L-Theanine 200 mg by Bronson

POSSIBLY EFFECTIVE

• Anxiety. Oral passion flower has a long history of use as a sedative and may improve symptoms of anxiety in some patients. Details: Preliminary clinical research shows that taking a specific dried alcoholic extract of passion flower (Sedanxio, Tilman SA) 400 mg orally twice daily for 2-8 weeks reduces the severity of non-specific anxiety when compared to baseline (88198). The validity of this finding is limited by the lack of a placebo group. Passionflower has also been evaluated as an adjunct to conventional medication. One clinical small study in patients with generalized anxiety disorder shows that taking a specific passion flower extract (Pasipay, Iran Darouk Pharmaceutical Company) 15 drops three times daily along with sertraline 50-100 mg daily for one month reduces anxiety when compared with taking sertraline alone (95036). Passion flower has also been compared to conventional treatments. One preliminary clinical study shows that taking passion flower extract 90-180 mg daily reduces symptoms of non-specific anxiety when compared to baseline, and seems to be comparable to taking mexazolam (15391). A small clinical study in patients with generalized anxiety disorder shows that taking a specific passion flower extract (Pasipay, Iran Darouk Pharmaceutical Company) 45 drops orally once daily for 28 days reduces anxiety similarly to oxazepam 30 mg daily. However, passion flower appears to have a slower onset of action than oxazepam (8007). This finding is limited because it did not utilize a therapeutic dosing regimen for oxazepam, which is given 3-4 times daily to account for its short half-life. Passion flower has also been studied in combination with other ingredients. A small clinical study in healthy adults shows that taking a combination of herbal extracts containing passion flower 40 mg, valerian root, black horehound, and hawthorn (Euphytose, Bayer HealthCare) 6 times daily with meals for 14 days reduces anxiety and sympathetic and autonomic nervous system activation in response to a psychosocial stressor when compared with placebo (111222). It is unclear if these effects are due to valerian, other ingredients, or the combination.
• Insomnia. Moderate-sized clinical studies suggest that oral passion flower may modestly improve total sleep time in patients with insomnia; however, its effects on sleep latency and maintenance are mixed. Details: A moderate-sized clinical study in adults in India with insomnia and stress shows that taking passion flower extract 600 mg daily at bedtime for 30 days increases total sleep time by about 30 minutes and reduces both the time to fall asleep and wake time after sleep onset by about 10 minutes when compared with placebo (114529). The validity of these findings is limited by lack of reporting on baseline use of medications or other substances which may impact sleep and exclusion of patients with severe insomnia. Another moderate-sized clinical study in adults with insomnia shows that taking passion flower extract 60 mg every evening before bedtime for 2 weeks increases total sleep time by around 23 minutes, but doesn't seem to improve sleep efficiency, sleep latency, or awakening after sleep onset, when compared with placebo (102866). Additionally, a smaller clinical study in young adults with mild fluctuations in sleep quality shows that drinking tea prepared by steeping passion flower aerial parts 2 grams in 250 mL of boiling water for 10 minutes every evening, about an hour before bedtime for 7 nights, improves subjective ratings of sleep quality, but not other sleep parameters, when compared with placebo (parsley tea) (17374). Passion flower has also been studied in combination with other ingredients. One small clinical study in adults with primary insomnia shows that taking a specific combination product containing passion flower 80 mg, valerian 300 mg, and hops 30 mg (NSF-3, M/s Tablets India) orally at bedtime for 2 weeks yields similar effects on subjective measures of sleep as zolpidem 10 mg nightly (88193).
• Pre-procedural anxiety. Oral passion flower modestly reduces preoperative anxiety. Details: Two small clinical studies in adults awaiting dental surgery or inguinal hernia repair surgery shows that taking a specific passion flower extract (Pasipay, Iran Darouk Pharmaceutical Company) reduces preoperative anxiety when compared with placebo. Passion flower extract was given as 20 drops or 500 mg 90 minutes prior to surgery, with or without another dose on the evening before surgery (88195,88196). Another small clinical study shows that drinking 5 mL of syrup containing passion flower aqueous extract (Passiflora syrup, Sandoz) 700 mg orally 30 minutes before epidural catheter insertion for inguinal hernia repair surgery seems to attenuate anxiety; the placebo group experienced a significant increase in anxiety (88194). This finding is limited because there were no statistical comparisons conducted between groups. Passion flower has also been compared with conventional medications. Three clinical studies show that taking passion flower prior to dental surgery decreases preoperative anxiety similarly to oral midazolam 15 mg. One study used passion flower 260 mg, administered 30 minutes prior to the surgery (95038), the second used 500 mg, administered 60 minutes prior (104206), and the third used 600 mg, administered 45 minutes prior (110014). Of the two studies that evaluated patient preference, patients in one study preferred midazolam, possibly due to its ability to cause perioperative amnesia (95038), whereas there was no preference in the other study (110014). Another clinical study shows that taking passion flower 1000 mg one hour prior to elective minor or moderate surgery reduces preoperative anxiety similarly to melatonin 6 mg; however, passion flower seems to cause more cognitive impairment than melatonin (95037).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Adjustment disorders. Oral passion flower has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: One clinical study in patients with adjustment disorder with anxious mood shows that taking two tablets of a specific combination product (Euphytose, Bayer Healthcare) three times daily seems to decrease anxiety symptoms when compared with placebo. One tablet contains the dry extracts of passion flower 40 mg, valerian 40 mg, hawthorn 10 mg, and black horehound 10 mg, as well as the caffeine-containing stimulant herbs kola nut 15 mg and guarana 15 mg (6250). It is unclear if this effect is due to passion flower, other ingredients, or the combination.
