Valerian and passionflower for sleep problems: what herbal calming can offer
A tea, a coated tablet, a gentle brake for the nervous system. Sometimes that is enough. Often it is not. Why the question of what wakes you at night may matter more than the question of what calms you.
Calming is not the same as cause. When your body sounds the alarm at night, the question is not only how to turn it down. It is also why it is ringing in the first place.
It is 3:12 a.m. You are lying awake. Not a little awake, but wide awake. Your heart is beating a bit too fast, your mind jumps straight to the next day. You turn over and count how many hours are left. And at some point you reach for the pack on your bedside table. Valerian. Maybe with passionflower.
I know this pattern from many conversations. And I understand the reach for the plant very well. It feels gentler than a sleeping pill. More natural. More harmless. And for some people it really is a pleasant companion.
But there is one question that often gets lost along the way. If you are wide awake at three in the morning, you rarely lack calming. More often, a system is speaking up that switches to alarm mode at night. The stress system. Or metabolism. Or both at the same time. That is exactly what this article is about.
What to expect in this article
- How valerian and passionflower might act on the GABA system
- What three meta-analyses on valerian actually show
- The thin but interesting evidence on passionflower
- Why the European guideline puts behavioural therapy first
- The KPNI sleep model: brake, accelerator, alarm system
- How cortisol and drops in blood sugar at night may wake you
- Safety: alcohol, medication, pregnancy, liver
- Three levers you can understand and use from tonight
The gentle brake: how plants might act on the GABA system
Imagine your nervous system as a car. It has an accelerator and a brake. The accelerator is called glutamate, joined by stress hormones such as adrenaline and cortisol. The most important brake is called GABA. When GABA docks onto its receptor, a small channel opens. The nerve cell becomes calmer and harder to excite.
Many classic sleeping pills strengthen exactly this brake. Valerian and passionflower have also long been associated with the GABA system. For valerian, there are interesting lab data on this.
A team led by Khom at the University of Vienna tested valerenic acid, a constituent of valerian root, on artificially produced GABA-A receptors. The substance enhanced the GABA current, but only in receptors with certain building blocks, the beta2 and beta3 subunits. The benzodiazepine antagonist flumazenil could not cancel out this effect. What this means for you: valerian might act at a different site than classic sedatives.
Khom S et al. Neuropharmacology. 2007;53(1):178-187. DOI: 10.1016/j.neuropharm.2007.04.018 [In vitro, oocyte model]Benke and colleagues from Zurich found a binding site on the GABA-A receptor where valerenic acid docked even at very low concentrations. In normal mice, the substance showed an anxiety-relieving effect in behavioural tests. In mice whose beta3 building block had been specifically altered, this effect did not occur. This suggests that exactly this receptor type might play a role. In humans, however, this chain has not been directly demonstrated.
Benke D et al. Neuropharmacology. 2009;56(1):174-181. DOI: 10.1016/j.neuropharm.2008.06.013 [In vivo, mouse, plus in vitro]This is biologically plausible. And it explains why valerian is described as a gentle brake rather than a heavy sedative. But a brake has a limit. It can slow a car down. It cannot influence why someone is pressing hard on the accelerator at the same time.
Most people ask: Which plant calms me best? The perhaps more helpful question is: Who is pressing my accelerator at night?
As long as the accelerator is pushed to the floor, every brake is working against an engine running at full throttle. And now you know why a gentle plant is noticeable for some people and changes almost nothing for others.
Valerian: what the meta-analyses show, and what they do not
Maybe you have already tried valerian and thought: somehow better. Or: I do not notice anything. Both fit the research surprisingly well. Because the research on valerian is a textbook example of how important it is to look closely at what was actually measured.
relative benefit ratio for “sleep improved” in 6 studies, with signs of publication bias
difference in time to fall asleep compared with placebo, not statistically significant
studies with 6,894 people in the broadest review to date
Bent and colleagues from the University of California, San Francisco, analysed 16 studies with 1,093 people. Six studies simply asked: sleep improved or not? Here the relative benefit ratio was 1.8 in favour of valerian, although there were signs of publication bias. Most studies had clear methodological weaknesses. The authors’ conclusion: valerian might improve sleep quality without causing side effects.
