Determining how pepper spray strength is calculated is a key factor when buying pepper spray. Due to the significant amount of misinformation that some manufacturers disseminate in order to get you to believe that their pepper spray is stronger than their competitors, RedHotPepperSpray's mission is to give you the straight unbiased answer.
The best universal measure of the overall “heat” of pepper spray can be determined by its Scoville Heat Unit rating, or SHU. This is a measure of the “hotness” of the pepper.