Mother nature is smart- It made sure we feel pain if we stay too long under the sun by giving us sunburns. And yet we prevent that alarm signal by using sunscreens with SPF that allow us to stay longer in the sun, in turn leading to more UVA exposure & an increased risk of skin cancer like melanoma. Thus sunblock inadvertently may lead to increased skin cancer by allowing us to stay longer than we should in the sun.
Choosing the right sunblock or sunscreen (although these terms are used interchangeably they are not the same) is essential for protecting your skin from the harmful effects of the sun's ultraviolet (UV) rays. UV is divided into 3 wavelengths. One of which is fully blocked by the ozone layer, the shortest and most harmful (UVC 200-290nm). It is followed by UVB (290-320 nm) which accounts for 5-10% of the UV that reaches the earth and is responsible for vitamin D synthesis, sunburns, and increased risk of skin cancers mostly basal and squamous cells (multiple sunburns increase the risk for melanoma). The remaining 90-95% of the UV reaching the earth are UVA rays (Longest wavelength, penetrates deepest, passes through glass & clouds, responsible for aging of the skin and increased melanoma risk, and accentuate the harmful effect of UVB)
Here are some factors to consider when selecting a sunblock:
- Sun Protection Factor (SPF): This number is based on protection from the UVB (the wavelength causing sunburns). It does not reflect its UVA (remember the Melanoma) protection capacity. Look for a sunblock with a broad-spectrum SPF of 41 or higher. To be truly representative of the SPF number you need to apply the right amount of cream on your skin (see below for the proper amount to use).
- Broad-spectrum protection: Ensure that the sunblock offers broad-spectrum protection, meaning it protects against both UVA and UVB rays. UVA rays are associated with premature aging and can penetrate deeper into the skin, while UVB rays primarily cause sunburn.
- Water-resistant: If you plan to swim or engage in activities that may cause you to sweat, choose a water-resistant sunblock. However, keep in mind that even water-resistant sunscreens should be reapplied according to the product instructions.
- Skin type: Consider your skin type when selecting a sunblock. If you have sensitive skin, look for sunblocks that are labeled as hypoallergenic or formulated for sensitive skin. If you have oily or acne-prone skin, opt for oil-free or non-comedogenic (non-pore-clogging) sunblocks.
- Application type: Sunblocks come in different forms, such as lotions, creams, sprays, and sticks. Choose a formulation that you find easy to apply and suits your preferences. For example, sprays may be convenient for hard-to-reach areas but their volume and efficacy, in my opinion, are unreliable and potentially harmful to the environment and your lungs.
- Personal preference: Consider factors like fragrance, texture, and additional features like moisturizing properties or specific skincare benefits. Some sunblocks also come in tinted or matte formulations, which can be appealing for cosmetic reasons. I like the tinted sunblocks as I can see clearly if I missed a spot based on the color of my skin while at the same time preventing a pasty appearance.
- Expiration date: Expired sunscreens may not provide adequate protection.
Remember, it's crucial to apply sunblock generously and reapply it every two hours or more frequently if you're sweating or swimming. Sunscreen should be used in combination with other sun protection measures, such as seeking shade, wearing protective clothing (including hats and sunglasses), and avoiding peak sun hours. You can check the UV index for more information.
Some supplements that help but do not prevent sunburns (I tried them on myself) are:
1) Heliocare- a natural antioxidant taken from a fern tree. The active ingredient is an extract called Polypodium leucotomos extract (PLE). You can take one pill every morning and an additional pill if you plan to stay longer in the sun (it does not prevent you from getting sunburn- trust me I tried it).
2) NMN (Nicotinamide mononucleotide) or NR (Nicotinamide riboside) are both forms of vitamin B3 that help repair DNA damage in the cell. I’ve been taking a daily dose of 1000mg since 2016.
3) You can buy sun protective clothing or add it as a detergent into the laundry to give extra protection to your regular clothes (A white T-shirt has an UPF (ultraviolet protection factor) of about 7, if wet about 3) eg: SunGuard Laundry Aid converts your regular shirt into UPF 30. UPF & SPF aren’t the same. SPF tells you how many times longer you can stay in the sun before you get a sunburn, UPF tells you how much of the sun is easily blocked by the clothes. UPF of 7 means 1/7 = 14% of the UV passes onto your skin (86% of the UV is blocked).
The recommended amount of sunblock to apply is approximately one ounce, which is equivalent to a shot glass full, to cover the exposed areas of your body. Here are some general guidelines for applying sunblock effectively:
- Face and neck: Apply a nickel-sized amount (about half a teaspoon) of sunblock to your face and neck.
