Ranked by evidence within the category
Heart and metabolic supplements: what the evidence says
This category covers 119 supplements for cholesterol, blood pressure, blood sugar and circulation: 6 are rated strong, 42 moderate and 71 limited. The strongest evidence is for lowering LDL cholesterol with plant sterols, oat and barley beta-glucan and red yeast rice, for potassium from food and salt substitutes to lower blood pressure, and for algae omega-3 as a vegan source of DHA. The large moderate tier mostly offers small effects on a single marker, such as garlic, hibiscus or cocoa flavanols for blood pressure and berberine or fenugreek for blood glucose. The limited list includes niacin, chromium, apple cider vinegar and most support formulas.
Evidence last reviewed: September 2026
Strong evidence (6)
Raising potassium intake lowers blood pressure, and in the one large hard-outcome trial it reduced stroke and death.
Algal oil is a genuine plant-based source of preformed DHA (and increasingly EPA) that raises blood omega-3 levels as effectively as fish.
Red yeast rice genuinely lowers LDL cholesterol — because it contains monacolin K, which is chemically identical to the drug lovastatin.
Plant sterols and stanols reliably lower LDL cholesterol by about 8-12% at 2 g/day — one of the best-established non-drug lipid interventions.
Oat beta-glucan is one of the few supplements with a genuinely strong, regulator-endorsed evidence base: at 3 g/day it lowers LDL cholesterol by roughly 4-5% across dozens of randomized trials.
The soluble fibre from barley, one of the few supplement ingredients with an authorised cholesterol-lowering health claim.
Moderate evidence (42)
Arginine is the direct substrate for nitric oxide, but oral arginine is heavily degraded in the gut and liver before it reaches circulation, which is why citrulline usually outperforms it.
Taurine is a cheap, safe conditionally essential amino acid with genuinely decent cardiometabolic data: meta-analyses show reductions in blood pressure and improvements in lipids.
Fenugreek's best-supported use is glycemic control: meta-analyses of RCTs show meaningful reductions in fasting glucose and HbA1c in type 2 diabetes and prediabetes.
Krill oil delivers EPA and DHA in phospholipid form and modestly lowers triglycerides, much like fish oil, at a much higher price per gram of omega-3.
Nigella sativa has surprisingly consistent meta-analytic support for small reductions in blood pressure, fasting glucose and LDL-cholesterol.
Garlic reliably produces a small blood-pressure reduction in people who are actually hypertensive — roughly the effect of a low-dose drug in some trials — plus a modest cholesterol drop.
Small trials fairly consistently show lipid and blood-pressure improvements, and the pooled effect sizes are large enough to be suspicious — nearly every trial is small, short, and from a handful of research groups.
One of the better-supported Ayurvedic botanicals: two independent meta-analyses find consistent improvements in cholesterol, fasting glucose, and CRP.
CoQ10 has reasonable evidence for symptom and outcome improvement in chronic heart failure as an add-on to standard therapy, and a modest blood pressure effect.
Standardised hawthorn extract modestly improves exercise tolerance and symptoms in chronic heart failure as an add-on, but the largest properly powered trial found no survival benefit.
Hibiscus tea produces a small but reasonably consistent reduction in blood pressure across randomised trials — roughly 4-7 mmHg systolic.
Pomegranate consistently produces a small blood pressure reduction of a few mmHg in pooled trials.
Cocoa flavanols reliably improve endothelial function and shave a couple of mmHg off blood pressure.
Grape seed extract produces a small, fairly reproducible drop in systolic blood pressure and improves endothelial function.
Berberine genuinely lowers blood glucose and LDL cholesterol, with effect sizes in the same range as low-dose metformin — but almost all trials are small, short and from a single region, and the methodological quality is poor.
Alpha-lipoic acid has genuine, replicated evidence for reducing the symptoms of diabetic peripheral neuropathy at 600 mg/day, where it is an approved treatment in some countries.
One of the better-studied flavonoids, with a small but real blood-pressure-lowering effect at doses above 500 mg/day.
Oral aloe vera gel produces small but fairly consistent reductions in fasting glucose and HbA1c in prediabetes and untreated type 2 diabetes, though the trials are small and low quality.
Benfotiamine is a fat-soluble thiamine derivative that genuinely reaches the bloodstream far better than ordinary thiamine.
Propionyl-L-carnitine is a carnitine ester with better uptake into vascular and cardiac tissue than plain L-carnitine, studied mainly as a drug for peripheral arterial disease.
