Study of the Efficacy and Safety of Nicotinamide in Patients With Liver Fibrosis (NICOFIB)

The objective of this clinical trial, a pilot study, is to assess the impact of nicotinamide (NAM) on individuals with hepatic fibrosis. The main question it aims to answer is: \- To determine if the treatment with NAM is able to arrest, or even reduce, the hepatic fibrosis. In addition, we also want to study the effect of NAM on: * General parameters (weight, HOMA-IR, etc). * Adiposity distribution (liver and body). * Systemic inflammation. * Thermogenic capacity of adipose tissue. * Microbiota composition. Researchers will compare NAM to a placebo, to see if NAM can arrest or revert hepatic fibrosis and its associated effects. Participants will take either NAM or placebo. The dosage will be 1.2g/m2 NAM per day, for one year.