What is the difference between chemical and physical sunscreens?

In the last five to ten years, living and practicing in Ballito as a general medical doctor (GP), I have seen a rise in the incidence of skin cancers. We can however, protect ourselves and our loved ones by making sure sun protection is incorporated in our daily routine.

It is a necessity for all skin types to protect daily with a dermatologically-approved sunblock.

2 types are available - chemical and physical. The main difference between chemical and physical sunscreens lies in the type of UV filters they use. Sunscreens reduce the deleterious effects of ultraviolet radiation (UVR) by absorbing, reflecting, or scattering photons. Ultraviolet radiation includes UVB, which is primarily responsible for sunburn and skin cancers, as well as UVA, which has been implicated in photoaging.

Chemical Sunscreens:

• Use organic UV filters with chemicals like oxybenzone, avobenzone, octinoxate, etc.

• These filters absorb UV radiation and convert it into a small amount of heat that is released from the skin

• Chemical sunscreens are easy to apply, absorb quickly into the skin, and often provide moisturizing benefits

• They primarily absorb UV radiation but may also reflect a small percentage of light

• Allergic reactions are rare, especially with newer filters

• Photostability varies depending on the specific chemicals used

• Offer protection against both UVA and UVB rays but may break down when exposed to the sun, requiring regular reapplication

  
  

Physical (Mineral) Sunscreens:

• Use inorganic UV filters like zinc oxide and titanium dioxide

• These filters sit on the surface of the skin and reflect, scatter and absorb UV radiation

• Older formulas left a thick white residue but modern micronized particles provide a cosmetically elegant finish

• Allergic reactions to zinc oxide and titanium dioxide are unlikely

• Provide immediate protection upon application with no need to wait

• May rub off more easily when towel drying

• Regular reapplication is advised, especially after swimming or heavy sweating.

Tailor made solutions

Both chemical and physical sunscreens are effective at protecting against UV damage when used correctly. My choice between them often comes down to personal preference, skin type, and any sensitivities. Many modern sunscreens combine both chemical and physical filters for broad spectrum protection. My team and I are always available to assist in choosing the correct sunblock for your skin needs and skin type. Let's win this battle against skin cancer by being pro-active with our sun protection.