| Health

Should You Wear Sunblock?

By Tyler Woodward

"Men, women and children over 6 months of age should use sunscreen every day" ~ The Skin Cancer Foundation

Today more cases of skin cancer are diagnosed annually than every other type of cancer combined. Meanwhile, vitamin D deficiency is said to be an epidemic affecting over a billion people worldwide. Today nearly everyone is using sunblock, yet both the rate of skin cancer and vitamin D deficiency are rising... Something doesn't add up, what's the missing link?

Key Takeaways:


    rates of skin cancer

    Skin cancer is on the rise across America and is actually the most commonly diagnosed cancer. In fact, more cases of skin cancer are diagnosed annually than all other forms of cancer combined. From 1997 to 2014 there has been a 77% increase in the diagnosis and treatment of skin cancer. Ironically, sunscreen and sunblocks seem to be getting more and more popular, so what is driving this increase in skin cancer? It is well established today that the sun releases harmful forms of UV (ultraviolet) radiation which can cause damage to your skin if absorbed in excess. This results in sunburn, sun poisoning, and even possibly cancer down the line. 

    On the other hand, it is also well established that it is extremely important to get enough sun daily to facilitate your body’s natural vitamin D  production. Not to mention the sun’s ability to give us that glorious golden-brown tan that so many of us desire and often associate with good health and beauty.  

    So which one is it?

    Wear sunscreen or don’t?

    Embrace the sun or avoid it?

    Let’s dig in…

    Sunlight & UV Radiation:

    Sunlight & UV

    This graph is known as the light spectrum. Basically, it categorizes the type of light/radiation by how fast the light moves or its wavelength. Gamma rays and x-rays have the shortest wavelength, AM and shortwave radio have the longest wavelength, and the visible light spectrum ends up somewhere in the middle. The sun emits what are known as ultraviolet rays which we split up into three types of radiation: 

    • Ultraviolet light A (UVA light)
      • UVA light has the longest wavelength of the three and is able to penetrate through our atmosphere. Luckily UVA light is the least concerning of the three because of its longer wavelength, but it can still damage your eyes if absorbed directly and may also contribute to skin damage. Although we cannot see UVA light, certain species of birds and insects are able to.
    • Ultraviolet light B (UVB light)
      • UVB light (also known as UVB rays) is between UVA and UVC in terms of wavelength and about 95% of UVB light is absorbed3 when passing through the atmosphere. UVB light is the main cause of skin damage and cancer, but it is also required for vitamin D production and therefore necessary for our survival. 
    • Ultraviolet Light C (UVC light)
      • UVC light is the most harmful form of radiation, but it is estimated that nearly 100% of it is absorbed in the atmosphere. Interestingly, synthetically produced UVC light is commonly used as a disinfectant by killing any microorganisms present in the food, water, air, or surface of choice.

    The UV Index:

    UV Index

    The UV index is a scale provided for by the EPA (environmental protection agency) that ranks how strong the sun’s rays will be on a given day. The UV index is always given for the predicted UV strength at noon, when the sun is at its peak. The UV index will vary depending on a number of factors including:

    • Cloud Coverage - Depending on the types of clouds and how thick they are, clouds can either block radiation from passing through or deflect the radiation, strengthening it
    • Altitude - UV radiation increases by about 2% every 1,000 feet above sea level
    • Longitude (Distance From The Equator) - The sun is strongest at the equator
    • Types of Land - Snow reflects up to 80% of UV radiation, sand reflects about 15% and water about 10%

    Understanding Sunblock:

    Sunscreen was invented by Franz Geiter in 1938 as a method of protecting his skin from sunburn after hiking through swiss alps. The original formula was made up of a red petroleum jelly which, when applied to the skin, helped to reduce the amount of radiation that passed through into the skin. The original formula was cited to have an SPF (Sun-protection factor) of about 24. In the following years, a US soldier added cocoa butter and coconut oil to the petroleum jelly, which would eventually become the first commercially produced sunscreen, Coppertone. 

