Jack3d is very popular (see these Jack3d Reviews) because it gives monstrous pumps and intense focus and stimulation in the gym (and on the sports field). Because it impresses its users so much, many people wonder about the side effects of Jack3d.

Thankfully, the side effects from the Jack3d Ingredients covered in "What is Jack3d?" (see this entire site - it has TONS of info!) are minimal.

The majority of Jack3d's side effects come from its caffeine. Jack 3d can cause nervousness, excitement, restlessness, insomnia, flushing, slight gastrointestinal bloating, muscle twitching, irritability, and irregular or rapid heart beat.

This is why we don’t EVER believe in using more than three scoops of Jack3d at a time - the above side effects typically happen when someone takes 300mg of caffeine or more at once, so don't do that.

Additionally, some people get some side effects from the 1,3 dimethylamylamine in Jack3d. This can cause headache, slight nausea, lightheadedness, “snippy” mood, and paranoia. However, there is not enough of this chemical for us to have seen much of this.

In conclusion, some people may see some side effects from Jack3d, especially if they are stimulant/caffeine sensitive. For those people, we recommend starting on 1/2 scoop, and moving up to 1 or 1.5 scoops.