Three miles into the loop around White Rock Lake, phone dead in my back pocket, I rattle off a former client's seven-digit office extension out loud — a number I haven't dialed since before I retired — like my hand is already reaching for a receiver that isn't there.
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Here's the part of that recall moment nobody wants to hear: it doesn't prove the whole thirty-day supplement testing experiment worked. Not by itself. My spreadsheet says my numbers moved, and there's a personal audit's worth of brain health data behind that — but if you're chasing the same cognitive ROI I was, most people running this kind of log are sitting on numbers that don't mean what they think they mean.
The Myth Behind Every 30-Day Supplement Log
The myth is simple: people assume that if they write a number down every day for thirty days, they've got clean data. They don't, not without guardrails. The first four days of any log I run now don't count as data at all — they're a washout window, and I get into exactly why elsewhere. The exact column-by-column structure I use is its own post — The Accountant's Guide to Structuring Your Brain Health Spreadsheet — and this piece assumes you've already got a version of it running.
My whiteboard across the room still carries the evidence of what happens when you don't guard the data: half-erased ingredient names and more question marks than answers, left over from a stretch where I assumed every change in the numbers belonged to whatever I was actively testing that week.
For three decades I made a living reconciling spreadsheets for other people — client ledgers, tax filings, the occasional forensic mess nobody else wanted to touch. What pushed me into early retirement wasn't one big failure. It was noticing the mental scaffolding researchers call executive functions slipping in small, repeated ways — names, extensions, the thread of a conversation. So I started tracking it the only way I know how, in a spreadsheet, because a guy who spent thirty years reconciling numbers for a living doesn't suddenly start trusting his gut over a cell reference.
How Stacking Supplements Quietly Contaminates the Data
Mistake number one, and it's the one I'm most embarrassed about: before I ever opened a spreadsheet, I'd already been taking fish oil capsules from Costco every morning for six months, out of nothing more than vague guilt about not eating enough salmon. That's also exactly how you end up trusting a label that hasn't earned it — a different audit, one I already covered in why my spreadsheet rejected 6 leading brain supplements. When I started testing an audio-based program called The Brain Song that same stretch, I never stopped the fish oil — so any movement in my focus numbers had two possible causes stacked on top of each other, and my spreadsheet had no way to tell them apart.
It took a phone call to Neil Trevisan, an old colleague from the firm who is reflexively suspicious of any health claim that doesn't come with a decimal point attached, to point out what should have been obvious: I was running two experiments and calling it one. The fix is boring but non-negotiable: change one variable at a time, or you're not auditing anything, you're just guessing with extra steps.
What Does a Missed Stretch of Logging Actually Cost You?
Mistake number two showed up when a bad flu put me flat on my back for several days straight. I stopped logging, not on purpose — I just didn't have it in me to rate my focus on a ten-point scale when I could barely rate my own ability to stand up. When I came back to the sheet, I tried to fill in those missing days from memory, and the numbers I guessed were suspiciously smooth, none of the daily noise you'd expect from a real measurement.
A reader named Dorinda Szymanski, who runs her own version of this kind of log, once emailed asking exactly how I handle a gap like that. The honest answer is that I don't fill it in anymore. A missing day goes into the sheet as blank, not as a guess dressed up as data, because a guess with a number attached is worse for an audit than no number at all.
Two Ways to Approach the Capsule Side of Testing
Not everything I've tested is audio-based. On the traditional capsule side, I've spent real time with NeuroPrime, which leans partly on phosphatidylserine — a fatty compound that's already a major building block of brain cell membranes. The actual clinical research on it, mostly done in older adults, is a mixed bag: some trials show a real benefit, others show close to nothing, and the difference seems to come down to how much room for improvement someone had to begin with. That's not a sales pitch, it's just what an honest read of the research says.
On the more accessible end, Neuro-Thrive has been a steady, unremarkable performer in my tracking, and which of the two is the better return depends on math I get into elsewhere, because a higher price tag by itself tells you nothing about the actual yield. Crack open a fresh bottle of either one and you get that same dry, herbal smell leaking out the second the cap breaks its seal — not unpleasant, just the family scent of this whole category. My shelf of empty bottles, oldest to newest, has enough of them lined up now to look like tree rings.
Why an Extra Cup of Coffee Wrecked a Clean Result
Mistake number three cost me a good stretch of confidence in a product that probably didn't deserve it. I had one run where my focus numbers jumped higher than anything I'd logged before, and I was ready to call it my best result of the whole test. Then I went back through the sheet's other columns, the ones I almost never look at, and noticed I'd also started a second afternoon coffee that same stretch, chasing a filing deadline that had nothing to do with any supplement.
There's a separate pattern in my data about afternoon energy dips that I now track completely on its own, precisely because caffeine timing kept muddying it every time I let the two overlap. Caffeine isn't a villain here — it's just a variable, and an untracked variable will happily take credit for a win it didn't earn.
A Flat Line Doesn't Always Mean the Product Failed
One more pattern showed up around the same time I was refining the recall side of this testing, which I wrote up separately in How I Fixed My Mid-Sentence Word Search — and it very nearly made me quit on the audio program that had been working. The early gains from The Brain Song were real, and then, well into the test, the line on my chart went flat. My first instinct was to call it a dud and move on, the kind of conclusion a spreadsheet practically begs you to reach, because a flat line looks so final.
Instead of dropping it, I started rotating in The Genius Song on alternating stretches, and the flat line broke. That told me something different than "the product stopped working" — it told me my own attention had adapted to one specific stimulus, the same way you stop noticing a ticking clock after enough exposure. A plateau in a personal audit is at least as likely to be tolerance as it is failure, and treating every flat stretch as a verdict is how people quit on things that were never actually broken.
So What Actually Counts as Clean Data in a Personal Audit?
Add it up and the actual lesson has nothing to do with which product wins. Before I trust a single number in my own sheet now, I check it against four questions: did I change more than one thing at once, did I skip a day and paper over the gap afterward, did caffeine or sleep move without me logging it, and has enough time passed that a flat result could be tolerance instead of failure. Any one of those four can quietly wreck an otherwise honest month of tracking, and most people running a supplement log never check for even one of them.
If you want to run your own version of this test, The Brain Song is still the cheapest way to start. Just build the guardrails in before day one, not after you've already got thirty days of numbers you're not sure you can trust.
Disclaimer: I am a retired accountant, not a health professional. These observations are based on my personal tracking spreadsheet and subjective experience. Please consult with a physician before starting any new supplement or health program.