Dermatologist Debriefs

Understanding UV Filters: What You Need to Know

• Stefanie Williams

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Ready to boost your sun protection knowledge? In this episode, dermatologist Dr. Stefanie Williams unpacks the complexities of sunscreens. Learn about the fundamental differences between physical and chemical UV filters, and which is best suited for your skin type. Do you suffer from sensitive or acne-prone skin? Understanding how each sunscreen works can guide you to choose the right product.

Dr Stefanie tackles common misconceptions, such as whether there’s a real difference between dedicated sunscreens and SPF moisturisers and explores why both physical and chemical filters are effective against UV rays but not infrared or visible light. 

Dr. Stefanie also shares straightforward tips on maintaining optimal vitamin D levels while protecting your skin from harmful UV rays. If you've ever wondered about the right choice of sunscreen, this conversation is a must listen.

Speaker 1:

Dermatologist debriefs. Join no-nonsense dermatologist Dr Stephanie Williams as she debunks myths and shares her professional insights, separating facts from fiction in just a few minutes about the different types of sun protection filters.

Speaker 2:

So if you pick up a sun protection product, it will generally contain one of two types of UV filters, or sometimes it might contain both and these two types are physical filters, also known as mineral filters, and chemical filters, also known as mineral filters and chemical filters, also known as organic filters. And for the avoidance of doubt, when I say organic in this context I am talking about the chemistry term. So that means they're compounds containing carbon hydrogen or carbon carbon bonds. So this has nothing to do with organic supermarket produce. These two types of UV filters have a different mechanism of action and also some other different kind of properties. So physical filters work a little bit like a mirror. They create a barrier on top of our skin that reflects and scatters UV rays before they even enter the skin. Chemical filters, in contrast, work more like a sponge. They absorb UV rays, convert them into heat and then release that heat from the skin. So chemical filters do allow UV to enter the skin, but convert it into a less aggressive type of electromagnetic radiation, namely infrared irradiation. Physical UV filters contain active ingredients like, for example, zinc oxide or titanium dioxide. Chemical sunscreens use organic compounds such as avobenzone, octinoxate or oxybenzone, and there are pros and cons to both groups. Physical sunscreens are generally better for sensitive and allergy prone skin because they are less likely to cause allergies and irritation. Chemical sunscreens, on the other hand, tend to be lighter in texture, making them typically more suitable for congested and breakout prone skin. So if you suffer with acne, you may get along better with a formulation containing chemical sunscreens. Chemical sunscreens are also often easier to apply and are cosmetically more elegant, which makes them very popular for daily use in sun protection moisturizers. Physical sunscreens may leave a white cast on the skin, especially in darker skin tones, although newer micronized formulations and tinted versions have greatly improved on this issue greatly improved on this issue. And I do really like physical filters because they are quite inert and they reflect the sunlight before it even enters the skin, which is a nice concept. Also, physical sunscreens start working immediately upon application, whereas chemical sunscreens need about 15 or 20 minutes to become effective after you've applied it on the skin. Physical filters generally are more broad spectrum in their effect, which means that they cover a wider range of not only UVB but also UVA light. However, a combination of different chemical filters can get around this issue. So both types physical and chemical filters or products let's say physical and chemical filters or products, let's say can provide effective broad spectrum protection as long as they are formulated correctly and, of course, used as directed. So the choice between physical and chemical sunscreens often comes down to personal preference and the skin type and condition.

Speaker 2:

However, one thing I want to mention is that both physical and chemical sunscreens only protect from UV light ultraviolet light. In an ideal world, they do that in a broad spectrum way, meaning covering both UVB and UVA, but what neither of them does is protect the skin from infrared or visible light. So these are, of course, the other two types of sunlight that our skin is exposed to when we are outdoors, and both of these also contribute to, for example, irregular pigmentation and other skin issues. And that's where antioxidants such as topical vitamin C come in, because even if you are using a really well-formulated sun protection product with UV filters, you are only ever protecting the skin from ultraviolet light, but there are more types of electromagnetic irradiation emitted from the sun than just UV light.

Speaker 2:

Another question I'm often asked when talking about sun protection products is whether there's a difference between a dedicated sunscreen of, say, spf 50 and a moisturizer with SPF 50. And the answer is no. Spf is SPF is SPF. So if it says SPF 50, then it has been tested to that effect in the lab and you get the same degree of protection whether this product is labeled as a sunscreen SPF 50 or whether it's a I don't know for example, something labeled as a day moisturizer that contains an SPF 50. So it's completely fine to use them interchangeably.

Speaker 2:

With regards to your protection level and I want to finish this session off with a tip so if you are wearing daily SPF to slow down the skin's aging process, for example, always, always, always, combine this with a vitamin D supplement. You can get vitamin D supplements over the counter and you could start with a dose of, for example, 2,000 to 4,000 units per day. You may need more I personally take 8,000 per day, for example but I would recommend a blood test if you are taking higher levels to make sure that you're not going overboard. And speaking about going overboard, please also listen to one of my previous posts from a couple of weeks ago or so, where I talked about the question whether we are maybe overdoing sun protection. I know very controversial topic and I will leave you with that, I will speak to you again soon. I hope this all makes sense. Goodbye.