Ashwagandha Sleep Quality: The Langade 2019 Trial Explained
The most-cited piece of evidence for ashwagandha and sleep is a single peer-reviewed trial. Here’s what it actually measured, what the numbers mean, and why the protocol matters more than the brand.
Quick answer: Langade 2019 was a randomized, double-blind, placebo-controlled trial in 80 adults with self-reported insomnia. Treatment: 600mg/day KSM-66® (300mg twice daily) for 10 weeks. Result: sleep efficiency improved from 75.6% to 83.5% (P=0.002). Optibio® Ashwagandha KSM-66® uses the trial extract and dose.†
Trial design at a glance
- Subjects: 80 adults with self-reported insomnia and anxiety
- Design: Randomized, double-blind, placebo-controlled, parallel-group
- Treatment: 300mg KSM-66® twice daily (600mg/day total) vs identical-appearing placebo
- Duration: 10 weeks
- Primary endpoints: Sleep efficiency (% of time in bed actually asleep), sleep onset latency, total sleep time, wake after sleep onset, Hamilton Anxiety Rating Scale
What the numbers mean
Sleep efficiency 75.6% → 83.5% on an 8-hour-in-bed schedule equals roughly 38 additional minutes of actual sleep per night. That’s a clinically meaningful improvement, comparable to first-line CBT-I (cognitive behavioral therapy for insomnia) effect sizes in similar populations.
Sleep onset latency, the time from lights-off to falling asleep, dropped significantly. Subjects reported less “wired-but-tired” lying awake at 11pm.
Anxiety scores (Hamilton) dropped meaningfully too. Insomnia and anxiety are physiologically linked, both driven by cortisol-axis dysregulation, so the parallel improvement makes mechanistic sense.
Why the protocol matters more than the brand
The trial used KSM-66® root extract at 600mg/day for 10 weeks. To replicate the published outcomes, you need:
- Same extract, KSM-66®, not generic ashwagandha and not Sensoril®/Shoden® (different patented extracts at different dose ranges)
- Same dose, 600mg/day. Most retail ashwagandha products dose 100 to 500mg, below the trial threshold.
- Same duration, 6 to 10 weeks consistently. Skipping doses or stopping early won’t produce the trial result.
Frequently asked questions
What does “sleep efficiency” mean?
The percentage of time in bed that you’re actually asleep (vs lying awake or wake after sleep onset). 85% is the threshold for “normal” sleep efficiency in adult sleep medicine.
Was Langade 2019 a high-quality trial?
Yes, randomized, double-blind, placebo-controlled, parallel-group with adequate sample size (n=80). Published in Cureus, peer-reviewed.
Has the result been replicated?
Yes. A 2021 meta-analysis pooling 5 RCTs (400 participants) confirmed ashwagandha’s effects on sleep efficiency, sleep onset latency, and total sleep time.
Can I expect the same 7.9-percentage-point sleep-efficiency gain?
Individual response varies. Trial averages don’t equal individual outcomes. The directional effect, better sleep over weeks of consistent dosing, is reliably reproduced across multiple RCTs.
The bottom line
The Langade 2019 sleep-efficiency trial is the strongest single piece of evidence for ashwagandha and sleep. To replicate its outcome, use the same extract (KSM-66®) at the same dose (600mg/day) for the same duration (6 to 10 weeks). Optibio® Ashwagandha KSM-66® matches the trial exactly.†
Related: best ashwagandha for sleep, does ashwagandha help sleep?, our science page.
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†These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.