If you’re deciding between eating nitrate-rich foods and trying a nitric oxide supplement, here’s an honest, evidence-based comparison of what each actually does.
What Food-Based Sources Do
Eating nitrate-rich vegetables — like beetroot, spinach, and other leafy greens — may modestly help support healthy blood pressure for some people. This is a real, well-studied pathway (see our full breakdown of the research), with a real, if modest, measured effect, plus the general nutritional benefits of eating more vegetables.
What Supplements Actually Do — and Why “L-Arginine or L-Citrulline” Isn’t One Choice
Nitric oxide itself is a short-lived gas your body produces — supplements don’t contain nitric oxide directly; instead, they provide ingredients your body can use to make more of it. The two most common are L-arginine and L-citrulline, and they aren’t interchangeable the way they’re often marketed. Your body absorbs and processes them differently: a meaningful share of an oral L-arginine dose gets broken down before it ever reaches your bloodstream, while L-citrulline largely avoids that early breakdown and, gram for gram, tends to raise your body’s own arginine levels more effectively. This is a real, measured pharmacological difference, confirmed in a controlled human trial — not just a marketing distinction.
For exercise performance specifically, nitrate-rich beetroot juice may modestly improve aerobic performance for some athletes — a real, meta-analytically supported finding (33 studies, over 500 participants), though the researchers behind that analysis describe the effect as genuinely modest, more likely to matter for competitive athletes than casual exercisers. Separately, L-citrulline (typically as citrulline malate) has its own real, independent research base for strength and endurance performance — this isn’t simply a different delivery method for the same beetroot effect; it’s a separate body of evidence with its own real findings.
The Honest Comparison
| Food-based (nitrate-rich vegetables) | L-Arginine | L-Citrulline | |
|---|---|---|---|
| Delivers nitric oxide directly? | No — same precursor pathway as supplements | No | No |
| How efficiently it raises your body’s own arginine | N/A (via the nitrate pathway) | Less efficient — partly broken down before reaching the bloodstream | More efficient — largely avoids that early breakdown |
| Real evidence for blood pressure | Yes, modest, well-studied | Evidence is mixed and product-dependent | Evidence is mixed and product-dependent |
| Real evidence for exercise performance | N/A directly (see beetroot juice, below) | Weaker, less consistent evidence base | A real, independent evidence base of its own |
| Additional nutritional value | Yes — vitamins, fiber, other nutrients | No — isolated compound only | No — isolated compound only |
| Regulatory oversight | Standard food safety | Dietary supplements are less tightly regulated than medications | Dietary supplements are less tightly regulated than medications |
| Cost | Generally lower | Moderate | Generally higher than L-arginine |
The Bottom Line
For most people, food-based sources offer the best-evidenced, lowest-risk starting point — the same real pathway supplements are trying to support, plus genuine nutritional value supplements don’t provide. Claims that nitric oxide supplements can “detox” the body, reverse aging, or reliably treat chronic disease are not supported by current evidence — see our full look at nitric oxide supplement myths for more on what the marketing gets wrong. If you’re specifically interested in the exercise-performance research, beetroot juice and L-citrulline each have their own real, if modest, supporting evidence — they aren’t simply the same thing in different forms.
If you’re considering a supplement, especially alongside any medication, talk with a doctor or pharmacist first.
References
- Norouzzadeh, M., Rashedi, M. H., Payandeh, N., Harijani, A. M., & Shahinfar, H. (2024). The effects of dietary nitrate on blood pressure and vascular health: An umbrella review and updated meta-analysis and meta-regression. Journal of Functional Foods, 114, 106082. https://doi.org/10.1016/j.jff.2024.106082
- Cai, C., Huang, P., Cheng, X., & Zhou, J. (2026). Effectiveness of beetroot juice on aerobic and anaerobic exercise performance: Systematic review and meta-analysis. Frontiers in Nutrition, 13, 1844096. https://doi.org/10.3389/fnut.2026.1844096
- Kaynarkaya, B., Eren, Ş., & Şeker, E. N. (2026). Nitric oxide supplement: Evidence-based benefits, risks, and practical guidance. Acibadem International Health Library. https://acibademinternational.com/health-library/nitric-oxide-supplement-evidence-based-benefits-risks-and-practical-guidance/
- Schwedhelm, E., Maas, R., Freese, R., et al. (2008). Pharmacokinetic and pharmacodynamic properties of oral L-citrulline and L-arginine: impact on nitric oxide metabolism. British Journal of Clinical Pharmacology, 65(1), 51–59. https://doi.org/10.1111/j.1365-2125.2007.02990.x
About this article
Researched and written by: HealthUpward Editorial Team
Last updated: August 29, 2026
Evidence basis: Based on peer-reviewed research and reputable public health organizations cited within this article.
Medical review: This article has completed HealthUpward’s editorial review process. It has not been reviewed by a licensed healthcare professional.
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