• Alcohol use disorder. Oral passion flower has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in adults experiencing alcohol withdrawal symptoms shows that taking one capsule of a combination product (Relief) three times daily for 15 days reduces the frequency of excessive sweating, reduces serum liver enzyme levels, and improves appetite and quality of life when compared to baseline. One capsule contains passion flower extract 30 mg, black seed extract 100 mg, cocoa extract 90 mg, radish extract 165 mg, and saffron extract 15 mg (97280). The validity of these findings is limited by the lack of a comparator group.
• Attention deficit-hyperactivity disorder (ADHD). It is unclear if oral passion flower is beneficial in patients with ADHD. Details: A small clinical trial in children aged 6-13 years with ADHD shows that taking tablets of passion flower (Pasipay, Iran Darouk Pharmaceutical Company) 0.02 mg/kg orally twice daily for 8 weeks reduces parent and teacher ratings of ADHD symptoms no better than taking methylphenidate (0.5 mg/kg twice daily) (88197).
• Benzodiazepine withdrawal. It is unclear if oral passion flower is beneficial for benzodiazepine withdrawal. Details: A moderate-sized observational study in adults with depression or anxiety on antidepressants undergoing a benzodiazepine taper after chronic benzodiazepine use suggests that taking a specific dry extract of passion flower (Tractana, Baldacci) 200-600 mg daily for 3 months is associated with a faster benzodiazepine dose reduction and greater percentage of patients with at least 50% reduction or complete benzodiazepine discontinuation after 1 and 3 months from taper initiation when compared with control (111651). The validity of these effects is limited by a lack of placebo group and the retrospective observational study design.
• Congestive heart failure (CHF). Oral passion flower has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in patients with mild CHF shows that taking a combination of passion flower and hawthorn extracts 2 mL three times daily for 6 weeks increases six-minute walking distance when compared with placebo. However, it does not appear to improve exercise capacity on a bicycle ergometer test (19201). It is unclear if this effect is due to passion flower, hawthorn, or the combination. Additionally, hawthorn has been evaluated alone for the management of CHF, with some research suggesting that although it may improve symptoms, it may also be associated with worsened clinical outcomes.
• Fibromyalgia. Although there is interest in using oral passion flower for fibromyalgia, there is insufficient reliable information about the clinical effects of passion flower for this condition.
• Menopausal symptoms. Although there is interest in using oral passion flower for menopausal symptoms, there is insufficient reliable information about the clinical effects of passion flower for this purpose.
• Muscle cramps. Although there is interest in using oral passion flower for muscle cramps, there is insufficient reliable information about the clinical effects of passion flower for this purpose.
• Neuropathic pain. Although there is interest in using oral passion flower for neuropathic pain, there is insufficient reliable information about the clinical effects of passion flower for this condition.
• Opioid withdrawal. It is unclear if oral passion flower helps to prevent opioid withdrawal. Details: A small preliminary clinical study in adults who are completing an inpatient withdrawal program for opioid addiction shows that taking passion flower liquid extract 60 drops, in combination with clonidine 0.8 mg daily, is better than clonidine alone when used for reducing symptoms such as anxiety, irritability, insomnia, and agitation. However, the combination is no better than clonidine alone for reducing physical symptoms such as tremor and nausea (2303).
• Seizures. Although there is interest in using oral passion flower for seizures, there is insufficient reliable information about the clinical effects of passion flower for this condition.
• Stress. It is unclear if oral passion flower reduces stress. Details: A moderate-sized clinical study in adults in India with stress and insomnia shows that taking passion flower 600 mg daily at bedtime for 30 days modestly reduces stress when compared with placebo (114529). It is unclear how changes in stressors over the course of the study may have affected results. Additionally, a small clinical study in healthy adults shows that taking a specific combination product (Relaxane, Max Zeller Söhne AG) containing passion flower 90 mg, lemon balm 50 mg, valerian 90 mg, and butterbur 90 mg three times daily for 3 days modestly reduces subjective anxiety scores during social stress testing when compared with placebo or no treatment (97276). It is unclear if this effect is due to passion flower, other ingredients, or the combination. More evidence is needed to rate passion flower for these uses.

