What are the Rapid Burn Keto Side Effects? As we all know that the Rapid Burn Keto s made of natural materials and this product should not have any side effects. Of course, the user needs to be careful with any new supplements you take. It also contains 1 or 1 vitamin D pill from your local drug store. Just notice how it feel and stop using it if it makes you feel more uncomfortable. But again we do not think that you will have a problem.