Sunscreen Jargon Explained

Shopping for sunscreen can be confusing. There are so many terms and acronyms to consider that it can be difficult to keep track of what everything means. That’s why we’ve put together this handy guide to all the important sunscreen terminology you need to know.


SPF stands for Sun Protection Factor, and the number beside it indicates how well the sunscreen protects the skin against sunburn. 

It helps customers compare the level of sunburn protection provided by different sunscreens. For example, SPF 25 sunscreens provide more sunburn protection than SPF 8 sunscreens.

UVA Rays

Ultraviolet Radiation is what we commonly call sunlight.

UVA rays constitute 90-95% of the ultraviolet light reaching the earth.  They have a relatively long wavelength (320-400nm) and are not absorbed by the ozone layer. 

UVA light penetrates the furthest into the skin and is involved in the initial stages of suntanning.  UVA tends to suppress the immune function and is implicated in premature aging of the skin.

All forms of ultraviolet radiation are believed to contribute to the development of skin cancer. 

The UVA rays penetrate deeper into the skin and are strongly absorbed by the melanocytes which are involved both in melanin production (sun tanning) and in melanoma formation. 

UVA rays also have a depressing effect on the immune system.   

UVB Rays

UVB rays are partially absorbed by the ozone layer and have a medium wavelength (290-320 nm).  They do not penetrate the skin as far as the UVA rays do and are the primary cause of sunburn. 

They are also responsible for most of the tissue damage which results in wrinkles and aging of the skin and are implicated in cataract formation.

Sunlight is not all bad.  Most of the body’s vitamin D supply is generated by the skin’s exposure to UVB rays. Vitamin D helps regulate the amount of calcium and phosphate in the body and is needed to keep bones, teeth and muscles healthy.

Chemical and Physical Sunscreens

Broad spectrum sunscreens are designed to protect against sunburn  from UVB rays and damage from UVA rays. They come in two forms

Chemical Sunscreens – contain chemicals such as octylmethoxycinnamate as the active ingredient.  They prevent sunburn by absorbing the ultraviolet UVB rays.

Physical/mineral sunscreens – contain inert materials such and titanium dioxide and zinc oxide and work by reflecting the ultraviolet (UVA and UVB) rays away from the skin.

Reef Safe

This means that the ingredients used the in the product are not toxic to coral or any marine life in the coral reef ecosystem

Broad Spectrum

This means that the product protects the skin from ultraviolet radiation by absorbing or blocking both UVA and UVB rays

Mineral Sun Filter

This is a non-chemical, naturally occurring mineral ingredient, either zinc oxide or titanium dioxide, which protects the skin from the sun’s damaging UVA/UVB rays