The short answer
Most healthy adults who take NerveHoney as directed will probably notice nothing worse than mild drowsiness. The risks concentrate in particular groups: people on sedating medicines, people with liver disease, older adults at risk of falls, and anyone pregnant or breastfeeding. The seller's FAQ advises a doctor's input for pregnant or nursing women, people under 18 and anyone with a medical condition. That advice is sound, even though the same page claims the formula has no side effects.
Side effects by ingredient
| Ingredient | Known side effects and cautions | Source |
|---|---|---|
| Passionflower 145 mg | Drowsiness, dizziness, confusion; one case of nausea, drowsiness and QT prolongation; not for pregnancy; stop two weeks before surgery | [1] [2] |
| Corydalis 100 mg | Liver injury linked to its alkaloids; sedation and breathing depression in overdose of l-THP products | [3] [4] [5] |
| California poppy seed 45 mg | Sedation; may add to other sedatives | [6] |
| Marshmallow root 110 mg | Generally well tolerated; may slow absorption of drugs taken at the same time; lactation data lacking | [7] [8] |
| Prickly pear 20:1 50 mg | No specific safety signal at this dose; human data come from a different Opuntia species | [9] |
Drowsiness and sedative stacking
The two calming herbs act on GABA-A receptors, the same receptor family as benzodiazepines [10] [11]. On its own, at these doses, the effect is mild. Combined with other sedating substances, it adds up. A published case describes a patient on lorazepam who developed hand tremor, dizziness and muscle fatigue after adding passionflower and valerian [12].
Check with a prescriber or pharmacist before combining NerveHoney with benzodiazepines (such as lorazepam or alprazolam), z-drugs (such as zolpidem), opioids, gabapentin or pregabalin, sedating antihistamines, muscle relaxants, or antidepressants. Avoid alcohol until you know how you react, and do not drive if you feel drowsy.
The liver caution
Corydalis is the ingredient that needs the most respect. In the 1990s, a Chinese herbal product called Jin Bu Huan, built on the corydalis alkaloid l-tetrahydropalmatine, caused acute hepatitis in adults and dangerous sedation with slowed breathing in children who swallowed it [3]. NIH's LiverTox database lists Chinese and other Asian herbal medicines among recognized causes of drug-induced liver injury [5], and a 2025 study described idiosyncratic hepatotoxicity from Corydalis yanhusuo, meaning injury that strikes unpredictably in a minority of people [4].
NerveHoney's 100 mg of powder is a modest amount, and the label gives no alkaloid content. That uncertainty is the point: you cannot know your dose of the alkaloids. If you have liver disease, drink heavily or take medicines that stress the liver, skip it. Anyone taking it should stop and seek care for dark urine, pale stools, yellowing of the skin or eyes, or pain under the right ribs.
Heart rhythm, pregnancy and surgery
Heart rhythm. A single case report describes a woman who developed nausea, vomiting, drowsiness and a prolonged QT interval on the ECG after taking passionflower tablets [2]. It is rare, but people with known rhythm problems or on QT-prolonging drugs should ask a cardiologist. Pregnancy and breastfeeding. NIH says passionflower should not be used in pregnancy because some of its compounds may cause uterine contractions [1]. Marshmallow root lacks breastfeeding data [8]. There is no reason to take this formula while pregnant or nursing. Surgery. Because of possible effects on the nervous system and interactions with anesthesia, NIH advises stopping passionflower at least two weeks before scheduled surgery [1].Older adults and falls
Nerve symptoms in the feet already affect balance, which is one reason peripheral neuropathy raises the risk of falls. Adding a calming herb at night, when people get up to use the bathroom, can make that worse. Older adults should start in the evening with a nightlight on, take care when standing, and stop if they feel unsteady.
Timing with other medicines
Mucilage herbs like marshmallow root form a gel that can slow the absorption of medicines taken at the same moment. Leave an hour or two between NerveHoney and prescription drugs, particularly ones where steady levels matter, such as thyroid hormone, anticoagulants or diabetes medicines.
A pharmacist checklist
Bring this list to a pharmacist, along with the NerveHoney label, before you start. It takes five minutes and covers the questions that matter:
- Do any of my medicines cause drowsiness, and how will a calming herb add to them?