    Sunblock vs. Sunscreen:

    Sunblocks and sunscreens essentially work by creating a “layer” between your skin and the sun. Sunblocks, also commonly referred to as mineral oils or physical sunscreen, use inorganic compounds  (they don't contain carbon) and are generally insoluble. Meaning that they are not absorbed into your skin, rather they lay on top of it. Sunblocks normally utilize compounds containing zinc oxide and/or titanium dioxide.

    Sunscreens, also known as chemical sunscreens, generally are formed using organic (carbon-based) compounds and are soluble or absorbed into your skin. Sunscreens aim to “offload” some of the sun’s radiation by absorbing them into the lotion instead of into your skin. As the sunscreen works by absorbing radiation, the compounds naturally break down and release heat. Sunscreens (even broad spectrum) typically use avobenzone, oxybenzone, or PABA (para-aminobenzoic acid) in their formulations. 

    *Note* - It is important to recognize that anything that we put on our skin, whether or not it is absorbed, has the potential to damage our skin and/or disrupt our endocrine (hormonal) system. So it is important to make sure that the ingredients present in the sunscreen or sunblock do not exhibit any harmful effects on our body. 

    What about SPF?

    SPF stands for sun protection factor. “Factor” in this case literally means what you multiply by to calculate how much longer you can be in the sun without burning or reddening compared to your bare skin. If you normally burn after 30 minutes in the sun, by applying SPF 30, it will theoretically take you 30X as  long to burn. I would take this liberally as according to most dermatologists the majority of people do not apply enough sunblock and this does not take into consideration the UV index of where you are currently located.

    Skin Structure & Cancer:


    To understand how and why skin cancer occurs, we must have some understanding of the structure of our skins and how it forms.

    Our skin is comprised of three layers:

    The Epidermis - The epidermis (“epi” meaning outer and “dermis” meaning skin) is the outermost layer of the skin  which creates a waterproof barrier between our body and the environment. This is where skin cancers most commonly occur. There are three main types of skin cells or keratinocytes that exist in the epidermis:

    • Squamous cells - The outermost layer of our skin is made up of flat squamous cells which die due to lack of oxygen as they move further away from our capillaries. This creates the waterproof barrier present in our skin. These cells are replaced about every 14 days6.
    • Basal cells - Basal cells are fast replicating cells that replace the squamous cells as they are shed off of our skin's surface.
    • Melanocytes - Melanocytes produce the pigment melanin, which is responsible for our natural skin color and our ability to tan as our cells absorb sunlight. Depending on your skin tone, everyone produces a different amount of melanin. People with the darkest skin naturally produce the most melanin and vice versa for those with more fair skin. For every melanocyte there are about 10 basal cells that exist. 

    The Dermis - The dermis, which resides below the epidermis, contains our connective tissue, sweat glands, hair follicles, and all of the capillaries present in our skin.

    The Subcutis or Subcutaneous Layer - Also known as the hypodermis (hypo meaning below), the subcutis is the layer of fat that resides beneath the dermis and also contains the main arteries that bring blood to our skin. 

    Main Types Of Skin Cancer: 

    • Squamous Cell Carcinoma - Accounts for about 20% of skin cancers7
      • Squamous cell carcinoma is the least dangerous form of skin cancer because it occurs on the outermost layer of our skin. This makes it the easiest to remove, while also making it less likely to spread.
    • Basal Cell Carcinoma - Accounts for about 80% of skin cancers and is by  the most common form of skin cancer
      • Basal cell carcinoma is also very rare to spread to other parts of the body, but if left untreated/unremoved, it is possible to spread. Basal cells is 
    • Melanoma - (affecting the melanocytes) is the most rare, but also most dangerous form of skin cancer

    Cancer 101:


    Disclaimer - *This is a very simplified version of cancer*

    Cancer is the result of a change in our genes and the expression of our genes, which results in the loss of function of the cell. Cancer cells have a few characteristics that separates them from normal, healthy cells:

    • Cancer cells proliferate/replicate indefinitely and, depending on the form and stage of cancer, can replicate very rapidly. Cancer cells do not require any external signals from the environment or nearby cells to replicate.
    • When normal cells replicate, they undergo a series of checks and balances to ensure that they are functioning optimally, and if not, will undergo apoptosis or programmed cell death. Cancer cells do not undergo apoptosis, despite not forming properly.
    • Cancer cells often lose their normal structure, which can allow them to metastasize (spread) throughout the body because they are no longer anchored to cells around them. 

    What About Benign Vs Malignant Tumors?

    Benign tumors are noncancerous and do not metastasize or spread throughout the body. Benign tumors are much less worrisome, but can still have negative effects on your health by consuming excess nutrients. Also, if they grow large enough, they can exert pressure on nearby blood vessels and nerves. Malignant tumors are cancerous tumors that have the ability to spread throughout the body. Benign tumors do have the potential to become cancerous or malignant. 

    Vitamin D:

    Vitamin D

    Vitamin D, also known as the sun nutrient, is an essential hormone that our body is naturally capable of producing by absorbing sunlight, specifically UVB rays. Yes, vitamin D is actually a steroid hormone and regulates the function of over 200 genes and is essential for growth and development8. Vitamin D also exhibits a protective effect on our skin, protecting our skin from skin cancer9.  

    Vitamin D deficiency affects over a billion people worldwide and can result in countless health issues like obesity, diabetes, hypertension, Alzheimer’s, and osteoporosis. In order to produce vitamin D, our skin needs to absorb enough UVB radiation from the sun through our skin to facilitate its production. Normally,  50-90% of our body's vitamin D is produced by absorbing sunlight in the skin.  We can consume vitamin D through our diet or supplementation, but this is typically not enough to satisfy our vitamin D requirements.

    Additionally, the darker your skin tone, the more sunlight you will have to absorb to produce  enough vitamin D. This is one of the explanations in evolution as to why our skin tones became lighter as we moved away from the equator. People living near the equator experience much more intense sun exposure and require darker skin to protect themselves from the sun’s radiation. As our species migrated away from the equator and our sun exposure/intensity lessened, lighter skin tones became more advantageous, as they allowed us to produce enough vitamin D with less sun exposure.  

    While the role of vitamin D deficiency and skin cancer is still undetermined, having adequate Vitamin D levels has been associated repeatedly with decreased risk of other forms of cancer. Another study found, "The majority of studies found a protective relationship between sufficient vitamin D status and lower risk of cancer" (Garland et. al).

    Vitamin D3

    As you now know how important Vitamin D is for the body, if you want to ensure that you are getting enough make sure to check out our vitamin D supplement. Our liquid D3 supplement is encased in liquid MCT coconut oil in order to ensure that it is highly absorbed by the body. We also include more than enough servings in each bottle to last you well beyond the winter months.

    We now understand that sunlight and UVB radiation is necessary for the production of Vitamin D in our body. We also know that excess sunlight/radiation can cause mutations in our genes, which can result in the formation of cancer. Lastly, we know that sunblock and sunscreen aim to limit the amount of radiation we absorb from the sun. 

    The question remains: Should You Wear Sunblock?

    Should You Wear Sunblock

    Sadly, the answer is not in black and white and the answer really depends on the individual. Let me explain…

    We need to receive adequate sunlight in order to remain in good health and this means absorbing enough radiation. The key to this equation is to not absorb excess radiation. Too much sunlight causes skin reddening and eventually burning, resulting in our skin cells literally dying. The outermost layer of our skin cells, the squamous cells, replace rapidly enough that they rarely become cancerous. The bigger issue is when too much radiation reaches the “bottom” of the epidermis, affecting our melanocytes and basal cells. These cells do not replicate themselves nearly as often and if exposed to too much radiation over time, they can accumulate harmful mutations that can result in cancer.  