Re-esterified triglyceride omega-3 is absorbed better than the cheap ethyl ester form, so a given labelled dose raises blood levels more.
Jiaogulan (Gynostemma pentaphyllum) is the best-supported herb in this group: multiple small RCTs show modest improvements in blood lipids and blood glucose, likely via AMPK activation.
Mulberry leaf extract contains 1-deoxynojirimycin (DNJ), a genuine alpha-glucosidase inhibitor that blunts post-meal blood glucose spikes in controlled trials.
Salacia is an alpha-glucosidase inhibitor from South Asian traditional medicine with a genuine, reproducible effect on post-meal glucose and a small HbA1c benefit in randomised trials — roughly a 0.
Barberry trials in type 2 diabetes show real but modest glucose and lipid improvements — HbA1c down about 0.
Ruscus aculeatus root extract is a real venotonic with reasonable evidence for reducing leg heaviness, pain and swelling in chronic venous insufficiency.
Standardized horse chestnut seed extract (dosed by its aescin content) is one of the better-supported oral options for chronic venous insufficiency, with Cochrane finding consistent reductions in leg pain and leg volume.
Diosmin — usually sold as micronized purified flavonoid fraction (90% diosmin, 10% hesperidin) — has the largest trial base of any vein supplement and is a prescription medicine in much of Europe and Latin America.
Ubiquinol is the reduced form of CoQ10 and does raise blood CoQ10 more efficiently than plain ubiquinone powder — but well-formulated (solubilized) ubiquinone matches it, so the 2-3x price premium is often unjustified.
The active disulphide form of vitamin B5, with a genuine but modest LDL-lowering effect.
Unconcentrated whole fish oil from salmon.
The common supermarket cinnamon, sold standardised for blood sugar.
A leafy weed rich in alpha-linolenic acid, taken for blood sugar and cholesterol.
A water-soluble tomato concentrate that makes platelets less sticky.
A zero-calorie sweetener from Stevia rebaudiana.
Formulas built around plant sterols, soluble fibre and red yeast rice.
B6, B12 and folate combinations reliably lower homocysteine.
Flavonoid formulas for heavy, aching legs and varicose veins.
Dried okra pod or seed powder, whose viscous mucilage slows carbohydrate absorption.
A semi-synthetic hydroxyethyl derivative of the flavonoid rutin, used in Europe as a venoactive drug for chronic venous insufficiency.
Red vine leaf extract, standardised as AS 195, taken for heavy, aching, swollen legs.
A rare sugar with about 90 percent of the sweetness of sucrose but a much smaller glycaemic effect.
Limited evidence (71)
Niacin reliably raises HDL and lowers triglycerides, but two large outcome trials showed no reduction in cardiovascular events on top of statins — and real harm, including new-onset diabetes, infections and bleeding.
MK-7 reliably improves vitamin K biomarkers — it carboxylates osteocalcin and matrix Gla protein exactly as advertised.
Chromium picolinate is sold for blood sugar and weight loss on the strength of noisy, low-quality meta-analyses.
Vanadium salts genuinely mimic insulin in cell and animal models, but the human trials are tiny, mostly uncontrolled, and used doses roughly 10,000 times dietary intake with real toxicity.
Flaxseed oil is a concentrated source of ALA, a plant omega-3, but humans convert almost none of it to EPA and DHA.
Olive leaf extract shows small, inconsistent improvements in blood pressure and lipids across a thin set of mostly short trials — nowhere near the antiviral and immune claims made for it in marketing.
Small, unimpressive lipid effects — around 7 mg/dL off LDL in trials of mixed quality — and nothing controlled supporting the detox, immunity, or energy claims it's mostly sold on.
A genuinely nutrient-dense leaf whose supplement claims don't hold up: a 2025 GRADE-assessed meta-analysis found no consistent cardiometabolic benefit and rated the certainty of evidence as very low for every single outcome.
Bergamot polyphenols show promising cholesterol and glucose reductions, but almost all the positive data come from a small cluster of trials by overlapping research groups in one region.
Policosanol is a textbook case of results that only appear in one country.
Nattokinase is a fibrin-degrading enzyme from fermented soy with plausible mechanism and small positive trials, but the human evidence base is small, geographically narrow and short-term.
Cinnamon produces small reductions in fasting glucose in type 2 diabetes, but the effect on HbA1c — the outcome that actually matters — is inconsistent across meta-analyses.
Gymnema's most reliable effect is a curious one: its gymnemic acids temporarily switch off your ability to taste sweetness.
A Cochrane review found no significant glucose-lowering benefit for bitter melon versus placebo, and none versus metformin or glibenclamide.
