Most people believe exposure to the sun can cause cancer. However, many people are still unaware that the chemicals in your favorite sunscreen may CAUSE CANCER!
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“Research has found that many sunscreens contain chemicals that mimic estrogen in the body, disrupt the endocrine system, and can play a significant role in breast cancer development” [1]. Hormone disruptors can affect how estrogen and other hormones act in the body by blocking them or mimicking them. "Because estrogen can make hormone-receptor-positive breast cancer develop and grow, many women choose to limit their exposure to these chemicals that can act like estrogen” [2].
In May of 2019, the U.S. Food and Drug Administration published an article entitled, “Shedding New Light on Sunscreen Absorption” in which the author discussed new JAMA research showing that some sunscreen chemicals can penetrate the skin and end up in our blood at levels above FDA’s thresholds for safety testing.
The study published in the May 2019 Journal of the American Medical Association gained much attention at the time. It found that every patient included in the randomized clinical trial (RCT) testing over-the-counter (OTC) sunscreens “quickly developed systemic levels of active ingredients that exceeded the 0.5 ng/mL concentration the US Food and Drug Administration (FDA) guidance says should trigger systemic safety testing” [7]. The study concluded that “systemic concentrations greater than 0.5 ng/mL were reached for all 4 products after 4 applications on day 1. The most common adverse event was rash, which developed in 1 participant with each sunscreen” [8].
The FDA continues to recommend broad-spectrum sunscreens with SPF values of at least 15 and states these measures should be used with other protective gear as critical elements for preventing skin cancer and protecting the skin from sunburn and other UV damage [13].
Everyone should do their best to avoid sunscreen chemicals linked to systemic absorption and cancer. Make sure you read the labels on sunscreens, cosmetics, and other personal care products prior to purchasing. Try your best to avoid products that list chemical UV filters, “such as octinoxate, octyl methoxycinnamate, benzophenone, oxybenzone, PABA, and padimate O” [1]. There are some safer products on the shelf that contain zinc oxide or titanium as the main active ingredient. I have used a variety of organic and non-organic zinc oxide and “natural” sunscreens over the past few years. Some I have tried were great, and others were awful! I am the type of person who loves to learn new skills and make my own products, so naturally, I did a bit of research and purchased supplies in order to make clean, non-toxic sunscreen for my family. If you are unsure if the product you are using is clean or not, you can use EWG or Think Dirty to check your products.
Studies on SPF Values of Natural Ingredients
Most of the ingredients in this natural sunscreen recipe have a natural SPF value that has been reported in scientific studies. There are also several other natural oils that have SPF value, this list is not inclusive. I will do a brief review of related studies.
A 2000 study in Food Chemistry found that Red Raspberry seed oil has an SPF of 28-50 against UVB rays and 8 SPF against UVA rays [10].
Zinc Oxide has an average SPF of 2-20, depending on the percentage of active ingredients included in the product. “Microfine zinc oxide protects against a wide range of UVA, including UVA 1 (340 to 400 nm). It is very photostable and does not react with other UV filters. It is more effective than titanium dioxide in regard to UVA protection” [4].
Carrot seed oil has a natural SPF of 40. A 2016 study reports carrot seed oil, “contains a-pinene, camphene, b-pinene, sabinene, myrcene, y-terpinene, limonene, b-bisabolene, geranyl acetate, and carotol. It helps in healing abscesses, boils, and other skin disorders. It nourishes, tightens, and rejuvenates skin” [11].
All of the following are referred to as Carrier Oils and can be used interchangeably
A 2016 study in the International Journal of Pharmacology Research reported that the SPF of wheat germ oil was found to be 22 [12].
Studies indicate Avocado oil has a natural SPF of 15, contains high levels of phytosterols and antioxidants like vitamin E, and has a healthy amount of monounsaturated fats [11].
Research published in the 2010 Pharmacognosy Research reported the SPF value of a variety of natural oils. The research “concluded that olive oil and coconut oil have the best SPF values, a finding that will be helpful in the selection of fixed oil during the formulation of sunscreens” [3]. Olive oil and coconut oil were found to have an SPF value of around 8. Castor oil was shown to have an SPF value of around 6, and the SPF value of almond oil was reported to be around 5. Jojoba and Sunflower oils have a similar SPF of about 4 to 6 [12].
Hemp Seed Oil has a natural SPF of 6. The oil has unique transmittance in both UVB and UVA (320–400 nm) regions and can, therefore, be used as a UV protectant with relatively high shielding power (SPF) and protection factor (PFA) scores. Therefore, hempseed oil may provide protection against both UVA and UVB [9].
