Bought with my own money. No commercial relationship with Beet It or James White Drinks. This post contains affiliate links, including to the beetroot shot I’m using and the Hilo monitor I measure with.
It was 3am and I was reading about beetroot. Not for the first time. But this time I’d actually ordered some to run a proper beetroot blood pressure trial, and I had that specific low-level anxiety you get when you’ve committed money to testing a claim and you’re not entirely sure you’ll be honest with yourself about what you find.
The anxiety is the point. I know how this goes. You try something, your numbers improve, you decide it worked. Maybe it did. Maybe you were sleeping better that week. Maybe you’d been less stressed, or done more steps, or eaten less salt. Maybe the beetroot did absolutely nothing and you just got lucky with the timing. You’ll never know, because you didn’t decide in advance what “worked” would actually look like.
So this page exists to stop me doing that. This is the pre-registered protocol for a beetroot blood pressure trial: the hypothesis, the baseline, and exactly what I’ll count as a result — all written before Day 1. I can’t change any of it once the trial starts. If I do, I’ll say so.
The launch post explaining why I’m doing this is here, if you want the story before the protocol.
The beetroot blood pressure trial hypothesis
One Beet It Sport Nitrate 400 shot every morning for 30 days will reduce my mean daytime systolic blood pressure by 3 mmHg or more, compared to my June 2026 baseline.
Three millimetres of mercury. That threshold comes from the published literature: it’s around the lower end of what the trials show for dietary nitrate in people with elevated BP. Anything smaller than that and I can’t distinguish signal from the natural day-to-day variation in my readings. If you want the full breakdown of the studies and their effect sizes, I’ve written it up on the dietary nitrate evidence summary page.
The baseline
I’ve been wearing a Hilo continuous blood pressure monitor every day since 2022. It’s a Class IIa medical device, clinically validated, not a consumer fitness tracker pretending to measure BP. It takes readings through the day and night using optical sensors and gives me a running picture of what my blood pressure is actually doing, rather than a single clinic reading taken while I’m already tense about being in a clinic. Full review here.
My baseline for this trial is the June 2026 Hilo monthly report. That’s the month immediately before the trial starts, and the most recent stable period I have before I introduce any intervention.
| Metric | Value |
|---|---|
| Mean daytime systolic | 133 mmHg |
| Mean daytime diastolic | 85 mmHg |
| Mean daytime HR | 73 bpm |
| Daytime systolic SD | 3 mmHg |
| Daytime readings | 400 |
The standard deviation of 3 mmHg matters. It means my baseline is actually quite tight: 400 readings clustering closely around 133. So a genuine 3 mmHg signal would have to emerge through a distribution that doesn’t have much give in it. That’s either good (the threshold is meaningful) or bad (the noise will drown any real effect). Either way, it’s what the data shows, and I’m not adjusting the threshold to make it easier.
One limitation I’m stating upfront: I don’t have a clinical upper-arm cuff for weekly cross-checks during this trial. The Hilo is consistent and validated, but it produces trend-grade values rather than absolute gold-standard readings. It’s the right tool for tracking change within a person over time, which is exactly what I’m using it for. I’ll be honest about that ceiling in the results post.
The intervention
Beet It Sport Nitrate 400. One 70ml shot every morning for 30 days, starting 25 June 2026. Same time each morning, with food. Informed-Sport certified, 400mg dietary nitrate per shot, which is the dose the actual research uses.
One specific rule worth knowing about: no antibacterial mouthwash during the trial. The nitrate mechanism depends on oral bacteria converting nitrate to nitrite in your mouth before your body can use it. Chlorhexidine mouthwash kills those bacteria, and there’s good evidence that it can knock out most of the BP effect on its own. I’m not using mouthwash. I’m telling you this because it’s one of those things the supplement ads never mention, even though it’s in the same literature they’re citing to sell you the product.
The washout
After Day 30, I stop the shots and monitor for another 14 days. If BP drifts back toward 133 during that window, it strengthens the case that the intervention was doing something. If it stays low, that weakens it. Either way I’m reporting what happens, not what I was hoping for.
The analysis
Three comparisons: intervention mean versus baseline, washout mean versus baseline, washout mean versus intervention. Shown as a time series with the three phases marked. Effect reported as a plain mmHg difference. No p-values: with one person’s autocorrelated daily data, a p-value would produce false confidence and I’d rather just say what happened.
What I’ll count as a result
Signal: Mean daytime systolic during intervention is 3 mmHg or more below baseline. That means 130 mmHg or lower.
Null: Mean daytime systolic is less than 3 mmHg below baseline. Beetroot probably didn’t do what the science suggests it should.
Inconclusive: Something changed but I can’t separate the beetroot from everything else that was changing at the same time. This is the most likely outcome, and I’ll say so plainly if it happens.
These definitions are locked from Day 1. I can’t look at the results and then decide what the threshold should have been.
The confounders I’m already aware of
This is the honest problem with this experiment, and I’m putting it here rather than at the end because it matters.
During these same 30 days I’m rebuilding aerobic fitness after a knee injury. More exercise lowers blood pressure. I’m also trying to sleep longer than my current short average. Better sleep lowers blood pressure. My body composition is changing. That affects blood pressure too. Any improvement I see during the trial could come from any of those things, or some combination of all of them, with beetroot contributing nothing at all.
I’m keeping a daily confounder log for exactly this reason. It won’t make attribution clean. But it means the results post will at least be honest about what else was moving.
Pre-registration published 25 June 2026. Results to follow approximately 24 July 2026 (end of intervention) and 7 August 2026 (end of washout).
I publish the ones that fail too
The trial is finished and the answer was no change at all. You can read the full results here. I set the threshold before I started and published it either way. Subscribe and I will send you the next thing I test, working or not.
I’m Pete Harrison. I’m 55, I run a business, and I have a mild case of insomnia that means I spend a lot of time at 3am reading about gadgets, gear and ways to make life work better. Things I Learnt at 3am is where I write honestly about the things I’ve actually bought, tested and lived with. No fluff, no rehashing the spec sheet. Just the real verdict from someone who uses this stuff every day.
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