The Ultimate Guide To Sunscreens: Physical vs Chemical

posted on: July 1, 2015

Chemical SUNSCREEN VS Physical SUNBLOCK

 

 

Sunscreen and Sunblock are descriptions used interchangeably but it is important to know that technically they are different products-it is a matter of chemical protection versus physical protection.

Here are some abbreviations you may not know the meaning of:

UV=Ultraviolet referring to radiation.

UVA Rays=Long wavelengths which penetrates skin deeper, the culprits in premature aging, wrinkles and sunspots. Present whether it is sunny or not. Weaker than UVB rays, they can still contribute to skin cancer.

UVB Rays=Slightly more energy than UVA rays, exposure can cause skin to burn and  lead to melanoma and other forms of skin cancer.

Here is a quick comparison of Chemical Sunscreens VS. Physical Sunscreens

Physical:

-Noticeable on skin, most sunblock leaves a thin white-ish layer on skin

-Contains ingredients like Zinc Oxide and Titanium Dioxide which physically block the sun, reflects the rays off skin, almost like a mirror.

-Effective immediately after application because it remains on the skin surface-doesn’t need to be soaked into the skin

Deflects UVA and UVB rays, reduces the radiation that hits the skin

A few Physical Sunscreen I recommend:

1. Blue Lizard Sunscreen– This is the best sunblock that is difficult to find. It is an Australian based company and can be purchased online. You can even buy this stuff by the gallon! The bottle also turns blue when exposed to UV rays. No need to question if you’re getting  UV exposure on that cloudy day, just look to the bottle for the answer.

2. The Honest Company Sunblock Stick– Putting sun protection on your kids faces is the worst (even for this Derm momma). Most kids hate putting lotion on their face and with one quick move they always end up getting it in their eye. This stick makes physical application of the sunscreen a breeze with no mess.

3. Colorscience Sunblock Powder– I’ve talked about this product many times before. While it wouldn’t be my whole body go-to if at the beach it’s great to apply over make-up or even put on the part on your scalp, an area that is often overlooked when it comes to sunscreen application and easily burned.

This YouTube clip below shows with a UV camera how Sunblock acts as a physical barrier on the skin, you can see clearly once the subjects smear Sunblock on their face!

sunblock

Chemical Sunscreens:

-Usually appears clear on skin

-Contains special ingredients that act as chemical filters and reduce ultraviolet radiation penetration to the skin

-Must be applied at least 30 min. before sun exposure to soak into skin

Absorbs UVB rays

-Any sunscreen with less than 15 SPF is a waste of time and money

1. Aveeno Protect and Hydrate Lotion Sunscreen– One of the biggest complaints I hear about physical sunblock is that “it’s too thick”. This product absorbs quickly and moisturizes the skin, plus it is recommended by the Skin Cancer Foundation

2. Sun Bum Original Sunscreen Lotion– This product also absorbs easily into the skin and has that classic beachy scent. Is it weird that I keep a bottle of this stashed in my desk, and take a whiff when I need a mental break? “Sun Bum, take me awayyyyyyyyy!”

3. Supergoop Everyday Sunscreen– Non-comedogenic formulation designed for everyday use over the whole body. This is a great choice is you are particularly sensitive to paraben, synthetic fragrance or oxybenzones.

Please note:

  • “Waterproof” is better than “water-resistant”, but it doesn’t mean that lotion can be applied once and you’re covered for the rest of the day. “Waterproof” can maintain an SPF level 80 min. after swimming or sweating, whereas “water-resistant” maintains SPF only 40 min. after being in water.
  • Oils, even if they have SPF, aren’t really a protective form of sun protection. The oil intensifies the rays, as if you are basting your body. Unless you want roasted turkey skin, don’t use tanning oils.
  • According to the Melanoma Foundation, Even on a cloudy day 80 percent of the sun’s ultraviolet rays pass through the clouds. Especially important to wear sunblock even on an overcast day.

I personally hate spray-on sunscreens. Yes, they are convenient as can be, but almost no one applies them correctly. To get the level of SPF protection suggested on the can you must apply the sunscreen to dry skin with no wind present and you must apply a LIBERAL amount of the spray to the skin (the skin should look wet) and then you need to rub in the spray into the skin. You then must wait for everything to dry and absorb into the skin before it starts working. Do you know anyone who does all of these steps? I have some patients refuse to wear anything but sprays (cough…cough…my husband) so I tell them it’s better than nothing, but in general I highly advise against them. Also, you want to avoid inhaling spray sunscreens as there is still investigation occurring on any potential risk in the lungs.

Bottom Line: These days, sunscreen and sunblock are so interchangeable, they are not scientific terms to describe sun protection. In my field we compare the two as “chemical vs. physical”. Many lotions are a combination of both so it is best to look at the labels; mineral ingredients like Titanium Dioxide or Zinc Oxide-those inorganic ingredients physically block the sun.

Regardless of whether you use sunblock or sunscreen, they both have the ability to protect you from damaging ultraviolet rays and should be a part of your daily routine.

 

  • Anna

    Thank you for the guidance on sunscreen.

    I have a question. Is Shiseido sunscreen safe to use? I have been using it for years but I don’t notice any sun spots on my face.

    • Erin

      The most important things is that you are reapplying your sunscreen throughout the day as it wears off after a few hours. If you like that brand then stick with it!