    How much sunlight is too much?

    Again, this answer comes down to how strong the sun is and your skin pigment. People with darker skin need much more radiation to burn and also need to absorb more sunlight to produce enough Vitamin D. As long as your skin is not burning, sunblock is likely not necessary. 

    Is tanning (naturally) bad for your skin?

    This is going to be a controversial opinion, but I would say no. Tanning is our body’s natural response to being exposed to sunlight and radiation. Our melanocytes begin to produce increased amounts of melanin which temporarily darkens the pigment of our skin. Are people with darker skin tones’ less healthy or more at risk for cancer because their body naturally produces more melanin? No, absolutely not, in fact they exhibit a much lower rate of skin cancer.

    Tanning is one of our body’s built-in protection mechanisms to reduce our risk of absorbing excess radiation. This is not to say that tanning is “healthy”, as it is a stress placed on our body. Tanning in many ways is a lot like going to the gym. When you lift weights, you create a stress or stimulus on your muscles. If your body has the capability to recover from that stimulus, it can result in new adaptations of increased muscle size and strength. When excess stress is placed on your body that it can no longer recover from is when the negative effects begin to incur. 

    What about tanning beds?

    Tanning beds are a highly concentrated form of sunlight radiation that is designed so your cells produce a lot of melanin very rapidly. The more sun radiation you are exposing yourself to in a smaller amount of time, the more stress you are placing on your body. Tanning beds also mostly utilize UVA light/radiation, which our body cannot use to produce vitamin D. I would also assume that because of how close the UV lights are to your body in a tanning bed compared to the sun, they may also penetrate deeper into your skin more rapidly than sunlight. This may result in more mutations occurring in your basal cells and melanocytes at a faster rate. The use of tanning beds has been shown to increase the risk of melanoma by 20%, squamous cell carcinoma by 67%, and basal cell carcinoma by 29%10.

    Does tanning cause wrinkles?

    It is pretty well established that tanning causes wrinkles in your skin to form over time, but this is not the whole story. Wrinkles are caused by the breakdown of the elastin and collagen fibers in the deeper layers of our skin, the dermis and subcutaneous layers. As these fibers break down, our skin loses its elasticity, or its ability to stretch, resulting in the formation of wrinkles and/or the leathery skin typically associated with life-long sunbums. The collagen fibers in our skin have the ability to heal over time, while elastin fibers cannot.

    The remainder of the story comes down to the differences in our nutrition compared to that of our ancestors. Our diet today consists of significantly more polyunsaturated fats compared to our ancestors. If you read my article, “Fats: The Macronutrient Guide”, you understand that the double bonds present in unsaturated fats make them much less stable. When polyunsaturated fats are introduced in our body due to the high heat, the double bonds oxidize resulting in free radicals being released in our body.  The release of free radicals into the body can cause oxidative stress, inflammation, among many other health issues down the line.

    These polyunsaturated fats that we consume in our diet can end up being used in the cellular membranes in newly formed cells. When these polyunsaturated fats in our skin cells are exposed to both heat and sunlight, they oxidize causing additional damage in our skin which can impair the skin's ability to heal itself. This leads to skin damage and the formation of wrinkles over time . Avoiding these polyunsaturated fats when possible can significantly reduce the harmful effects of the sun’s radiation. 

    Additionally, the consumption of polyunsaturated fats (PUFAs) has been repeatedly associated with the increased risk of skin cancer among others. Here are a few studies showing this:

    Read More: The Nonessential, "Essential" Fatty Acids

    So, the answer comes down to wearing sunblock when you need to in order to avoid absorbing excess radiation.  

