The model of obesity induced by monosodium glutamate cytotoxicity on the hypothalamic nuclei is widely used in the literature. However, MSG promotes persistent muscle changes and there is a significant lack of studies that seek to elucidate the mechanisms by which damage refractory to reversal is established. This study aimed to investigate the early and chronic effects of MSG induction of obesity upon systemic and muscular parameters of Wistar rats. The animals were exposed to MSG subcutaneously (4 mg·g⁻¹ b.w.) or saline (1.25 mg·g⁻¹ b.w.) daily from PND01 to PND05 (n = 24). Afterwards, in PND15, 12 animals were euthanized to determine the plasma and inflammatory profile and to assess muscle damage. In PND142, the remaining animals were euthanized, and samples for histological and biochemical analyses were obtained. Our results suggest that early exposure to MSG reduced growth, increased adiposity, and inducted hyperinsulinemia and a pro-inflammatory scenario. In adulthood, the following were observed: peripheral insulin resistance, increased fibrosis, oxidative distress, and a reduction in muscle mass, oxidative capacity, and neuromuscular junctions, increased fibrosis, and oxidative distress. Thus, we can conclude that the condition found in adult life and the difficulty restoring in the muscle profile is related to the metabolic damage established early on.

Omega-3 and omega-6 fatty acids play essential roles in human health, being widely used in the prevention and treatment of various conditions, such as cardiovascular diseases, inflammation, and metabolic disorders. However, their oral administration faces significant challenges, including low solubility, rapid oxidation, and low bioavailability, which limit their therapeutic efficacy. This article explores recent advances in oral drug delivery systems designed for polyunsaturated fatty acids, highlighting how innovative technologies, such as nanoemulsions, liposomes, microencapsulation, and solid lipid nanoparticles (SLNs/NLCs), can improve their stability, absorption and clinical performance. In addition, the main natural sources of these compounds, as well as their extraction and purification methods, and the challenges related to their absorption and metabolism are discussed. This narrative review was based mainly on a comprehensive search of peer-reviewed literature published between 2015 and 2025 in PubMed, Scopus, and Web of Science. The therapeutic benefits of these emerging approaches are analyzed by comparing conventional methods with modern delivery strategies to optimize the use of omega-3 and omega-6 in the body. Finally, the article outlines future perspectives and regulatory challenges associated with these technologies, highlighting their potential to revolutionize the administration of essential fatty acids and broaden their applications in medicine and nutrition.