Bent S et al. Am J Med. 2006;119(12):1005-1012. DOI: 10.1016/j.amjmed.2006.02.026 [Meta-analysis, k=16, n=1093]Fernández-San-Martín and a team from Barcelona analysed 18 randomised, placebo-controlled trials. For time to fall asleep, the difference from placebo was 0.70 minutes, not statistically significant. Sleep quality scales showed no difference either. Only on the yes-or-no question about subjective improvement was valerian ahead, with a relative ratio of 1.37. The authors concluded: subjective improvement is possible, objectively measurable efficacy has not been demonstrated.
Fernández-San-Martín MI et al. Sleep Med. 2010;11(6):505-511. DOI: 10.1016/j.sleep.2009.12.009 [Meta-analysis, k=18 RCTs]Shinjyo, Waddell and Green screened 60 studies with a total of 6,894 people, including 10 studies with 1,065 people in the meta-analysis on subjective sleep quality. Their interpretation: the contradictory results might be due to the variable quality of the extracts. Some constituents are considered unstable. They found no serious side effects in any age group between 7 and 80 years.
Shinjyo N, Waddell G, Green J. J Evid Based Integr Med. 2020;25:2515690X20967323. DOI: 10.1177/2515690X20967323 [Systematic review, meta-analysis, 60 studies, n=6894]So what do we make of this? This is how I read these data. Valerian seems to improve the feeling of having slept better in some people. In measurements of sleep onset time and sleep architecture, this has hardly been visible so far. On top of that comes a large placebo component, which stands out in sleep studies almost every time.
Placebo is not a dirty word here. If you have an evening ritual, a warm tea, a deliberate pause, you signal safety to your nervous system. That can bring about real relaxation. We should just stay honest about where it may be coming from.
If your sleep feels better without much changing measurably, that is not worthless. But it is a hint that the plant may change your experience of the night rather than its cause.
For a restless phase, that may be enough. For a sleep problem that has lasted for months, probably not. And now you know why the same pack is a blessing for your friend and a disappointment for you.
Passionflower: gentle, rich in tradition and thinly supported
Passionflower is the quieter sister on the shelf. It is often found in combination products with valerian, lemon balm or hops. In Europe, it has long been used for inner restlessness and problems falling asleep. The question is how much of this shows up in studies.
Ngan and Conduit from Monash University in Australia had 41 young adults aged 18 to 35 drink passionflower tea for one week and placebo tea for another week. Of six values in the sleep diary, one differed clearly: sleep quality was rated better with passionflower. The authors speak of short-term, subjective benefits for healthy adults with mild fluctuations in sleep.
Ngan A, Conduit R. Phytother Res. 2011;25(8):1153-1159. DOI: 10.1002/ptr.3400 [RCT, crossover, n=41]Lee and colleagues from South Korea gave 110 adults with diagnosed insomnia either passionflower extract or placebo for two weeks. In the sleep lab, total sleep time increased by around 23 minutes on average with passionflower, and practically not at all with placebo. The difference was only just statistically significant. Sleep efficiency and time awake at night did improve in the passionflower group, but did not differ from placebo.
Lee J et al. Int Clin Psychopharmacol. 2020;35(1):29-35. DOI: 10.1097/YIC.0000000000000291 [RCT, n=110]Janda and colleagues from Szczecin found nine clinical studies with durations ranging from one day to 30 days. Most reported less anxiety, and with only mild symptoms the effect was weaker. Side effects such as memory problems were not observed. Miroddi and colleagues had previously examined the methods of the studies critically: small groups, unclear information on the extract, blinding and placebo. Their conclusion: a good safety profile, but the traditional efficacy needs more rigorous studies.
