UVB risks such as skin cancer and premature aging of the skin are directly related to local cumulative UVB exposure at a skin site over a person’s lifetime. UVB can be obtained from both artificial light sources and natural sunlight. Artificial light sources can include this UVB phototherapy unit and, to a lesser extent, cosmetic tanning machines (mainly UVA and very small amount of UVB – and even more dangerous for cancers and skin wrinkling). The UVB content of natural sunlight depends on many factors including the time of year (with June 21st being peak UVB for the northern hemisphere), time of day (with early afternoon being the daily maximum), geographic latitude (greater UVB towards the earth’s equator), altitude (greater UVB at higher elevations), and other environmental factors such as cloud cover. Natural sunlight typically results in greater cumulative UVB exposure on the face/head, lower arms, chest and shoulders/upper back.

Skin burning can be caused by excessive UVB exposure, and occurs when the minimum erythema dose (1 MED) has been exceeded. Skin cancer has been linked to skin burning (erythema), especially when the burns occur at a young age.

The only effective method to determine your Vitamin-D level is by Vitamin-D blood testing.

Considering the above, a reasonable strategy for safe and effective Vitamin-D phototherapy is to:

1. Follow all of the instructions provided.
2. “Generalize” (or “evenly distribute”) the UVB light, so all areas of the skin can contribute to making Vitamin-D in the skin, which lowers the UVB dose to any particular area while maximizing Vitamin-D production. Depending on the unit used, this usually requires more than one patient body position.
3. Exclude areas of skin that have received large cumulative doses of UVB in a person’s lifetime, or areas that were previously sunburned, such as possibly the face/head, lower arms, chest and shoulders/upper back. These areas should be protected by sunscreen or physically covered using clothing. Consider cutting away portions of clothing to expose certain areas, to protect the face/head when using a full body unit.
4. If within 24 hours a significant amount of UVB has been received from other sources, such as natural sunlight or a tanning machine (mainly UVA), skip phototherapy treatments or exclude affected areas from treatment.
5. Record the treatment time given to each skin area.
6. Take regular Vitamin-D blood tests, to find the lowest UVB dose and frequency necessary to maintain the desired Vitamin-D level.