Source Naturals Acidophilus is a specially cultured strain of viable, freeze-dried Lactobacillus acidophilus. The body relies on "friendly flora" residing in the intestines for internal protection against putrifactive yeasts and bacteria, which can secrete toxins and hoard vital nutrients. Acidophilus supports colon health by altering the microflora ecology and favoring "friendly" flora. It also manufactures some B-vitamins, especially folic acid.Source Naturals Acetyl L-Carnitine & Alpha Lipoic Acid contains two critical nutrients, acetyl l-carnitine and alpha-lipoic acid, to support your vital metabolic functions. These compounds support the body s own system for the maintenance of cell function as we age.