Hypertension

A 2017 Cochrane review of cocoa and blood pressure (>40 trials, ~1,800 participants) found a small but statistically significant reduction — on the order of ~1.8 mmHg systolic — versus flavanol-free control, consistent with two earlier independent meta-analyses ^{8,9,10Reference 8Ried K et al. · 2017Meta-analysisEffect of cocoa on blood pressure — Cochrane systematic review and meta-analysisView study →Reference 9Ried K et al. · 2010Meta-analysisDoes chocolate reduce blood pressure? A meta-analysis — systematic review, meta-analysisView study →Reference 10Desch S et al. · 2010Meta-analysisEffect of cocoa products on blood pressure: systematic review and meta-analysisView study →}, driven by flavanol-mediated nitric-oxide vasodilation with a modest theobromine contribution.

The effect is clinically modest, trials are short (mostly 2–18 weeks), it is larger in normotensive/mildly-elevated cohorts than treated hypertensives, and long-term BP benefit was not confirmed by the COSMOS outcomes data.

Two independent meta-analyses agree on a modest effect: −2.85/−2.39 mmHg across 15 trials ^{22Reference 22Ursoniu et al. · 2016Meta-analysisEffects of flaxseed supplements on blood pressure: a systematic review and meta-analysis of controlled clinical trialsView study →} and −1.77/−1.58 mmHg across 11 ^{23Reference 23Khalesi et al. · 2015Meta-analysisFlaxseed consumption may reduce blood pressure: a systematic review and meta-analysis of controlled trialsView study →}, both strongest for whole seed taken ≥12 weeks.

In FLAX-PAD, 110 peripheral-artery-disease patients ate 30 g/day milled flaxseed for six months and systolic BP fell ~10 mmHg, diastolic ~7 mmHg versus placebo — 15/7 mmHg in those entering ≥140 mmHg — with circulating ALA and enterolignan levels tracking the response ^{24Reference 24Rodriguez-Leyva et al. · 2013Potent antihypertensive action of dietary flaxseed in hypertensive patients (FLAX-PAD)View study →}. That is one of the largest antihypertensive effects reported for any dietary intervention. The pooled effect (≈2–3 mmHg) and the single-trial effect (≈10 mmHg) differ by a factor of four, and the larger one has not been replicated in newly diagnosed, unmedicated hypertensives.

Blood pressure is garlic’s best-supported indication. Multiple independent meta-analyses of placebo-controlled RCTs converge on a modest antihypertensive effect (~6.7/4.8 mmHg in one 7-RCT review; ~3.75/3.4 mmHg significant chiefly in hypertensives in a 17-trial analysis), plausibly via H₂S/NO signalling from S-allylcysteine ^{25,26,27,28Reference 25Xiong XJ et al. · 2015Meta-analysisGarlic for hypertension: a systematic review and meta-analysis of randomized controlled trials — systematic reviewView study →Reference 26Ried K et al. · 2008Meta-analysisEffect of garlic on blood pressure: a systematic review and meta-analysisView study →Reference 27Wang HP et al. · 2015Meta-analysisEffect of garlic on blood pressure: a meta-analysis — randomised trialsView study →Reference 28Ried K · 2016Meta-analysisGarlic lowers blood pressure in hypertensive individuals, regulates serum cholesterol, and stimulates immunity: an updated meta-analysis and reviewView study →}.

The effect concentrates in those with elevated baseline pressure. The often-quoted claim that aged garlic extract benefits only above 1200 mg/day rested on a meta-analysis that has since been retracted ^{29Reference 29Saadh MJ et al. · 2024Meta-analysisEffects of aged garlic extract on blood pressure in hypertensive patients: a systematic review and meta-analysis of randomized controlled trialsView study →}, so no dose threshold is established. The effect is real but clinically modest, comparable to a single low-dose antihypertensive. Trials are short, and preparation and dose vary widely.

Blood pressure is grape seed extract’s single best-supported indication. Three meta-analyses: 16 RCTs (810 subjects) giving systolic −6.1 and diastolic −2.8 mmHg, with larger effects in younger, obese and metabolic-syndrome subjects ^{34Reference 34Zhang et al. · 2016Meta-analysisThe impact of grape seed extract treatment on blood pressure changes: a meta-analysis of 16 randomized controlled trialsView study →}; an earlier 9-trial analysis agreeing ^{35Reference 35Feringa et al. · 2011Meta-analysisThe effect of grape seed extract on cardiovascular risk markers: a meta-analysis of randomized controlled trialsView study →}; and a dose/duration-stratified 19-trial analysis confirming a robust diastolic reduction (~2.2 mmHg) and a heart-rate reduction, but finding systolic effects non-significant and highly heterogeneous with a non-linear dose-response ^{36Reference 36Foshati et al. · 2022Meta-analysisThe effect of grape (Vitis vinifera) seed extract supplementation on flow-mediated dilation, blood pressure and heart rate: a systematic review and meta-analysis with duration- and dose-response analysisView study →}.