Janda K et al. Nutrients. 2020;12(12):3894. DOI: 10.3390/nu12123894 [Systematic review, k=9] · Miroddi M et al. J Ethnopharmacol. 2013;150(3):791-804. DOI: 10.1016/j.jep.2013.09.047 [Review]All in all, passionflower is of more interest for restlessness and tension than for a full-blown sleep disorder. That fits its traditional use. The European Medicines Agency lists passionflower as a traditional herbal medicinal product (traditional use) for mild symptoms of stress and as an aid to falling asleep. This is based on long-standing use, not on rigorous proof of efficacy. Certain dry valerian extracts have a somewhat better-supported classification there (well-established use).
What the European guideline says, and why I take it seriously
Maybe this section surprises you in a guide about medicinal plants. But I consider it the most important one. Because this is where it says what, based on current knowledge, forms the foundation for chronic insomnia.
A working group of the European Sleep Research Society led by Riemann from Freiburg published the European guideline on insomnia in 2017 and 2023. Both versions recommend cognitive behavioural therapy for insomnia, CBT-I for short, as the first treatment for chronic insomnia. This applies to adults of all ages, in person or digitally. The 2023 version explicitly does not recommend herbal medicines. According to the guideline, light and exercise may be useful as a complement.
Riemann D et al. J Sleep Res. 2017;26(6):675-700. DOI: 10.1111/jsr.12594 [Systematic review, European guideline] · Riemann D et al. J Sleep Res. 2023;32(6):e14035. DOI: 10.1111/jsr.14035 [Review, European guideline, update]I stand behind this recommendation. CBT-I sounds like psychotherapy, but it is very practical. A fixed wake-up time. Linking the bed with sleep again instead of with brooding. Temporarily matching the time in bed to the sleep you actually get. Defusing circling thoughts. It sounds unspectacular and still shows the most stable effects in studies.
So conventional sleep medicine is doing something very sensible here. What an integrative view can add is a second question. Not only: how do I retrain my sleep? But also: which physical signals keep my nervous system awake at night? This is where the KPNI model comes in.
The KPNI sleep model: brake, accelerator and alarm system
You do not sleep with your head alone. You sleep with your whole body. Clinical psychoneuroimmunology, KPNI for short, therefore looks at four systems at the same time. They are in constant conversation with each other at night.
Nervous system
GABA brakes, the sympathetic nervous system accelerates. In chronic insomnia, a state of round-the-clock overexcitation is being discussed, known in technical terms as hyperarousal.
Hormonal system
The stress axis made up of the hypothalamus, pituitary gland and adrenal gland releases ACTH and cortisol. Adrenaline is the fast alarm signal. Both can wake you up.
Metabolism
The brain needs glucose at night too. If blood sugar drops significantly, the body responds with counter-regulation via adrenaline, cortisol and glucagon.
Immune system
Lack of sleep may raise inflammatory messengers, and inflammation may disturb sleep. A cycle that runs in both directions.
Let us look at the hormonal axis. There are data here that support the picture of an overactive accelerator.
Vgontzas and colleagues from Penn State University observed 11 young people with chronic insomnia and 13 good sleepers for four nights in the sleep lab. Over 24 hours, ACTH was significantly higher in the people with insomnia, and cortisol tended to be as well, most clearly in the evening and in the first half of the night. Those who slept worst objectively released the most cortisol. The authors interpreted this as overexcitation of the nervous system, not as a mere consequence of too little sleep. Their advice: lower the overall level of arousal, not just improve nighttime sleep.
Vgontzas AN et al. J Clin Endocrinol Metab. 2001;86(8):3787-3794. DOI: 10.1210/jcem.86.8.7778 [Pathophysiology, case-control, n=24]In 2022, Dressle and a team from Freiburg pooled twenty case-control studies, with 449 people with insomnia and 357 good sleepers. The people with insomnia had moderately elevated cortisol levels on average. In blood samples, the difference was somewhat clearer still. This suggests that the stress axis might play a role in many people with insomnia, even if it is certainly not the main cause for everyone.
