The Difference Between Chemical and Physical Sunscreens

One of the most important products to have in your skincare arsenal is a good sunscreen. While sunscreen should be applied year-round, as the weather starts to warm up it’s worthwhile revisiting the fundamentals of sunscreen to make sure you’re using the right product for your skin. Sunscreen is formulated to protect your skin from the damaging effects of the sun. However, as sunscreens may differ, it can be useful to know the basics, particularly when it comes to physical and chemical sunscreens. Exposure to UV rays can have numerous negative effects on your skin, from irritation and premature ageing, to skin cancer [1]. Living in a country with one of the highest rates of skin cancer in the world, it’s critical to ensure you’re protecting yourself with a product that’s best suited to your skin.

What is chemical sunscreen?

Chemical sunscreens are formulated using chemical compounds that penetrate the skin to absorb sun rays, which are then converted into heat before being released from the body.

Chemical sunscreens are often formulated to be lightweight, long-wearing, and water-resistant, making them ideal for people who participate in physical activities like playing sport, sweating a lot during the day, or swimming.

What is physical sunscreen?

As the name suggests, physical sunscreens act as a physical barrier between your skin and the sun. Rather than absorbing into the skin like their chemical counterparts, physical sunscreens sit on the surface of the skin and reflect the sun’s rays. Physical sunscreens are broad-spectrum, protecting against both UVA and UVB rays. Their formulations are often more natural, making them great for sensitive skin. However, due to the consistency of the product, people with oily- or breakout-prone skin may find it a little heavy.

Ingredients found in chemical sunscreen

As single chemicals tend not to be broad-spectrum, meaning they only protect against either UVA or UVB rays, chemical sunscreens are often formulated using a mixture of ingredients to optimize UV defence. Common ingredients found in chemical sunscreens include ecamsule, bemotrizinol, octyl methoxycinnamate [2]. Antioxidants are also frequently found in chemical sunscreens, helping to provide additional protection against photodamage from exposure to environmental pollutants and UV radiation [3].

Ingredients found in physical sunscreen

Physical sunscreens, also known as mineral or natural sunscreens, comprise active mineral ingredients like titanium dioxide and zinc oxide that create a physical barrier to reflect sun rays from the skin. [4]

Pros and cons of chemical and physical sunscreen

Physical sunscreens are often less irritating, making them perfect for those with sensitive skin. However, they can be thick and heavy, which isn’t ideal for those with oily and breakout-prone skin. Due to the presence of zinc oxide, the product can sometimes leave a white cast on the surface of the skin, but with ever-evolving nanotechnology, the formulas are constantly improving and becoming more sheer.

As for chemical sunscreens, the ingredients can cause issues for those with sensitive complexions and skin conditions. Chemical sunscreens tend to be more durable, making them perfect for a day at the beach.

What to look for when choosing sunscreen

As always, different products work for different skin types, so it may take a little trial and error to find what works best for you. Before using a product, we recommend doing a patch test to avoid any major reactions.

To keep things simple, here’s a list of the key points to look out for when shopping for sunscreen:

Broad spectrum (UVA and UVB protection)
Fragrance-free
Non-comedogenic/ won’t block your pores
Oil-free
Paraben-free
SPF 30 or higher

Recommended sunscreen for different skin types

If you suffer from sensitive skin, or skin conditions such as dermatitis or eczema, physical sunscreens should provide you with a non-irritating formula. Chemical sunscreens are ideal for those who have blemish-prone skin, due to their lightweight formula. Luckily, Cetaphil offers a range of sunscreens that cater for both oily and sensitive skin types. The Cetaphil Sun SPF50+ Ultra-light Lotion offers broad-spectrum protection for up to four hours. This formula is suitable for everyday use and can be applied under your daily makeup. Alternatively, the Cetaphil UVA/UVB Defence SPF50+ conveniently combines hydration with UV protection in the form of a lightweight, daily moisturiser. If you’re after something for the kids, the Cetaphil Sun SPF50+ Kids Liposomal Lotion has been specially formulated for children’s sensitive skin.

Regardless of what product you use, sunscreen should be applied at least 15-20 minutes before exposure to the sun and reapplied regularly every two to four hours throughout the day.

ALWAYS READ THE LABEL. FOLLOW THE DIRECTIONS FOR USE. Limit sun exposure and use protective clothing, hats and eyewear. Keep out of eyes. Reapply sunscreen regularly.