A caffeinated polyphenol-rich tea with modest, inconsistent effects on blood lipids and no convincing weight-loss data.
The carotenoid behind the tomato-and-prostate story, where the intervention trials have been consistently negative.
Apple cider vinegar reliably blunts the glucose spike after a carbohydrate meal, but the long-term trials behind the health claims are small, short and low quality, and the weight-loss claims in particular are not supported.
A standardized celery seed extract lowered blood pressure substantially in a small crossover trial, but essentially all the human data come from one research team.
Tocotrienols are the less-studied half of the vitamin E family, extracted from palm or annatto.
The story that K2 routes calcium into bone and away from arteries is a mechanistic hypothesis that has now been properly tested — and the two best randomised trials of vitamin D plus K2 found no slowing of arterial or valve calcification.
Marketed as the "heart" magnesium on the strength of a 1996 hypothesis paper, not trial data.
Sold on one striking heart-failure trial from 2009 that has never been replicated, and delivers very little actual magnesium per capsule.
Omega-3 gummies typically deliver 50-150 mg of EPA+DHA per serving versus the 1-4 g used in cardiovascular and triglyceride trials — the fatty acid works, but this format usually does not deliver enough of it, and the manufacturing process is hard on a fragile oil.
Panax notoginseng (san qi, tienchi) is a distinct species from Asian ginseng with a different saponin profile and a genuinely different use: it is given as an injectable stroke drug in China (Xuesaitong) with a large but low-quality trial base.
Eucommia ulmoides bark (du zhong) has one small clinical trial showing a modest blood pressure reduction, and essentially nothing else in humans.
Arjuna bark is the classic Ayurvedic heart herb, and it is well tolerated, but the best-designed trial to date failed its primary endpoint in heart failure.
Guggul is the textbook case of an herb that looked good in early Indian trials and then failed in the West: a JAMA-published RCT found guggulipid raised LDL cholesterol rather than lowering it.
Banaba leaf standardized to corosolic acid produces short-term reductions in blood glucose in small human studies, but the trials are tiny, mostly industry-run and decades old, with no HbA1c-level evidence.
A bitter Brazilian herb (Baccharis trimera) sold for liver detox, blood sugar, and weight loss with zero human randomized trials behind any of those claims.
Marketed as 'vegetable insulin,' Bauhinia forficata has one clearly negative trial of the traditional tea and one positive trial of a standardized 300 mg extract.
A Peruvian seed oil around half alpha-linolenic acid, with two small human trials showing modest improvements in cholesterol and blood pressure.
A delphinidin-rich Chilean berry with a real, replicated acute effect on post-meal glucose and the most consistent signal in dry eye — but chronic cardiometabolic effects are inconsistent and most trials are small and funded by the extract's manufacturer.
Chokeberry is one of the most anthocyanin-dense fruits known, but the most rigorous meta-analysis to date — 10 RCTs, 666 participants, with trial sequential analysis — found no significant effect on blood pressure, lipids, glucose or body weight, at very low certainty.
Baobab fruit pulp is roughly half dietary fibre and does blunt the glucose rise from starchy meals in small acute trials — a real but modest fibre-and-polyphenol effect.
Theaflavins are the pigments that make black tea black, sold as a liver-friendlier alternative to high-dose EGCG for cholesterol.
Hesperidin is the main flavanone in oranges and the junior partner in most vein formulas.
The rutin in supplement bottles is not the rutin in the studies.
Theobromine, the main methylxanthine in cocoa, is marketed as a smooth, jitter-free caffeine alternative.
Dihydroberberine is a reduced berberine derivative that genuinely reaches the bloodstream better than berberine HCl — but the only human trial testing whether that translates into better glucose control found it did not.
Nopal (Opuntia ficus-indica) is a genuinely nutritious food whose soluble fiber modestly binds dietary fat and blunts glucose, but supplement-dose extracts produce small and inconsistent effects.
These multi-ingredient capsules stack six to fifteen botanicals and minerals, but almost all of them are dosed well below what the underlying trials used.
Lumbrokinase is a group of fibrinolytic enzymes from earthworms, used as a prescription-grade drug in China with a real but low-quality trial base in ischemic stroke.
Omega 3-6-9 blends solve a problem almost nobody has: omega-6 and omega-9 are abundant in any normal diet, and the blends dilute the only fraction with real evidence — EPA and DHA.
A traditional Chinese root used for angina and circulation.
A traditional Chinese root used for headache and blood flow.
