Sun protection remains one of the cornerstones of any serious skincare regime. Ask any dermatologist what single step will make the biggest difference to preserving youthful skin, and the answer is almost universal: wear sunscreen, every single day, year round. But with so many formulations on the market, how does one choose? Understanding the difference between physical and chemical UV filters is a good place to start.
Two approaches, one goal
Pick up any sun protection product and chances are it will contain one of two types of UV filter, sometimes both. Physical filters (also known as mineral filters) and chemical filters (also known as organic filters) each take a fundamentally different approach to protecting skin from ultraviolet radiation.
Physical sunscreens work rather like a mirror. They create a protective barrier on top of the skin that reflects and scatters UV rays before they even penetrate. The active ingredients here are minerals such as zinc oxide and titanium dioxide. Think of it as a shield sitting on the skin’s surface, bouncing harmful rays away.
Chemical sunscreens, by contrast, function more like a sponge. They allow UV rays to enter the skin, then absorb them and convert them into heat, which is released harmlessly. Common active ingredients include avobenzone, octinoxate and oxybenzone. These compounds are organic in the chemistry sense of the word (containing carbon bonds), which has nothing whatsoever to do with organic supermarket produce.
Weighing up the pros and cons
Neither type is inherently superior. The choice often comes down to individual skin concerns and personal preference.
For sensitive or allergy prone skin, physical sunscreens tend to be the better option. Because they sit on top of the skin rather than being absorbed, they are far less likely to cause irritation or allergic reactions. They also start working the moment they are applied, which is a practical bonus for anyone who does not want to wait around before heading outdoors.
For congested or breakout prone skin, chemical formulations often prove more suitable. Their lighter textures are less likely to clog pores, making them a sensible choice for anyone battling acne. These products also tend to be more cosmetically elegant, blending seamlessly into the skin without the heavy, greasy feel that once characterised sun protection.
The traditional bugbear with physical sunscreens has been the dreaded white cast, particularly noticeable on darker skin tones. Happily, newer micronised formulations and tinted versions have largely solved this problem. Modern mineral sunscreens can look perfectly natural once applied.
One point worth noting: chemical sunscreens need around fifteen to twenty minutes to become effective after application. Physical sunscreens work immediately. For anyone prone to forgetting their morning routine until the last minute before leaving the house, this distinction matters.
The broader picture on broad spectrum
Physical filters generally offer more inherently broad spectrum protection, covering a wider range of both UVB and UVA wavelengths. However, well formulated chemical sunscreens can achieve equally comprehensive coverage by combining several different filters. Both types, when properly formulated and used as directed, provide effective broad spectrum protection.
The key word here is ‘properly formulated’. A good broad spectrum sunscreen should have a minimum 1:3 UVA to UVB protection ratio. Look for products with SPF 30 to 50 and a high UVA rating, whether the formulation relies on physical filters, chemical filters or a combination of both.
What sunscreen cannot do
Here is something that often gets overlooked in the sun protection conversation. Both physical and chemical UV filters protect against ultraviolet light only. That sounds comprehensive until one considers that UV accounts for just 10% of solar radiation. Infrared radiation makes up 50%, while visible light constitutes the remaining 40%.
Both infrared and visible light contribute to skin concerns including premature ageing and irregular pigmentation. Neither can be blocked by UV filters, regardless of how sophisticated the formulation.
This is where antioxidants come in. Applying a topical vitamin C serum underneath sunscreen creates an additional layer of defence, helping to neutralise free radicals generated by infrared and visible light. Even the best SPF 50 allows a small percentage of UV through. Antioxidants help mop up any residual damage that slips past the sun protection barrier.
SPF is SPF is SPF
A common question: is there any difference between a dedicated sunscreen labelled SPF 50 and a moisturiser with SPF 50? The short answer is no. SPF ratings are determined through standardised lab testing, so SPF 50 means SPF 50 regardless of what else the product claims to be. A day cream with SPF 50 offers the same level of protection as a product specifically marketed as sunscreen with the same rating. Use whichever formulation suits the skin better and fits more comfortably into the daily routine.
A final word on vitamin D
For anyone committed to wearing daily sun protection to preserve their complexion, there is one essential companion measure: supplementing with vitamin D. The skin synthesises this crucial vitamin when exposed to sunlight, and diligent sun protection can compromise natural production.
A vitamin D3 supplement of around 2,000 to 4,000 units daily provides a sensible starting point. Higher doses may be appropriate for some individuals, but a blood test is advisable for anyone taking larger amounts to ensure levels remain within the optimal range. This simple addition allows one to protect the skin without compromising on overall health.
Sun protection made simple? Choose a broad spectrum SPF 30 to 50 formulation that suits the skin type, wear an antioxidant serum underneath, apply daily (year round, not just in summer), and take a vitamin D supplement. The choice between physical and chemical filters is ultimately a matter of personal preference and what works best for individual skin.
Whether you have a medical skin condition which needs treatment or simply want to look your very best, our specialised dermatology team will help you achieve the very best result.