Dressle RJ et al. Sleep Med Rev. 2022;62:101588. DOI: 10.1016/j.smrv.2022.101588 [Meta-analysis, k=20, 449 vs. 357 people]Irwin from the Cousins Center for Psychoneuroimmunology in Los Angeles summarised how closely sleep and the immune system are connected. Disturbed sleep may weaken defences against viruses and fuel inflammatory processes. Conversely, inflammation itself may disturb sleep. This is mediated via hormonal axes and the autonomic nervous system. What this means for you: sleep is not a side issue, but a central window of regulation.
Irwin MR. Annu Rev Psychol. 2015;66:143-172. DOI: 10.1146/annurev-psych-010213-115205 [Review, psychoneuroimmunology]If cortisol and adrenaline kick in too early at night, you are not necessarily lacking calm. Then an alarm system is running that goes off for a reason. A plant may perhaps lower the volume of the alarm a little. It may not reach the trigger.
And now you know why herbal calming may take effect mainly when the nighttime stress axis is addressed as well.
When blood sugar wakes you up
Now it gets personal. Because there is a trigger for waking up at night that hardly anyone thinks of unless they have diabetes. Blood sugar. Before I explain the physiology to you, I would like to tell you about an observation from my practice.
Trouble staying asleep, and the trail led to blood sugar
A patient came to me because of trouble staying asleep. The obvious question would have been whether her nervous system was lacking calm, for instance in the GABA system. And whether a stronger herbal brake might be the answer.
When we looked more closely, a different pattern emerged. Her waking up at night was temporally linked to drops in her blood sugar during the night. What was in the foreground was not a lack of calm, but a metabolic signal that woke her body.
The lesson I take from this: if you wake up at night, you do not always need more brake. Sometimes the first step is to ask which system is sounding the alarm.
Why is this physiologically plausible? Your brain is a heavy consumer of glucose, even during sleep. It monitors blood sugar the way a smoke detector monitors the air. If the value drops significantly, an emergency chain kicks in. Adrenaline is released, along with cortisol, glucagon and growth hormone. They draw stored sugar from the liver. And adrenaline can wake you up very reliably.
Schultes and colleagues from the University of Lübeck lowered blood sugar in a controlled way to 2.2 mmol/L during sleep in 16 healthy people and 16 people with type 1 diabetes. Of the healthy participants, 10 woke up; of the people with diabetes, only one. In everyone who woke up, adrenaline rose markedly, on average about seven and a half minutes before brain waves showed wakefulness. The authors interpret waking up as part of a central protective response, running in parallel with hormonal counter-regulation.
Schultes B et al. PLoS Med. 2007;4(2):e69. DOI: 10.1371/journal.pmed.0040069 [Pathophysiology, controlled study, n=32]Jauch-Chara and the same Lübeck group repeated the experiment in 16 healthy people, once right after falling asleep and once after about three and a half hours of sleep. Early in the night, 10 out of 16 woke up; in the second half of the night, all 16 did. Hormonal counter-regulation was weaker late in the night. What this means for you: the second half of the night seems to be a particularly sensitive phase.
Jauch-Chara K et al. Diabetes. 2007;56(7):1938-1942. DOI: 10.2337/db07-0044 [Pathophysiology, crossover, n=16]These experiments lowered blood sugar artificially and sharply. They show the mechanism, not how often it happens in everyday life. In healthy people without diabetes, values this low are rare. How often milder drops at night already contribute to waking up has been studied very little so far. To be honest, this is an open research question.
Shah and colleagues had 153 healthy people without diabetes aged between 7 and 80 wear a blinded glucose sensor for up to ten days. Mean glucose was around 98 to 99 mg/dL. Values below 70 mg/dL occurred for a median of only about 15 minutes per day. These reference data help to put a sensor curve into context in the first place.
