Sunscreen Dialog: What I Think One Needs to Know

Do I need Sunscreen?.jpg

What do I need to know about sunscreen?

Wow, where to begin?

Um, the beginning?

Well, big picture, if one is interested in skincare, one needs to wear an adequate amount of a Broad Spectrum SPF 30-50 sunscreen every single day, without fail.


Wearing the adequate amount of an adequate sunscreen protects the skin from sunburn, premature skin aging, and many kinds of skin cancer.

That seems like quite the point of the idea of skincare.

Indeed. May I go point by point through the above summary?

Have at it. Should we start with “interested in skincare?”

Yes, let’s begin there. So, if one puts anything on one’s face, one should also pursue a sunscreen. Can I go through some examples?

Sure. Why use a sunscreen with a moisturizer?

If one uses a moisturizer, applying a sunscreen will not only provide a further occlusive shield from preventing the skin becoming dry and haggard, but it will also prevent water from sublimating from the skin due to the skin barrier being impaired by radiation damage.

What about retinol?

If one uses an anti aging product that contains any form of Vitamin A derivative, it is important to understand that it is treating the signs of skin photoaging. As in, over time, the skin gets becomes aged, by light, from the sun. So it seems logical to pursue protection from further damage when one goes in on reversal.

How about an Alpha Hydroxy Acid?

As above, why fix a problem only to create a new one?

How about Vitamin C?

If one is using a Vitamin C or other antioxidants as a means of preventing oxidative stress on the skin, one would be sagely advised to apply a sunscreen as well, since its function will prevent a lot of free radical formation.

Wow, okay. So it seems that a sunscreen is only helpful to the pursuance of the effects of other topical beauty products. Can you clarify “adequate amount”?

Certainly. A lot of sunscreen. A LOT.

Can you be more specific?

Yes, you will want to apply around a third of a teaspoon’s worth of sunscreen on your face alone.

That is a lot.

Indeed. A good tip is to apply two layers of sunscreen – this helps improve the evenness of the sunscreen film.

I see. Can you discuss “Broad Spectrum SPF 30-50”?

There is a lot to cover here. May I start with just SPF?

Okay, out with it.

SPF stands for “Sun Protection Factor,” and is a measure of a product’s ability to protect against sunburn. Not other light related skin conditions: sunburn.

Interesting. Why just sunburn?

The short answer is that it is kind of old fashioned, and I would quite like to leave it there for today.

Okay. So what about “30-50”? Why that number?

I will cover this in a lot more detail in a future Dialog. Today, please understand than an SPF 30 protects one’s skin from 97.7% of UVB. An SPF 50 protects against 98% of UVB. An SPF of like, 100 would protect against 99% of UVB. These differences are not meaningless, by the way, 99% is better than 97%, obviously, but once one reaches an SPF of 30, the increasing protection becomes less and less significant.

I look forward to hearing about SPF in more histrionic detail.

Honeybun, trust and believe. It is fascinating. Let’s continue.

Let’s. “Broad Spectrum”?

Again, for brevity, I will say a sunscreen labeled “Broad Spectrum” is a sunscreen that protects against UVB as well as UVA. There is no point in using a sunscreen that isn’t broad spectrum, so I’m glad to report that most sunscreens are.

Sounds pretty straightforward to me.

It is actually very complicated. I’m being brief.

Why is broad spectrum even a different thing? Shouldn’t sunscreens protect against both UVA and UVB?

I understand why you feel that way, but no, not necessarily. Different sunscreen ingredients protect against different wavelengths of UV light. Some are great at preventing burns, some are great at protecting from pigment production. So, the inclusion of a “Broad Spectrum” claim should give you confidence that the sunscreen will act as one expects it to.

Okay, sure. “Every single day?”

Yes. Every day, 365, until one’s final breath. While the amount of ambient UVB may fluctuate seasonally, UVA is omnipresent. If the sun is out, UV is out. If you are indoors, please be advised that UVA is not blocked by windows. If it is raining, please be advised that UVA is not blocked by clouds. If you can see natural light, UV can see your skin. If one cares about one’s skin, one needs a broad spectrum SPF each and every day. No excuses.



... okay. Anyway, I have a few questions.

Let’s hear them.

What is the best sunscreen?

I am quite resistant to answering this question, as I can’t see your skin.


Allow me to use an analogy?


My friends who go to the gym often say things like “the best time to work out is the time you are able to work out.” This is to say, one can do loads of research on the effects of exercise at various times, based on various factors, and indicate the best time to work out to achieve a particular benefit. This is all fabulous. However, it isn’t really a great recommendation, as it imposes a framework for exercising that isn’t possible for many people. Thus, the recommendation is to work out when one is able. With me?

Yes, but what does this have to do with sunscreen?

I’m getting to the point. My opinion is that the best sunscreen is your favorite sunscreen. You will use your favorite sunscreen, and sunscreen is only beneficial if you use it.

