Sunscreen 101: The Basics
One of the most common questions I get, especially in the summer months, is, "What is the best sunscreen?" The answer is that there is no single best brand of sunscreen. The best one for you will be one that you will use on a daily basis and that does not cause other problems such as breakouts or redness.
Here, I provide the basics you need to know about how to choose a sunscreen to make sure your skin is protected from harmful UV rays. If you don't yet know your Baumann Skin Type, take the quiz below first so you can get customized recommendations.
There is no single best brand or type of sunscreen - it depends on your skin type and preferences.
Take the quiz to find out your skin type and the best sunscreen recommendations that are a match for your skin.
Many people do not apply enough sunscreen to get the UV protection amount listed on the bottle. Make sure you are applying enough based on this guide.
Table of content
How to Choose a Sunscreen
There is no best brand or type of sunscreen. To choose the best one for you, you'll need to consider many factors, such as:
- Your Baumann Skin Type
- How long you will be in the sun?
- Do you prefer a chemical-free sunscreen or 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?
The most important aspect of choosing a good sunscreen is picking one that you will feel good about using every single day. Ask yourself the questions above to help guide your shopping decision.
Types of Sunscreens
There are many different types of sunscreens, including chemical, physical (non-chemical), and organic sunscreens.
Chemical Sunscreens
The sunscreens that have the best broad-spectrum UVA and UVB protection are chemical sunscreens. They work by absorbing UV rays and converting them into heat. This prevents UV rays from penetrating into the deeper layers of the skin. Examples of chemical sunscreen ingredients include avobenzone, octinoxate, and oxybenzone.
However, chemical sunscreens have other issues such as environmental safety, risk to marine life, risk of allergy, comedogenicity, and instability of sunscreen ingredients. If you prefer not to use chemical sunscreens for these reasons, consider a physical sunscreen.
Non-Tinted Chemical Sunscreens
Physical Sunscreens
Physical sunscreens, also called mineral sunscreens, are made of micronized pieces of metal like zinc and titanium that form a physical layer on the skin’s surface to protect it from UV rays.
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 to maximize protection.
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.
Tinted Physical (Mineral) Sunscreens
Organic sunscreens
All organic and natural sunscreens are made from zinc oxide or titanium dioxide. They 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.
How Much Sunscreen to Apply
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 apply enough sunscreen to make sure your skin is getting maximum UV protection! Here's an easy rule-of-thumb for how much sunscreen to apply, commonly called the "teaspoon rule of sunscreen":
- Use 1/4 teaspoon of lotion, cream or gel sunscreen on your face.
- Use 1/4 teaspoon sunscreen on your neck and décolleté.
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 to 2 hours since you applied your morning routine, or if you've been swimming or have sweat a lot from working out.
What SPF Is Best to Use?
If you will be indoors and not near a window, you can use SPF 15 on your face. However, if you plan to be in the direct sun for over 15 minutes, use a SPF of 45 or higher.
If you plan to sweat or be in the water, use a water-resistant 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. You can also wear or pack sun-protective clothing to give your skin a break from long periods of sun exposure.
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. The 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.
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.
Do I Need to Wear Sunscreen Indoors?
Yes, 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.
Does Sunscreen Protect Against Blue Light?
Mineral sunscreens that contain iron oxides do protect against blue light, which is the type of light emitted from your computer or phone. This light can age the skin and increase hyperpigmentation. The best way to protect your skin is to use products with iron oxides in them.
If you have melasma, you should wear a always wear an SPF or facial foundation makeup with iron oxides. Most tinted SPF products have iron oxides in them. The darker the tint is, the more iron oxides these products contain.
Below are the six best dermatologist-recommended sunscreens that contain iron oxides:
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 a powder 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.
Dr. Baumann's Sunscreen Recommendations
For daily use, choose a natural mineral sunscreen for the face containing these ingredients:
- 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.
- 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.
- 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.
- 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.
- 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.
- 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, I have found favorites that work for my DSNW 4 Skin Type.
Once you know your skin type, we can help you find your favorites, too! Whichever SPF you choose, remember these important tips:
- Wear it every single day
- Apply at least 1/4 teaspoon of sunscreen to your face
- Reapply after getting wet or sweating
- Reapply every hour
- Don’t rely on powder SPFs or the sunscreen within your foundation
Let us help you find the best sunscreen for your skin type!
Does sunscreen expire?
Yes, sunscreen has an expiration date! Do not use expired sunscreen, since it loses potency over time. Store sunscreen in a cool, dry, dark environment to make sure it doesn't break down faster than its expiration date.
Should you wear sunscreen higher than SPF 50?
Some people do not recommend using very high SPFs. This is because the amount of added UV protection you get after SPF 50 is very small, so people may feel a false sense of security when using SPF 100, for example, as it does not offer much more protection than SPF 50.
What is the "three finger" sunscreen rule?
The three-finger sunscreen rule is a quick way to measure out how much sunscreen to use for your face and neck: simply squeeze out three strips of sunscreen along the length of your index, middle, and ring fingers. This amount is generally enough to get good, even coverage and help protect your skin from UV rays.
Best references and scientific publications on sunscreen:
- Baumann L. Ch. 46 Sunscreen in Baumann's Cosmetic Dermatology 3rd ed. (McGraw Hill 2022)
- 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.
- 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.
- Petersen, B., & Wulf, H. C. (2014). Application of sunscreen− theory and reality. Photodermatology, photoimmunology & photomedicine, 30(2-3), 96-101.