Beetroot vs nitric oxide supplements — this comparison comes up often among endurance athletes.
Both approaches aim to increase nitric oxide in the body. Nitric oxide relaxes blood vessels, improves oxygen delivery to working muscles, and may reduce the oxygen cost of exercise.
But the way they work is different. And the research support is not equal.
Beetroot vs Nitric Oxide Supplements: The Short Answer
Beetroot provides dietary nitrate, which the body converts to nitric oxide through a well-studied pathway. Nitric oxide supplements typically contain L-arginine or L-citrulline, amino acids that act as precursors.
Both can work. The evidence for beetroot and performance is stronger, particularly for endurance.
| Beetroot | NO Supplements | |
| Active compound | Dietary nitrate | L-arginine, L-citrulline |
| Conversion pathway | Nitrate → nitrite → nitric oxide | Amino acid → nitric oxide |
| Research support | Strong (endurance) | Moderate (mixed results) |
| Best for | Endurance, oxygen economy | Blood flow, pumps, short efforts |
What the Research Says
Beetroot and Endurance
Beetroot is one of the most studied natural supplements in sport. The International Olympic Committee rates dietary nitrate as Level A — one of only five supplements with the highest evidence rating.
Bailey et al. (2009) found that dietary nitrate reduced the oxygen cost of submaximal exercise and extended time-to-exhaustion by up to 16%.
Wylie et al. (2013) established the effective dose range: approximately 5–8mmol of nitrate, consumed 2–3 hours before exercise.
Source: Bailey et al. (2009) — Journal of Applied Physiology
Source: Wylie et al. (2013) — Journal of Applied Physiology
L-Arginine and L-Citrulline
L-arginine is a direct precursor to nitric oxide. However, oral L-arginine has poor bioavailability — much of it is broken down before reaching the bloodstream.
Bailey et al. (2010) compared L-arginine with beetroot juice and found that beetroot was more effective at reducing blood pressure and improving exercise tolerance.
L-citrulline is more bioavailable than L-arginine. It converts to L-arginine in the kidneys, then to nitric oxide. Some studies show improved blood flow and reduced fatigue during short, high-intensity efforts. The evidence for endurance performance is less consistent than for nitrate.
Source: Bailey et al. (2010) — Beetroot vs L-arginine
Key Differences
1. The Pathway
Beetroot relies on the nitrate → nitrite → nitric oxide pathway. This is oxygen-independent. It works well during exercise, when oxygen levels in muscle tissue drop.
L-arginine relies on the nitric oxide synthase pathway. This pathway requires oxygen. During intense exercise, oxygen levels fall, and this pathway becomes less efficient.
This is one reason beetroot is better suited to endurance.
2. The Research Base
Dietary nitrate has over 180 peer-reviewed human performance trials. The evidence is consistent: lower oxygen cost, improved time-to-exhaustion, better efficiency.
The evidence for L-arginine is mixed. For L-citrulline, there is support for blood flow and short-duration performance, but less consistency for endurance.
3. The Practical Dose
To achieve an effective nitrate dose from beetroot, you need approximately 5–8mmol, which is achievable with concentrated juice or powder.
To achieve an effective dose of L-citrulline, typical protocols use 6–8g per day. This is more expensive and less practical for most athletes.
What Athletes Report
Athlete experiences are anecdotal and individual results vary.
Arvid Johannesen — Norwegian & Nordic Champion Cyclist
"380 watts at 145 bpm with Stamox. Without: 153 bpm. That's 8 beats lower at the same power."
Rémi Bury — RCS French Cyclist
"Same LT2 workout, 4 weeks apart: +10 watts, -10 bpm over 8 minutes. The results are clear."
These results are from individual athletes. They are not clinical evidence. But they are consistent with the research on nitrate and oxygen economy.
Which Should You Choose?
| Goal | Suggested | Notes |
| Endurance performance | Beetroot (dietary nitrate) | Strongest evidence. 2–3 hours pre-exercise. |
| Short, high-intensity efforts | L-citrulline | Some evidence for blood flow and fatigue. |
| General cardiovascular health | Either | Both support nitric oxide production. |
| Measurable HR drop at same output | Beetroot | Consistent athlete reports. |
For most endurance athletes, the research supports starting with dietary nitrate.
Common Questions
Is beetroot better than L-arginine?
The research suggests beetroot is more effective for endurance. L-arginine has poor oral bioavailability.
Can I take both?
Some athletes combine them. There is limited research on stacking. Start with one and measure.
What dose of beetroot is effective?
Approximately 5–8mmol nitrate, 2–3 hours before exercise.
What dose of L-citrulline is used in studies?
Typically 6–8g per day.
Related Reading
Best time to take beetroot powder — the 2–3 hour window explained.
Beetroot capsules vs powder vs juice — which form to choose.
L-Citrulline vs Beetroot — a deeper comparison.
Stamox Oxy-Plus — a beetroot powder used by athletes since 2007.
Stamox Oxy-Plus is a beetroot powder used by athletes since 2007. Measurable results. 12-week guarantee.