    Cancer-Causing Agents in Sunblocks:


    As I mentioned before, anything that you put on your skin has the potential to cause damage to the nearby cells. Many sunscreens and sunblocks today, as well as many cosmetics, contain carcinogens or cancer-causing agents that result in mutations in the DNA of skin cells. I highly recommend checking out Christopher Walker’s video on the subject: https://www.youtube.com/watch?v=XBu-qQl8jIg&t=181s

    Here is a list of US government classified carcinogens and endocrine disruptors that are used in many of the sunscreens and sunblocks that we use in order to protect ourselves from the sun:

    • Benzophenone
    • 4-mbc
    • Avobenzone
    • Homosalate
    • Octocrylene
    • Octinoxate

    I have included a list of studies at the bottom of this article from Christopher Walker’s video that demonstrate the carcinogenic effects of these substances.

    Healthy Sunblocks:

    coconut oil

    If you are looking for a sunblock that does its intended effect without compromising our health, I recommend looking for zinc-oxide based sunblock or mineral oil. Coconut oil or cocoa butter can also be a great addition or used by itself as a low intensity sunblock. Here are a few all-natural sunscreen that I highly recommend: 

    1. Pronounce Skincare SkinShade
    2. SunBum
    3. Pronounce Skincare

    *We are not associated with any of these sunscreen brands*


    My goal in writing this article, as always, is to provide you with logically-based principles that you can use to form your own conclusions regarding any information you may come across within this subject. Remember, I am not a doctor or medical professional. I just look at the science and put it into layman’s term, so anyone can understand it and are able to make more educated decisions on these topics as a result. I really hope you found this article interesting and if you have anything to add to this article, or any comments or criticism, feel free to reach out to me on our facebook groups (The Thermo Diet Community Group, The UMZU Community Group) or on Instagram @tylerwoodward_fit. Also, please feel free to share this article with anyone that might be interested.

    Thanks for reading!

    Until next time… be good

    ~Tyler Woodward


      1. https://journals.lww.com/jdnaonline/fulltext/2020/05000/skin_cancer_rates_rising.2.aspx
      2. https://health.usnews.com/health-care/for-better/articles/why-is-skin-cancer-rising
      3. https://www.sciencedirect.com/science/article/pii/S1044579X20301140?via%3Dihub
      4. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1470481/
      5. http://solar-center.stanford.edu/about/uvlight.html#:~:text=About%2095%25%20of%20all%20UV,completely%20absorbed%20by%20Earth's%20atmosphere.
      6. https://www.weldricks.co.uk/news/the-history-of-sunscreen
      7. https://www.epa.gov/sites/production/files/documents/uviguide.pdf
      8. https://www.nursingtimes.net/clinical-archive/dermatology/skin-1-the-structure-and-functions-of-the-skin-25-11-2019/
      9. https://www.cancer.org/cancer/basal-and-squamous-cell-skin-cancer/about/what-is-basal-and-squamous-cell.html
      10. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3068797/
      11. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3687803/
      12. https://www.aad.org/public/diseases/skin-cancer/surprising-facts-about-indoor-tanning
      13. https://www.the-dermatologist.com/article/7850
      14. https://cancerres.aacrjournals.org/content/62/2/433
      15. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3761560/
      16. https://cebp.aacrjournals.org/content/27/7/776?utm_source=ETOC+Master&utm_campaign=daeed37e9a-EMAIL_CAMPAIGN_2018_06_28_08_05&utm_medium=email&utm_term=0_aae0ec8d4d-daeed37e9a-160765125

    Benzophenone - sunscreen






    4 MBC - sunscreen




    Avobenzone - sunscreen



    Homosalate - sunscreen


    OctoCrylene - sunscreen




    Octinoxate - chemical sunscreen


    Endocrine Disruptors

    Benzophenone - 






    4 MBC -

    https://www.ncbi.nlm.nih.gov/pubmed/2... (This study also included other chemicals stating that there are negative effects induced by these chemicals in animals which include reproductive/developmental toxicity and disruption of hypothalamic-pituitary-thyroid axis.)