Palmitoylethanolamide as a Supplement: The Importance of Dose-Dependent Effects for Improving Nervous Tissue Health in an In Vitro Model

Palmitoylethanolamide (PEA) is a highly lipophilic molecule with low solubility, making absorption difficult. Recent techniques like micronisation, ultra-micronisation and combining PEA with solvents have improved their bioavailability and stability. Our study analysed particle size differences and absorption kinetics using specific solvents (PEAΩ and PEA DynoΩ) over time (0.5 h–6 h) in a dose-dependent manner (200 mg–1800 mg). The results showed that PEAΩ and PEA DynoΩ achieved 82–63% absorption at 3 h, compared to 30–60% for micronised, ultra-micronised PEA and a commercial product, highlighting the optimal dose range of 300 mg–600 mg. In addition, a 3D model of the peripheral nerve was utilised to explain the efficacy after gut passage and support the most effective dose (300 mg or 600 mg) achieved at the gut level. PEAΩ and PEA DynoΩ, which are associated with better intestinal bioavailability compared to PEA-micronised, PEA ultra-micronised and a commercial product, have allowed not only a reduction in the inflammatory context but also an improvement of peripheral nerve well-being by increasing specific markers like MPZ (26–36% vs. 8–15%), p75 (25–32% vs. 13–16%) and NRG1 (22–29.5% vs. 11–14%). These results highlight the potential of advanced PEA formulations to overcome solubility challenges and maintain in vitro efficacy, modulating peripheral nerve well-being.