The Effect of Griffonia simplicifolia on Pain Intensity, Central and Peripheral Sensitization, and Pain Modulation in Healthy Volunteers-A Randomized, Double-Blinded, Placebo-Controlled Crossover Trial
Abstract
Background: The plant Griffonia simplicifolia is marketed as a dietary supplement; it is said to have antidepressant and sleep-promoting properties. Its main ingredient, 5-hydroxytryptophan (5-HTP), is the immediate precursor of serotonin and crosses the blood-brain barrier, thereby enhancing central serotonergic neurotransmission. Reduced serotonergic activity has been associated with affective disorders, sleep disturbances, and impaired central pain modulation. Despite this neurobiological rationale, evidence for analgesic efficacy remains limited. This study investigated the effects of Griffonia simplicifolia on peripheral and central sensitization and descending pain inhibition. Methods: In a randomized, double-blind, placebo-controlled crossover trial, 18 healthy volunteers underwent quantitative sensory testing (QST). Participants received 100 mg Griffonia simplicifolia orally once daily for 28 days or matching placebo. Sensory parameters were reassessed, followed by repetitive phasic heat application (RPHA) to induce short-term peripheral and central sensitization. After a 4-week washout period, participants crossed over to the alternate intervention. Results: A total of 17 participants completed the study. Griffonia simplicifolia showed no significant effect on acute pain perception after RPHA (β = -4.17; 95% CI -14.44 to 6.10; p = 0.401). The only significant difference was an increased distance of mechanical allodynia in the verum group (β = 0.82; 95% CI 0.05-1.59;…
How strong is the evidence?
Evidence Hub reads this as a randomized trial, done in people. Its evidence level is 3 of 5 (Moderate · trial / cohort / secondary analysis). Trials without a large randomized design, cohorts and secondary analyses give moderate evidence. Reported size: 18 participants or records.
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