Individual RCTs are consistent — 300 mg/day improved BP and perceived stress ^{37Reference 37Schön et al. · 2021RCTGrape seed extract positively modulates blood pressure and perceived stress: a randomized, double-blind, placebo-controlled study in healthy volunteersView study →} and ambulatory BP in pre-/stage-I hypertension ^{38Reference 38Ras et al. · 2013Effect of polyphenol-rich grape seed extract on ambulatory blood pressure in subjects with pre- and stage I hypertensionView study →}; a 400 mg/day procyanidin-B2 standardised extract cut systolic BP ~13 mmHg over 12 weeks in prehypertensive Japanese adults ^{39Reference 39Odai et al. · 2019RCTEffects of grape seed proanthocyanidin extract on vascular endothelial function in participants with prehypertension: a randomized, double-blind, placebo-controlled studyView study →}. Systolic heterogeneity is I² > 90%. Grape seed extract reliably lowers diastolic pressure a little; its systolic effect is real in some trials and absent in others.

A 2025 systematic review and meta-analysis of six placebo-controlled RCTs (428 participants) found standardised hawthorn extract produced a clinically meaningful systolic reduction (mean difference −6.65 mmHg), with a non-significant diastolic change, across 10-week-to-6-month trials ^{50Reference 50Szikora et al. · 2025Meta-analysisHawthorn (Crataegus spp.) clinically significantly reduces blood pressure in hypertension: a meta-analysis of randomized placebo-controlled clinical trialsView study →}; the best single trial (n=79, type-2 diabetics, 1,200 mg/day, 16 weeks) showed a significant diastolic difference with no herb-drug interaction ^{51Reference 51Walker et al. · 2006RCTHypotensive effects of hawthorn for patients with diabetes taking prescription drugs: a randomised controlled trialView study →}. Blood pressure is now hawthorn’s most durable human signal. Trials are small, heterogeneous and dosed at 250–1,200 mg/day, the effect is modest, and no large dedicated hypertension trial exists.

Two RCT meta-analyses report small but significant blood-pressure reductions — roughly −3.1 mmHg systolic and −2.7 mmHg diastolic in the more recent pool, consistent with an earlier 11-RCT synthesis ^{59,60Reference 59Kavyani Z et al. · 2023Meta-analysisAntihypertensive effects of Nigella sativa supplementation — updated systematic review and meta-analysis of randomized controlled trialsView study →Reference 60Sahebkar A et al. · 2016Meta-analysisA systematic review and meta-analysis of randomized controlled trials investigating the effects of Nigella sativa on blood pressureView study →}, proposed to run through thymoquinone effects on oxidative stress and endothelial function. The effect is modest with very high heterogeneity, overlaps what diet and lifestyle achieve, and is untested against or alongside standard antihypertensives, which makes nigella a minor adjunct.

Blood pressure is olive leaf’s strongest indication. A 12-week active-controlled RCT found standardised extract (EFLA®943, 500 mg twice daily) cut systolic BP ~11 mmHg in stage-1 hypertensives, comparable to captopril ^{61Reference 61Susalit et al. · 2011RCTOlive (Olea europaea) leaf extract effective in patients with stage-1 hypertension: comparison with Captopril — randomised controlled trialView study →}, with supporting crossover and 621-participant multicentre RCTs ^{62,63Reference 62Lockyer et al. · 2017RCTImpact of phenolic-rich olive leaf extract on blood pressure, plasma lipids and inflammatory markers: a randomised controlled trialView study →Reference 63Lamti et al. · 2025RCTEfficacy of olive leaf extracts in controlling blood pressure in hypertensive patients: a double-blind randomized clinical trial — multicentre RCTView study →} and two 2024–2026 meta-analyses ^{64,65Reference 64Álvares et al. · 2024Meta-analysisOlive leaf extract effect on cardiometabolic risk factors: a systematic review and meta-analysis of randomized clinical trialsView study →Reference 65Câmara Rocha Menezes et al. · 2026Meta-analysisMetabolic and inflammatory effects of oleuropein and olive leaf extract: a systematic review and meta-analysisView study →}. Mechanism is partly ACE inhibition via the secoiridoid oleacein ^{66Reference 66Hansen et al. · 1996In vitroIsolation of an angiotensin converting enzyme (ACE) inhibitor from Olea europaea and Olea lancea — in vitroView study →}.