- Arms and shoulders: Use about one ounce (two tablespoons) of sunblock to cover both arms and shoulders.
- Legs: Apply approximately two ounces (four tablespoons) of sunblock to cover both legs.
Remember that these measurements may vary depending on your body size and the extent of the skin that needs to be protected. It's better to apply a little more sunblock than not enough to ensure adequate coverage.
Additionally, it's essential to apply sunblock at least 15 to 30 minutes before going outdoors to allow it to absorb into the skin. Reapply sunblock every two hours or more frequently if you are sweating heavily or swimming, even if the sunblock claims to be water-resistant.
Don't forget to pay attention to commonly missed areas, such as the ears, lips, brows, back of the neck, hands, nails, and feet.
While sunblocks/sunscreens are generally considered safe and effective, some individuals may experience certain side effects. Here are some potential side effects associated with sunblocks:
- Skin irritation: Some people may experience skin irritation or allergic reactions to certain ingredients in sunblocks. This can manifest as redness, itching, or a rash. If you have sensitive skin or a history of allergies, it's important to look for sunblocks labeled as hypoallergenic or formulated for sensitive skin. Patch testing on a small area of skin before widespread use can also help identify any potential reactions.
- Eye irritation: Sunblocks should be kept away from the eyes as they can cause irritation or stinging. If sunblock accidentally gets into your eyes, rinse them with water immediately.
- Acne or breakouts: Certain sunblocks, particularly those with thicker formulations or certain comedogenic (pore-clogging) ingredients, may contribute to acne or breakouts in individuals prone to such skin conditions. To avoid this, look for sunblocks labeled as oil-free or non-comedogenic.
- Greasy or heavy feeling: Some sunblocks, especially those with higher SPF or water-resistant formulations, can feel greasy or heavy on the skin. This may be less preferable for those with oily or combination skin types. Choosing lighter formulations or those specifically labeled as lightweight can help minimize this effect.
- Residue on clothing: Some sunblocks may leave a white residue on clothing, particularly those containing physical sunscreen ingredients like titanium dioxide or zinc oxide. It's advisable to allow the sunblock to fully absorb into the skin and dry before dressing to minimize this issue.
- Vitamin D synthesis: Sunblocks, by their nature, block the UV rays necessary for the body to produce vitamin D. While it's important to protect the skin from excessive sun exposure, it's also essential to ensure adequate vitamin D levels through diet or supplementation. Take vitamin D with vitamin K2 for better absorption. (see our other posts on the topic)
Physical (Sunblock) Vs. chemical (sunscreen)
Here's a breakdown of the differences between them:
Physical Sunblocks (Mineral Sunscreens):
- Ingredients: Physical sunblocks contain mineral ingredients, primarily titanium dioxide and/or zinc oxide. These minerals work by sitting on top of the skin and physically blocking or reflecting UV rays away from the skin.
- Protection mechanism: Physical sunblocks create a physical barrier on the skin's surface that prevents UV rays from penetrating the skin.
- Broad-spectrum protection: They provide broad-spectrum protection, shielding against both UVA and UVB rays.
- Immediate effectiveness: Physical sunblocks start working as soon as they are applied to the skin.
- Minimal risk of irritation: They are generally well-tolerated by most skin types, including sensitive skin, as they are less likely to cause skin irritation or allergic reactions.
- Visible residue: Physical sunblocks can sometimes leave a white or chalky residue on the skin, which can be less desirable for those with darker skin tones.
- Environmental impact: Some traditional forms of physical sunblocks may contain nanoparticles of minerals, which have raised concerns about their impact on the environment when washed off into water sources. I recommend using micronized not nanoparticle sunblocks.
Chemical Sunblocks (more correctly termed Sunscreens):
- Ingredients: Chemical sunblocks contain organic (carbon-based) compounds, such as avobenzone, oxybenzone, octinoxate, and others. These chemicals work by absorbing UV rays and converting them into heat, which is then released from the skin.
- Protection mechanism: Chemical sunblocks work by penetrating the skin and absorbing UV rays before they can cause damage.
- Broad-spectrum protection: Most chemical sunblocks provide broad-spectrum protection against UVA and UVB rays, although some ingredients may be more effective against one type of ray than the other.
- Activation time: Chemical sunblocks require about 15-30 minutes to be absorbed into the skin and become effective. It begins working/getting neutralized the moment you applied it whether you are outdoors or indoors so make sure you count 2 hours from the moment you applied it and remember to reapply.
