Summary: Phospha Muscle is a natural supplement designed to increase an individual’s testosterone levels to increase their fitness results. The product relies on two main ingredients to achieve muscle growth and post-workout recovery. Both of the ingredients have been scientifically tested, and the main ingredient is patented. The main ingredient has also proven its effectiveness through clinical trials. However, the effectiveness of the product hasn’t been studied for long term use of the supplement, so more trials need to take place.