- Do any of my medicines strain the liver, or do I have any liver test results on file?
- Do I take anything where steady blood levels matter, such as thyroid hormone, warfarin or diabetes medicines, so that timing should be separated?
- Do I take any medicine that affects heart rhythm?
- Is anything I take already for nerve pain, such as gabapentin, pregabalin or duloxetine, that this might duplicate or interact with?
- Am I taking other supplements with vitamin B6, kava, valerian, melatonin or similar herbs?
Pharmacists see interaction questions every day and can check databases most consumers cannot reach.
Questions readers ask about side effects
Can NerveHoney raise blood pressure? None of the five herbs is known for that; calming herbs are more likely to lower alertness than raise pressure. Does it affect blood sugar? No ingredient is known to change glucose meaningfully at these doses. People with diabetes should keep monitoring as usual. Is it safe for older adults? Often, with care about drowsiness and falls at night, and with a medicine review first. Can I drink alcohol on it? Better not, at least until you know how you react. Both are sedating, and both pass through the liver.Side effects in context
It is worth keeping these cautions in proportion. Most people who take passionflower in trials report no side effects or only mild sleepiness, and the serious events described above are rare case reports. The point of listing them is not to frighten but to make sure the people at higher risk, those on sedatives, with liver disease, pregnant, or about to have surgery, know to check first. For everyone else, starting in the evening, avoiding alcohol and watching for the warning signs covers most of the risk.
If you react
Stop taking the capsules. For mild drowsiness or stomach upset, that is usually enough. For anything more, liver symptoms, palpitations, confusion, a rash or breathing trouble, seek medical care. Report reactions to the FDA through MedWatch [13], which is how safety signals for herbal products are detected. If you want your money back, the 60-day refund still applies; email [email protected] and keep the bottles.
Checked the numbers?
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
- 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/
- Horowitz RS, Feldhaus K, Dart RC, Stermitz FR, Beck JJ. The clinical spectrum of Jin Bu Huan toxicity. Arch Intern Med. 1996;156(8):899-903. pubmed.ncbi.nlm.nih.gov/8774209/
- Guo L, Lin L, Ling J, et al. A new discovery: Corydalis yanhusuo causes idiosyncratic hepatotoxicity and its potential mechanisms. Biomed Chromatogr. 2025;39:e70093. pubmed.ncbi.nlm.nih.gov/40277353/
- LiverTox: Clinical and Research Information on Drug-Induced Liver Injury. Chinese and other Asian herbal medicines. Bethesda (MD): National Institute of Diabetes and Digestive and Kidney Diseases; 2012-. pubmed.ncbi.nlm.nih.gov/31643904/
- Rolland A, Fleurentin J, Lanhers MC, et al. Behavioural effects of the American traditional plant Eschscholzia californica: sedative and anxiolytic properties. Planta Med. 1991;57(3):212-216. pubmed.ncbi.nlm.nih.gov/1680240/
- European Medicines Agency, Committee on Herbal Medicinal Products. Althaeae radix (marshmallow root): herbal medicine overview and monograph. www.ema.europa.eu/en/medicines/herbal/althaeae-radix
- Drugs and Lactation Database (LactMed). Marshmallow. Bethesda (MD): National Library of Medicine; 2006-. pubmed.ncbi.nlm.nih.gov/30000899/
- Wiese J, McPherson S, Odden MC, Shlipak MG. Effect of Opuntia ficus indica on symptoms of the alcohol hangover. Arch Intern Med. 2004;164(12):1334-1340. pubmed.ncbi.nlm.nih.gov/15226168/
- Fedurco M, Gregorová J, Šebrlová K, et al. Modulatory effects of Eschscholzia californica alkaloids on recombinant GABAA receptors. Biochem Res Int. 2015;2015:617620. pubmed.ncbi.nlm.nih.gov/26509084/
- 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/
- 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/
- U.S. Food and Drug Administration. MedWatch: The FDA Safety Information and Adverse Event Reporting Program. www.fda.gov/safety/medwatch-fda-safety-information-and-adverse-event-reporting-program