Substance P is your body’s way of communicating to you when and where you are experiencing pain.  Once you are aware of this pain, your natural instinct is to take an aspirin, acetaminophen, or NSAID, or even apply a topical product that contains high levels of menthol.  These products are designed simply to mask your pain.  They may work, but only temporarily.  The reason for this short term relief is because your body recognizes that the pain is masked and creates more communicators (Substance P) because your brain needs to get the message of pain.  This is why the first time you had a headache and took an aspirin it worked like a miracle, but as time went on you had to increase your dosage, or even upgrade to a more potent form, in order to achieve relief.  Since your body cannot dissipate Substance P naturally, it is up to you to reduce it and restore your natural pain threshold.  Applying Capsicum topically is the only scientifically proven way to achieve this!  Just a word of warning though, Capsicum is derived from chili peppers and can cause burning and severe skin irritation if used in high concentrations.