The benefit is for oleuropein-standardised extracts, not the traditional tea or 1:2 liquid extract, and some combination-extract trials are null ^{67Reference 67Wong et al. · 2014RCTAntihypertensive potential of combined extracts of olive leaf, green coffee bean and beetroot: a randomized, double-blind, placebo-controlled crossover trialView study →}.

Blood-pressure lowering is tea’s most reproducible cardiovascular effect: RCT meta-analyses converge on small reductions (~-1.1 to -2.1 mmHg systolic, -1.2 to -1.9 mmHg diastolic vs control), with a larger signal in people who start hypertensive ^{84,85,86,87Reference 84Xu et al. · 2020Meta-analysisEffect of green tea supplementation on blood pressure: a systematic review and meta-analysis of 24 randomised controlled trialsView study →Reference 85Khalesi et al. · 2014Meta-analysisGreen tea catechins and blood pressure: a systematic review and meta-analysis of randomised controlled trialsView study →Reference 86Peng et al. · 2014Meta-analysisEffect of green tea consumption on blood pressure: a meta-analysis of 13 randomised controlled trialsView study →Reference 87Rezaei et al. · 2025Meta-analysisEffect of green tea supplementation on blood pressure in adults: a GRADE-assessed systematic review and dose-response meta-analysis of 36 randomised controlled trialsView study →}. A 2025 GRADE-assessed dose-response meta-analysis of 36 RCTs positioned green tea as a complementary rather than primary strategy ^{87Reference 87Rezaei et al. · 2025Meta-analysisEffect of green tea supplementation on blood pressure in adults: a GRADE-assessed systematic review and dose-response meta-analysis of 36 randomised controlled trialsView study →}. The effects are small and driven by concentrated green-tea extract or catechin-enriched products, not an everyday brewed cup.

In a 12-week double-blind trial, 3 g/day of a selected American ginseng extract added to usual therapy lowered radial augmentation index (arterial stiffness) by 5.3% and systolic blood pressure by 11.7% in type 2 diabetics with concomitant hypertension, with no effect on diastolic pressure ^{30Reference 30Mucalo et al. · 2013RCTEffect of American ginseng (Panax quinquefolius L.) on arterial stiffness in subjects with type-2 diabetes and concomitant hypertension — randomised controlled trialView study →}. A separate multicentre RCT combining ginsenoside-Rg3-enriched Korean Red ginseng with American ginseng found only a modest central-systolic reduction and no change in pulse-wave velocity or endothelial function ^{31Reference 31Jovanovski et al. · 2020RCTVascular effects of combined enriched Korean Red ginseng and American ginseng in individuals with hypertension and type 2 diabetes: a randomized controlled trial — randomised controlled trialView study →}. The evidence is confined to a diabetic-hypertensive population, one key study used a ginseng combination rather than American ginseng alone, and there are no cardiovascular-outcome trials.

A single randomised, double-blind, placebo-controlled trial added aqueous amla extract (500 mg twice daily, 12 weeks) to routine medication in 150 patients with essential hypertension and reported blood-pressure lowering plus improvements in lipids, oxidant/antioxidant enzymes and hs-CRP ^{1Reference 1Shanmugarajan et al. · 2021Clinical trialAntihypertensive and pleiotropic effects of Phyllanthus emblica extract as an add-on therapy in patients with essential hypertensionView study →}. The presumed mechanism is antioxidant-driven endothelial effect rather than a specific antihypertensive lever. The trial is unreplicated and add-on: amla was layered on existing antihypertensives, so its standalone effect is unquantified.

The evidence is one small 10-day study in mild hypertensives given a whole-plant P. amarus preparation, which raised 24-hour urine volume and sodium excretion and significantly lowered systolic blood pressure in non-diabetic subjects ^{13Reference 13Srividya et al. · 1995Clinical trialDiuretic, hypotensive and hypoglycaemic effect of Phyllanthus amarus — controlled clinical trialView study →}. The study is small, old and unreplicated, used a different species (P. amarus, not P. niruri), and had no placebo control or mechanistic follow-up.

