How many nights does Lacticaseibacillus paracasei NY1301 + DDMP need before you can judge it (measured on sleep latency)?

The answer: 168 nights. A 2026 double-blind randomized trial found that NY1301 + DDMP reduced sleep latency by 18.82% relative to placebo — equal to -2.07 minutes (95% CI: -3.96 to -0.17; p = 0.033) at week 8. That 18.82% matters because our 650-night dataset sets the detection threshold at 168 nights to 18.53%. The published effect clears that threshold. Barely. That makes 168 nights the minimum horizon for separating signal from noise on a real body.

Why sleep latency is hard to judge without a long horizon

Sleep latency measures the time between lights out and your first consolidated sleep period. In our dataset, the median is 11 minutes. That sounds workable. The noise is not.

The coefficient of variation (CV) for sleep latency in our data is 84.41%. High CV means one body swings widely from night to night with nothing changing. The relative coefficient of variation (RCV) reaches 233.96%. In plain terms: ordinary night-to-night variance exceeds the documented effect of this compound. Sleep latency is one of the noisiest variables in the dataset.

The gap looks like this in practice. The trial found -2.07 minutes of average difference. But your latency going from 9 to 15 minutes on an ordinary Tuesday — both perfectly normal values in this dataset — already buries weeks of intervention signal. You cannot separate cause from coincidence in one week, two weeks, or even two months. Without an accumulated horizon, no statistical ground exists to judge anything.

What the trial did, exactly

Tomizawa, Sugimoto & Fukao (2026), Journal of Clinical Medicine 15(11):4175, enrolled 171 healthy Japanese adults aged 20 to 59. The design was a double-blind, placebo-controlled randomized controlled trial with parallel groups. The active arm received one 65 mL bottle per day for 8 weeks (56 days). Each bottle contained 6 × 10¹⁰ CFU of probiotic NY1301 plus 2.2 mg DDMP, an antioxidant derived from soy. Final analysis included 161 participants.

The measurement device was an Oura ring — the same type of device used in the reference dataset behind this publication.

Sleep latency at week 8: mean difference of -2.07 minutes versus placebo. 95% confidence interval: -3.96 to -0.17. p = 0.033.

Threshold table — single-body data

Below are the minimum detectable change thresholds from 650 nights of one body for the variable sleep_latency_min. Each row shows the smallest relative change (as a percentage) needed to count as signal — not normal fluctuation — at that cumulative time horizon.

Nights accumulated	Minimum detectable change
28	45.38%
56	32.09%
84	26.2%
112	22.69%
140	20.29%
168	18.53%

The published effect is 18.82%. The 168-night threshold is 18.53%. The gap between those two numbers is under one percentage point. The effect clears the threshold — and only at 168 nights. Before that horizon, every threshold in the table sits above 18.82%. At 28 nights, you would need to observe 45.38% change. The trial found 18.82%. A randomized trial can detect that by averaging across 161 participants. One body does not have that statistical advantage.

Three facts the headline cannot hide

First: sleep latency was a secondary endpoint. The primary endpoint of this trial was subjective fatigue. That primary endpoint failed — no statistically significant difference between active and placebo on the main measure. A positive finding on a secondary outcome, when the primary fails, carries a higher risk of being a chance result. This is not a fraud claim. It is what the protocol records and what honest reading requires to communicate.

Second: the effect belongs to the combination, not its parts. NY1301 (the probiotic) and DDMP (the antioxidant) were administered together in the same bottle. The trial did not include arms testing each ingredient separately. The observed effect cannot be attributed to either component alone. NY1301 without DDMP is a different intervention. So is DDMP without NY1301.

Third: the study was funded by Nissin York Co., the manufacturer of the product. The design was double-blind, which limits the most obvious bias channels. Funding source does not invalidate the result, but it is a fact the record must carry.

These three facts do not erase the numbers. The design was double-blind. The instrument was Oura. The data carries a 95% CI and a p below the conventional threshold. But they determine how much weight to assign — and that weight is less than a standalone trial with a successful primary endpoint would deserve.

The limit

This data does not say NY1301 + DDMP will reduce your sleep latency.

What it says: in a trial of 161 healthy Japanese adults, the combination was associated with a 2.07-minute reduction in Oura-measured sleep latency. That effect, expressed as a relative change, clears the signal threshold of our own dataset at 168 cumulative nights.

What it does not say:

• That the effect holds beyond the 8-week trial window.
• That it applies to people with elevated sleep latency. The trial recruited healthy adults; participants with documented sleep disorders were excluded.
• That NY1301 alone, without DDMP, produces the same result.
• That -2.07 minutes is noticeable without a device. The magnitude is below the threshold of manual detection.
• That the result replicates. This is the first published trial with this combination.

The 168-night horizon is the minimum needed to begin judging. It does not establish that the signal will appear. It says: if the effect exists at the published magnitude, 168 nights provide enough statistical ground to detect it.

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Mental Work — all protocols · related file: magnesium-for-sleep · open science — the dataset