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POSSIBLY EFFECTIVE

• Cognitive function. Oral L-theanine may improve some aspects of cognitive function. It is unclear if using L-theanine in conjunction with caffeine can enhance the effects of either ingredient. Details: A single dose of L-theanine 100 mg seems to improve vigilant attention, reducing error rates in cognitive tests when compared with placebo (91747). However, taking L-theanine (Suntheanine, Taiyo Kagaku) 200 mg daily for 4 weeks does not improve verbal fluency, memory, motor speed, or executive function in an adult population, although it may moderately improve verbal fluency in a subgroup of people with lower cognitive function at baseline (101986). When L-theanine is combined with caffeine, a meta-analysis and multiple individual clinical studies show that the combination improves alertness, as well as accuracy during a test that requires switching attention between different tasks, but does not improve reaction time (38116,91750,96335,96336). Some research also shows that L-theanine plus caffeine improves cognitive performance and reduces task-induced fatigue when compared with baseline and placebo. However, it is unclear if this is due to the individual ingredients or the combination (38116,96335,96336). Some research suggests that the combination is no better than either individual ingredient alone (91747,96335,96336).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Age-related cognitive decline. It is unclear if oral L-theanine, taken continuously or as a single dose, improves cognition in older adults. Details: A small clinical study in healthy, Japanese adults aged 50-69 years shows that taking a specific product (Suntheanine; Taiyo International.) containing L-theanine 101 mg daily after breakfast for 12 weeks does not improve mini-mental state exam (MMSE) scores when compared with placebo. However, a single-dose analysis from this study shows that administration of L-theanine 101 mg may improve the quality of working memory and reaction times during a cognitive function test when compared with placebo (108553). Patients were permitted to consume polyphenol-rich beverages during the study period; however, consumption was not documented, limiting the validity of this finding.
• Alzheimer disease. Although there is interest in using oral theanine for Alzheimer disease, there is insufficient reliable information about the clinical effects of theanine for this condition.
• Anxiety. It is unclear if oral L-theanine is beneficial in patients with anxiety. Results of clinical research are conflicting. Details: A preliminary clinical study shows that taking a single dose of a specific L-theanine product (Suntheanine, Taiyo Kagaku) 200 mg does not reduce experimentally-induced anticipatory anxiety when compared with placebo (12188). However, another preliminary clinical study in healthy adults with stress-related anxiety shows that taking L-theanine 200 mg daily for 4 weeks reduces anxiety scale scores and sleep disturbance when compared with placebo (101986).
• Attention. It is unclear if oral theanine improves attention. Details: A small clinical study in healthy males shows that taking a single dose of L-theanine 200 mg improves selective attention similar to a single dose of caffeine 160 mg (96337). However, other small clinical studies in adults show that taking L-theanine 100-400 mg does not improve most measures of attention, especially sustained attention or attention in executive control tasks, but doses of 100-200 mg may improve performance in simple attentional tasks when compared with placebo (96338,111396). Some of these studies suggest that taking L-theanine with caffeine appears to provide more benefit than either individual ingredient alone (96337,96338).
• Attention deficit-hyperactivity disorder (ADHD). Oral L-theanine seems to improve some aspects of ADHD, including cognition and sleep. Details: Some preliminary clinical research in children with ADHD shows that taking a one-time dose of L-theanine 2.5 mg/kg increases cognition scores, but does not improve results on sustained attention or inhibitory control tests, when compared with placebo. Taking L-theanine with caffeine 2 mg/kg also increases cognition scores and improves performance on a sustained attention test, but does not improve inhibitory control, when compared with placebo (104141). Other preliminary clinical research in males aged 8-12 years with ADHD shows that taking a specific L-theanine product (Suntheanine, Taiyo Kagaku) 200 mg orally twice daily for 6 weeks increases the percent of time spent in restful sleep by about 5% and decreases the number of bouts of nocturnal activity by about 6 when compared with placebo (91744).
• Cancer. Although there is interest in using oral theanine for cancer, there is insufficient reliable information about the clinical effects of theanine for this condition.
• Chemotherapy-induced diarrhea. Oral L-theanine has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in patients with colon cancer shows that taking L-cystine 700 mg and L-theanine 280 mg (Ajinomoto Co. Inc.) orally once daily, starting one week before chemotherapy with TS-1 (Taiho Pharmaceutical) and continuing for 28 days, increases the rate of therapy completion by 49%, reduces the incidence of diarrhea by 37%, reduces appetite loss by 33%, and improves the reported tolerability of chemotherapy when compared with chemotherapy alone (96334). However, this combination does not appear to be beneficial in patients with gastric cancer, or in those with colorectal cancer receiving 4 courses of capecitabine-based adjuvant chemotherapy. (96334,101985).
