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Trainer Talk

Oleoresin Capsicum— The Science Behind Pepper Spray

Oleoresin Capsicum— The Science Behind Pepper Spray


Oleoresin Capsicum (OC), commonly known as “pepper spray,” is a highly inflammatory, oil-based extract from chili pepper plants in the genus Capsicum. Capsaicinoids—most notably capsaicin (pronounced cap-SAY-sin)—are the compounds that provide the pungency and “heat” of the pepper, and these are the basis of OC chemical irritants.

Background and “metrics”

In 1912, Wilbur Scoville, while working at the Parke-Davis pharmaceutical company, devised a standard for measuring the spiciness of chili peppers, using human testers. His measurement system became known as Scoville Heat Units (SHU). On the Scoville scale, pure capsaicin has a rating of 16 million SHU. To put this heat rating into perspective, popular hot sauces have a Scoville rating between 700 and 2500 SHU—meaning these condiments actually have a minuscule percentage of capsaicin. Pain relieving creams, many of which also use capsaicin, typically contain 0.1% or less of this active chemical in their formulas.

By contrast, modern law enforcement OC (and the highest potency personal self defense sprays) measure 1.33 percent major capsaicinoids, with an SHU rating of 2 million. The amount of capsaicin in the product is what determines the "intensity" of the formulation. In other words, the higher the percentage, the longer the recovery time.

Effects of OC exposure

Direct exposure to OC results in a painful burning sensation of the skin and mucous membranes. It causes stinging, redness and an involuntary closing of the eyes. OC can also cause a variety of immediate but temporary respiratory symptoms, which could be coughing, gagging and an inability to speak. OC has the potential to work quickly, but full effect can take approximately 30-45 seconds. Effects can last from 30-45 minutes, depending on the individual and any decontamination procedures used.


The best way to minimize and shorten the effects of direct or indirect OC exposure is to flush the eyes with cool water, and remain in a well-ventilated area, whether indoors or out. Washing affected areas with a mild, unscented dishwashing soap can help break down the OC resin and speed recovery time. Never “rub” the eyes—this can cause damage to the cornea.

Law enforcement vs. civilian use of OC spray

Most every law enforcement agency and officer uses some form of pepper spray. It has proven effective for crowd control, and against resistive arrestees. While there are far too many variables to list, the goal for officers using OC is to gain control. In a civilian setting, however, the primary goal of using OC spray is to disengage—to provide a means of escape from an attack or potentially dangerous situation. The same tool, used in two entirely different settings, accomplishes the “3 Ds” of defensive tactics:

• Distract: The painful burning sensation and involuntary closing of the eyes can divert the focus, attention and intention of an attacker.

• Disorient: OC exposure can confuse an attacker's sense of movement, positioning or surroundings. The subject’s focus on pain can allow am office the opportunity to gain control, or the civilian a chance to escape.

• Disable: A direct result of inhalation of the spray is coughing, gagging and shortness of breath which can temporarily weaken and limit an attacker's physical movement or actions.

Note that while OC does not affect everyone the same, a 2018 study by the Wake Forest University School of Medicine concluded that pepper spray reduces aggressive behavior by up to 90% on average. Also consider that OC devices employing a cone-shaped mist pattern (as opposed to streams or gels) can accelerate the respiratory effects. ASP’s Defender OC products employ this type of spray pattern.


As with all defense and control skills, success with OC depends on effective training. Such training should incorporate understanding of principles, proper use of the tools, and body mechanics. Finally, in the LE realm, OC—like all of our tools—is just one element in the use of force. Effectiveness and safety in a potentially dangerous situation is not just a matter of having the right equipment. All of your skills come to bear in confrontations with resistive and combative subjects.

Jim Klauba

Chicago Police Department (Ret.)

ASP Trainer since 2011