Natural and Herbal Sleep Aids: What the Evidence Really Shows
Valerian, passionflower, lavender, hops, glycine, L-theanine, ashwagandha. The shelf is full, the promises are big. What can actually help, what is marketing, and where do these aids fit between melatonin and magnesium. An honest look at studies, strengths and limits.
Almost every patient with sleep problems has already tried something herbal. Usually valerian from the pharmacy, often disappointed. The problem is rarely the aid, but the lack of fit: an anxiolytic against a rhythm problem, a sedative against a nighttime cortisol drop. Herbal aids work via specific mechanisms, and they help when the pattern fits. Valerian may improve subjective sleep quality (Bent 2006 in American Journal of Medicine), ashwagandha may help with stress-related sleep problems (Cheah 2021 in PLoS One, standardized mean difference minus 0.59), oral lavender oil Silexan may improve anxiety-driven sleep (Woelk and Schläfke 2010 in Phytomedicine). But none of these is a miracle cure, and none replaces the search for the cause. The right herbal aid is an answer to a specific question, not a pill for everything. In this spoke I sort the aids by mechanism and by evidence.
This spoke is the plant and micronutrient workshop of the sleep cluster. We go through the most important natural sleep aids one by one (valerian, passionflower, hops, lavender Silexan, glycine, L-theanine, ashwagandha), sort them by mechanism of action and strength of evidence, clarify what actually makes sense for trouble staying asleep, show the typical misconceptions, illuminate the four KPNI lenses and give three concrete levers for the coming weeks. We cover melatonin and magnesium here only in passing, because they have their own spokes.
Why "herbal" does not automatically mean "effective" or "harmless"
Two misunderstandings accompany herbal sleep aids. First, the assumption that natural equals effective. The study evidence for many aids is thin, heterogeneous or shaped by publication bias. Second, the assumption that herbal equals free of side effects. That is not quite true: interactions with medication, liver strain, paradoxical reactions and problems during pregnancy and breastfeeding are real.
The more useful view is mechanistic. Herbal and natural sleep aids can be roughly divided into four directions of action, and the key is to choose the aid that fits the pattern at hand.
GABA-related calming
Valerian, hops and passionflower probably work partly via the GABA system, the brain's most important inhibitory neurotransmitter system. Useful for nervous restlessness and trouble falling asleep due to tension. Effect often moderate and individual.
Anxiety and rumination reduction
Lavender oil Silexan and ashwagandha lower tension and the stress response. Sleep improves here indirectly, through less nighttime rumination and lower arousal. Suitable when the mind will not come to rest.
Neuromodulation
Glycine (inhibitory neurotransmitter, lowers core body temperature) and L-theanine (promotes alpha waves, relaxes without sedating) are gentle modulators. Supportive rather than decisive, well tolerated.
Rhythm and muscle
This is where melatonin (sleep-wake rhythm, see Spoke 5) and magnesium (muscle relaxation, nervous system, see Spoke 4) sit. Strictly speaking not classic plant extracts, but frequent combination partners. Suitable for a rhythm shift or for restlessness and cramps.
Valerian: the best-known aid with moderate evidence
Valerian (Valeriana officinalis) is the classic herbal sleep aid in German-speaking countries. Its effect is discussed, among other things, via the GABA system and valerenic acid. The evidence is there, but less clear than the market presence suggests.
Valerian for sleep: 16 studies, 1093 patients
Meta-analysis Stephen Bent and colleagues published a systematic review with meta-analysis on valerian for sleep quality in the American Journal of Medicine in 2006. 16 randomized placebo-controlled trials with a total of 1093 patients were included. 6 studies reported a dichotomous outcome (sleep improved yes or no) and showed a statistically significant benefit: relative risk for improved sleep 1.8 (95 percent confidence interval 1.2 to 2.9). However, the authors explicitly emphasize two limitations: many studies had considerable methodological weaknesses, and there were indications of publication bias. The doses, preparations and treatment durations varied widely. The authors' conclusion: valerian might improve sleep quality without side effects, future studies must use standardized preparations.
