TB500 is a multifaceted peptide produced synthetically in the lab. It has the same structure and function with Thymosin Beta 4 which is produced by the thymus gland in the body . TB500 and  Thymosin Beta 4 both are composed of 43 amino acids in like sequence and have the same effects on healing and recovery. In short, TB500 is a synthetic version of Thymosin Beta 4. Therefore, we use both names interchangeably as all effects are identical.