Sunscreen Basics

Things to consider when choosing sunscreen

There is no best brand of sunscreen. You need to choose one based on many things such as:

Your Baumann Skin Type

How long you will be in the sun?

If you want chemical- free are not?

Will you wear it in the ocean or rivers where sunscreen can hurt marine life

Do you want tinted or non tinted

Is a cream, stick, gel, lotion or spray better for you

What are you doing when you wear the sunscreen? Skiing? Running? Swimming?

This blog will discuss sunscreen basics and help you shop for sunscreens.

What sunscreen is best for me quiz

Sunscreens can be chemical free, tinted, un-tinted and comedogenic or noncomedogenic. They may be sprays, lotions, sticks, creams or gels.

You need to match your sunscreen to your skin type.

Our dermatologist-developed quiz will give you a list of sunscreens from many brands to choose from.

Whether you chose by price, brand, or preferences such as all natural- you can be confident these sunscreens are right for your skin type.

What is the Best Sunscreen in the World?

The best sunscreen in the world is the one you will use every day that has a SPF of at least 15.

The sunscreens that have the best broad-spectrum UVA and UVB protection are chemical sunscreens.

However, these have other issues such as environmental safety, risk to marine life, risk of allergy, comedogenicity, and instability of sunscreen ingredients.

Sunscreens are often used together to boost protection.

One example of a good sunscreen ingredient to look for on the product label is Cell Ox Shield.

This combination sunscreen ingredient which contains the sunscreen ingredients: Avobenzone, Homosalate, Octisalate, Octocrylene, and Oxybenzone.

Although Cell Ox Shield is found in Anthelios sunscreens, it is not the same as the Mexoryl SX, Mexoryl XL, and Tinsorb S-containing sunscreens called Antherios found in Europe and Canada.

To find a sunscreen right for you- take the quiz.

These are some of our favorite dermatologist-recommended chemical-free sunscreens:

How much sunscreen to apply?

Use 1/4 teaspoon of lotion, cream or gel sunscreen on your face.

Use 1/4 teaspoon sunscreen on your neck and décolleté.

This is called the teaspoon rule of sunscreen.

What order do you layer sunscreen?

Sunscreen should be the last skin care product that you apply in the morning routine steps.

Reapply before going out in the sun if it has been over 1-2 hours since you applied your am routine.

We can tell you exactly what skin care routine steps are right for your Baumann Skin Type.

What are the different types of sunscreens?

Chemical Sunscreens

Chemical sunscreens absorb UV rays and convert them into heat- preventing penetration into the deeper layers of the skin. Examples include avobenzone, octinoxate, and oxybenzone.

Chemical sunscreens that are noncomedogenic:

Physical Sunscreens

Physical sunscreens are made of micronized pieces or metal like zinc and titanium that form a layer on the skin’s surface to protect it from UV rays.

These are also called mineral sunscreens.

Physical sunscreens block both UVA and UVB rays. However, they do not protect the skin from all of the wavelengths of UVA and are therefore often combined with chemical sunscreens.

Mineral sunscreens are often white and not as spreadable as chemical sunscreens but are considered safer for the body and environment.

Examples include zinc oxide and titanium dioxide.

I prefer mineral sunscreens for my patients.

Mineral sunscreens that are noncomedogenic:

Organic sunscreens

All organic and natural sunscreens are made from zinc oxide or titanium dioxide. T

hey may have plant-derived antioxidants included in them as well.

A good organic sunscreen is hard to find and I do not have any good recommendations for you.

Please let me know if you have found one you like.

Most of them are comedogenic or very sticky and hard to wash off.


What SPF to Use?

For the face- if you will be indoors and not near a windew- SPF 15 is enough for the face.

However, if you plan to be in the direct sun for over 15 minutes, use a SPF of 45+.

If you plan to sweat or be in the water- use a water resistant or water proof SPF of 45+.

If you are going to be in the sun for over an hour, use the highest SPF you can find and reapply every hour.

How is SPF calculated?

Before we continue, please note that the rules about SPF labeling are different in various countries and that the following information is based on the sunscreen labeling rules in the USA.

Chemical and physical sunscreen ingredients prevent redness caused by ultraviolet exposure. The SPF labeling process is strictly regulated by the FDA and in order to put an SPF number on a skincare product label studies must be done.

The sun protection factor (SPF) represents how much ultraviolet light B can be shone on the skin before redness occurs.

SPF number is measured by placing 2mg / cm2 of sunscreen on human skin, usually the buttocks area (if it's a cream, the amount is about 0.4 ounces of the cream). The area is then exposed to a certain amount of UVB light and the amount of redness is measured in the sunscreen-covered area versus the other side of the buttocks that does not have any sunscreen applied (the control side). The difference between the dose of UVB required to cause redness on the sunscreen side versus the control side is the SPF. For example, an SPF 15 sunscreen means that it takes 15 times the amount of ultraviolet B to turn the skin red. The amount of UVB required to turn the skin red is called the MED (minimal erythema dose).


SPF does not measure UVA protection

There isn't a recognized or agreed-upon standard for measuring UVA-containing sunscreens in the US, so the SPF always applies to protection from UVB. This is because each large company has its own way of measuring UVA protection, and no one has been able to agree on which is best so the FDA has not set the measuring standards. It seems that they do not want to favor one company over another because the company that did not use the chosen standard would have to repeat all of their sunscreen tests. This is unfortunate for us because we do not know how well sunscreens protect us from UVA in the US. The only other options are to buy European sunscreens or to look for “Broad Spectrum Sunscreen” which protects from both UVA and UVB rays.