Bent S, Padula A, Moore D, Patterson M, Mehling W. Am J Med. 2006;119(12):1005-12. doi:10.1016/j.amjmed.2006.02.026 · PMID: 17145239
In practice this means: valerian may help, but the effect is moderate and not reproducible in everyone. The usual use is standardized dry extracts in the evening, and it often takes regular use over 2 to 4 weeks. The effect does not necessarily appear on the first night. A common usage error: expecting a single low dose to work like a sleeping pill. Valerian is well tolerated, but may cause morning grogginess and rarely paradoxical restlessness.
Passionflower and hops: often the companions of valerian
Passionflower (Passiflora incarnata) and hops (Humulus lupulus) are often found in combination products with valerian. The idea behind this is a shared calming, GABA-related effect.
Passionflower for stress, anxiety and sleep: 9 clinical studies
Systematic review Katarzyna Janda and colleagues published a systematic review on the neuropsychiatric effects of passionflower in Nutrients in 2020. 9 clinical studies were included, with very different durations (from one day to 30 days) and participants aged 18 and over. The majority of studies reported a reduction in anxiety scores after taking passionflower preparations, with the effect being less pronounced in people with only mildly expressed anxiety symptoms. No serious side effects were observed, in particular no memory loss and no decline in psychometric functions. The authors cautiously conclude that passionflower may help with some symptoms in neuropsychiatric patients.
Janda K, Wojtkowska K, Jakubczyk K, Antoniewicz J, Skonieczna-Żydecka K. Nutrients. 2020;12(12):3894. doi:10.3390/nu12123894 · PMID: 33352740
For passionflower, then, something similar applies as for valerian: cautiously positive indications, mainly via the anxiety and tension axis, but limited and heterogeneous evidence, well tolerated. For hops alone the evidence is even thinner. Hops is almost never studied in isolation, but in combination with valerian, so the individual effect is hard to quantify. The combination products have shown indications of improvement in some studies, but separating out the hops contribution remains unclear. My practical approach: passionflower and hops are sensible companions in combination products, not an aid on which to build a sleep therapy alone.
Lavender oil Silexan: the best-documented anxiolytic among the plants
Here an important distinction is decisive. Lavender as aromatherapy or tea has a weak and inconsistent study evidence. The standardized oral lavender oil preparation Silexan, by contrast, has one of the most convincing clinical studies among the herbal aids, although primarily for anxiety, not directly as a sleep aid.
Silexan compared with lorazepam in generalized anxiety disorder
RCT Hans-Peter Woelk and Siegfried Schläfke published a multicenter, double-blind, randomized study in Phytomedicine in 2010. They compared the oral lavender oil capsule preparation Silexan over 6 weeks with the benzodiazepine lorazepam in adults with generalized anxiety disorder. The primary endpoint was the change in the Hamilton anxiety score. This dropped comparably in both groups: by 11.3 points (45 percent) in the Silexan group and by 11.6 points (46 percent) in the lorazepam group, starting from 25 points at baseline. The results from the sleep diary also showed comparable positive effects of both substances. Crucially: Silexan showed no sedative effect and no potential for dependence. The authors conclude that Silexan may be an effective and well-tolerated alternative to benzodiazepines in relieving generalized anxiety.
Woelk H, Schläfke S. Phytomedicine. 2010;17(2):94-9. doi:10.1016/j.phymed.2009.10.006 · PMID: 19962288
Silexan is not a classic sleep-inducing agent that makes you drowsy. It may lower inner tension and anxiety, and sleep improves as a consequence. That is exactly the right approach for people whose sleep is disturbed by rumination, worries and tension. For a pure rhythm problem or a night interrupted by pain or apnea, it is the wrong tool. The most common side effect is belching with a lavender taste.
Glycine and L-theanine: the gentle amino acids
Glycine and L-theanine are not plant extracts in the narrow sense but amino acids. However, they regularly come up in the natural sleep discussion because they are gentle, well tolerated and backed by growing, if limited, evidence.
