Additionally, niacin may also ameliorate MASLD by, on one side, inhibiting hepatic lipogenesis [29] and, on another, by reducing free fatty acid flux to the liver because of the inhibiting effect on adipose tissue lipolysis via the nicotinic acid-specific receptor GPR109A-mediated signaling pathway [29,33]. This evidence concerns the gene HCAR2 and metabolic dysfunction-associated steatotic liver disease.