How much SPF should I use to get the SPF on the label?

Most people only use 25% of the necessary amount of SPF to meet the SPF on the label. This means that an SPF of 15 is not really 15 because not enough was applied which is why you are told to use higher SPF levels.

You must use at least ¼ teaspoon of SPF for your face to achieve the SPF on the label and you should reapply after water immersion, excess sweating, and at least every hour.

Do I need to wear sunscreen indoors?

You need to use a UVA blocking SPF indoors because UVA can go though windows.

This means you also need to wear a UVA blocking SPF in cars and airplanes.

Do I need to wear sunscreen in front of a computer?

The light from a computer screen or phone can age the skin and increase hyperpigmentation.

The best way to protect your skin is to us products with iron oxides in them.

If you have melasma, you should wear a always wear a SPF or facial foundation makeup with iron oxides.

Most tinted SPF products have iron oxides in them.

Which sunscreens contain iron oxides?

Makeup foundations and tinted sunscreens contains iron oxides.

The darker the tint is- the more iron oxides the SPF contains.

These are the 6 best dermatologist-recommended sunscreens with iron oxides:

Alastin Silk Shield All Mineral SPF30

ISDIN Eryfotona Ageless Tinted Mineral Sunscreen SPF 50

Sente Invisible Shield SPF 49 Untinted

Revision Skincare Intellishade Tinted Moisturizer SPF 45

SkinCeuticals Physical Matte UV Defense SPF 50

SkinCeuticals Physical Fusion UV Defense SPF 50

UVA vs UVB Sunscreens

The United States has few sunscreen choices than other parts of the world. Of US-approved sunscreens, only Avobenzone (Parsol) blocks the entire spectrum of UVA (310nm to 400nm).

Zinc oxide blocks both UVA and UVB rays, while titanium dioxide provides better UVB protection than zinc oxide. This is why zinc oxide and titanium dioxide are often used together. (1-3)

This sunscreen ingredient table lists sunscreen ingredients and which wavelengths of UV they block.

Are sunscreen powders good?

Experts do not recommend sunscreen powders because they do not really work.

You can use an SPF powder or SPF-containing foundation over top of your main sunscreen, but for optimal protection do not use it alone.

You must use another lotion, gel or cream form of sunscreen with a sunscreen powder.

SPF powders are not effective because you would have to put on 14 times the normal amount to get the SPF listed on the label.

See the image to see how much sunscreen powder you need to use.

Our Dermatologist's Opinion On Sunscreen Filters

For daily use, choose a natural mineral sunscreen for the face containing these ingredients:

  1. Zinc oxide - One of the best sunscreen choices because it is natural/non-toxic to humans and the environment, and it also protects from UVA and UVB rays. It has a low risk for irritation. Micronized looks less white on the skin.
  2. Titanium Dioxide - A natural mineral sunscreen that reflects UV radiation away from the skin that is also natural/non-toxic to humans and the environment. Best when combined with zinc oxide.
  3. Iron Oxide - A natural mineral that blocks blue light from phones and computer screens that is used to give a tint to sunscreens. This is why tinted sunscreens provide more sun and light protection than non-tinted sunscreens.

Our favorite mineral-based physical non-comedogenic tinted sunscreens for the face are:

For prolonged outdoor sun exposure, you may choose a chemical sunscreen for the face to increase UVA and UVB protection. However, every chemical sunscreen has a downside:

  1. Avobenzone (Parsol) - has the best protection, but it stings. Rosacea skin types often get irritated by avobenzone. If you are going to be sweating a lot, it can run into your eyes and burn. Our advice is to either a. do not put this avobenzone-containing sunscreen on your forehead (wear a cap and choose a different sunscreen for the forehead) or b. do not use this when you expect to sweat a lot.
  2. Octinoxate - Octyl methoxycinnamate is a UVB absorbing ingredient that is added to boost UVB protection in chemical sunscreens. Although many studies have shown it is safe for humans and coral reefs, it is a controversial ingredient because some studies have suggested it is toxic to reefs and may have endocrine effects. Although the risk is small, we recommend not using Octyl methoxycinnamate-containing sunscreen in the ocean, on large areas of the body, or on children under the age of. Many people also have photoallergy to octinoxate.
  3. Octisalate - Only has UVB protection, no UVA protection.

The Bottom Line

I have very allergic sensitive skin, so I can only use mineral sunscreens. But since my skin is dry, I also want a sunscreen that is hydrating and tinted to help even out my skin tone. So, for my DSNW 4 Skin Type, the sunscreens I prefer are:

Best references and scientific publications on sunscreen:

  1. Baumann L. Ch. 46 Sunscreen in Baumann's Cosmetic Dermatology 3rd ed. (McGraw Hill 2022)
  2. Schneider, S. L., & Lim, H. W. (2019). A review of inorganic UV filters zinc oxide and titanium dioxide. Photodermatology, photoimmunology & photomedicine, 35(6), 442-446.
  3. Antoniou, C., Kosmadaki, M. G., Stratigos, A. J., & Katsambas, A. D. (2008). Sunscreens–what's important to know. Journal of the European academy of dermatology and venereology, 22(9), 1110-1119.
  4. Petersen, B., & Wulf, H. C. (2014). Application of sunscreen− theory and reality. Photodermatology, photoimmunology & photomedicine, 30(2-3), 96-101.

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