Several supplements have solid clinical evidence for modestly lowering blood pressure, with the strongest results seen for potassium, magnesium, omega-3 fatty acids, and coenzyme Q10. The reductions are real but moderate, typically in the range of 2 to 6 mmHg for systolic pressure. That may not sound like much, but even small drops at that level reduce the long-term risk of stroke and heart disease.
Potassium
Potassium is one of the most well-supported supplements for blood pressure. Doubling your potassium intake is associated with a reduction of about 4 to 8 mmHg in systolic blood pressure and 2.5 to 4 mmHg in diastolic pressure in people with hypertension. It works partly by helping your kidneys flush out more sodium and partly by relaxing blood vessel walls.
Most guidelines recommend getting potassium through food first, specifically by swapping processed snacks and sodas for fruits, vegetables, and their juices. Bananas, potatoes, spinach, and beans are all potassium-rich. Supplements are an option for people with hypertension who can’t get enough through diet alone, but potassium pills require some caution. If you take a class of blood pressure medications that already raise potassium levels (like ACE inhibitors or certain diuretics), adding potassium on top can push levels dangerously high. Blood work to check your levels is a reasonable step before starting.
Magnesium
Magnesium supplementation consistently lowers blood pressure by a modest but meaningful amount. A large meta-analysis of randomized trials found that magnesium reduces systolic pressure by 3 to 4 mmHg and diastolic by about 2.5 mmHg, with stronger effects at doses above 370 mg per day. Higher intakes, in the range of 500 to 1,000 mg daily, may reduce blood pressure by as much as 5.6/2.8 mmHg.
In one study of 48 people with mild hypertension, those who took 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. Effects tend to show up within about 8 weeks. Magnesium can also enhance the blood pressure-lowering effect of ACE inhibitors, so if you’re already on medication, let your prescriber know before adding it.
Omega-3 Fatty Acids (Fish Oil)
The omega-3 fats EPA and DHA, the kind found in fish oil, lower systolic blood pressure across a wide range of doses. For diastolic pressure, though, you need at least 2 grams per day of combined EPA and DHA to see a meaningful effect. At doses of 3 to 4 grams daily, trials show systolic reductions of about 3.9 mmHg and diastolic reductions of about 1.9 mmHg.
The strongest benefits appear in people with hypertension who are not already taking blood pressure medication. A standard over-the-counter fish oil capsule contains roughly 300 mg of combined EPA and DHA, so reaching 2 grams or more means taking several capsules daily or choosing a concentrated formula. Fatty fish like salmon, mackerel, and sardines are the food-based alternative, though reaching therapeutic doses through diet alone takes deliberate effort.
Coenzyme Q10 (CoQ10)
A 2025 meta-analysis of 45 randomized trials found that CoQ10 supplementation reduces systolic blood pressure by about 3.4 mmHg. The effect on diastolic pressure was not statistically significant. Interestingly, lower doses (under 200 mg per day) and longer treatment periods (more than 8 weeks) produced the greatest systolic reductions. CoQ10 has a favorable safety profile, making it a reasonable option for people looking for non-drug support, particularly those with mildly elevated systolic readings.
Beetroot Juice and Hibiscus Tea
Beetroot juice is rich in natural nitrates, which your body converts into nitric oxide, a molecule that relaxes and widens blood vessels. It’s one of the few food-based supplements with rapid, measurable effects on blood pressure, often within hours of a single dose, though sustained benefits require regular consumption.
Hibiscus tea (sometimes labeled “sour tea”) also has clinical support. In a trial of people with stage 1 hypertension, drinking two cups of hibiscus tea daily for one month produced significantly greater reductions in both systolic and diastolic blood pressure compared to lifestyle changes alone. It’s a low-risk option that can easily fit into a daily routine.
Aged Garlic Extract
Aged garlic extract, which is different from raw garlic or standard garlic supplements, has shown blood pressure-lowering effects in clinical trials. In one 12-week trial, people with treated but uncontrolled hypertension who took 1.2 grams of aged garlic extract daily saw significant drops in systolic blood pressure by weeks 4 and 12. The active compound is produced during the aging process, which is why raw garlic cloves don’t reliably produce the same result. Look for products that specify “aged garlic extract” on the label.
Vitamin C
Vitamin C at a dose of about 500 mg per day reduces systolic blood pressure by roughly 4.8 mmHg in people with hypertension, based on a meta-analysis of clinical trials lasting a median of 8 weeks. It did not significantly lower diastolic pressure. This puts it in a similar range to magnesium for systolic effects, though the evidence base is smaller.
Vitamin D: Only If You’re Deficient
Vitamin D is a special case. Supplementation does not lower blood pressure in people who already have adequate levels. But for people who are both vitamin D deficient and hypertensive, correcting that deficiency can produce meaningful reductions. More than 10 clinical trials have shown that daily vitamin D supplementation restores blood levels and significantly reduces blood pressure in this specific group. One trial found that 800 to 2,000 IU per day reduced systolic pressure by about 3 to 4 mmHg in deficient adults over 60. If your blood pressure is elevated and you haven’t had your vitamin D checked, it’s worth asking for a test. If your levels are already normal, adding more won’t help your blood pressure.
How Long Before You See Results
Most supplements take 4 to 12 weeks of consistent daily use before producing a stable, measurable change in blood pressure. Some, like aged garlic extract, show initial effects by week 4. L-arginine, an amino acid that helps produce nitric oxide, appears to reach its full effect within about 4 weeks, lowering systolic pressure by around 5.4 mmHg and diastolic by 2.7 mmHg in trials lasting 2 to 12 weeks. For magnesium, most trials run 8 weeks or longer. CoQ10 appears to work better with interventions lasting beyond 8 weeks.
Beetroot juice is the exception, producing acute effects within hours, though long-term daily intake is needed for lasting benefit. In general, if you’ve been taking a supplement consistently for three months without any change in your home blood pressure readings, it’s probably not doing much for you.
Combining Supplements With Medication
If you’re already on blood pressure medication, adding supplements that lower blood pressure further can sometimes push readings too low, causing dizziness or lightheadedness. Magnesium in particular can amplify the effect of ACE inhibitors. Potassium supplements paired with ACE inhibitors or potassium-sparing diuretics can raise blood potassium to unsafe levels. These aren’t reasons to avoid supplements entirely, but they are reasons to have your blood pressure and electrolytes checked periodically if you’re stacking supplements on top of prescription drugs.
No single supplement replaces medication for moderate or severe hypertension. Where supplements tend to be most useful is for people with mildly elevated blood pressure who want to avoid or delay medication, or for people on medication whose numbers are still slightly above target. In both cases, supplements work best alongside the basics: regular physical activity, reduced sodium intake, and maintaining a healthy weight.