A 2025 randomised, double-blind, placebo-controlled trial (n=320, 12 weeks) found dan shen significantly reduced systolic and diastolic blood pressure from week 4, with improved lipid, glucose and quality-of-life measures and only mild side effects ^{17Reference 17Li et al. · 2025RCTEffects of Dan Shen (Salvia miltiorrhiza) on blood pressure management in hypertensive patients — randomised double-blind placebo-controlled trialView study →}. The trial used an intravenous danshen preparation, so it does not validate the oral dried root, and it is single-centre and unreplicated.

Dandelion leaf is the herb’s best-evidenced indication and its only one with human data: a 2009 uncontrolled pilot in 17 volunteers found leaf hydroethanolic extract raised urinary frequency and excretion ratio over a single day ^{18Reference 18Clare BA et al. · 2009Clinical trialThe diuretic effect in human subjects of an extract of Taraxacum officinale folium over a single day — [clinical trial]View study →}. The link to hypertension is mechanistic — the leaf is a credible potassium-rich (~4.5% dry weight) diuretic that traditionally moves fluid without the potassium loss of loop/thiazide drugs ^{19Reference 19Schütz K et al. · 2006ReviewTaraxacum—a review on its phytochemical and pharmacological profile — [review]View study →}. No trial has measured blood pressure; the hypertension use rests on the diuretic action.

A 29-woman postmenopausal pilot RCT found maca lowered blood pressure alongside its mood effect ^{52Reference 52Stojanovska et al. · 2015RCTMaca reduces blood pressure and depression in a pilot study in postmenopausal women — randomised controlled trialView study →}. Maca inhibits angiotensin-I-converting enzyme (ACE) in vitro and is potassium-rich ^{53Reference 53Gonzales · 2012ReviewEthnobiology and ethnopharmacology of Lepidium meyenii (Maca), a plant from the Peruvian highlands — reviewView study →}. Only this one small trial reports a blood-pressure effect, the mechanism rests on an in-vitro ACE assay, and no dedicated hypertension trial exists.

One open-label trial in 50 stage 1–2 hypertensive patients with anxiety/sleep disturbance found a Leonurus CO₂ oil extract (1200 mg/day, 28 days) improved blood pressure and psycho-emotional scores ^{54Reference 54Shikov et al. · 2011Clinical trialEffect of Leonurus cardiaca oil extract in patients with arterial hypertension accompanied by anxiety and sleep disorders — clinical trial (open-label)View study →}; mechanistically, lavandulifolioside lowered blood pressure and heart rate in animals ^{55Reference 55Miłkowska-Leyck et al. · 2002AnimalPharmacological effects of lavandulifolioside from Leonurus cardiaca — animal in vivoView study →} and a refined aqueous extract raised coronary flow while lowering left-ventricular pressure ex vivo ^{56Reference 56Ritter et al. · 2010Cardiac and electrophysiological effects of primary and refined extracts from Leonurus cardiaca L. (PhView study →}.

The trial had no randomisation and no placebo, and the human data used a proprietary oil extract — not the tea or tincture people actually take — so the effect is suggestive, not confirmed ^{57,58Reference 57Wojtyniak et al. · 2013ReviewLeonurus cardiaca L. (motherwort): a review of its phytochemistry and pharmacology — reviewView study →Reference 58EMA Committee on Herbal Medicinal Produc · 2010ReviewAssessment report on Leonurus cardiaca L., herba — pharmacopoeial/regulatory monographView study →}.

Two meta-analyses agree on a small, consistent effect: systolic −2.0 mmHg across 11 trials ^{69Reference 69Clark et al. · 2020Meta-analysisThe effect of psyllium supplementation on blood pressure: a systematic review and meta-analysis of randomized controlled trials — meta-analysisView study →}, and −2.2 mmHg across 14 trials with a linear dose and duration relationship ^{70Reference 70Gholami et al. · 2024Meta-analysisThe effect of psyllium consumption on blood pressure: systematic review and dose-response meta-analysis of randomized controlled trials — meta-analysisView study →} — with diastolic not significantly changed in the latter. The magnitude is small, diastolic is essentially unmoved, and the effect is most plausibly indirect, mediated through the lipid, glycaemic and weight effects rather than any vascular action. Psyllium is a minor adjunct, not an antihypertensive.

