Several supplements have solid clinical evidence for modestly lowering blood pressure, with magnesium, potassium, omega-3 fatty acids, and CoQ10 showing the most consistent results. The reductions are real but modest, typically in the range of 2 to 6 mmHg for systolic pressure. That may not sound like much, but even small sustained drops in blood pressure reduce the long-term risk of heart attack and stroke.
Magnesium
Magnesium is one of the best-studied supplements for blood pressure. Doses between 500 mg and 1,000 mg per day have been shown to lower systolic blood pressure (the top number) by 2.7 to 5.6 mmHg and diastolic pressure (the bottom number) by 1.7 to 3.4 mmHg. The strongest results come from people who already have high blood pressure and who combine supplementation with lifestyle changes like exercise and better diet.
In one controlled trial of 48 people with mild hypertension, those taking 600 mg of magnesium daily alongside lifestyle changes saw their 24-hour blood pressure drop by 5.6/2.8 mmHg, compared to just 1.3/1.8 mmHg in the group making lifestyle changes alone. Most studies used supplementation periods of 8 weeks to 6 months. Magnesium oxide and magnesium aspartate are the forms most commonly tested, though magnesium citrate and glycinate are popular for their better absorption and fewer digestive side effects.
Potassium
Potassium works by helping your kidneys flush out excess sodium, which is one of the primary drivers of high blood pressure. The two minerals essentially compete: when potassium levels rise, your body excretes more sodium through urine, which relaxes blood vessel walls and lowers pressure. The 2025 high blood pressure guidelines from the American College of Cardiology recommend potassium supplementation for adults with elevated blood pressure or hypertension, ideally from dietary sources.
The adequate daily intake is 2,600 mg for women and 3,400 mg for men. Most people fall well short of that. Foods like bananas, potatoes, beans, spinach, and yogurt are rich sources. If you take blood pressure medications that affect potassium levels, particularly certain diuretics or ACE inhibitors, supplementing without medical guidance can push potassium too high, which creates its own serious risks. People with chronic kidney disease also need to be cautious, since impaired kidneys can’t clear excess potassium efficiently.
Omega-3 Fatty Acids
Fish oil supplements containing EPA and DHA, the two main omega-3 fatty acids, lower blood pressure in a dose-dependent way, but the sweet spot is higher than what most people take. A large meta-analysis of 71 trials found that the optimal dose is between 2 and 3 grams per day of combined EPA and DHA. At that range, systolic pressure dropped by about 2.6 mmHg and diastolic by about 1.7 mmHg.
That’s important context, because a standard fish oil capsule typically contains only 300 to 500 mg of combined EPA and DHA, meaning you’d need four to eight capsules daily to reach the effective range. Concentrated fish oil products make this more practical. The blood pressure benefits were stronger in people who already had high blood pressure, high cholesterol, or were older. Doses above 3 grams per day showed additional benefits in these higher-risk groups specifically.
CoQ10
Coenzyme Q10, often listed as CoQ10 on supplement labels, is a compound your body produces naturally that helps cells generate energy. Levels decline with age and with the use of statin medications. A systematic review of 29 trials found that CoQ10 supplementation lowered systolic blood pressure by an average of 4.77 mmHg in people with metabolic conditions like diabetes or high cholesterol. The effect on diastolic pressure was smaller and not statistically significant.
The dose-response relationship follows a U-shaped curve, meaning more isn’t better. The greatest reductions in systolic pressure occurred at 100 to 200 mg per day. Higher doses didn’t produce additional benefit. The strongest effects appeared in people with diabetes or abnormal cholesterol levels, suggesting CoQ10 may be particularly useful as a complement to treatment in those populations rather than as a standalone approach for otherwise healthy people.
Aged Garlic Extract
Garlic supplements, particularly aged garlic extract, have shown modest blood pressure benefits. In a triple-blind controlled trial of people with stage 1 hypertension who were already on blood pressure medication, 12 weeks of aged garlic extract reduced systolic pressure by about 1.8 mmHg and diastolic by 1.5 mmHg. These are small numbers, and the confidence intervals in the study were wide enough that individual responses varied considerably. Garlic extract is unlikely to move the needle meaningfully on its own, but it may contribute a small additional effect as part of a broader approach.
Supplements That Don’t Help
Vitamin D is frequently promoted for blood pressure, but the evidence doesn’t support it. A CDC-published meta-analysis of randomized controlled trials found essentially zero reduction in either systolic or diastolic blood pressure after vitamin D supplementation. The change in systolic pressure was literally 0.00 mmHg across pooled studies, and no subgroup showed a meaningful benefit. The one exception may be people who are severely deficient in vitamin D, where risk of hypertension rises sharply below a certain blood level. But correcting a deficiency is different from supplementing for blood pressure, and even that connection remains inconsistent in interventional studies.
Supplements That Can Raise Blood Pressure
Some herbal supplements actively work against you if you’re trying to lower blood pressure. Licorice root is a well-known offender that causes sodium retention and potassium loss. Ephedra (ma-huang), ginseng, guarana, and arnica can all raise blood pressure or interfere with how blood pressure medications work. If you’re taking any herbal products, it’s worth checking whether they’re on that list.
How Long Before You See Results
Dietary changes, particularly the DASH eating pattern rich in fruits, vegetables, and low-fat dairy, can lower blood pressure within the first week. Sodium reduction takes longer, with improvements continuing through at least four weeks and possibly beyond. Supplement trials typically run 8 to 12 weeks before measuring outcomes, and that’s a reasonable timeframe to expect before seeing changes on a home blood pressure monitor.
The reductions from any single supplement are modest. Magnesium might give you 3 to 5 points off your systolic reading. Omega-3s might contribute another 2 to 3. CoQ10 another 4 to 5 in the right population. These numbers add up, especially when combined with dietary potassium, sodium reduction, regular exercise, and weight management. For people with mildly elevated blood pressure, that combination can sometimes be enough to avoid medication. For those already on medication, supplements can complement the treatment but aren’t a replacement for it.