• Cognitive impairment. Oral L-theanine has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: One very small clinical study in adults with mild cognitive impairment shows that taking a product containing L-theanine 120 mg and green tea extract 720 mg (LGNC-07, LG Household & Health Care, Ltd) orally twice daily after meals for 16 weeks modestly improves memory and attention when compared with baseline. However, taking this product does not appear to improve memory and attention when patients with self-reported memory problems, but without mild cognitive impairment, are also considered (96339).
• Depression. It is unclear if oral L-theanine is beneficial in patients with depression. Details: A small clinical study shows that taking a specific L-theanine product (Suntheanine, Taiyo Kagaku Co. Ltd.) 250 mg at bedtime for 8 weeks reduces symptoms and improves sleep quality when compared to baseline in individuals with mild major depressive disorder (MDD) (96331). The validity of these findings is limited by the lack of a comparator group. Another small clinical study in adults with MDD shows that taking L-theanine 200 mg daily with sertraline for 6 weeks reduces depression symptoms and increases remission rates but does not improve treatment response rates when compared with sertraline and placebo (112278). The validity of these effects is limited by the small sample size and short study duration. Additionally, it is unclear if the reduction in depressive symptoms is clinically significant.
• Erythema. Oral L-theanine has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in healthy females with self-perceived skin sensitivity shows that taking a specific supplement containing L-theanine, ashwagandha, and saffron (InnerCalm, Arbonne) daily for 8 weeks reduces facial pigmentation when compared to baseline (111399). The validity of this finding is limited by a lack of a placebo group. It is unclear if these effects are due to L-theanine, other ingredients, or the combination.
• Generalized anxiety disorder (GAD). It is unclear if oral L-theanine is beneficial for reducing anxiety in people with GAD. Details: One small clinical study in adults with GAD shows that taking L-theanine 225 mg twice daily for 4 weeks, then 450 mg twice daily for 4 weeks, in conjunction with prescribed antidepressants, does not reduce anxiety scores when compared with antidepressants and placebo (104976).
• Hypertension. Although there is interest in using oral theanine for hypertension, there is insufficient reliable information about the clinical effects of theanine for this condition.
• Influenza. Oral L-theanine has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research shows that taking a combination of green tea catechins (THEA-FLAN 90S, Ito-en Co.) 378 mg, standardized to contain epigallocatechin gallate 270 mg and L-theanine (Suntheanine, Taiyo Kagaku) 210 mg daily for 5 months reduces the risk of developing clinically diagnosed influenza when compared with placebo. However, the combination does not seem to prevent laboratory-confirmed influenza infection (54021).
• Insomnia. It is unclear if oral L-theanine is beneficial for insomnia. Details: A very small clinical study in young healthy adults with sleep quality worsened by caffeine intake shows that taking L-theanine 50 mg (Suntheanine, Taiyo Kagaku Co. Ltd) once 10 minutes before bedtime suppresses caffeine-induced elevations in wake after sleep onset time but does not improve parameters of sleep quality including sleep onset latency, sleep time, or number of times waking after sleep onset when compared with placebo (112275). L-theanine has also been studied in combination with other ingredients. A small clinical study in adults with insomnia or disturbed sleep patterns shows that a specific product (RLX2; LiveLife Biosciences AG) containing L-theanine 50 mg and a specific casein peptide, alpha-s1-casein tryptic hydrolysate, 150 mg, taken one hour before bedtime for 4 weeks, increases sleep duration by 45 minutes and improves habitual sleep efficiency and daytime dysfunction when compared with baseline (108556). Another very small clinical study in healthy adults shows that taking a combination product containing tryptophan, glycine, magnesium, tart cherry powder, and L-theanine 2 hours before bedtime decreases sleep onset latency and increases total sleep duration, leading to better sleep efficiency and reduced morning sleepiness, when compared with placebo (111184). Another combination product containing L-theanine, ashwagandha, and saffron (InnerCalm, Arbonne), taken daily for 8 weeks, seems to improve sleep quality when compared to baseline (111399). However, the validity of this finding is limited by a lack of a control group. It is unclear if the effects described above are due to L-theanine, other ingredients, or the combination.