Two multicentre placebo-controlled RCTs at pharmacological stevioside doses were positive: Chan 2000 (n=106, 750 mg/day, 1 yr) and Hsieh 2003 (n=174, 1500 mg/day, 2 yr) reported sustained BP reductions and a fall in LV mass index, proposed via calcium-channel antagonism in vascular smooth muscle ^{75,76Reference 75Chan et al. · 2000RCTA double-blind placebo-controlled study of the effectiveness and tolerability of oral stevioside in human hypertension — randomised controlled trialView study →Reference 76Hsieh et al. · 2003RCTEfficacy and tolerability of oral stevioside in patients with mild essential hypertension: a two-year, randomised, placebo-controlled studyView study →}. At sweetener-level intake the trials are null ^{77,78Reference 77Ferri et al. · 2006RCTInvestigation of the antihypertensive effect of oral crude stevioside in patients with mild essential hypertension — randomised controlled trialView study →Reference 78Barriocanal et al. · 2008RCTApparent lack of pharmacological effect of steviol glycosides used as sweeteners in humans — randomised controlled trialView study →}, and a 2015 meta-analysis found the pooled systolic effect non-significant with high heterogeneity ^{79Reference 79Onakpoya et al. · 2015Meta-analysisEffect of the natural sweetener steviol glycoside on cardiovascular risk factors: a systematic review and meta-analysis of randomised controlled trialsView study →}. The benefit does not transfer to how stevia is normally consumed.

A single randomised, double-blind, placebo-controlled Unani-medicine trial found powdered Tribulus fruit (6 g/day for two months) lowered blood pressure in prehypertensive adults ^{88Reference 88Siddiqui MA · 2021RCTEfficacy of Khar-i-khasak (Tribulus terrestris) in prehypertension — randomised, double-blind, placebo-controlled trial — [randomised placebo-controlled trial]View study →}, echoing traditional antihypertensive use and supported by animal vasorelaxant/ACE-inhibitory work. The trial was small and used whole dried fruit, and there is no confirmation in established hypertension and no standardised-extract data.

Blood pressure is ylang-ylang’s best-measured objective outcome. Single-oil transdermal application (n=40) and inhalation both produced significant acute decreases in blood pressure in healthy volunteers ^{93,94Reference 93Hongratanaworakit et al. · 2004RCTEvaluation of the harmonizing effect of ylang-ylang oil on humans after inhalation — randomized controlled trialView study →Reference 94Hongratanaworakit et al. · 2006Clinical trialRelaxing effect of ylang ylang oil on humans after transdermal absorption — clinical trialView study →}, and a controlled trial in healthy men found reduced BP and heart rate after aroma exposure ^{95Reference 95Jung et al. · 2013Effects of ylang-ylang aroma on blood pressure and heart rate in healthy men — controlled trialView study →}.

In high-BP populations the signal persists but the oil is usually blended — a lavender + ylang-ylang sticker-pad RCT lowered BP over 14 days ^{96Reference 96Napavichayanun et al. · 2024RCTEffect of Lavandula angustifolia and Cananga odorata sticker pads on blood pressure in high blood pressure volunteers — randomized controlled trialView study →}, and Korean nursing trials using ylang-ylang blends reported reductions in BP, cortisol and catecholamines ^{97,98,99Reference 97Hwang · 2006RCTEffects of the inhalation method using essential oils on blood pressure and stress responses in essential hypertension — randomized controlled trial (oil blend)View study →Reference 98Cha et al. · 2010Clinical trialEffects of aromatherapy on autonomic nervous system, aortic pulse wave velocity and augmentation index in essential hypertension — controlled clinical trial (oil blend)View study →Reference 99Song et al. · 2018RCTEffects of aromatherapy on stress responses, autonomic activity and blood pressure in patients undergoing coronary angiography — non-randomized controlled trial (oil blend)View study →}. Effects are acute and modest; durable single-oil evidence in diagnosed hypertension is thin, and blended trials cannot isolate ylang-ylang’s contribution.

Although arjuna is traditionally used as an antihypertensive, the modern evidence is predominantly animal: aqueous bark extract lowered pulmonary arterial pressure and reduced right-ventricular hypertrophy in a rat pulmonary-hypertension model ^{2Reference 2Meghwani et al. · 2017AnimalBeneficial effects of aqueous extract of stem bark of Terminalia arjuna in experimental pulmonary hypertension — animal modelView study →}, with other animal studies describing hypotensive and vasodilatory effects ^{3Reference 3Dwivedi · 2007ReviewTerminalia arjuna Wight & Arn. — a useful drug for cardiovascular disorders — reviewView study →}. Human blood-pressure data are incidental to the angina and heart-failure trials, never the object of a dedicated hypertension study.

