Arginine vs citrulline: which raises nitric oxide better?
Citrulline is the better oral choice for raising arginine and nitric oxide. Arginine is largely broken down in the gut before it reaches the blood, while citrulline is absorbed and converted to arginine in the kidneys. Performance benefits for either are emerging at best. In South Africa, citrulline malate costs R4.78–R8.62 per 6 g (October 2026).
- Oral arginine is largely broken down by gut arginase; citrulline is absorbed and converted to arginine in the kidneys.
- A 2021 critical review rated citrulline malate's exercise-performance evidence as equivocal.
- Common protocol: 6–8 g citrulline malate about 60 minutes before training.
- South African citrulline malate costs R4.78–R8.62 per 6 g (October 2026).
Which raises nitric oxide better, arginine or citrulline?
Citrulline, when taken by mouth. Nitric oxide (NO), the molecule that widens blood vessels, is made from arginine. The logical move is to take arginine, but oral arginine is largely broken down by the enzyme arginase in the gut before it reaches the circulation. Citrulline escapes that step, is absorbed, and is converted to arginine in the kidneys. A double-blind crossover study in 20 healthy volunteers (Schwedhelm et al., 2008) compared oral citrulline and arginine for exactly this reason.
Does a higher arginine level mean better performance?
Not necessarily. Raising blood arginine is one thing; improving training is another. A 2021 critical review of citrulline malate (Gough et al.) called the evidence for exercise performance equivocal, with small effects and doubts over product ratios. The proposed benefits are more reps in high-repetition sets and less soreness, and the evidence for endurance is weak. Neither citrulline nor arginine appears among the Group A supplements (those with strong evidence) in the AIS framework summary. Dietary nitrate (beetroot) is a Group A supplement with stronger evidence for endurance.
How much do you take?
| Supplement | Common protocol |
|---|---|
| Citrulline malate (2:1) | 6–8 g, about 60 minutes before training |
| Pure L-citrulline | about 3–6 g in studies |
| Arginine | doses vary; included at about 2 g in Biogen Rage Rampage per serving |
Arginine is also found in pre-workouts. Biogen Rage Rampage 400 g (R539.99) lists L-arginine 2 000 mg per roughly 20 g serving, and NPL Hyper Pump lists L-arginine without doses. See pre-workout brands compared.
What does citrulline cost in South Africa?
As of October 2026 (R per 6 g of citrulline malate): My Whey 250 g R4.78 (R199, Takealot), ATP Fitness 250 g R6.72 (R280, ATP shop), Biogen 250 g R7.92 (R329.99, Dis-Chem Living Fit) and NPL 240 g R8.62 (R344.99). ATP Fitness is a pure, unsweetened single ingredient, but it is about 40% dearer than My Whey, a young brand and without published sport certification. See best citrulline in South Africa.
Who should be careful?
Both can lower blood pressure. They may add to the effects of nitrates, PDE5 inhibitors (such as sildenafil) and antihypertensives, so speak to your doctor if you take these. Stomach upset is possible at higher doses. We do not recommend either as a treatment for any circulation problem; if you have leg pain, chest pain or erectile problems, see a doctor rather than a supplement. Under-18s, pregnant people and anyone with kidney disease should seek medical advice.
What is the bottom line?
If you want to try an NO-related supplement, citrulline is the more logical choice than arginine. Check citrulline malate vs L-citrulline, citrulline dose for pumps and best citrulline.
Products mentioned, with dated prices
| Product | Size | Price | R per 6 g | R per serving | Sweeteners |
|---|---|---|---|---|---|
| My Whey Pure Citrulline Malate 2:1 Powder 250 g | 250 g | R199Takealot (listing via PriceCheck), Oct 2026 | R4.78 | — | not stated |
| ATP Fitness Citrulline Malate | 250 g | R280ATP Fitness shop, Oct 2026 | R6.72 | — | None |
| Biogen L-Citrulline Malate Powder Unflavoured 250 g | 250 g | R330Dis-Chem Living Fit, Oct 2026 | R7.92 | — | not stated |
| Biogen Rage Rampage Pre-Workout 400 g | 400 g | R540Dis-Chem Living Fit, Oct 2026 | — | R27.00 | Sucralose |
ATP Fitness is a commercial partner of Healthnews24 and its products are featured on this site. Rankings follow our published method, and every pick, including ATP Fitness, shows its price maths and trade-offs. Read our disclosure.
Compare the options
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Related questions
- Citrulline malate vs L-citrulline: which is better?
- What is the best citrulline malate in South Africa?
- What is the right citrulline malate dose?
- Does pre-workout raise blood pressure?
- How do South African pre-workout brands compare?
Sources
- Schwedhelm E et al. (2008) Pharmacokinetic and pharmacodynamic properties of oral L-citrulline and L-arginine: impact on nitric oxide metabolism
- Gough LA et al. (2021) A critical review of citrulline malate supplementation and exercise performance. Eur J Appl Physiol
- Australian Institute of Sport Supplement Framework: Group A
Educational information only, not medical advice. Speak to a doctor, pharmacist or registered dietitian before using supplements if you are pregnant or breastfeeding, under 18, taking medication, or living with kidney, liver or heart disease.
Cite this page: Healthnews24, “Arginine vs citrulline: which raises nitric oxide better?”, updated 27 October 2026, https://www.healthnews24.co.za/answers/arginine-vs-citrulline-for-blood-flow/. Plain-text version: /answers/arginine-vs-citrulline-for-blood-flow.md