This is a feasibility interventional study seeking to determine the safety and efficacy of the Solius Photobiologic System in increasing the serum levels of 25(OH)D in a vitamin D deficient/insufficient adult population.

The investigators will conduct an interventional study to determine the changes in the changes in serum 25-hydroxyvitamin D levels between subjects who receive weekly exposures to Ultraviolet B Radiation (UVB) generated by the Solius Photobiological System for 4 weeks. Subjects will first undergo an evaluation of each individual's sensitivity to the Solius Photobiological System UVB using the device titration system for the first 5 weeks. Once determined after the 5 weeks, the subjects will be enrolled in a 4-week study where they will be exposed to their individualized titration evaluation. Approximately 14 adult participants will be enrolled for serum 25-hydroxyvitamin D screening. The investigators expect to enroll 10 vitamin D-deficient or insufficient subjects in this study. Serum 25-hydroxyvitamin D levels will be measured prior to the first titration (week 2), prior to the intervention (week 6) and after the end of the study, and and the changes in serum 25-hydroxyvitamin D levels will be analyzed. The investigators expect that the levels will increase from the baseline.

Inclusion Criteria:

1. Age at least 22 years old
2. Male or Female
3. Skin Type I-VI
4. Women of childbearing potential must be on birth control and not pregnant based on a negative pregnancy test at baseline.
5. Ability and Willingness to give informed consent and comply to protocol requirements
6. Serum total 25(OH)D < 30 ng/mL

Exclusion Criteria:

1. Ongoing treatment with supplemental or pharmacological doses of vitamin D, vitamin D metabolites or analogues
2. Pregnant
3. History of underlying photosensitivity
4. Use of medications that cause a photosensitivity reaction (including but not limited to): tetracycline, tretinoin, amiodarone, doxycycline, naproxen, diphenhydramine, methotrexate, and hydrochlorothiazide
5. History of skin cancer
6. Plan to received significant sun exposure below the 33rd parallel during study
7. Used tanning or phototherapy devices within the last 30 days
8. Vitamin D supplement use of more than 600 IUs daily.
9. Systemic steroids use
10. H1 antihistamine use in the last 7 days
11. Diagnosed with light allergies (including but not limited to): actinic prurigo, polymorphous light eruption, or solar urticaria
12. Diagnosed with light sensitivities (including but not limited to): protoporphyria, photodermatitis, xeroderma pigmentosum, lupus erythematosus, chronic actinic dermatitis, or UV-sensitive syndrome

9 weeks