Shah VN et al. J Clin Endocrinol Metab. 2019;104(10):4356-4364. DOI: 10.1210/jc.2018-02763 [Real-world, prospective multicenter cohort, n=153]An important practical note: not every low reading on a sensor at night is real. If you lie on the arm with the sensor, the pressure can briefly produce falsely low values. That is why a sensor curve belongs in an expert evaluation, together with a sleep diary.
And why would blood sugar drop at night in the first place? Possible reasons are being discussed: a sugary evening meal with a fast insulin response, alcohol in the evening, which may slow the release of sugar from the liver, very long gaps between meals combined with intense training, or certain medications. Whether one of these plays a role for you can only be clarified on an individual basis.
Waking up with a pounding heart at three in the morning feels like anxiety. But sometimes it is chemistry first: a surge of adrenaline that is actually trying to rescue your blood sugar. Your mind then just jumps onto a train that is already moving.
That takes the pressure off. You are not simply “too stressed to sleep”. Your body may be doing exactly what it is built for. And now you know why a calming plant may be able to do little at this point.
Good sleep is not a luxury. It is the night in which your body tidies up, your immune system sorts itself out and your mind gets space again. If you sleep through the night, you gain more than hours. You gain freedom for the day.
Shukri Jarmoukli, ViveCura BerlinSafety: what you should know before taking them
Herbal sounds harmless. And indeed, the large reviews show an overall good safety profile for valerian and passionflower. Even so, both are active substances that influence the nervous system. That deserves respect.
- Alcohol and sedatives: Valerian and passionflower may possibly enhance the sedating effect of alcohol, benzodiazepines, Z-drugs, sedating antidepressants or antihistamines. Do not combine them without talking to your doctor.
- Medication in general: If you take medication regularly, talk to your treating doctor or your pharmacy before taking them.
- Driving and machinery: Your ability to react may be impaired after taking them. Keep this in mind when driving or working with machines.
- Pregnancy, breastfeeding, children: Reliable data are lacking here. The European herbal monographs advise against use in children under 12 years of age and during pregnancy and breastfeeding without medical advice.
- Liver: There are individual case reports of liver damage in temporal association with valerian or combination products containing valerian. If you notice yellowing of the skin, dark urine or upper abdominal pain, stop taking it immediately and have it checked by a doctor.
- Quality: Registered herbal medicinal products are subject to stricter requirements than dietary supplements. When extract quality varies, the effects are also hard to predict.
Cohen and Del Toro, as well as Vassiliadis and colleagues, each described individual cases of liver damage in temporal association with valerian. In individual cases, the cause is hard to establish, and several substances are often involved. The large reviews found no serious side effects. What this means for you: no reason to panic, but a reason to be careful if you have a liver condition.
Cohen DL, Del Toro Y. J Clin Gastroenterol. 2008;42(8):961-962. DOI: 10.1097/MCG.0b013e3180500348 [Case report] · Vassiliadis T et al. Sleep Med. 2009;10(8):935. DOI: 10.1016/j.sleep.2008.09.009 [Case report, letter]One last point that matters to me. A plant can dampen a symptom so much that an important cause stays undetected for longer. Sleep apnoea, a thyroid disorder, depression, pain or a metabolic disorder deserve to be looked into. The gentle brake should never cover up the warning light.
Three levers for your nights
I am deliberately not giving you a dosing schedule here. Which plant in which form suits you depends on your situation, your medication and your test results. I am giving you directions. Three levers that you can understand and put into context from tonight.
Note when you wake up, not just whether
Keep a simple sleep diary for two weeks. Time of waking, pounding heart or sweating, evening meal, alcohol, stress of the day. Recurring patterns in the second half of the night may be a clue pointing to the stress axis or metabolism. The diary is also the first tool of behavioural therapy for insomnia.
Take your foot off the accelerator before you brake
A fixed wake-up time, daylight in the morning, a real wind-down hour in the evening without work and screens, a bed reserved for sleep. These building blocks of CBT-I are meant to act precisely on the overactive arousal system. If you then still want to use a plant as a companion, it is working against a quieter engine.