L-theanine improves subjective sleep quality in healthy adults
RCT Shinsuke Hidese and colleagues published a randomized, placebo-controlled, double-blind crossover study in 30 healthy adults in Nutrients in 2019. 200 milligrams of L-theanine daily over 4 weeks lowered the scores for depression, anxiety (trait anxiety) and the Pittsburgh Sleep Quality Index. Compared directly with placebo, the subscales sleep onset latency, sleep disturbance and use of sleep medication improved in particular. In addition, verbal fluency and executive functions improved. The authors conclude that L-theanine has the potential to promote mental health in people with stress-related complaints.
Hidese S, Ogawa S, Ota M, et al. Nutrients. 2019;11(10):2362. doi:10.3390/nu11102362 · PMID: 31623400
Glycine reduces daytime sleepiness after sleep deprivation
RCT Makoto Bannai and colleagues published a study on glycine in partially sleep-restricted healthy volunteers in Frontiers in Neurology in 2012. Sleep was reduced by 25 percent over three nights. Before going to bed, 3 grams of glycine or placebo were taken. In the glycine group there was a significant reduction in fatigue the following day and a trend toward less daytime sleepiness, measured with a visual analog scale and questionnaire. A performance test showed a significant improvement in psychomotor vigilance. Earlier work by the same research group had shown that glycine improves subjective sleep quality. Glycine lowers core body temperature, which can favor falling asleep.
Bannai M, Kawai N, Ono K, Nakahara K, Murakami N. Front Neurol. 2012;3:61. doi:10.3389/fneur.2012.00061 · PMID: 22529837
A third building block supports the glycine signal: Craig Thomas and colleagues showed in European Journal of Nutrition in 2023 that a glycine-rich collagen preparation (15 grams per day, one hour before going to bed) in physically active males with sleep complaints reduced the number of nighttime awakening events on polysomnography and improved cognitive function in the morning. It had no effect on sleep onset latency or sleep efficiency. Glycine is thus a gentle modulator with indications of less fragmentation, not a decisive sleep aid.
My practical approach: L-theanine (usually 200 milligrams in the evening) suits people who find it hard to switch off and suffer from tension. Glycine (usually 3 grams before going to bed) is worth a try with mild reductions in sleep quality. Both are well tolerated, but both are fine-tuning, not heavyweights.
Ashwagandha: the adaptogen with the best sleep meta-analysis
Ashwagandha (Withania somnifera) is an adaptogen from the Ayurvedic tradition that primarily acts on the stress axis. Among the aids discussed here it has one of the more robust evidence bases, especially in the context of stress-related sleep problems.
Ashwagandha extract on sleep: 5 RCTs, 400 participants
Meta-analysis Kae Ling Cheah and colleagues published a systematic review with meta-analysis on the effect of ashwagandha extract on sleep in PLoS One in 2021. 5 randomized controlled trials with 400 participants were analyzed. Ashwagandha extract showed a small but significant effect on overall sleep (standardized mean difference minus 0.59, 95 percent confidence interval minus 0.75 to minus 0.42). The effects were more pronounced in the subgroup of adults with diagnosed insomnia, at doses from 600 milligrams per day and with a treatment duration of at least 8 weeks. Mental alertness on rising and the level of anxiety also improved. No serious side effects were reported. The authors explicitly point out that data on long-term safety are limited.
Cheah KL, Norhayati MN, Husniati Yaacob L, Abdul Rahman R. PLoS One. 2021;16(9):e0257843. doi:10.1371/journal.pone.0257843 · PMID: 34559859
Withania somnifera for anxiety and insomnia: 5 RCTs, 254 patients
Meta-analysis Kaneez Fatima and colleagues published a systematic review with meta-analysis on the safety and efficacy of Withania somnifera for anxiety and insomnia in Human Psychopharmacology in 2024. Pooled results from 5 RCTs with 254 patients showed a significant reduction in the Hamilton anxiety score as well as an improvement in several sleep parameters: sleep onset latency, total sleep time, Pittsburgh Sleep Quality Index and sleep efficiency. There was no significant effect on wake after sleep onset and total time in bed. The authors emphasize the high statistical heterogeneity and call for larger studies for confirmation.
