Hair thinning/hair loss may occur in the first few months after bariatric surgery, as is true with any surgery.  After six months post-surgery, nutritional deficiencies (or excess) may be contributing to continued hair loss.  Please make sure that you are following the long-term vitamin and mineral supplement recommendations given to you by the dietitian.  Second, please make sure that you are following the guidelines for having your labs drawn after surgery to assess for deficiencies.  Last, make an appointment for evaluation.