine supplementation on exercise performance: a meta-analysis. Amino Acids. 2012;43(1):25–37. PMID: 22270875
• Pérez-Guisado J, Jakeman PM. Citrulline malate enhances athletic anaerobic performance and relieves muscle soreness. J Strength Cond Res. 2010;24(5):1215–1222. PMID: 20386132
• Wax B, et al. Effects of supplemental citrulline malate ingestion during repeated bouts of lower-body exercise in advanced weightlifters. J Strength Cond Res. 2015;29(3):786–792. PMID: 25226311
• Suzuki T, et al. Oral L-citrulline supplementation enhances cycling time trial performance in healthy trained men. J Int Soc Sports Nutr. 2016;13:6. PMID: 26900386
• Stout JR, et al. Effects of twenty-eight days of beta-alanine and creatine monohydrate supplementation on the physical working capacity at neuromuscular fatigue threshold. J Strength Cond Res. 2006;20(4):928–931. PMID: 17194255