Fatima K, Malik J, Muskan F, et al. Hum Psychopharmacol. 2024;39(6):e2911. doi:10.1002/hup.2911 · PMID: 39083548
Ashwagandha is not suitable for everyone. It may irritate the stomach, and in individual cases liver strain has been reported. It may affect thyroid function, hence caution in thyroid disease. Because of its immunomodulating effect, restraint is advisable in autoimmune conditions. It should be avoided during pregnancy and breastfeeding. When taking sedatives, thyroid hormones or immunosuppressants, its use should be clarified with a physician.
The 4 KPNI lenses on herbal sleep aids
Nervous system
Valerian, hops and passionflower probably modulate the GABA system, the most important inhibitory neurotransmitter system. L-theanine promotes alpha waves and a relaxed waking state. Glycine is an inhibitory neurotransmitter and can lower core body temperature. Where the nervous system is overactivated, these aids take effect.
Hormonal system
Ashwagandha acts via the stress axis and may dampen elevated cortisol responses, which can improve stress-related sleep. Caution: it may affect the thyroid. Melatonin (see Spoke 5) is the central sleep hormone that controls the rhythm and combines well with herbal anxiolytics.
Immune system
Chronic sleep deprivation and silent inflammation reinforce each other. Adaptogens such as ashwagandha are immunomodulating, which is a reason for caution in autoimmunity. A calmer stress axis through better nights tends to lower inflammatory activation. The axis is reciprocal.
Metabolism
Glycine lowers core body temperature, a signal that favors falling asleep. Magnesium (see Spoke 4) is a cofactor in hundreds of enzymatic reactions and is involved in muscle and nerve relaxation. Late alcohol and caffeine disturb the metabolism of sleep regardless of the best herbal aid.
What does not work: typical misconceptions
Herbal does not mean free of side effects. Valerian may cause grogginess in the morning, ashwagandha may irritate the stomach and affect the thyroid, many aids interact with sedatives, antidepressants and alcohol. During pregnancy and breastfeeding safety data are lacking for most aids, so restraint applies here. Anyone who regularly takes medication should clarify the combination with a physician rather than combining blindly.
Herbal aids work via specific mechanisms. An anxiolytic such as Silexan may help with anxiety-driven sleep, but not with a rhythm problem. A GABA-related calmer may help with tension, but not with sleep apnea. Anyone who uses the wrong aid against the wrong pattern experiences it as ineffective and wrongly concludes that herbal aids generally do not work. The fit decides.
With herbal aids, more is rarely better. Cheah 2021 shows for ashwagandha a sensible range from 600 milligrams per day, not arbitrarily higher. Increasing the dose without a plan mainly raises the risk of side effects and interactions. If an aid stays without effect at a sensible dose over several weeks, doubling the dose is rarely the solution, but rather an indication of the wrong pattern or an untreated cause.
No herbal aid compensates for late caffeine intake, screen light until midnight, alcohol in the evening, untreated sleep apnea or chronic stress without regulation. The aids are support, not a substitute. Anyone who ignores the basics and only stacks preparations treats the symptom and lets the cause run on.
The right aid for the right pattern, at a sensible dose, over enough time.
Valerian and passionflower for tension, Silexan and ashwagandha for anxiety- and stress-driven sleep, glycine and L-theanine as gentle fine-tuning. First understand the pattern, then test one to two aids in a targeted way. That is more effective than five preparations at once.
Three concrete levers for the coming weeks
First determine the pattern, then choose the aid
Before you buy a preparation, clarify: is it trouble falling asleep or trouble staying asleep? Is there tension and rumination, or rather a shifted rhythm, or restlessness and cramps? For tension and rumination, Silexan or ashwagandha fit, for nervous restlessness valerian or passionflower, for a rhythm shift rather melatonin (Spoke 5), for cramps and restlessness rather magnesium (Spoke 4). The fit is more important than the brand.
Test one to two aids over at least 2 to 4 weeks
Herbal aids often need time. Choose one, at most two aids at a sensible dose (for example ashwagandha from 600 milligrams per day after Cheah 2021, L-theanine 200 milligrams after Hidese 2019) and test over 2 to 4 weeks with a short sleep diary. Do not expect an effect on the first night. If nothing happens after several weeks, switch the aid or question the pattern instead of blindly increasing the dose.