Marketed as a natural source of lovastatin and beta-glucans for cholesterol.
The bitter flavonoid of grapefruit.
A polymethoxyflavone from citrus peel with striking metabolic and circadian effects in mice.
The main lignan of sesame seed.
A mixture of ferulated plant sterols from rice bran oil.
Sold as niacin without the flush.
A plant oil about 60% alpha-linolenic acid, marketed as a vegan omega-3.
Squid-derived oil with a high DHA-to-EPA ratio.
The overlooked third marine omega-3, sitting between EPA and DHA.
A monounsaturated fat from sea buckthorn or anchovy, sold for inflammation and lipids.
The fruit of Panax ginseng, richer in ginsenoside Re than the root.
The culinary bay leaf tested as a blood sugar supplement.
A cooking oil high in linoleic acid, sold in capsules largely on the back of two small trials in postmenopausal women with diabetes.
ACE-inhibiting peptides from dried bonito fish, sold for blood pressure.
A sweetener from luo han guo, sweet because of its mogrosides.
Multi-ingredient formulas mixing herbs, magnesium and other nutrients.
Garlic slowly heat-aged until it turns dark and sweet, sold for cholesterol and antioxidant effects.
Ficus carica leaf, traditionally taken as a decoction for diabetes in Mediterranean folk medicine.
Guava leaf tea, approved in Japan as a food for specified health use for post-meal blood sugar.
Syzygium cumini fruit and seed powder, one of the best known Ayurvedic remedies for diabetes.
A methylated inositol found in carob and soy, proposed to act as an insulin second messenger.
An insoluble fibre from fungal cell walls (usually Aspergillus niger), marketed for oxidised LDL and cardiovascular risk.
Procyanidin-rich extracts from unripe apples, sold for cholesterol, body fat and muscle.
A plant oil high in alpha-linolenic acid, positioned as an alternative to flaxseed oil.
Oil from Echium plantagineum seeds, rich in stearidonic acid, a plant fatty acid that bypasses the rate-limiting step in EPA synthesis.
Blends combining Ginkgo biloba with nitric-oxide precursors such as L-arginine or L-citrulline, sold for cold hands, heavy legs and vascular health.
Comparison guides for this category
Fish oil, krill, cod liver, algae or flaxseed?
Psyllium, glucomannan, inulin, oat beta-glucan or acacia?
Glycinate, citrate, malate, threonate, oxide and more
Is the reduced form worth twice the price?
D3, D2, vegan D3, calcifediol, D3+K2 or infant drops?
L-carnitine, acetyl-L-carnitine, L-carnitine L-tartrate or propionyl-L-carnitine?
Fish oil, rTG concentrate, cod liver, krill, algae, salmon, calamari, DPA, gummies, kids' or prenatal?
Is the R isomer worth the higher price?
Vitamin K1, K2 as MK-7, or K2 as MK-4?
Alpha-tocopherol, mixed tocopherols or tocotrienols?
Thiamine, benfotiamine, TTFD or sulbutiamine?
Niacin, niacinamide or inositol hexanicotinate?
Plain vitamin B5, or the form with cholesterol data?
General potassium pills or the citrate salt?
Does the niacin-bound form beat the basic salts?
Myo-inositol, D-chiro-inositol or D-pinitol?
Is the better-absorbed form worth it?
Does the type of cinnamon matter?
Green tea extract, matcha, white, oolong, pu-erh or black tea theaflavins?
Panax ginseng root, American ginseng or ginseng berry extract?
Ground flaxseed, flaxseed oil or flax lignans?
L-arginine, arginine silicate or AAKG?
Plain rutin or the semi-synthetic hydroxyethylrutoside?
Whole spirulina powder or its isolated blue pigment?
Aged garlic extract, stabilised allicin or black garlic?
Berberine, chromium or apple cider vinegar?
Goals these supplements are ranked for
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An evidence-ranked guide to supplements for blood pressure: what lowers it, by roughly how much, and which popular products to skip.
An evidence-ranked guide to supplements for blood sugar: which ones measurably lower glucose, which only blunt post-meal spikes, and what…
An evidence-ranked guide to anti-inflammatory supplements: which ones move markers or joint pain, which suit specific conditions, and what…
Our verdict
For cholesterol, start with soluble fibre such as oat beta-glucan, or with plant sterols, which reliably lower LDL; red yeast rice works too, but it behaves like a statin drug, with the same risks. Be sceptical of any supplement offered as a replacement for medication, and remember that improving a marker is not the same as preventing heart attacks, as the homocysteine and cocoa trials showed.