Low-field nuclear magnetic resonance-based stimulation: a physical framework and research agenda for deep-tissue, non-thermal biophysical interaction

Introduction Low-field nuclear magnetic resonance (NMR)-based stimulation is an emerging non-invasive biophysical approach for tissue modulation, penetrating deeper than optical or mechanical techniques. However, the mechanisms linking physical exposure to biological response remain unclear.Areas covered This review examines the physical principles of low-field NMR-based stimulation, focusing on cyclic adiabatic passage, longitudinal relaxation time (T1), and how field parameters and tissue relaxation properties may shape the distribution of the perturbation. Low-field NMR-based stimulation studies were identified in PubMed and Ovid/Embase from inception to 28 December 2025; other literature was identified through targeted searches and the authors’ domain knowledge. Clinical studies suggest a favorable safety profile and improvements in pain, function and quality of life in several musculoskeletal indications, although between-group superiority was inconsistent. Experimental studies indicate modulation of inflammatory signaling, mitochondrial function, metabolism and redox-sensitive pathways. Four mechanistic questions are emphasized: how relaxation-weighted perturbations reach intracellular signaling; how a spin-level perturbation could trigger biochemical change; what determines specificity; and how weak perturbations are amplified.Expert opinion Low-field NMR-based stimulation constitutes a physically definable exposure regime, but an NMR-specific biological transduction mechanism has not yet been established. Progress requires rigorously controlled, parameter-resolved experiments capable of supporting or rejecting resonance-specific interpretations.