Look at your evening plate and have causes checked by a doctor
An evening meal with protein, healthy fat and fibre instead of a quick sugary snack may make your blood sugar curve at night calmer. Alcohol in the evening may disturb the second half of the night in particular. If you still regularly wake up with a racing heart or sweating, have your blood sugar, stress axis, thyroid and breathing during sleep looked at by a doctor. A glucose sensor worn for a few days can be one building block in this, but it belongs in an expert evaluation.
Valerian and passionflower are not a sham. They can be a pleasant companion for some people, especially with mild restlessness. But they are a brake, not a search for causes.
If you keep waking up at night, there is often a system sounding the alarm: the stress axis, blood sugar or both. If you first understand who is pressing your accelerator, the gentle brake can finally do what it is meant for.
More from the Medicinal Plants Guide
More articles in this guide
Where this topic connects
Sleep touches the nervous system, hormones, metabolism and the immune system all at once. These articles go deeper into the other levels.
Morning light and your internal clock
How morning light may shape your sleep rhythm and the cortisol awakening response.
Natural forcesBreathing techniques and the vagus nerve
How a long exhalation may take your foot off the nervous system’s accelerator.
Nervous systemFasting and blood sugar
What glucose curves and insulin may reveal about your metabolism.
MetabolismWhich magnesium suits you?
An honest comparison of the forms, including with a view to sleep and relaxation.
SupplementsFrequently asked questions
Can valerian support falling asleep and staying asleep?
What is known about passionflower and sleep?
How are valerian and passionflower thought to act in the brain?
Why does the European insomnia guideline not recommend medicinal plants?
Why do I always wake up at the same time at night?
Can a drop in blood sugar at night wake you up?
Can I combine valerian with alcohol or sleeping pills?
Are valerian and passionflower suitable during pregnancy, breastfeeding or for children?
Can valerian harm the liver?
When should I have sleep problems checked by a doctor?
Sources
All studies were checked via PubMed against title, authors, year, journal and DOI; the central statements on valerian, passionflower and cortisol were additionally checked via Consensus. The study type is given in square brackets. There are many small and methodologically heterogeneous studies on valerian and passionflower. On the link between mild drops in blood sugar at night and waking up in people without diabetes, there have so far been mainly physiological experiments, not large observational studies. These links are biologically plausible, but not demonstrated with the same certainty as through large randomised trials.
- 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):1005-1012. DOI: 10.1016/j.amjmed.2006.02.026 [Meta-analysis, k=16, n=1093]
- Fernández-San-Martín MI, Masa-Font R, Palacios-Soler L et al. Effectiveness of Valerian on insomnia: a meta-analysis of randomized placebo-controlled trials. Sleep Med. 2010;11(6):505-511. DOI: 10.1016/j.sleep.2009.12.009 [Meta-analysis, k=18 RCTs]
- Shinjyo N, Waddell G, Green J. Valerian Root in Treating Sleep Problems and Associated Disorders: A Systematic Review and Meta-Analysis. J Evid Based Integr Med. 2020;25:2515690X20967323. DOI: 10.1177/2515690X20967323 [Systematic review, meta-analysis, 60 studies, n=6894]
- Ngan A, Conduit R. A double-blind, placebo-controlled investigation of the effects of Passiflora incarnata (passionflower) herbal tea on subjective sleep quality. Phytother Res. 2011;25(8):1153-1159. DOI: 10.1002/ptr.3400 [RCT, crossover, n=41]