- Potential for irritation: Some individuals may be sensitive or allergic to specific chemical sunscreen ingredients, leading to skin irritation or photoallergic contact dermatitis.
- No visible residue: Chemical sunblocks generally do not leave a visible residue on the skin, making them more desirable for all skin tones.
- Environmental considerations: Certain chemical sunscreen ingredients, like oxybenzone, have raised concerns regarding their potential impact on coral reefs and aquatic ecosystems. Some regions have implemented bans or restrictions on these ingredients to protect marine environments. (examples of places that ban these sunscreens are Hawaii and Australia)
There has been some debate and concern regarding the potential hormonal effects of certain chemical sunblock ingredients, specifically oxybenzone and related compounds. These concerns stem from studies suggesting that these chemicals may have the ability to mimic or disrupt hormones in the body. However, it's important to note that the evidence on this topic is still evolving, and the overall risk to human health is not yet fully understood.
Here are some key points to consider:
- Hormonal disruption: Oxybenzone, one of the most scrutinized chemical sunblock ingredients, has been shown to have weak estrogenic effects in laboratory studies. This means that it may have the potential to interact with hormone receptors in the body. However, the concentrations of oxybenzone used in these studies are much higher than what is typically found in sunblock products.
- Human exposure: When used as directed, the amount of oxybenzone and other chemical sunscreen ingredients that are absorbed through the skin and enter the bloodstream is generally considered minimal. Nonetheless, further research is needed to understand the potential effects of long-term, low-level exposure.
- Regulatory standards: Regulatory agencies, such as the U.S. Food and Drug Administration (FDA) and the European Commission's Scientific Committee on Consumer Safety, have evaluated the safety of chemical sunscreen ingredients. They consider currently approved chemical sunblock ingredients safe for use in sunscreens when used as directed.
- Cancer risk: Regarding the link between chemical sunblocks and cancer, there is limited evidence and conflicting studies on this topic. Some studies suggest a potential association between oxybenzone and an increased risk of certain cancers, while others do not support this link. It is most harmful to children due to its association with skeletal endocrine disruption and DNA cell damage. The International Agency for Research on Cancer (IARC), which is part of the World Health Organization (WHO), has stated that there is currently inadequate evidence to determine the carcinogenicity of oxybenzone.
It's important to approach the topic of sun protection holistically. The use of any sunblock, whether physical or chemical, is crucial to protect against the harmful effects of UV radiation. The known risks of excessive sun exposure, such as sunburn and skin cancer, outweigh the theoretical risks associated with the use of sunblock.
Several studies have been conducted to explore the potential correlation between sunblocks and cancer. However, it's important to note that the current body of scientific evidence does not provide conclusive findings that directly link the use of sunblocks to an increased risk of cancer. Here are some notable studies and key findings:
- Oxybenzone and hormone disruption: Some laboratory studies have indicated that oxybenzone, a chemical sunblock ingredient, may have weak estrogenic effects and the potential to disrupt hormone signaling. However, these studies have typically used higher concentrations of oxybenzone than what is typically found in sunblock products. The extent and significance of these effects in real-world conditions and their impact on human health are still being investigated.
- Epidemiological studies on melanoma risk: Melanoma, a type of skin cancer, is associated with excessive exposure to UV radiation. Several epidemiological studies have examined the relationship between sunscreen use and melanoma risk. While some studies have suggested a potential association between sunscreen use and increased melanoma risk, others have found no significant correlation. It's worth noting that these studies often have limitations, such as recall bias and confounding factors, and more research is needed to draw definitive conclusions.
- Sunblock effectiveness in reducing skin cancer risk: Multiple studies have demonstrated the effectiveness of sunblocks in reducing the risk of skin cancer. Proper sun protection, including the use of sunblocks, has consistently been shown to help prevent sunburn and reduce the risk of various types of skin cancer, including basal cell carcinoma and squamous cell carcinoma.
- Regulatory assessments: Regulatory agencies, such as the U.S. Food and Drug Administration (FDA) and the European Commission's Scientific Committee on Consumer Safety, evaluate the safety of sunblock ingredients based on available scientific data. These agencies have generally concluded that approved sunblock ingredients are safe for use when used as directed, although ongoing research and safety evaluations continue.
It's important to consider that protecting the skin from UV radiation through the use of sunblocks, along with other sun protection measures, remains crucial in preventing sunburn and reducing the risk of skin cancer. It's always advisable to follow product instructions and consult with a dermatologist for personalized guidance based on individual circumstances.
As always here at @levitdermatology we are committed to helping you live longer, healthier and safer- Our mission: Health and Beauty is our duty!
Be good, do good, and may good come your way.