Vitamin D or the sunshine vitamin is formed in the body when the skin is exposed to the sunlight. However, too much exposure to sunlight can have adverse effects on health.
Therefore, the use of sunscreen has increased in order to protect against skin cancer and sunburns. But does the use of sunscreen interfere with the formation of vitamin D? This question has always been a matter of concern and people are still in two minds whether to use or not to use a sunscreen before stepping out in the sun.
What Does Research Have to Say About This?
Sunlight has 3 types of waves of ultraviolet (UV) light:
| Wave Type | Wavelength |
| Ultraviolet A (UVA) | 315- 399 nm |
| Ultraviolet B (UVB) | 280-314 nm |
| Ultraviolet C (UVC) | 100-279 nm |
Ultraviolet C (UVC) is not reached to the earth because it is absorbed by the ozone layer.
Ultraviolet B (UVB) is required for the synthesis of vitamin D.
Studies have reported that sunscreen with a high UVA protection factor enables higher vitamin D synthesis because it allows more transmission of UVB. Thus, more vitamin D can be produced. (1)
Research has found that daily use of sunscreen may not compromise the synthesis of vitamin D. It should be noted that application of a thin layer of sunscreen (less than 2 mg/cm²) on the skin may not interfere with the absorption of vitamin D. But applying a thick layer of sunscreen (more than 2 mg/cm²) can hinder vitamin D production by 99% because less ultraviolet B photons enter the skin. (2)
| Thin Layer | less than 2 mg/cm² |
| Thick Layer | more than 2 mg/cm² |
In addition to this, people who wear sunscreen plus totally cover their skin with clothing or by wearing hats and staying in the shade when outdoors are at a higher risk of developing vitamin D deficiency. Hence, wearing sunscreen may not be the culprit, but the liberal application of sunscreen and little or no exposure of the skin to the sunlight can do harm. (3)
| Sunscreen Application | Effects |
| Thin Layer (Uncovered Skin) | Negligible effects in Vitamin D Production |
| Thin Layer (Covered Skin) | Hinder Vitamin D Production |
| Thick Layer (Uncovered or covered Skin) | Hinder Vitamin D Production |
Fact: You can apply a thin layer of sunscreen to protect against sunburn.
Therefore, sunscreen with less than SPF 30 when applied optimally can protect the skin against sunburn as well as allow synthesis of vitamin D. (4)
