Benefits
Traditional use for symptoms of nervous tension
The European Medicines Agency herbal committee accepts motherwort tea, powder, tinctures and liquid extract as traditional herbal medicines to relieve symptoms of nervous tension in adults. This rests on long-standing use, not trials; the committee found no clinical studies that could support a well-established use. See a doctor if symptoms last beyond 4 weeks.
Traditional use for a nervous, pounding heartbeat
The same EU monograph covers nervous heart complaints such as palpitations, but only after a doctor has excluded a serious cause; EU assessors named arrhythmia, thyroid overactivity and heart disease as examples. This use also rests on tradition alone, and in 2019 four committee members dissented from the decision not to revise the monograph, one asking for stronger warnings.
Calm and sleep scores in a 28-day single-group study
In 50 adults with raised blood pressure plus anxiety and sleep complaints, 1,200 mg a day of a motherwort oil extract for 28 days was followed by better anxiety, mood and sleep scores; doctors rated 80% as moderately or markedly improved and 12% as not responding. There was no control group, so placebo and time effects cannot be separated.
Blood pressure readings in the same single-group study
According to the EU assessment report on the same 50-person study, average blood pressure fell from baseline (for example, from 144.5/96.1 to 129.4/85.9 mmHg in the milder group) with no significant change in heart rate. EU assessors said no efficacy conclusion is possible because the study was short and uncontrolled, and the oil extract differs from EU tinctures and teas.
Mood and visual tests in anxious young people
Two Russian studies gave motherwort tincture to anxious young people. One reported calmer mood and better color discrimination with the tincture or the drug tofisopam; the other reported that changes in mood and light sensitivity were less pronounced with the tincture than with melatonin. The English abstracts give no group sizes, tincture doses or placebo group, and EU assessors noted the missing details.
Heart rhythm and calming effects in lab and animal studies
In isolated rabbit hearts and heart cells, a refined motherwort extract slowed electrical conduction and blocked calcium channels, and in rat receptor assays motherwort extract bound the GABA-A receptor. In animals, modified motherwort dry extracts reduced anxiety-like behavior. These are lab and animal findings that have not been confirmed in people.
Mechanism of action
Binding at the GABA-A receptor (lab)
In rat brain receptor assays, a standardized motherwort extract inhibited binding at the GABA site of the GABA-A receptor (IC50 21 µg/ml), with much weaker binding at the benzodiazepine site. None of the isolated constituents tested explained the effect, so the active compound is unknown. Not tested in people.
Calcium channel and potassium current effects in heart tissue (lab)
A refined water extract of motherwort, enriched in stachydrine (about 6.7%), reduced left ventricular pressure and raised coronary flow in isolated rabbit hearts, and in heart cells it blocked L-type calcium current, reduced a repolarizing potassium current (IKr) and prolonged the action potential. Heart effects were seen at 1 to 2 mg/ml applied directly to the heart, not after oral doses.
Mitochondrial and antioxidant effects (lab)
In isolated rat heart mitochondria, motherwort extract and its flavonoids and chlorogenic acid partly uncoupled energy production, partly slowed the respiratory chain and reduced free radical generation. The authors proposed this as a cardioprotective route, but it is a test-tube finding only.
Clinical trials
Single-group clinical study of a Leonurus cardiaca extract made with soybean oil (1:10), 600 mg twice daily for 28 days, with no placebo or control group; extract, design and blood pressure details are as described in the EU (EMA 2010) assessment report. Funding is not stated in the abstract; the first author is from the Saint-Petersburg Institute of Pharmacy. (Shikov et al. 2011, Phytother Res)
50 men and women with stage 1 (22) or stage 2 (28) arterial hypertension and symptoms of anxiety and sleep disorders (stage split per the EU assessment report).
Blood pressure and anxiety, mood and sleep scores improved from baseline; on the Clinical Global Impression scale 32% improved markedly, 48% moderately, 8% weakly and 12% did not respond. Heart rate did not change significantly and side effects were described as minimal. EU assessors judged that no efficacy conclusion can be drawn because there was no control group and the study was short.
Russian comparison of melatonin (0.75 mg at night for 10 days) with motherwort tincture, with no placebo group described; published in Russian with a short English abstract. (Ovanesov et al. 2006, Eksp Klin Farmakol)
Anxious young subjects; the number of participants and the tincture dose are not given in the English abstract.
Melatonin lowered retinal brightness-sensitivity thresholds and improved emotional state; the abstract reports that similar changes were less pronounced after motherwort tincture. No statistics for the tincture are given in the abstract, and EU assessors noted that no details are presented.
Russian single-author study of repeated dosing with the prescription anxiety drug tofisopam or motherwort tincture; published in Russian with a short English abstract and no placebo group described. (Ovanesov 2005, Eksp Klin Farmakol)
Young people with heightened anxiety; group sizes and doses are not given in the English abstract.
Both tofisopam and the tincture were reported to lower anxiety and improve color discrimination for all four colors tested. Without a described placebo group or published details, the result cannot be attributed to motherwort.
Laboratory study: a bioassay-guided refined aqueous extract was infused into isolated perfused rabbit hearts and tested by voltage clamp on rat, guinea pig and transfected human cell models. (Ritter et al. 2010, Planta Med)
No human participants; isolated animal hearts and cells.
At 1.0 and 2.0 mg/ml the extract lowered left ventricular pressure, raised relative coronary flow and prolonged the PQ interval. It blocked L-type calcium current, reduced the IKr potassium current and prolonged action potential duration without affecting sodium current. These concentrations were applied directly to heart tissue and do not show what oral doses do.
Receptor binding assays on rat GABA-A receptors with standardized L. cardiaca and L. japonicus extracts and five isolated constituents. (Rauwald et al. 2015, Planta Med)
No human participants; rat receptor preparations.
Both extracts and leonurine inhibited binding at the GABA site (IC50 21 µg/ml for L. cardiaca, 46 µg/ml for L. japonicus, 15 µg/ml for leonurine), with 15 to 30 times weaker binding at the benzodiazepine site. L. cardiaca does not contain leonurine, and none of its other tested constituents was active, so its active principle is unknown.