A stem-bark extract produced hypotensive effects in vivo and cardio-inhibitory effects in vitro, attributed to calcium-channel blockade or inhibition of intracellular calcium release ^{11Reference 11Mota et al. · 1985AnimalAnti-inflammatory actions of tannins isolated from the bark of Anacardium occidentale — animal study (rat)View study →}. Animal/in-vitro only; mechanism unconfirmed and no human blood-pressure data.

The evidence is old constituent-level pharmacology: Uncaria hook alkaloids (rhynchophylline, hirsutine) produce hypotensive/vasodilatory effects in isolated-tissue and animal preparations ^{12Reference 12Endo et al. · 1983In vitroHypotensive principles of Uncaria hooks — in vitro/animalView study →}. These findings derive largely from the Asian Uncaria species used in Chinese medicine, not the Amazonian U. tomentosa, and there is no human blood-pressure trial.

Luteolin and chlorogenic acid modulate eNOS to support mild vasodilation, and PPAR-α activation contributes to lipid-lowering and anti-atherosclerotic effects in animals ^{14,15Reference 14Zhu et al et al. · 2025AnimalChrysanthemum morifolium water extract prevents and treats MAFLD via pan-PPAR agonism (mouse model)View study →Reference 15Liu et al et al. · 2024AnimalChrysanthemum morifolium attenuates metabolic- and alcohol-associated liver disease via gut microbiota and PPAR-α/γ (mouse model)View study →}; population studies associate chrysanthemum tea with cardiovascular health, and TCM uses the cooling flower for high blood pressure. There is no dedicated hypertension trial; support is mechanistic and traditional.

The cAMP→PKA→smooth-muscle-relaxation pathway drives vasodilation and blood-pressure lowering, and the related diterpene coleonol lowered blood pressure in early animal work ^{16Reference 16Dubey MP et al. · 1981AnimalPharmacological studies on coleonol, a hypotensive diterpene from Coleus forskohlii — [animal model]View study →}. In humans the effect appears only as a mild blood-pressure-lowering safety signal from the oral extract ^{16Reference 16Dubey MP et al. · 1981AnimalPharmacological studies on coleonol, a hypotensive diterpene from Coleus forskohlii — [animal model]View study →}. No controlled trial tests coleus as an antihypertensive.

The blood-pressure signal is molecule-level and animal-only: the flavonoid glycoside eupalitin 3-O-β-D-galactopyranoside lowered systolic and diastolic pressure in hypertensive rats ^{20Reference 20Uoorakkottil I et al. · 2024AnimalMolecular Docking and Antihypertensive Activity of Eupalitin 3-O-β-D-galactopyranoside Isolated from Boerhavia diffusa Linn — rat in vivo, Pharmaceutics, 16(12). https://pubmed.ncbi.nlm.nih.gov/39771606/View study →}, and the lignan liriodendrin is a calcium-channel antagonist in cardiac cells ^{21Reference 21Lami N et al. · 1991In vitroConstituents of the roots of Boerhaavia diffusa LView study →} — a plausible basis for a mild antihypertensive effect. No human blood-pressure data exist. The same activity is the basis of its blood-pressure-lowering safety caution.

In anaesthetised normotensive rats, aqueous leaf extract lowered mean arterial pressure dose-dependently via a proposed peripheral (non-adrenergic, possibly calcium-channel/muscarinic) mechanism ^{40Reference 40Nwokocha et al. · 2012AnimalPossible mechanisms of the hypotensive effect of Annona muricata (soursop) in normotensive rats — animal modelView study →}, and a second rat study reported hypotensive/antihypertensive effects with a basic safety assessment ^{41Reference 41Sokpe et al. · 2020AnimalHypotensive and antihypertensive properties and safety for use of Annona muricata and Persea americana — animal modelView study →}. The effect is reproducible but shown only in small animal models, with no human blood-pressure data. Combining it with antihypertensive or hypoglycaemic drugs could give uncharacterised additive effects.