• Obsessive-compulsive disorder (OCD). It is unclear if oral L-theanine is beneficial for OCD. Details: A small clinical study in adults with OCD shows that taking L-theanine 100 mg twice daily for 10 weeks with fluvoxamine reduces OCD symptoms, particularly obsessive symptoms, and increases the proportion of patients with a complete response to treatment but does not improve compulsive symptoms, partial response rates, or remission rates when compared with placebo and fluvoxamine (112276).
• Postoperative recovery. Oral theanine has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study of adults with esophageal cancer undergoing esophagectomy shows that taking theanine 280 mg and cystine 700 mg daily, staring 4 days before surgery and continued for 13 days after surgery, does not improve measures of physical activity but does improve exercise tolerance and some measures of quality of life when compared with placebo (111400). It is unclear if these findings are due to theanine, cystine, or the combination.
• Schizophrenia. It is unclear if oral L-theanine is beneficial in patients with schizophrenia; the available evidence is limited and conflicting. Details: One small preliminary clinical study in adults with schizophrenia or schizoaffective disorder shows that taking L-theanine (Biosynergy) 200 mg orally twice daily for 8 weeks along with antipsychotic medications improves positive symptoms, anxiety, and general psychopathology symptoms, such as poor impulse control and disorientation, when compared with placebo. However, theanine does not improve general disease severity, negative symptoms, depression, cognitive function, extrapyramidal side effects, or quality of life (96341). In contrast, two small clinical studies show that taking L-theanine 400 mg (Suntheanine, BioSynergy Health Alternatives) with antipsychotics and with or without pregnenolone 50 mg daily for 8 weeks reduces negative symptoms, general psychopathology symptoms, and anxiety when compared with placebo in patients with schizophrenia or schizoaffective disorder. However, there were no improvements in positive schizophrenia symptoms, extrapyramidal side effects, or symptoms of depression (97923,112277). The inconsistency of results might be due to the small study sizes and the subjectivity of the outcomes measured.
• Stress. It is unclear if oral L-theanine is beneficial in patients with stress. Details: One very small clinical study shows that taking L-theanine 200 mg prior to a stress-inducing exam reduces tension-anxiety and may prevent blood pressure increases caused by psychological stress when compared with placebo (91746). Other preliminary clinical research in pharmacy students shows that taking theanine 200 mg twice daily for one week prior, and then for the first 10 days of a pharmacy practice period, decreases subjective stress scores when compared with placebo (91745). Another small clinical study in healthy young adults shows that drinking a beverage containing L-theanine 200 mg alone or combined with L-arginine 50 mg after a psychological stressor reduces stress, as measured by salivary alpha-amylase activity, when compared with placebo. The combination of L-arginine and L-theanine did not differ from L-theanine alone, suggesting that the combination does not act synergistically to reduce markers of stress (110393). However, not all research has been positive. A small clinical study shows that taking a specific L-theanine product (Suntheanine, Taiyo Kagaku) 200 mg induces subjective feelings of tranquility in relaxed people, but not those with experimentally-induced anticipatory anxiety, when compared with placebo (12188). Also, a small, clinical crossover study in healthy, moderately stressed adults shows that taking a single dose of a specific product (Alphawave; Ethical Naturals) containing L-theanine 200 mg prior to a stress-inducing exam does not improve anxiety at any time point when compared with placebo (108554). Due to the single-dose nature of this study, the effects of continued administration of this product are unclear. L-theanine has also been evaluated in combination with other ingredients. A small clinical study in adults with stress shows that taking a specific combination product (Mg-Teadiola, Sanofi-Aventis Group), containing green tea extract 125 mg (providing 50 mg L-theanine), magnesium 150 mg, vitamin B6 0.2 mg, vitamin B9 0.1 mg, vitamin B12 1.25 mcg, and rhodiola 222 mg, orally once daily for 28 days modestly improves stress and anxiety scores when compared with placebo. Improvements in stress scores, but not anxiety scores, appear to persist at 28 days after treatment completion (108672). It is unclear if any effects are due to L-theanine, other ingredients, or the combination.
• Tourette syndrome. It is unclear if oral L-theanine is beneficial in children with Tourette syndrome. Details: A small, nonblinded clinical study in children aged 4-17 years with untreated Tourette syndrome or with chronic tic disorder and associated symptoms of anxiety shows that taking a liquid nutritional supplement providing L-theanine 200 mg and vitamin B6 2.8 mg daily for 2 months improves scores on the Yale Global Tic Severity Scale, but does not reduce anxiety, when compared with patients receiving psychoeducation (108555). This study may have been inadequately powered to detect a difference between groups. More evidence is needed to rate theanine for these uses.

