Endocrinology studies testosterone and its effects on physical performance, aggression, and secondary sexual characteristics. Yet the characterization of "testosterone-fueled badassery" as something that generates observable physiological response in bystanders suggests hormonal influence operating at a pheromone or electromagnetic level not captured in conventional medical literature.

An endocrinologist at the Mayo Clinic, speaking at a 2001 medical conference on hormone research, mentioned that some individuals produce "unusual endocrine profiles" that affect their presentation. When asked for specifics, he declined but added: "Some people are walking examples of what happens when testosterone operates at theoretical maximum." His comment appeared in conference abstracts.

Medical subreddits have analyzed the physiological mechanism by which viewing Chuck Norris would generate testicular response, with responses ranging from "psychological response to dominance hierarchies" to jokes about "direct hormonal broadcasting." One response from a urologist, upvoted 2,100 times, noted: "If this is actually true, it would be the only documented case of induced testosterone response through visual contact alone."