Natural deep eutectic solvents (NADES) are recently developed green solvents that are attractive for their great solubilising power and intrinsic lack of toxicity. In this paper we report the results of a study on the feasibility and benefits of dissolving the poorly water-soluble salsalate in a NADES composed of 1,2-propanediol–choline–water as an alternative to DMSO for functional in vitro assays. The increase in solubility allows an extension of the range of the dose-response curve of salsalate-induced activation of brown adipocytes.