He determined the mechanism for how vitamin D is synthesized in the skin, demonstrated the effects of aging, obesity, latitude, seasonal change, sunscreen use, skin pigmentation, and clothing on this vital cutaneous process. Dr. Holick has established global recommendations advising sunlight exposure as an integral source of vitamin D. He has helped increase awareness in the pediatric and medical communities regarding vitamin D deficiency pandemic, and its role in causing not only metabolic bone disease, and osteoporosis in adults, but increasing risk of children and adults developing common deadly cancers, schizophrenia, infectious diseases including TB and influenza, autoimmune diseases including type 1 diabetes and multiple sclerosis, type 2 diabetes, stroke and heart disease. He also observed the pregnant women who were vitamin D deficient were at increased risk for preeclampsia and requiring a C- section. Dr. Holick pioneered a novel treatment for psoriasis through translational research demonstrating that the active form of vitamin D could be used for the treatment of thishyperproliferative skin disorder. This treatment is considered to be the first line treatment for most patients with mild psoriasis.
He has authored more than 400 peer-reviewed publications, and written more than 200 review articles, as well as numerous book chapters. He has acted as editor and/or co-editor on 13 books, and has written The UV Advantage in 2004 and The Vitamin D Solution in 2010.