QUALITY: Manufactured in the USA in a cGMP registered facility. Physician formulated and backed by Theralogix's Medical Advisory Board. TESTED AND CERTIFIED: Independently verified for content accuracy, purity, and freedom of contaminants through NSF International. Free from dyes, certified gluten-free, and vegetarian. OPTIMAL DOSING: Our vitamin D3 150 mcg (6,000 IU) tablets are recommended for restoring a very low vitamin D level. EVIDENCE-BASED: Numerous studies suggest that optimal vitamin D levels promote bone and heart health, immune and muscular function, and play many other roles in keeping us healthy.*. THE ESSENTIAL SUNSHINE VITAMIN: Thera-D vitamin D provides the same biologically active form of Vitamin D created in our bodies after direct sunlight exposure, without the risk of UVB’s.