Clarify the basics and interactions first
Before any preparation, check the basics: caffeine after the early afternoon, alcohol in the evening, late screen light, irregular sleep times. These factors make any aid less effective. Also clarify interactions: do you take sedatives, antidepressants, thyroid or blood pressure medication? Are you pregnant or breastfeeding? Then the choice should be discussed with a physician before you start.
How herbal aids relate to melatonin and magnesium
Herbal sleep aids, melatonin and magnesium address different levers and are not mutually exclusive. Melatonin mainly controls the sleep-wake rhythm and the time of falling asleep, so it is the first choice for rhythm shifts, shift work or jet lag (more on this in the spoke on melatonin). Magnesium works via muscle relaxation and the nervous system and may help with restlessness, nighttime cramps and inner tension (more on this in the spoke on magnesium). The herbal aids of this spoke act mainly on tension, anxiety and calming.
From this follows a sensible approach rather than a scattershot: identify the most likely pattern, choose the suitable main aid, and supplement in a targeted way if a second pattern is involved. Many commercial combination products mix melatonin with plant extracts, which can be sensible with a matching pattern, but is no substitute for the search for the cause. If, despite sensibly chosen aids, no improvement occurs over weeks, the sleep disorder should be assessed by a physician rather than lengthening the list of preparations.
Frequently asked questions about natural and herbal sleep aids
Which herbal sleep aid has the best evidence?
There is no herbal sleep aid with evidence as robust as a prescription sleep medication, and that is an honest statement. The best studied in terms of meta-analyses are ashwagandha and valerian. Cheah 2021 in PLoS One pooled 5 randomized controlled trials with 400 participants and found a small but significant effect of ashwagandha extract on overall sleep (standardized mean difference minus 0.59), more pronounced in people with diagnosed insomnia, at doses from 600 milligrams per day and a use duration from 8 weeks. Bent 2006 in American Journal of Medicine analyzed 16 valerian studies with 1093 patients and found a relative risk for improved sleep quality of 1.8, but explicitly pointed to publication bias and methodological weaknesses. Oral lavender oil Silexan is, according to Woelk and Schläfke 2010 in Phytomedicine, effective in generalized anxiety disorder with sleep problems. Which aid suits you depends on the pattern: trouble falling asleep or staying asleep, tension, rumination, stress.
Does valerian really work against sleep disorders?
Valerian (Valeriana officinalis) may improve subjective sleep quality, but the evidence is not as clear as its market presence suggests. Bent 2006 in American Journal of Medicine pooled 16 randomized placebo-controlled trials with 1093 patients. 6 studies with a dichotomous outcome (sleep improved yes or no) showed a relative risk of 1.8 for improved sleep quality. However, the authors explicitly emphasize two limitations: marked methodological weaknesses in many studies and indications of publication bias, that is, the tendency for positive results to be published more often. The doses and preparations were very heterogeneous. Bottom line: valerian may help, has few side effects, but the effect is moderate and not reproducible in everyone. Valerian often needs regular use over 2 to 4 weeks, and the effect does not necessarily appear on the first night.
What is Silexan and how does it differ from ordinary lavender?
Silexan is a standardized oral lavender oil preparation (capsules), not to be confused with lavender aromatherapy or lavender tea. Woelk and Schläfke published a multicenter, double-blind, randomized study in Phytomedicine in 2010 in which Silexan was compared over 6 weeks with the benzodiazepine lorazepam in generalized anxiety disorder. The Hamilton anxiety score dropped comparably in both groups (by about 45 percent). The results from the sleep diary also showed comparable positive effects of both substances. Important: Silexan showed no sedative effect and no potential for dependence. That is a clinically relevant advantage. Silexan may help especially when sleep is disturbed by inner tension, rumination and anxiety, that is, via the detour of anxiety reduction. It is not a classic sleep-inducing agent but an anxiolytic with a positive side effect on sleep.
Does ashwagandha help with sleep?
