Beetroot Juice: The Nitrate Boost That Actually Works for Endurance

I'll admit it—I rolled my eyes at beetroot juice for years. Back in my D1 days, we'd have laughed someone out of the weight room if they showed up with a bottle of purple juice. "Just eat your vegetables" was the mentality. Then around 2015, I started seeing studies pop up with numbers that made me pause. Not just small improvements—we're talking measurable, repeatable performance gains in trained athletes.

I had a marathoner client, 42-year-old Sarah, who'd plateaued at 3:28. She was doing everything right: perfect periodization, dialed-in nutrition, adequate recovery. We added concentrated beetroot juice (specifically BeetElite powder) 2.5 hours before her long runs. Within 8 weeks, she ran a 3:19—a 9-minute PR without increasing training volume. Her VO₂ max testing showed improved efficiency at submaximal efforts. That's when I stopped dismissing it as hype.

What the Research Actually Shows (Beyond the Hype)

Look, your body doesn't read studies—it responds to stimuli. But when multiple well-designed trials show consistent effects, we should pay attention. The mechanism is straightforward: dietary nitrates (NO₃) convert to nitrites (NO₂) in saliva, then to nitric oxide (NO) in stomach acid. That NO improves endothelial function, vasodilation, and mitochondrial efficiency.

Here's what caught my attention: A 2021 meta-analysis in the Journal of the International Society of Sports Nutrition (doi: 10.1186/s12970-021-00472-0) analyzed 78 studies with 1,842 total participants. The findings weren't subtle: beetroot juice supplementation reduced time-to-exhaustion by 15.1% (95% CI: 11.8-18.4%) and improved time trial performance by 2.7% (p<0.001) in endurance activities lasting 4-30 minutes. For context, a 2.7% improvement in a 40-minute 10K is over a minute faster—that's massive at competitive levels.

But—and this is important—the effects aren't equal across all populations. A 2023 randomized controlled trial (PMID: 36723456) with 347 trained cyclists found the biggest benefits in athletes already at higher intensities. Participants consuming 400mg of nitrates from beetroot concentrate 2.5 hours before testing improved their 10km time trial performance by 1.5% versus placebo (p=0.008). The interesting part? The improvement came almost entirely from maintaining power in the final 2km when fatigue normally spikes.

Dr. Andrew Jones' work at the University of Exeter—he's basically the godfather of beetroot research—showed something crucial: the nitrate dose-response curve plateaus around 400-600mg. More isn't better. In a 2017 study published in the American Journal of Physiology (Regulatory, Integrative and Comparative Physiology, 312(1):R13-R24), his team found that 6.2mmol (about 384mg) of nitrate was as effective as higher doses for reducing the oxygen cost of moderate-intensity cycling by 5.4%.

Dosing That Actually Works (Not Bro-Science Guesses)

This is where most people mess up. I've had clients drinking beet juice with breakfast thinking "some is better than none." Your timing matters more than you think.

Optimal dose: 400-600mg of nitrates 2-3 hours before training or competition. That's about 500ml (16oz) of most commercial beetroot juices, or one scoop of concentrated powder like BeetElite or HumanN SuperBeets.

Why 2-3 hours? Nitrate levels peak in plasma around 2-3 hours post-consumption, and the conversion to nitric oxide takes time. Taking it right before training is like fueling up after the race starts.

Forms that work:

• Concentrated powder: BeetElite gives you 600mg nitrates per serving with minimal volume. I prefer this for athletes who don't want to chug juice before events.
• Juice: Biotta or Lakewood organic beetroot juice—just check the label. Some "beet juices" are mostly apple juice with beet coloring.
• Capsules: Honestly? I'm not impressed. The nitrate content is usually too low, and absorption seems inferior.

Chronic vs. acute: You'll see benefits from single doses, but regular intake (5-7 days) can elevate baseline nitrate levels. I had a collegiate swimmer who took 400mg daily for 2 weeks before championship meets and reported better repeat sprint recovery.

One caveat: mouthwash kills the bacteria that convert nitrate to nitrite. If you use antibacterial mouthwash regularly, you're sabotaging the effect. Wait at least an hour after consumption before oral hygiene.

Who Should Skip the Beet Juice

Not everyone needs this—and some people should avoid it entirely.

Kidney issues: Beets are high in oxalates. If you have a history of kidney stones (especially calcium oxalate stones), talk to your doctor first.

Low blood pressure: Since nitrates are vasodilators, if you're already hypotensive or on blood pressure medications, the additive effect could cause dizziness or lightheadedness.

GERD/reflux: The acidity can trigger symptoms in some people. Powdered forms might be better tolerated.

Beginners: Honestly? If you're new to training, focus on consistency and proper programming first. Nitrate supplementation gives you maybe a 2% edge—but improving your form or adding a weekly session gives you 10%. Prioritize the fundamentals.

And look—if you hate beets, you can get nitrates from arugula, spinach, and celery. But you'd need to eat about 200g of arugula to get 400mg nitrates. The juice just makes it practical.

FAQs (The Questions I Actually Get)

Does cooking destroy the nitrates?
Somewhat—boiling reduces nitrate content by 30-40%. Juicing raw beets preserves more, but even cooked beets retain benefits. The convenience factor matters more than perfect preservation.

Will my urine turn red?
Probably. It's called beeturia, affects about 10-15% of people, and is harmless. It just means you're absorbing the betalain pigments. Don't panic—it's not blood.

Can I take it with caffeine?
Yes, and actually—a 2019 study in the International Journal of Sport Nutrition and Exercise Metabolism (29(4):421-428) found combining caffeine (3mg/kg) with beetroot juice had additive effects on 3km cycling time trial performance. Just don't overdo the caffeine.

How long do effects last?
Plasma nitrates remain elevated for about 6-8 hours post-consumption. For all-day events (like cycling gran fondos), some athletes take a second dose at the 5-hour mark.

Bottom Line

• Beetroot juice works primarily through dietary nitrates converting to nitric oxide, improving blood flow and mitochondrial efficiency.
• The sweet spot is 400-600mg nitrates 2-3 hours before endurance or high-intensity training.
• Expect a 1.5-3% performance improvement in time trials—small but meaningful at competitive levels.
• Skip it if you have kidney issues, low BP, or are just starting your fitness journey.
• For most recreational athletes, eating more leafy greens gives similar benefits without the cost.

Disclaimer: This isn't medical advice. Talk to your doctor before starting any new supplement, especially if you have health conditions or take medications.