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LIKELY SAFE ...when used orally as a flavoring in foods. The US Food and Drug Administration (FDA) lists passion flower as a permitted food flavoring additive, to be used in the minimum quantity necessary (91203).

POSSIBLY SAFE ...when used orally and appropriately in medicinal amounts, short-term. Passion flower extract has been used with apparent safety at doses up to 800 mg daily for up to 8 weeks (88198,102866). A specific passion flower extract (Pasipay, Iran Darouk Pharmaceutical Company) has been safely used at a dose of 45 drops daily for up to one month (8007,95036). Also, a tea prepared by steeping 2 grams of the dried aerial parts of passion flower in 250 mL of boiling water for 10 minutes has been used nightly for 7 nights (17374). There is insufficient reliable information available about the safety of passion flower when used topically.

CHILDREN: POSSIBLY SAFE
when used orally and appropriately, short-term. A specific passion flower product (Pasipay, Iran Darouk Pharmaceutical Company) has been used safely in children aged 6-13 years at a dose of 0.04 mg/ kg daily for 8 weeks (88197).

PREGNANCY: POSSIBLY UNSAFE
when used orally. Some case reports suggest that passion flower use during the first and second trimesters of pregnancy may be associated with an increased risk for premature rupture of membranes and meconium aspiration syndrome; however, causality has not been confirmed (97279). The alkaloids harman and harmaline, which are sometimes found in passion flower, have been reported to have uterine stimulant activity (4,11020,95037). It is not known whether these constituents are present in sufficient quantities to have an effect.

LACTATION:
Insufficient reliable information available; avoid using.

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POSSIBLY SAFE ...when used orally and appropriately, short-term. L-theanine has been used safely in clinical research in doses of up to 900 mg daily for 8 weeks (12188,36439,96331,96332,96334,96341,97923,101986,104976). There is insufficient reliable information available about the safety of L-theanine when used long-term.

CHILDREN: POSSIBLY SAFE
when used orally and appropriately, short-term. A specific L-theanine product (Suntheanine, Taiyo Kagaku) 200 mg twice daily has been used safely in males aged 8-12 years for up to 6 weeks (91744).

PREGNANCY AND LACTATION:
Insufficient reliable information available; avoid using.

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CNS DEPRESSANTS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Concomitant use of passion flower with sedative drugs might cause additive effects and side effects.  Details Research in animals and humans shows that passion flower has sedative effects which can be additive when used with sedative medications like lorazepam (8007,19235,19236,19429,68309,104206).

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES Interaction Rating = Minor Be watchful with this combination. Severity = Insignificant •  Occurrence = Possible •  Level of Evidence = D Theoretically, passion flower might decrease the effects of CYP3A4 substrates.  Details In vitro research suggests that passion flower can induce CYP3A4 enzymes, albeit to a much lower degree than rifampin, a known CYP3A4 inducer (110704).

