Evaluation of the Clinical Efficacy of a Novel Palmitoylethanolamide–Equisetum arvense Supplement for the Management of Chronic Pain: Findings from a Prospective Clinical Trial

Background: Chronic pain represents a major therapeutic challenge due to the limited efficacy and tolerability of conventional pharmacological treatments. Equisetum arvense L., a medicinal plant with potent antioxidant properties, and palmitoylethanolamide (PEA), an endogenous fatty acid amide with well-established anti-inflammatory and analgesic effects, are increasingly recognised as promising nutraceutical agents. Methods: This prospective, single-centre clinical trial aimed to evaluate the efficacy and safety of a novel oral supplement (Assonal®PEA) combining 600 mg of PEA and 300 mg of Equisetum arvense L. in improving the reduction of pain and quality of life in patients with chronic pain, also obtaining information on the patient’s state of satisfaction after the treatment. Fifty patients suffering from chronic pain (low back pain and radiculopathy) for two months were enrolled and received the supplement over eight weeks in a tapered regimen (two tablets daily for two weeks, followed by one tablet daily). Results: Clinical outcomes were evaluated using validated instruments, including the Numeric Pain Rating Scale (NPRS), Verbal Rating Scale (VRS), Short-Form McGill Pain Questionnaire (SF-MPQ), Global Perceived Effect (GPE), and EuroQol-5D-5L. Results showed a significant decrease in pain intensity (NPRS: −3.8 points; VRS: −2.1 points; p < 0.0001), along with meaningful improvements in patient-perceived benefit, pain descriptors, and quality of life (EQ-5D-5L: +35%; p < 0.0001). Conclusions: These findings endorse the use of this novel PEA–Equisetum arvense formulation as a safe, well-tolerated, and potentially effective supplementary intervention for managing chronic pain. No adverse events were reported, and the overall response rate reached 94%.