Health Canada's Radiation Emitting Devices (RED) Act provides exposure time guidelines for sunbed use. These guidelines are intended to protect sunbed users from overexposure to UV radiation. Overexposure is defined as "exposure that exceeds the amount needed for vitamin D production and could lead to skin or eye damage. Acute overexposure induces sunburn." However, the effect of the recommended time exposure schedule on serum 25(OH)D response has not been characterized. Further, it is unknown if the maximum time exposures are required to reach and/or maintain optimal 25(OH)D levels. The aim of the current study is to characterize serum 25(OH)D response to regular sunbed use following the time exposure schedule recommended by Health Canada.

Inclusion Criteria:

• 18 years and older, male or female

Exclusion Criteria:

• History of skin cancer, granulomatous disease, liver disease, or kidney disease
• Photosensitive medications
• Pregnancy
• Vitamin D supplementation within last 60 days
• Sunbed use within last 60 days
• Planned travel to sunny destination during study period (January to April 2014)