ORGANIC ANION-TRANSPORTING POLYPEPTIDE SUBSTRATES (OATP) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, passion flower might reduce the bioavailability of OATP2B1 and OATP1A2 substrates.  Details In vitro research shows that the passion flower constituents apigenin and vitexin inhibit OATP2B1 and OATP1A2. This inhibition may be dose-dependent. One specific high-flavonoid passion flower extract (Valverde) seems to inhibit OATP2B1 and OATP1A2, while another extract with a lower flavonoid concentration (Arkocaps) shows less potent inhibition (105095). OATPs are responsible for the uptake of drugs and other compounds into the body; however, the specific activities of OATP2B1 and OATP1A2 are not well characterized.

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ANTIHYPERTENSIVE DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theanine might lower blood pressure, potentiating the effects of antihypertensive drugs.  Details Animal research shows that theanine can lower blood pressure in spontaneously hypertensive animals (7687,77354). Theoretically, concomitant use of theanine and antihypertensive drugs might potentiate the antihypertensive activity.

CNS DEPRESSANTS Interaction Rating = Minor Be watchful with this combination. Severity = Moderate •  Occurrence = Unlikely •  Level of Evidence = D Theoretically, theanine might have additive sedative effects when used in conjunction with CNS depressants. However, it is unclear if this concern is clinically relevant.  Details Theoretically, theanine may compete with glutamate and/or increase plasma gamma-aminobutyric acid (GABA) levels, which could cause CNS depression (96334). In one clinical study, some subjects taking oral theanine reported drowsiness (96331).

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General ...Orally, passion flower is well tolerated.
Most Common Adverse Effects:
Orally: Confusion, dizziness, hypersensitivity, and sedation.

Cardiovascular ...There is a case report involving a 34-year-old female who was hospitalized with severe nausea, vomiting, drowsiness, prolonged QT interval, and episodes of nonsustained ventricular tachycardia following use of passion flower extract tablets (Sedacalm, Bioplus Healthcare), 1500 mg on day 1 and 2000 mg on day 2 to relieve stress. All symptoms resolved within one week after passion flower was discontinued (6251).

Genitourinary ...The alkaloids harman and harmaline, which are sometimes found in small amounts in passion flower, have been reported to have uterine stimulant activity (4,11020,95037).

Hematologic ...Orally, passion flower has been reported to cause epistaxis in one clinical trial (95038). Vasculitis has also been reported with use of a specific herbal product (Relaxir) produced mainly from the fruits of passion flower (6).

Hepatic ...There is debate about whether passion flower contains cyanogenic glycosides. Several related Passiflora species do contain these constituents (3), including Passiflora edulis, which is associated with liver and pancreatic toxicity (7).

Immunologic ...An idiosyncratic hypersensitivity reaction characterized by urticaria and cutaneous vasculitis has been reported in a 77-year-old male with rheumatoid arthritis after taking a specific combination product that included passion flower extract (Naturest) (68308). It is unclear if these effects were caused by passion flower or other ingredients.
In clinical trials, passion flower has been reported to cause allergy symptoms including sinus irritation; however, the frequency of these events was statistically nonsignificant when compared to treatment with midazolam 15 mg (95038).

Musculoskeletal ...Orally, passion flower has been reported to cause muscle relaxation in a clinical trial (95038).

Neurologic/CNS ...Orally, sedation, dizziness, ataxia, and confusion have been reported in clinical trials. However, these events generally do not necessitate discontinuation (8007,15391,15392,95036,95038). Altered consciousness has been reported with use of a specific herbal product (Relaxir) produced mainly from the fruits of passion flower (6).

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General ...Orally, L-theanine seems to be well tolerated.
Most Common Adverse Effects:
Orally: Drowsiness, headaches.

Neurologic/CNS ...Orally, L-theanine may cause headaches (36439). Patients have also reported drowsiness, increased duration of sleep, and increased dream activity after oral L-theanine use (96331).
A case of subtle facial tic starting within 4 days of taking L-theanine 400 mg daily has been reported for a pediatric patient. Although the tics reportedly ceased once theanine was discontinued, the child had exhibited tics in the past. Therefore, the adverse effect was not thought to be related to L-theanine (91744).

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