MRI Black Powder Side Effects

Updated July 19, 2017

MRI's Black Powder is a popular pre-workout mix that weightlifters use to increase energy, focus and muscle pump, to reduce fatigue and to increase performance in the gym. However, Black Powder can also have side effects. Side effects typically come from one of three sources: caffeine/stimulants, magnesium and nitric oxide production. These can cause a rapid heartrate, nervousness, diarrhoea, a drop in blood pressure or vomiting.

Rapid Heartrate

Black Powder contains approximately 200 mg of caffeine, or about the equivalent of two cups of coffee per scoop. MRI recommends taking one scoop before a workout because of the caffeine and other stimulants it contains. According to Drug Information Online, those unaccustomed to products that contain caffeine may experience heart palpitations, dizziness, nervousness and irritability. Using the product within four hours of bedtime can also make it difficult to sleep. Depending on your sensitivity to stimulants, you may experience one or more of these side effects. These conditions typically lessen over time and continued use, because your body becomes more accustomed to the stimulants.


Because Black Powder contains magnesium oxide, it is possible to experience diarrhoea or simply an urge to go to the bathroom during your workout. Magnesium can be used on its own as a laxative; when it's included in a pre-workout drink, users can experience diarrhoea before or even during workouts.

Blood Pressure Drop

Black Powder increases nitric oxide production, which can lead to a drop in blood pressure as nitric oxide relaxes blood vessels. Nitric oxide gives you the pump bodybuilders strive for in the gym, and because blood is being pumped into your muscles during an intense workout, it is possible to become lightheaded or even to faint. It is also important to be careful that you don't cut yourself, because you may bleed more than usual due to the increase in blood flow.


Black Powder may also cause vomiting due to the combination of stimulants, increased nitric oxide and either the lack of a pre-workout meal or a poorly selected one. MRI recommends taking Black Powder on an empty stomach to enhance the nitric oxide effect. But doing this may cause you to vomit during your workout. This can also happen if you eat too close to your workout or select the wrong pre-workout meal. Typically, it's best to eat fast-digesting protein and slower-digesting carbohydrates 45 minutes to one hour pre-workout, according to "Muscle and Fitness" magazine.


Black Powder comes in three different flavours: fruit explosion, blue raspberry and orange burst. MRI recommends mixing one scoop with 236 to 473ml. of water. Because the company gives a range of liquid to mix the powder with, the strength of flavour will vary. Some people have reported that their dislike for the flavour can be enough to distract from their workout, if the taste continues to linger.

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About the Author

Based in Pittsburgh, Joseph Hanna has been writing professionally since 2009. He works in the health and fitness field and specializes in fitness and nutrition articles, writing for ehow and Answerbag. He also holds a Pennsylvania teaching certificate in English literature and composition. Hanna earned a Bachelor of Arts in communications and a master's degree in English education, both from Duquesne University.