The safety of sunscreens has come into question. One concern is the sun's role in activating the body's vitamin D metabolism. Vitamin D is necessary to keep bones strong. The question is whether sunscreens inhibit the metabolism of vitamin D by blocking the sun's rays. In North America vitamin D is present as an additive in many foods. In addition, the amount of sun required to activate its metabolism is minimal less than one hour of sun exposure per week to an area of the body as small as the palm of the hand. Even the most diligent users of sunscreen are likely to receive this amount of exposure on a weekly basis.

High SPF sunscreens have come into question recently because of the diminishing returns they provide as the SPF increases along with the potential problems that may be associated with them. The effectiveness of sunscreens dramatically increases from 45% blockage of UVB rays with SPF of 2 to 90% with an SPF of 10. The effectiveness tapers off to only an additional 5% UVB, blockage with an SPF of 25 (95% effective) and little or no difference as one moves into sunscreens with sun protection factors of 30 to 40.

Sunscreens that contain the PABA ester called padimate 0 (octyl dimethyl PABA) contain very tiny amounts of nitrosamme. Varieties of this nitrosamine have been found to be carcinogenic in animal studies. PABA type nitrosamines, however, have not been used in these studies and absorption of sunscreens into the skin is minimal. Given these facts, it is unlikely the small amount of nitrosamine present in the sunscreen will do any harm. On the other hand, there is no real benefit in using higher concentrations of sunscreen with padimate 0, such as an SPF of 40.

Allergic reactions can occur when applying any substance on the skin. Because the high numbered SPF sunscreens contain higher concentrations of active ingredients, irritation and/or allergic reactions are more likely to occur.

It is important to balance the issue of safety with the benefits offered by high SPF sunscreens. Remember, ultraviolet radiation is unhealthy and the more you protect yourself from it, the better off you will be in the long run. A sunscreen with an SPF of 15 which contains ingredients to protect against UVB and UVA radiation such as Ombrelle 15 is your best choice.