The plant and its compounds
Passionflower (Passiflora incarnata) is a climbing vine native to the southeastern United States. Its aerial parts, the leaves, stems and flowers, are the medicinal part, dried for tea or extracted with water and alcohol. The plant contains flavonoids, notably vitexin, isovitexin and chrysin, plus small amounts of harmala-type alkaloids. Laboratory studies tie its calming effect to the GABA system, the brain's main inhibitory network [1].
The European Medicines Agency recognizes passionflower as a traditional herbal medicine for relief of mild symptoms of mental stress and to aid sleep [2]. That is a recognition based on long use, not on proof from large trials, and it is the frame to keep in mind for everything below.
The anxiety trials
Akhondzadeh and colleagues, 2001. Thirty-six adults with generalized anxiety disorder were randomized to passionflower extract drops or the benzodiazepine oxazepam for four weeks. Both groups improved similarly on the Hamilton anxiety scale; the oxazepam group started improving sooner, and the passionflower group reported less impairment of job performance [3]. The trial was small and short, but it is the most cited human study of the herb. Movafegh and colleagues, 2008. Sixty patients scheduled for surgery received either 500 mg of passionflower or placebo about 90 minutes before anesthesia. Anxiety scores were lower in the passionflower group, without changes in psychomotor function at discharge [4]. Dantas and colleagues, 2017. Forty patients having wisdom teeth removed received passionflower 260 mg or midazolam 15 mg before the procedure in a crossover design. Anxiety control was comparable between the two [5].A 2020 systematic review of passionflower in neuropsychiatric conditions concluded that the results for anxiety were encouraging but that larger, better-designed trials were needed [6].
The sleep trials
Ngan and Conduit, 2011. Forty-one healthy adults drank passionflower tea or a placebo tea each evening for a week in a crossover design. Self-rated sleep quality was modestly better with passionflower; sleep diaries showed no significant change in other measures [7]. Lee and colleagues, 2020. One hundred and ten adults with insomnia disorder took a passionflower extract or placebo for two weeks. Overnight polysomnography showed longer total sleep time with passionflower, while questionnaire measures did not differ significantly from placebo [8].Taken together, these suggest a small, real effect on sleep, more visible on objective measures in one study and on subjective ones in another.
What about nerve pain?
This is the gap that matters for NerveHoney. No human trial has tested passionflower for neuropathic pain, numbness or tingling. The evidence offered for a nerve effect comes from animals: in a 2016 study, a passionflower extract reduced allodynia and other pain behaviors in rats with experimentally induced nerve pain, and the effect was blocked by drugs that act on GABA and opioid receptors [9].
That points to a plausible mechanism, but rat pain models translate poorly to people. The honest conclusion is that passionflower may help nerve discomfort indirectly, through calm and sleep, and that a direct effect is unproven.
Doses: trials versus the NerveHoney label
| Source | Preparation | Amount |
|---|---|---|
| Akhondzadeh 2001 | Extract drops | 45 drops a day |
| Dantas 2017 | Tablet | 260 mg, single dose |
| Movafegh 2008 | Tablet | 500 mg, single dose |
| Ngan 2011 | Tea | One cup each evening |
| NerveHoney label | Plant part and form not stated | 145 mg a day |
Because preparations differ, extracts against dried herb, standardized or not, doses cannot be compared one to one. NerveHoney's 145 mg sits below the tablet doses used in the procedure trials, and its label does not say whether it is extract or powder, or which part of the plant was used. It is in a plausible range for a mild effect and below the range used in the clearest studies.
Safety
Passionflower is generally well tolerated in short-term use. NIH lists drowsiness, dizziness and confusion as possible side effects and advises against use in pregnancy, because some compounds may stimulate uterine contractions [10]. It also recommends stopping two weeks before scheduled surgery.
Two case reports stand out. One describes a woman with nausea, vomiting, drowsiness and a prolonged QT interval on the ECG after taking passionflower tablets [11]. Another describes hand tremor, dizziness and muscle fatigue in a patient on lorazepam who added passionflower and valerian [12]. Both are rare, but they explain why combining passionflower with sedatives deserves a pharmacist's check.
Passionflower and nerve pain: what a proper trial would need
If someone wanted to know whether passionflower helps nerve pain, the study design is not mysterious. It would enroll people with a confirmed diagnosis, for example diabetic peripheral neuropathy, randomize them to a standardized extract or an identical placebo, and measure pain on a validated scale for at least eight to twelve weeks, alongside sleep and side effects. It would report how many people improved by a meaningful margin, not just average scores.
