Sleep advice has a marketing problem: the best-evidence interventions are free
Sleep advice has a marketing problem: the interventions with the best evidence are free, and the ones with podcast ads have the weakest data.
I ranked the popular interventions by Cohen's d - the standardized effect size from published meta-analyses - and the ordering flips the usual shopping list. Sleep consistency (same bedtime and wake time, seven days a week) sits near the top with effects around d of 0.7 to 0.9 on next-day cognitive measures in the shift-work literature. That's larger than most supplements' measured effect on anything, and it costs nothing. Resistance training twice weekly posts roughly d of 0.6 to 0.8 on all-cause mortality proxies in cohort meta-analyses, plus the largest measured effect on resting metabolic rate. Zone 2 cardio volume shows d of 0.5 to 0.7 on insulin sensitivity, dose-dependent up to about 150 weekly minutes.
The supplements cluster at d of 0.0 to 0.15. That doesn't mean they do nothing; it means they're the last dollars you spend after the free large-effect work is done - and the honest check is that an n=1 self-experiment can't reliably detect anything below about d of 0.5, so "I felt sharper" after a d-of-0.1 stack is measuring noise.
The full ranked table with citations, my 217-night sleep-consistency dataset, and the n=1 protocol template for testing anything above the detection threshold are at hackedself.com.
The ranking has a hole worth naming: Cohen's d is measured under study adherence, not real world adherence. A d of 0.8 for sleep consistency assumes you actually hold the schedule seven days a week for the length of the trial. A d of 0.1 supplement has near perfect adherence because it is one swallow. Expected real effect is d multiplied by the probability you sustain it, and ranked on that your table may reorder a long way.
Which is also a better answer to your marketing question than price is. The free interventions are not unmarketed because they are free, they are unmarketed because there is no transaction to fund it, and because the ask is change your behaviour every day forever rather than do one thing once. What people are avoiding is not the cost, it is the effort.
Same shape in our category for what it is worth. The highest effect SEO work is free and structural, and the thing with a price on it is the tool that tells you to go and do it.