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Sunscreen - The Good and The Bad

As I sat down with my cup of coffee to write this blog, I realized how confusing the sunscreen issue is. I read that Hawaii has pulled sunscreen off the market, (due to its toxicity to the coral reef system), and other articles on how some of the chemically based sunscreens can break down on your skin into free radicals, and can even cause toxic fumes. What the hell!? Everyone and their mother tells you to wear sunscreen, and you know you should, and then you are paralyzed as to which of the hundreds of varieties is best for you and your family.

There are chemicals, and you don’t know what is harmful and what is ok, and then there is SPF! And as soon as you think you have a handle on things, the rules change and what was great is now terrible. It's like coffee— it was good – and then it was bad — then it was a performance enhancer — then it was the devil again. Digging through the information and separating science from click-bate can be exhausting and often a waste of time.

Let me try to break sunscreen into some practical and scientific (not hysterical) information and help you to protect your skin (and if you have children your kid’s skin). This will be by no means comprehensive, because there is simply too much information out there, but it will be a good starting point.


Let's talk about the basics, why you actually need sunscreen and what we KNOW to be bad (scientifically, not just knee-jerk “chemicals are bad”) and what we know to be safe, and what is actually appealing to use — and then how best to use it.

You need sunscreen for two reasons – sun causes aging and skin cancer. The sun is primarily composed of two types of rays – UVB and UVA rays.  UVB is responsible for causing skin cancer and melanoma and UVA rays are primarily responsible for premature aging.  You want a sunscreen that protects from both UVB and UVA rays – or a so-called “broad spectrum” sunscreen.


There are two basic forms of sunscreens – there are sunscreens that are “physical blockers" and those that are "chemical blockers". 

Physical sunscreen contain active mineral ingredients that block the sun’s harmful rays.  These are sunscreens such as zinc oxide and titanium dioxide. These ingredients sit on top of the skin and deflect the suns rays. The benefits are they are generally broad spectrum and when they are applied they are effective immediately.  Also they tend to cause less skin irritation and reaction as they are not absorbed by the skin in the same way that chemical sunscreen is.  The downside of these sunscreens is that they tend to be thicker and not as easy to apply, can cause stains on the clothes and people can look a little “chalky” or "pasty”.  There are powder versions of this which are great for the face but are not practical for the entire body.

Chemical sunscreens contain organic compounds which create a chemical reaction and work by changing UV rays into heat and then release that heat from the skin.  The upside is they are silkier and easier to apply. The downside is the chemicals can be toxic and if not toxic the skin can have many more unpleasant reactions to these blockers, and unlike physical sunscreen some ONLY block the UVB rays allowing aging to occur!!


And now two sunscreen chemicals, oxybenzone and octinoxate, have been shown to damage corals in a variety of ways.  With chemical sunscreens you need to answer the following questions to determine if it is safe:

  • Will the chemical penetrate skin and reach living tissues?

  • Will it disrupt the hormone system?

  • Can it affect the reproductive and thyroid systems and, in the case of fetal or childhood exposure, permanently alter reproductive development or behavior?

  • Can it cause a skin allergy?

  • What if it is inhaled?

  • Other toxicity concerns?

The chemicals that seem to be considered NOT safe are PABA, and  oxybenzone and octinoxate. Animal studies show delayed puberty after exposure to octinoxate and altered estrous cycling for female mice exposed to oxybenzone. In addition to the relationship between oxybenzone and testosterone levels in adolescents, preliminary investigations by a team of researchers at the NIH and SUNY Albany suggest a link between higher concentrations of benzophenones and poorer reproductive success in men seeking assistance at a fertility clinic. Female exposures to oxybenzone and related chemicals have been linked to increased risk of endometriosis.  PABA was concerning in that it was linked to evidence that it damaged DNA and definitely caused a lot of skin irritation.


What is SPF? Imagine that your skin normally begins to burn after 10 minutes in full sun without any protection. A 30 SPF sunscreen would provide 30 times the protection of no sunscreen. That means 30 times longer before you start to burn, and this increases. BUT there does not seem to be much a difference between SPF 50 and above… SO, the thing to do is to get SPF 30 or above and reapply every 30-50 minutes. 


  1. Wear sunscreen

  2. Physical sunscreens are the safest and easiest on your skin

  3. If you don’t care about skin cancer – because it seems so esoteric, you probably give a crap about aging.  So wear sunscreen.

  4. Be practical – avoid midday sun, wear a hat, wear protective clothing.

  5. Powder mineral sunscreens look great – you can think of it as foundation, There are many cosmetic brands that have a wide range of colors for all skin tones.

  6. For the body – spray is really easy, but you need to make sure you apply it evenly and all over. Get a friend to help you.

  7. When exposed to sun for many hours you need to reapply sunscreen and after sweating and exposure to water.

  8. Throw out expired sunscreen – it may not work after expiration!

  9.  If you feel like you look pasty and want some ‘color” use fake tan (separate blog to follow).

Hopefully you have a little bit more clarity after reading this blog. The take-home message is that you can't just trust that the ingredients in products that you find in your local CVS or grocery store are safe! We need to check the ingredients and do our due diligence to make sure that what we put in and on our bodies is safe and effective.

Until next time,

Dr. Alexes Hazen



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