Inclusion Criteria:  Age at least 22 years old Male or Female Skin Type I-VI Women of childbearing potential must be on birth control and not pregnant based on a negative pregnancy test at baseline. Ability and Willingness to give informed consent and comply to protocol requirements Serum total 25(OH)D < 30 ng/mL  Exclusion Criteria:  Ongoing treatment with supplemental or pharmacological doses of vitamin D, vitamin D metabolites or analogues Pregnant History of underlying photosensitivity Use of medications that cause a photosensitivity reaction (including but not limited to): tetracycline, tretinoin, amiodarone, doxycycline, naproxen, diphenhydramine, methotrexate, and hydrochlorothiazide History of skin cancer Plan to received significant sun exposure below the 33rd parallel during study Used tanning or phototherapy devices within the last 30 days Vitamin D supplement use of more than 600 IUs daily. Systemic steroids use H1 antihistamine use in the last 7 days Diagnosed with light allergies (including but not limited to): actinic prurigo, polymorphous light eruption, or solar urticaria Diagnosed with light sensitivities (including but not limited to): protoporphyria, photodermatitis, xeroderma pigmentosum, lupus erythematosus, chronic actinic dermatitis, or UV-sensitive syndrome