Curcumin and Tetrahydrocurcumin as Multi-Organ Modulators of the Adipose Tissue–Gut–Liver Axis: Mechanistic Insights, Therapeutic Potential, and Translational Challenges

Obesity and its related disorders, such as type 2 diabetes mellitus (T2DM) and metabolic dysfunction-associated steatotic liver disease (MASLD), represent a worldwide health challenge, which is driven primarily by the dysfunction of the adipose tissue-gut-liver axis. This article compiles mechanistic and translational data on curcumin and its analogs as multi-organ regulators targeting this axis. Curcumin plays a pleiotropic role by modulating adipogenesis, lipid metabolism, inflammation, fibrosis, and thermogenic remodeling in adipose tissue, tailoring gut microbial diversity, gut barrier integrity, and metabolic endotoxemia. Curcumin in the liver attenuates steatosis, oxidation, and fibrosis by inhibiting lipogenesis, increasing β-oxidation, and modulating the NF-κB and TGF-β signal pathways. These actions result in overall systemic insulin sensitivity and energy balance. On the contrary, the clinical application of curcumin is restricted due to its low solubility, instability, and poor bioavailability. New formulations (nanoparticles/liposomes/micelles) together with structurally enhanced analogs such as tetrahydrocurcumin and monocarbonyl analogs (C66, B2BrBC) exhibited superior pharmacokinetic and tissue-targeting properties in preclinical models. Pilot and randomized clinical trials suggest that curcumin supplementation enhances glucose and lipid metabolism, reduces liver fat content, and modulates inflammatory markers; however, results across studies remain heterogeneous. Large, high-quality multicenter trials using rigorously standardized, bioavailable curcumin formulations are still required to reliably establish the efficacy and safety of curcumin in metabolic diseases. Next steps involve comparing curcumin analogs, conducting multi-omics analyses to understand host-microbiota-organ crosstalk, and determining cooperative approaches with lifestyle and pharmacological interventions. Taken together, curcumin and its next-generation derivatives may offer a novel therapeutic approach to intervene in the adipose tissue-gut-liver axis for the treatment of obesity-related metabolic diseases.