Ashwagandha (Withania somnifera) may help with sleep problems, especially when stress and tension are the main cause. Cheah 2021 in PLoS One pooled 5 randomized controlled trials with 400 participants in a meta-analysis and found a small but significant effect on overall sleep (standardized mean difference minus 0.59, 95 percent confidence interval minus 0.75 to minus 0.42). The effects were more pronounced in people with diagnosed insomnia, at doses from 600 milligrams per day and with a use duration of at least 8 weeks. Fatima 2024 in Human Psychopharmacology confirmed in a further meta-analysis of 5 RCTs (254 patients) a significant reduction in sleep onset latency, Pittsburgh Sleep Quality Index and an improvement in sleep efficiency. Important: data on long-term safety are limited. There are isolated reports of liver strain. Caution is warranted in thyroid disease, during pregnancy and breastfeeding, and in autoimmune conditions.
What do L-theanine and glycine do for sleep?
Both amino acids have cautiously positive but limited evidence. L-theanine (from green tea) may have a relaxing effect without sedating. Hidese 2019 in Nutrients found in a randomized placebo-controlled crossover study that 200 milligrams of L-theanine daily over 4 weeks improved the Pittsburgh Sleep Quality Index, especially the subscales sleep onset latency, sleep disturbance and use of sleep medication. L-theanine is suitable for people who find it hard to switch off. Glycine is an amino acid taken before going to bed. Bannai 2012 in Frontiers in Neurology showed that 3 grams of glycine in partial sleep deprivation reduced daytime sleepiness and fatigue and improved psychomotor vigilance. Thomas 2023 in European Journal of Nutrition found, with glycine-rich collagen, a reduction in nighttime awakening events. Both are well tolerated, but should not be understood as miracle cures. They are gentle modulators rather than strong sleep aids.
What is the best herbal sleep aid for staying asleep?
For staying asleep alone there is no herbal aid with convincing study evidence on sleep continuity. Most herbal aids address falling asleep or inner tension instead. When trouble staying asleep is in the foreground, it is worth first looking for the cause: a nighttime cortisol or blood sugar drop, alcohol in the evening, late caffeine intake, sleep apnea, nighttime rumination, menopause. Glycine and ashwagandha have shown indications of less nighttime waking in individual studies (Thomas 2023, Fatima 2024), but the evidence is limited. Magnesium may help with nighttime calf cramps or restlessness (see Spoke 4). Anyone who chronically cannot stay asleep despite herbal aids should have their sleep hygiene and possible organic causes assessed rather than increasing the dose. An aid does not replace a medical examination of the cause.
Can I combine herbal sleep aids with melatonin or magnesium?
In principle you can combine herbal aids with melatonin or magnesium, because they act on different levers. Melatonin mainly controls the sleep-wake rhythm and the time of falling asleep (see Spoke 5), magnesium works via muscle relaxation and the nervous system (see Spoke 4), herbal aids such as valerian, passionflower or lavender address tension and calming. Still, a scattershot of five preparations at once is not sensible. Better is a targeted approach: first identify the most likely pattern (rhythm problem, tension, cramps), then test one to two suitable aids over several weeks. Many commercial sleep combination products already combine melatonin with plant extracts. Important: watch for interactions with sedatives, antidepressants and blood pressure medication, and clarify with a physician if you take medication regularly.
Are herbal sleep aids free of side effects?
Herbal does not automatically mean free of side effects. Most of the aids discussed here are well tolerated, but there are relevant points. Valerian may cause morning grogginess, rarely paradoxical restlessness. Ashwagandha may irritate the stomach, in individual people liver strain has been reported, and it may affect thyroid function, hence caution in thyroid disease and autoimmunity. Lavender oil Silexan may cause belching with a lavender taste. Passionflower may cause drowsiness. Important general precautions: avoid most of these aids during pregnancy and breastfeeding, as data are lacking. Watch for interactions with sedatives, benzodiazepines, antidepressants and alcohol. Discontinue some aids before surgery. Do not combine with alcohol. And the most important point: a herbal sleep aid does not replace a medical assessment of the cause of a chronic sleep disorder.