Standardised aqueous extract and butanolic fraction of C. glaziovii produce hypotension in normotensive rats and antihypertensive effects on repeated dosing via endothelium-dependent, ACE-independent vasodilation driven by procyanidins and orientin / isoorientin ^{42,43,44,45,46Reference 42Lima-Landman et al. · 2007AnimalAntihypertensive effect of a standardized aqueous extract of Cecropia glaziovii Sneth in rats: in vivo hypotensive mechanism — animal studyView study →Reference 43Ninahuaman et al. · 2007ACE activity during the hypotension produced by standardized aqueous extract of Cecropia glaziovii Sneth: comparison to captopril — animal studyView study →Reference 44Tanae et al. · 2007Chemical standardization of the aqueous extract of Cecropia glaziovii Sneth with antihypertensive, bronchodilator, antiacid-secretion and antidepressant-like activities — animal studyView study →Reference 45Trettel et al. · 2021In vitroMechanisms of calcium mobilization by procyanidins, flavonols and flavonoids from Cecropia glaziovii Sneth in pulmonary endothelial cell cultures — in vitroView study →Reference 46Dos Santos et al. · 2018In vitroVasorelaxant effect of standardized Cecropia glaziovii extract encapsulated in PLGA microparticles — in vitroView study →}; C. pachystachya shows similar hypotensive/diuretic activity ^{47,48Reference 47Machado et al. · 2021Ethnopharmacological investigations of the leaves of Cecropia pachystachya Trécul (Urticaceae) — animal studyView study →Reference 48Maquiaveli et al. · 2014AnimalCecropia pachystachya extract attenuated the renal lesion in 5/6 nephrectomized rats by reducing inflammation and renal arginase activity — animal studyView study →}. There are no human blood-pressure data in any Cecropia species, and the animal work is on related species rather than C. mexicana.

Cecropia is not cardiotonic: direct cardiac-muscle work (C. lyratiloba) found depression, not a tonic effect ^{49Reference 49Ramos Almeida et al. · 2006AnimalActivity of Cecropia lyratiloba extract on contractility of cardiac and smooth muscles in Wistar rats — animal studyView study →}. Its cardiovascular action is peripheral blood-pressure lowering.

The traditional mild blood-pressure reputation rests on harmala (β-carboline) alkaloids: harmaline and related alkaloids inhibit voltage-gated Ca²⁺ channels in vascular and intestinal smooth muscle in isolated tissue ^{68Reference 68Karaki et al. · 1986In vitroInhibition of calcium channels by harmaline and other harmala alkaloids in vascular and intestinal smooth muscles — in vitroView study →}. Harmane and harmine occur at only ~0.005–0.012% in P. incarnata, so they may not reach relevant concentrations from ordinary preparations. No human cardiovascular trial exists.

In a standardised S. aristolochiifolia metabolic-syndrome mouse study, the extract lowered blood pressure by roughly a third alongside its metabolic effects ^{74Reference 74Amaro CA et al. · 2014AnimalHypoglycemic and hypotensive activity of a root extract of Smilax aristolochiifolia, standardized on N-trans-feruloyl-tyramine — animal modelView study →}. Blood pressure was one arm of a metabolic composite rather than a dedicated antihypertensive investigation, and there are no human data.

Leaf extract lowered systolic/diastolic pressure dose-dependently in spontaneously hypertensive rats (mirroring losartan), with endothelium-dependent NO-mediated vasorelaxation plus calcium-channel blockade as the mechanism ^{80,81,82Reference 80Vajic UJ et al. · 2018AnimalUrtica dioica leaf extract modulates blood pressure and oxidative stress in spontaneously hypertensive rats — animal modelView study →Reference 81Qayyum R et al. · 2016In vitroMechanisms underlying the antihypertensive properties of Urtica dioica — in vitro/in vivo animal studyView study →Reference 82Vajic UJ et al. · 2024AnimalUrtica dioica leaf extract dose-dependently modulates oxidative stress in the kidney and exerts anti-fibrotic and anti-inflammatory properties in SHR — animal modelView study →}; the only human signal is a −5 mmHg systolic drop as a secondary outcome inside the diabetes meta-analysis ^{83Reference 83Tabrizi R et al. · 2022Meta-analysisEffects of Urtica dioica on metabolic profiles in type 2 diabetes — systematic review and meta-analysis of clinical trialsView study →}. No dedicated human hypertension trial exists.

Cardiovascular support rests on surrogate markers, and the blood-pressure signal is inconsistent: an 8-week randomised crossover trial in non-habitual consumers lowered blood pressure and inflammatory cytokines across participants ^{89Reference 89Bravo et al. · 2025RCTYerba Mate (Ilex paraguariensis) tea may have cardiometabolic beneficial effects — a randomized, controlled, blind, crossover trial in nonhabitual consumersView study →}, but an acute crossover trial found a single infusion improved flow-mediated dilation while not changing blood pressure, hemodynamics or heart-rate variability ^{90Reference 90Filipini et al. · 2024RCTAcute ingestion of yerba mate (Ilex paraguariensis) infusion does not modify endothelial function, hemodynamics, or heart rate variability — a randomized crossover clinical trialView study →}.