No such trial exists for passionflower, or for the five-herb NerveHoney combination. Until one does, the claim that passionflower soothes nerves rests on rat studies [9] and on the reasonable inference that better sleep makes pain more bearable [13]. That inference is worth something. It is not the same as evidence that the herb treats nerve pain.
Questions readers ask about passionflower
Is passionflower the same as the passion fruit plant? No. Passion fruit comes from Passiflora edulis; the medicinal species is Passiflora incarnata. Is it habit-forming? No dependence has been described in the trials, which is one reason it interests researchers as an alternative to benzodiazepines. Trials were short, though. Can I take it during the day? Some people do, at low doses, for daytime anxiety. Test it on a day off first, since drowsiness is the main side effect [10]. Does tea work as well as capsules? One trial used tea and found a small sleep benefit [7]. Strength varies with the amount of herb and steeping time.What this means for a NerveHoney buyer
Passionflower is the reason NerveHoney might do something noticeable: a calmer evening and slightly better sleep, appearing within days to weeks. It is not a reason to expect nerve repair. If you mainly want the calming effect, a single-herb passionflower product would give it to you more simply, and often more cheaply. If you choose NerveHoney, you are paying for passionflower plus four other herbs whose evidence is much thinner, set out in our ingredient ledger.
Want the whole label in one place?
Six bottles cost $294 with free U.S. shipping ($1.63 a day); two bottles cost $167.99 with shipping. The 60-day refund clock starts on the order date.
Sources
- 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. pubmed.ncbi.nlm.nih.gov/24140586/
- European Medicines Agency, Committee on Herbal Medicinal Products. Passiflorae herba (passion flower): herbal medicine overview and monograph. www.ema.europa.eu/en/medicines/herbal/passiflorae-herba
- Akhondzadeh S, Naghavi HR, Vazirian M, Shayeganpour A, Rashidi H, Khani M. Passionflower in the treatment of generalized anxiety: a pilot double-blind randomized controlled trial with oxazepam. J Clin Pharm Ther. 2001;26(5):363-367. pubmed.ncbi.nlm.nih.gov/11679026/
- Movafegh A, Alizadeh R, Hajimohamadi F, Esfehani F, Nejatfar M. Preoperative oral Passiflora incarnata reduces anxiety in ambulatory surgery patients: a double-blind, placebo-controlled study. Anesth Analg. 2008;106(6):1728-1732. pubmed.ncbi.nlm.nih.gov/18499602/
- Dantas LP, de Oliveira-Ribeiro A, de Almeida-Souza LM, Groppo FC. Effects of Passiflora incarnata and midazolam for control of anxiety in patients undergoing dental extraction. Med Oral Patol Oral Cir Bucal. 2017;22(1):e95-e101. pubmed.ncbi.nlm.nih.gov/27918731/
- Janda K, Wojtkowska K, Jakubczyk K, Antoniewicz J, Skonieczna-Żydecka K. Passiflora incarnata in neuropsychiatric disorders: a systematic review. Nutrients. 2020;12(12):3894. pubmed.ncbi.nlm.nih.gov/33352740/
- 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. pubmed.ncbi.nlm.nih.gov/21294203/
- 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. pubmed.ncbi.nlm.nih.gov/31714321/
- Aman U, Subhan F, Shahid M, et al. Passiflora incarnata attenuation of neuropathic allodynia and vulvodynia apropos GABA-ergic and opioidergic antinociceptive and behavioural mechanisms. BMC Complement Altern Med. 2016;16:77. pubmed.ncbi.nlm.nih.gov/26912265/
- National Center for Complementary and Integrative Health. Passionflower. www.nccih.nih.gov/health/passionflower
- Fisher AA, Purcell P, Le Couteur DG. Toxicity of Passiflora incarnata L. J Toxicol Clin Toxicol. 2000;38(1):63-66. pubmed.ncbi.nlm.nih.gov/10696928/
- Carrasco MC, Vallejo JR, Pardo-de-Santayana M, Peral D, Martín MA, Altimiras J. Interactions of Valeriana officinalis L. and Passiflora incarnata L. in a patient treated with lorazepam. Phytother Res. 2009;23(12):1795-1796. pubmed.ncbi.nlm.nih.gov/19441067/
- Finan PH, Goodin BR, Smith MT. The association of sleep and pain: an update and a path forward. J Pain. 2013;14(12):1539-1552. pubmed.ncbi.nlm.nih.gov/24290442/