Acute spicy stimulation reduces laser-induced heat pain perception in healthy adults

Capsaicin, the pungent compound in chili peppers, can produce analgesia, yet the effects of acute oral spicy stimulation on pain perception are unclear. We tested its impact on laser-induced heat pain at high and low intensities and examined associations between habitual spicy-food behaviors and pain-related traits. In a within-subjects 2 (taste: spicy vs. non-spicy) × 2 (pain intensity: high vs. low) design, 48 healthy adults completed two sessions. In each session, participants held a chili- or water-based gelatin cube in the mouth for 5 min, then received 40 laser stimuli to the left hand (20 high, 20 low) and rated pain intensity and unpleasantness; they also completed questionnaires on spicy-food behaviors (preference, frequency, preferred spiciness) and pain perception (pain sensitivity, fear of pain). Spicy stimulation significantly reduced pain intensity and unpleasantness under high-pain conditions compared with non-spicy stimulation (both ps < .01), whereas no significant effects were observed under low-pain conditions (ps > .05). Higher spicy-food preference was associated with lower pain sensitivity and fear of pain. In conclusion, acute oral spicy stimulation produced an intensity-dependent analgesic effect that was evident under high-intensity pain but not low-intensity pain, relative to a non-spicy control. The associations between spicy-food habits and pain-related traits are correlational. Longitudinal or interventional studies are needed to establish causality and clarify underlying mechanisms. Together, these findings highlight the importance of stimulus intensity and individual differences when considering dietary-pain links. By bridging sensory, psychological, and cultural perspectives, this work deepens understanding of how dietary habits interact with pain perception and suggests potentially personalized, clinically relevant, culturally adapted approaches to pain modulation.