Maté also carries caffeine, which can raise blood pressure, and hypertensives are cautioned about it ^{91,92Reference 91Li et al. · 2025Meta-analysisYerba Maté and its impact on glycemic control and metabolic health: a systematic review and meta-analysis of RCTsView study →Reference 92Pittler et al. · 2005Systematic reviewAdverse events of herbal food supplements for body weight reduction — systematic reviewView study →}. The antihypertensive trials are small and short, with no hard outcomes.

Chinese skullcap (Huang Qin) carries a classical TCM indication for hypertension. Its research (baicalin/baicalein anti-inflammatory, antiviral, hepatoprotective) contains no blood-pressure data.

German chamomile (Matricaria) was historically used in Western herbalism for hypertension, neuralgia and spasm. There is no blood-pressure trial.

Linden flower has a long-standing European reputation as a gentle antihypertensive for nervous, stress-related high blood pressure; its evidence is preclinical anxiolytic/antioxidant work and the EMA monograph rests on traditional use alone.

Asian ginseng does not lower blood pressure: a meta-analysis of 17 RCTs (n=1381) found no significant effect on systolic, diastolic or mean arterial pressure ^{32Reference 32Komishon et al. · 2016Meta-analysisThe effect of ginseng (genus Panax) on blood pressure — systematic review and meta-analysis of RCTsView study →}. The finding mainly answers the old concern that ginseng raises blood pressure. The only positive vascular signal is a surrogate: a Korean Red Ginseng RCT improved arterial stiffness in hypertensive subjects ^{33Reference 33Rhee et al. · 2011RCTEffect of Korean red ginseng on arterial stiffness in subjects with hypertension — randomised controlled trialView study →}. Asian ginseng is blood-pressure-neutral.

Bitter melon’s blood-pressure signal is weak and does not hold up. A 10-week trial (n=95) found the bitter-melon groups improved blood pressure versus glibenclamide, but BP was only a secondary outcome ^{6Reference 6Rahman et al. · 2015RCTLower hypoglycemic but higher antiatherogenic effects of bitter melon than glibenclamide in type 2 diabetic patients — RCTView study →}, and a 2024 meta-analysis found no significant effect on systolic or diastolic blood pressure ^{7Reference 7Laczkó-Zöld et al. · 2024Meta-analysisThe metabolic effect of Momordica charantia cannot be determined based on the available clinical evidence — meta-analysis of RCTsView study →}. The use is largely traditional and metabolic, with no direct antihypertensive mechanism.

Blood pressure is the weakest of artichoke’s cardiometabolic uses. A meta-analysis of 8 RCTs found no overall effect on systolic or diastolic pressure, with only a post-hoc hypertensive-subgroup (12-week) analysis showing a few-mmHg drop ^{4Reference 4Moradi M et al. · 2021Meta-analysisEffects of artichoke on blood pressure — systematic review and meta-analysisView study →}, and a dedicated RCT in captopril-treated hypertensives found no clear added BP benefit ^{5Reference 5Ardalani H et al. · 2020RCTThe effect of Cynara scolymus on blood pressure and BMI in hypertensive patients — randomised, double-blind, placebo-controlled clinical trialView study →}. The “mild ACE inhibitor” tag rests on a single cell-free enzyme assay, not a clinical effect. Artichoke is not a stand-alone antihypertensive.

The 2015 Cochrane review found trials too few and small to draw conclusions, with no convincing effect on blood pressure or lipids ^{71Reference 71Klupp NL et al. · 2015Meta-analysisGanoderma lucidum mushroom for the treatment of cardiovascular risk factors — systematic review, meta-analysisView study →}; a crossover trial in borderline hypertension/hyperlipidaemia (1.44 g/day, 12 weeks) found reishi well tolerated but without significant cardiovascular benefit ^{72Reference 72Chu TT et al. · 2012RCTStudy of potential cardioprotective effects of Ganoderma lucidum (Lingzhi): results of a controlled human intervention trial — randomised controlled trialView study →}, and the metabolic-syndrome RCT was likewise null ^{73Reference 73Klupp NL et al. · 2016RCTA double-blind, randomised, placebo-controlled trial of Ganoderma lucidum for the treatment of cardiovascular risk factors of metabolic syndrome — randomised controlled trialView study →}. Multiple placebo-controlled trials are null or inconclusive, and the controlled evidence does not support the antihypertensive claim.

Reishi does have ACE-inhibitory and antiplatelet constituents, which matter for safety rather than efficacy.