Open Source Apothecary At Home / Heart and circulation

Heart failure and cardiac support: hawthorn, CoQ10 and the limits

Heart failure is a condition where the drugs save lives and the herbs do not. This page is mostly a warning.

remedy

Heart failure is managed with four drug classes that reduce mortality — an ACE inhibitor or ARB or ARNI, a beta-blocker, a mineralocorticoid receptor antagonist, and an SGLT2 inhibitor — plus diuretics for symptoms and devices in some patients. There is no herb that reduces mortality in heart failure, and there are several that make it worse.

Hawthorn has trials in heart failure showing improvement in symptoms and exercise tolerance in some pooled analyses, and no effect on mortality. It is used in Europe as an adjunct. The concern: hawthorn has vasodilator and positive inotropic activity, and it interacts with digoxin and with antihypertensives. Combining a vasodilating herb with heart-failure medication can cause symptomatic hypotension.

Coenzyme Q10. Statins reduce CoQ10 levels by inhibiting the same mevalonate pathway. Whether that translates into statin-associated muscle symptoms is a question with mixed trial results; some trials show a reduction in muscle pain, others do not. CoQ10 is safe and is not a treatment for heart failure, though one trial in heart failure showed a mortality signal that has not been consistently replicated.

Omega-3 and other supplements: mixed evidence, discussed on the cholesterol page.

What actually matters in heart failure. Taking the four drug classes at target dose, daily weight monitoring, fluid and salt management, and reporting changes early. A person with heart failure who adds a herbal diuretic or a sodium-containing preparation can destabilise themselves quickly.

The specific interactions to avoid. Anything that raises blood pressure (liquorice), anything that lowers potassium in someone on a loop diuretic (liquorice again), anything that interferes with digoxin (hawthorn, and several herbs that affect P-glycoprotein), and anything that adds to anticoagulation if on warfarin. Ephedra and other stimulants are absolutely contraindicated.

What the studies found

Preparation

The things that demonstrably work

• Take every prescribed heart-failure medicine at the dose prescribed. This is the treatment.
• Daily weight. Report a gain of 1 kg (2 lb) in a day or 2 kg (5 lb) in a week — that is fluid.
• Fluid and salt management as advised
• Daily gentle activity as tolerated and as advised by the cardiac team
• Flu vaccination and pneumococcal vaccination as advised

Hawthorn — only with a cardiologist's knowledge

• Standardised extract per label, if used at all
• Interacts with digoxin and antihypertensives. Do not add it silently.
• Does not reduce mortality

Coenzyme Q10 for statin muscle symptoms

• 100-200 mg daily; trials are mixed
• Safe; discuss with the prescriber, and report muscle pain properly rather than covering it

Do not use in heart failure without advice

• Liquorice (raises blood pressure, lowers potassium)
• Ephedra, ma huang and other stimulants — contraindicated
• Herbal diuretics
• Any product marketed as an "energy" or "metabolism" supplement

Cautions and interactions

• Do not self-manage heart failure with herbs. The mortality benefit is in the prescribed drugs.
• Liquorice is particularly dangerous in heart failure and with diuretics.
• Ephedra and stimulant herbs are contraindicated in cardiac disease.
• Hawthorn interacts with digoxin.
• Anything that raises or lowers potassium matters in heart failure — loop and thiazide diuretics plus potassium supplementation, or potassium-wasting liquorice, can both destabilise the patient.

When this is not a self-care problem — get help

• Sudden weight gain, worsening breathlessness (especially lying flat or waking at night), swollen ankles, or a new cough — urgent cardiac assessment.
• Chest pain, fainting, or breathlessness at rest — emergency care.

Known interactions

• Hawthorn + digoxin: interaction risk.
• Liquorice + diuretic + ACE inhibitor/ARB: potassium and blood pressure destabilisation.
• St John's wort + digoxin, warfarin, and many cardiac drugs: reduced levels through CYP3A4 and P-gp induction.

Related

• Blood pressure: the dietary interventions with real numbers
• Liquorice, glycyrrhizin, and the potassium it costs you
• Herb-drug interactions: the ones with numbers behind them
• Cholesterol: sterols, fibre, and the one that is a drug in disguise

Sources

1. Effects of coenzyme Q10 supplementation on myopathy in statin-treated patients: a systematic review and meta-analysis. Journal of nutritional science 2025; doi:10.1017/jns.2025.10043 PubMed 41158831
2. Efficacy and Safety of Omega-3 Fatty Acids in the Prevention of Cardiovascular Disease: A Systematic Review and Meta-analysis. Cardiovascular drugs and therapy 2024; doi:10.1152/ajpcell.00174.2012 PubMed 36103100
3. Medicine for chronic atrophic gastritis: a systematic review, meta- and network pharmacology analysis. Annals of medicine 2023; doi:10.1016/j.lfs.2022.120752 PubMed 38170849
4. Effects of coenzyme Q10 supplementation on statin-induced myopathy: a meta-analysis of randomized controlled trials. Irish journal of medical science 2022; doi:10.1093/eurheartj/ehv043 PubMed 33999383
5. Effect of Long-Term Marine ɷ-3 Fatty Acids Supplementation on the Risk of Atrial Fibrillation in Randomized Controlled Trials of Cardiovascular Outcomes: A Systematic Review and Meta-Analysis. Circulation 2021; doi:10.1161/CIRCULATIONAHA.121.055654 PubMed 34612056