More from the cluster "Treating Sleep Disorders Holistically"
- Pillar: Sleep Disorders Holistically
- Spoke 4: Magnesium and Sleep
- Spoke 5: Using Melatonin Correctly
- Spoke 6: Natural and Herbal Sleep Aids (you are here)
Connections to other topics
The pillar article places all the building blocks: sleep hygiene, rhythm, stress axis, nutrients and herbal aids. Here you see where this topic sits in the overall picture.
Magnesium works via muscle relaxation and the nervous system. Which form, which dose, and when it sensibly complements herbal aids.
Melatonin controls the internal clock and the time of falling asleep. First choice for shift work and jet lag, and a frequent combination partner of herbal anxiolytics.
Ashwagandha and Silexan act via the stress and anxiety axis. In the pillar you will find the framework for how stress regulation and sleep are connected.
Sources and further reading
- Cheah KL, Norhayati MN, Husniati Yaacob L, Abdul Rahman R. Effect of Ashwagandha (Withania somnifera) extract on sleep: A systematic review and meta-analysis. PLoS One. 2021;16(9):e0257843. doi:10.1371/journal.pone.0257843 · PMID: 34559859 [Meta-analysis]
- Fatima K, Malik J, Muskan F, et al. Safety and efficacy of Withania somnifera for anxiety and insomnia: Systematic review and meta-analysis. Hum Psychopharmacol. 2024;39(6):e2911. doi:10.1002/hup.2911 · PMID: 39083548 [Meta-analysis]
- Bent S, Padula A, Moore D, Patterson M, Mehling W. Valerian for sleep: a systematic review and meta-analysis. Am J Med. 2006;119(12):1005-12. doi:10.1016/j.amjmed.2006.02.026 · PMID: 17145239 [Meta-analysis]
- Janda K, Wojtkowska K, Jakubczyk K, Antoniewicz J, Skonieczna-Żydecka K. Passiflora incarnata in Neuropsychiatric Disorders - A Systematic Review. Nutrients. 2020;12(12):3894. doi:10.3390/nu12123894 · PMID: 33352740 [Systematic review]
- Woelk H, Schläfke S. A multi-center, double-blind, randomised study of the Lavender oil preparation Silexan in comparison to Lorazepam for generalized anxiety disorder. Phytomedicine. 2010;17(2):94-9. doi:10.1016/j.phymed.2009.10.006 · PMID: 19962288 [RCT]
- Hidese S, Ogawa S, Ota M, et al. Effects of L-Theanine Administration on Stress-Related Symptoms and Cognitive Functions in Healthy Adults: A Randomized Controlled Trial. Nutrients. 2019;11(10):2362. doi:10.3390/nu11102362 · PMID: 31623400 [RCT]
- Bannai M, Kawai N, Ono K, Nakahara K, Murakami N. The effects of glycine on subjective daytime performance in partially sleep-restricted healthy volunteers. Front Neurol. 2012;3:61. doi:10.3389/fneur.2012.00061 · PMID: 22529837 [RCT]
- Thomas C, Kingshott RN, Allott KM, et al. Collagen peptide supplementation before bedtime reduces sleep fragmentation and improves cognitive function in physically active males with sleep complaints. Eur J Nutr. 2023;63(1):323-335. doi:10.1007/s00394-023-03267-w · PMID: 37874350 [RCT]
- Moulin M, Crowley DC, Xiong L, Guthrie N, Lewis ED. Safety and Efficacy of AlphaWave L-Theanine Supplementation for 28 Days in Healthy Adults with Moderate Stress: A Randomized, Double-Blind, Placebo-Controlled Trial. Neurol Ther. 2024;13(4):1135-1153. doi:10.1007/s40120-024-00624-7 · PMID: 38758503 [RCT]
- Shammas RL, Marks CE, Broadwater G, et al. The Effect of Lavender Oil on Perioperative Pain, Anxiety, Depression, and Sleep after Microvascular Breast Reconstruction: A Prospective, Single-Blinded, Randomized, Controlled Trial. J Reconstr Microsurg. 2021;37(6):530-540. doi:10.1055/s-0041-1724465 · PMID: 33548936 [RCT]