- Lee J, Jung HY, Lee SI, Choi JH, Kim SG. Effects of Passiflora incarnata Linnaeus on polysomnographic sleep parameters in subjects with insomnia disorder: a double-blind randomized placebo-controlled study. Int Clin Psychopharmacol. 2020;35(1):29-35. DOI: 10.1097/YIC.0000000000000291 [RCT, n=110]
- 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 [Systematic review, k=9 clinical studies]
- Miroddi M, Calapai G, Navarra M, Minciullo PL, Gangemi S. Passiflora incarnata L.: ethnopharmacology, clinical application, safety and evaluation of clinical trials. J Ethnopharmacol. 2013;150(3):791-804. DOI: 10.1016/j.jep.2013.09.047 [Review]
- Khom S, Baburin I, Timin E et al. Valerenic acid potentiates and inhibits GABA(A) receptors: molecular mechanism and subunit specificity. Neuropharmacology. 2007;53(1):178-187. DOI: 10.1016/j.neuropharm.2007.04.018 [In vitro, oocyte model]
- Benke D, Barberis A, Kopp S et al. GABA A receptors as in vivo substrate for the anxiolytic action of valerenic acid, a major constituent of valerian root extracts. Neuropharmacology. 2009;56(1):174-181. DOI: 10.1016/j.neuropharm.2008.06.013 [In vivo, mouse, plus in vitro]
- Riemann D, Baglioni C, Bassetti C et al. European guideline for the diagnosis and treatment of insomnia. J Sleep Res. 2017;26(6):675-700. DOI: 10.1111/jsr.12594 [Systematic review, European guideline]
- Riemann D, Espie CA, Altena E et al. The European Insomnia Guideline: An update on the diagnosis and treatment of insomnia 2023. J Sleep Res. 2023;32(6):e14035. DOI: 10.1111/jsr.14035 [Review, European guideline, update]
- Vgontzas AN, Bixler EO, Lin HM et al. Chronic insomnia is associated with nyctohemeral activation of the hypothalamic-pituitary-adrenal axis: clinical implications. J Clin Endocrinol Metab. 2001;86(8):3787-3794. DOI: 10.1210/jcem.86.8.7778 [Pathophysiology, case-control, n=24]
- Dressle RJ, Feige B, Spiegelhalder K et al. HPA axis activity in patients with chronic insomnia: A systematic review and meta-analysis of case-control studies. Sleep Med Rev. 2022;62:101588. DOI: 10.1016/j.smrv.2022.101588 [Meta-analysis, k=20, 449 vs. 357 people]
- Irwin MR. Why sleep is important for health: a psychoneuroimmunology perspective. Annu Rev Psychol. 2015;66:143-172. DOI: 10.1146/annurev-psych-010213-115205 [Review, psychoneuroimmunology]
- Schultes B, Jauch-Chara K, Gais S et al. Defective awakening response to nocturnal hypoglycemia in patients with type 1 diabetes mellitus. PLoS Med. 2007;4(2):e69. DOI: 10.1371/journal.pmed.0040069 [Pathophysiology, controlled study, n=32]
- Jauch-Chara K, Hallschmid M, Gais S et al. Awakening and counterregulatory response to hypoglycemia during early and late sleep. Diabetes. 2007;56(7):1938-1942. DOI: 10.2337/db07-0044 [Pathophysiology, crossover, n=16]
- Shah VN, DuBose SN, Li Z et al. Continuous Glucose Monitoring Profiles in Healthy Nondiabetic Participants: A Multicenter Prospective Study. J Clin Endocrinol Metab. 2019;104(10):4356-4364. DOI: 10.1210/jc.2018-02763 [Real-world, prospective multicenter cohort, n=153]
- Cohen DL, Del Toro Y. A case of valerian-associated hepatotoxicity. J Clin Gastroenterol. 2008;42(8):961-962. DOI: 10.1097/MCG.0b013e3180500348 [Case report]
- Vassiliadis T, Anagnostis P, Patsiaoura K et al. Valeriana hepatotoxicity. Sleep Med. 2009;10(8):935. DOI: 10.1016/j.sleep.2008.09.009 [Case report, letter]
This article is for information purposes and does not replace medical advice. It describes connections from research and clinical experience, not individual treatment instructions and not dosage recommendations. If you take medication, are pregnant or breastfeeding, have a liver condition or have been sleeping poorly for months, please discuss the use of herbal products with a doctor in person.