The difference between vitamins B1 and B2 is mainly in terms of chemical structure, function and different symptoms in case of deficiency. 1. Different chemical structure: Vitamin B1 is also known as thiamin and vitamin B2 is also known as riboflavin. 2. Different functions: Vitamin B1 can promote the development of the nervous system and brain development, and can be used in the treatment of neuritis. Vitamin B2 is mainly involved in the oxidation of substances and energy metabolism, and promotes the development of skin, hair and nails. 3. The symptoms of deficiency are different: lack of vitamin B1 is prone to athlete’s foot, sometimes accompanied by fatigue and loss of appetite and other symptoms. Vitamin B2 deficiency can lead to dermatitis and mouth ulcers. The common point of vitamin B1 and B2 is that they belong to the B vitamins and are water-soluble vitamins.