uses JavaScript to provide the best possible experience for our content, but your browser has it disabled. Learn how to enable it here.



Certain supplements can cause decreases in blood pressure and should be used with caution if you already have low blood pressure. These are melatonin, arginine and large doses of magnesium. High doses of cannabidiol (CBD) can cause a modest decrease in blood pressure. Calcium may also cause a very small decrease in blood pressure. Preliminary studies have found black cohosh may lower blood pressure in animals, but it is unclear whether it has this effect in people.

There are also a number of supplements that have been shown to lower blood pressure in people with hypertension (high blood pressure). These include fish oil and omega-3 fatty acids, garlic, potassium, flaxseed, certain strains of probiotics, and green coffee bean extract.  While much of the evidence for these is focused on people with high blood pressure, they could potentially lower blood pressure in others. So, if you take one of these supplements and find your low blood pressure becomes even lower, try eliminating the supplement and see if your blood pressure improves.

Note that sexual enhancement supplements with undeclared drugs, such as sildenafil (Viagra) or tadalafil (Cialis) may also lower blood pressure (see the list of Recalls and Warnings for supplements found to contain these drugs).

For more about using these supplements, including the evidence, potential side effects, and our tests of products, use on the links above.

Join today to unlock all member benefits including full access to all CL Answers and over 1,300 reviews.

Join Now

Join now at


Join the conversation

December 17, 2014

What is considered large doses of magnesium?
Lea R
January 1, 2015

Hi Lea - The Tolerable Upper Intake Level for magnesium for adults is 350 mg daily, although doses from 200 mg to 600 mg have been used when taken for a specific purpose.
You can read more about this in the Magnesium Supplements Review:

Join today to unlock all member benefits including full access to CL Answers

Join Now

Join now at