They didn't sign up for better sleep. They got it anyway.
24 extra minutes per night, improved sleep quality, easier time falling asleep — all statistically significant, all unprompted.
Part of the Functional Beverage Study series — findings from Cohort 1, a real world, longitudinal study of 2,580 consumers across 20 products.
Most participants in our Cohort 1 study didn't enroll looking for a sleep benefit. They got one anyway — across every measure we tracked, including a validated clinical instrument. Sleep wasn't the pitch. It became the outcome.
The punchline
Only 8.9% of participants cited "better sleep" as their reason for joining the study. But sleep improved across every measure we tracked — hours, quality, ease of falling asleep, and a validated clinical sleep instrument — all statistically significant. The product they signed up to try for stress relief or curiosity was quietly improving their sleep.
Sleep wasn't the pitch. It became the outcome.
At enrollment, "better sleep" ranked fifth among reasons for trying functional beverages — behind stress relief (44.7%), being social (16.1%), pain relief (15.2%), and improved mood (7.1%). Most participants weren't looking for a sleep product.
But 48.3% of daily consumption happened at day's end to relax, and the median use time was 5:30 PM. The consumption pattern was already aligned with sleep — participants just weren't framing it that way.
24 extra minutes per night
Participants reported how many hours of sleep they got each night throughout the study — during the 7-day baseline (no product) and during the 14-day product use phase.
Average sleep without the product: 6 hours 37 minutes. Average sleep with the product: 7 hours 1 minute. That's 24 additional minutes per night (p < .05) — a 6.1% increase.
Sleep quality improved 13.6%
Each day, participants rated their quality of sleep the previous night.
The average sleep quality score increased from 5.24 to 5.95 — a 0.71 point improvement (p < .05). That's a 13.6% increase in self-reported sleep quality during the product use phase.
Falling asleep got easier
Participants also rated their ability to fall asleep each night on a 1–5 scale, where 1 = "much easier than usual" and 5 = "much harder than usual."
The average score dropped from 3.00 to 2.58 — a 14.1% improvement (p < .05). Participants found it meaningfully easier to fall asleep on nights they used the product.
And 13.5% of all duration responses were "fell asleep" — the product's effects literally ended because participants fell asleep. That's not a side effect. It's a use case.
PROMIS Sleep Disturbance: clinical-grade validation
Sleep disturbance was also measured using the PROMIS Sleep Disturbance Short Form 8b — a validated clinical instrument where 50 represents the general population average. Higher scores mean worse sleep disturbance.
Baseline: 55.34 (mild disturbance range). End of study: 50.80 (general population average). That's a 4.54 T-score point improvement (-8.2%, p < .05).
The improvement was statistically significant but fell just short of the minimally important difference threshold (5 T-score points). In practical terms: participants entered the study sleeping worse than average and exited sleeping at the population norm.
Who improved most
The sleep improvements weren't uniform. Interaction models revealed that several factors significantly moderated the effect:
Use consistency: High-consistency users started with the worst sleep disturbance scores and showed the greatest improvement — crossing over other groups to finish with the lowest disturbance by study end.
Dose: High-dose products drove the largest sleep improvements across all three daily measures.
Gender: Females showed the most improvement in sleep quality, sleep disturbance, and ability to fall asleep.
Age and weight: Older and heavier participants showed greater improvements in sleep quality and ease of falling asleep.
After the study, they told us
In the exit survey (N=1,925), participants reflected on their sleep during the study:
54.7% agreed their sleep quality improved while using functional beverages
53.2% agreed they fell asleep more easily
44.8% agreed they slept longer
More than half of participants — most of whom didn't enroll for a sleep benefit — reported better sleep quality and easier time falling asleep as an outcome of use.
What this suggests
1. Sleep is an unpriced value proposition in the functional beverage category. Only 8.9% of participants arrived looking for a sleep benefit, but 54.7% reported getting one. Category sizing models that don't account for sleep as a secondary driver are underestimating the addressable market — particularly as the $90B+ sleep wellness industry continues to grow.
2. The evening consumption pattern is the product-market fit most brands are underexploiting. 48.3% of consumption already happens at day's end, median use at 5:30 PM. The behavioral data points to "evening wind-down" as the highest value positioning territory for functional beverages — not nightlife, not social occasions.
3. Consistency compounds the benefit — and that's a retention story. High-consistency users saw the greatest sleep improvements. For investors and operators, this means the sleep benefit is a natural retention mechanism: the longer consumers stick with the product, the more they benefit.
4. There's a formulation implication. Dose drove the largest sleep improvements. If functional beverage brands are targeting the sleep use case — intentionally or not — dose needs to match the outcome the consumer is experiencing.
5. This bridges two high-growth categories. The functional beverage market and the sleep wellness market have been treated as separate. This data suggests they overlap — and that functional beverages may be competing not just with alcohol but with melatonin and other sleep supplements. That's a TAM expansion that most market models don't reflect.
Method note: Self-reported, real-world observational dataset (Cohort 1; N=2,580; 20 beverages).