That isn’t very helpful to me.

That is my true belief. There are many, many sunscreen product reviews on, so one can look there to find one that sounds suitable.

Do I need to reapply sunscreen?

Well, to get reliable protection: yes. Did you read the packaging?


The instructions on all sunscreens sold in the US indicate that sunscreens should be reapplied every two hours. This is to say, the product makes a medical claim: if you apply this product properly, your skin will be protected at a level of this product’s SPF for two hours. That is the claim: two hours of protection. Now. is there decent data that suggests one still sees benefit from applying sunscreen once per day? Yes, there is. Furthermore, most filters are reliably photostable, so it is reasonable to anticipate that applying every two hours is not a complete necessity.

What are you saying?

Well, I personally apply sunscreen often. Probably every 3-4 hours, when indoors. Do I think this is necessary? No, I don’t. I’ve made sunscreen reapplication a behavior. I just feel when I need to reapply. I feel like this probably yields positive results for my skin, and is probably negative for my wallet, all things considered.

So, what are you saying?

Well, I’d feel irresponsible if I were to write something other than “follow the instructions on the packaging.” Yet, I don’t always do that, and I’m like, crazy bananas about sunscreen. I imagine that I apply much more sunscreen than most people do, and more often. But every two hours is a lot if one is indoors, away from a big window through which the sun directly shines. I think one should be advised that if one hasn’t reapplied sunscreen in two hours, one should be aware that one will not be getting the protection indicated on the product. If one wants constant protection, reapplication is key.

I also know I am the only beauty person who doesn’t wear makeup, so I have no issue reapplying sunscreen throughout the day. So, yeah.

Sorry, what is your claim?

My claim is: if you expect to receive a sunscreen’s labeled SPF, you need to reapply every two hours. If you are outdoors or in direct sunlight, this is an absolute necessity for reliable protection.

When does sunscreen go in my routine?

Excellent question. At the end of one’s skincare, so on top of the heaviest of creams that one has applied. If one wears makeup, I’d wait a few minutes before applying primer, foundation et al. You want your sunscreen to be dry, completely before applying anything else. If the sunscreen isn’t dry, one risks shifting it around, and in so doing problematize the evenness of the sunscreen film.

I’ve read magazine articles that say sunscreen keeps me from getting Vitamin D. Can you speak to that?

I don’t wish to give medical advice here, but I will remark that avoiding sunscreen for the sake of Vitamin D is something that doesn’t make a ton of sense to me.

Can you briefly explain why?

God, I will try, but you know me: Long-Winded, Ranty Dan.

... briefly.

So, when one receives unprotected UV exposure, one receives some UVB, exposure to which burns the skin. There are a few specific wavelengths of UVB (<300nm) data-preserve-html-node="true" which also act to begin the synthesis of Vitamin D. However, in the real world, there is a lot more ambient UVA than there is UVB – one can’t get one without the other. When one’s skin is exposed to UVA, one’s skin responds with production of melanin, which darkens one’s skin, giving one a tan.

The function of a tan is protective, because melanin is a broad spectrum UV filter. So, if one exposes one’s skin for the purpose of Vitamin D synthesis, it logically follows that the more UV exposure one receives, the less Vitamin D one would be able to synthesize. This is perhaps a bit overstated and reductive, but it is something around which I can’t quite get my head.

I don’t understand. One more time?

One needs UV exposure to get vitamin D. As you get UV exposure, one’s skin produces melanin. Melanin filters UV. So as one gets exposure to synthesize Vitamin D, one limits ones own ability to produce vitamin D. Indeed, this mechanism’s method of action bears out clearly, as it has been reported that those with darker skin tones (read: have more melanin) have an increased likelihood of being Vitamin D deficient, like when Wendy Williams told Doctor Oz that she took a prescription Vitamin D supplement.

So how do you get Vitamin D?

Well, I don’t give it a lot of thought. I imagine that I get a certain amount of UV exposure due to missing spots with sunscreen, which is a total inevitability. It is worth writing that I get my labs done annually and I don’t seem to be deficient, so I imagine the Vitamin D-containing multivitamin I take must play some role here. I’d recommend one speak with one’s medical provider about their advisory regarding Vitamin D: how to ensure one has enough of it, and their preferred methods of reaching that amount. They’d have better advice than me.

I’ve read that a lot of sunscreen ingredients are toxic and bad. Can you respond to that?

In short: Eye to the roll. In actuality, there is inconclusive or insufficient research about a lot of the organic filters in sunscreens, and people can become allergic to some of them. I can empathize with people who have some concerns about them – I just disagree that they are harmful. A more robust discussion will follow in a future dialog.

Sounds like a plan. This was a lot of information. Can you summarize?

Certainly. I recommend wearing an adequate amount of your favorite Broad Spectrum SPF 30-50 sunscreen every single day, without fail.