Adipose tissue is not simply a storage depot for excess energy intake, it is also able to produce and release several substances with local (autocrine) and systemic (endocrine) actions. An up-to-date review of our knowledge in this area is given here. Several of the compounds deriving from adipose tissue have been shown to play a role in obesity-related health complications. The production of cytokines, such as Tumor Necrosis Factor-alpha (TNF-alpha), IL-6, and leptin, is implicated in the development of several disorders. Insulin resistance is one of the most clinically significant.