Shea, Cocoa, & Mango Butter
Shea butter is high in vitamins A and E. Depending on the source, Shea butter reportedly has an SPF of 2-10. “Cinnamate esters of triterpene alcohol, which are the main constituent of Shea butter’s unsaponifiable fraction, are known to have strong absorbance of UV radiation in the wavelength range at 250-300 nm” [6]. Cocoa and Mango butter have a similar consistency and SPF value. These kinds of butter can be used interchangeably in any homemade sunscreen recipe.
Homemade Sunscreen Recipe
Keep in mind this is a homemade product and a personal recipe. This product has not been clinically tested; therefore, it does not have any specific confirmed SPF value. Estimates are based on studies related to the SPF value of specific ingredients and are for anecdotal purposes only.
Servings 1 cup
Ingredients
1⁄2 cup Carrier oil of your choice (can infuse with herbs first if desired)
1⁄4 cup Coconut oil
1⁄4 cup shaved Beeswax or beeswax pastilles
2 TBSP Shea, Cocoa, or Mango Butter
1 tsp Red Raspberry seed oil
1 tsp Carrot seed oil
2 TBSP Zinc Oxide = 10%
Essential oils of your choice for scent (DO NOT USE ANY CITRUS OILS)
Instructions
1) Combine all the ingredients other than zinc oxide in a pint-sized or larger glass jar.
2) Fill a saucepan or double boiler with a couple of inches of water and place it on the stove.
3) Put a lid loosely on the jar and place it in the pan.
4) Shake or stir the jar occasionally to mix ingredients as they melt.
5) When the ingredients are completely incorporated and melted, stir in the zinc oxide. Make sure you do not inhale the zinc oxide. You can use a mask or t-shirt to cover your nose if needed.
6) Then, pour into whatever you will use for storage. The product can be stored in a new tin, deodorant push-up, lotion squeeze tube, glass/plastic jar, or container of your preference.
7) Stir a few times as it cools to make sure zinc oxide is incorporated.
8) Store at room temperature in a cool, dark location or in the refrigerator to increase shelf life.
I used Calendula-infused Avocado oil, which is why the color has a yellow/green tint. This natural sunscreen forms a solid and rolls up well, maintaining its shape. This recipe is also liquid enough to squeeze out of a traditional tube or lotion bottle. This natural sunscreen rubs in clear, not white. It is a little oily due to the ingredients, but not sticky. You can also make sunscreen bars by using many of the same ingredients!
You can adjust the SPF of your homemade sunscreen by adding/subtracting zinc oxide in relation to the amount of lotion.
Here's a general chart for zinc oxide recommendations:
For SPF 2-5: Use 5% zinc oxide
SPF 6-11: Use 10% zinc oxide
For SPF 12-19: Use 15% zinc oxide
SPF 20+: Use 20% zinc oxide
This recipe only contains 10% zinc oxide. I chose this percentage of zinc oxide because carrot seed oil and red raspberry seed oil are also high in SPF. If you increase the amount of zinc oxide, expect the product to be harder to rub in and whiter in appearance. To decrease to 5%, use only 1 TBS. To increase to 15%, use 3 TBS. To increase to 20%, use 4 TBS.
The SPF value has been shown to decrease with the increase in the concentration of Beeswax. However, “beeswax extract is able to retain the SPF of sunscreen for longer periods of time and should, therefore, still be an integral component in the sunscreen mixture” [5].
Please note:
This sunscreen is not waterproof. You will need to reapply after sweating or swimming, and every two hours at minimum. This product works well for my children and me. Please do not use it if you are allergic to any of the ingredients. You can leave out or substitute whichever oils and ingredients work best for you.
Unlike most sunscreens, natural and homemade sunscreens are controversial. Homemade sunscreens may not have as high (or broad spectrum) SPF and may not protect as fully against UVA and UVB rays. The best way to avoid sunburn or damage is to avoid sun exposure during afternoon hours when the sun is highest in the sky from about noon to 3 pm and to cover sensitive areas, especially if you will be exposed for long periods of time. I am not recommending avoiding traditional or store-bought sunscreen entirely, only that you find a clean product.
If you just don’t have the time or patience to make your own homemade sunscreen, do not fret, I have listed a few great non-toxic options below. I prefer to buy all organic ingredients to make my homemade sunscreen from Mountain Rose Herbs because they have the widest range of high-quality products, DIY ingredients, and supplies. When it comes to household items, I have found that iHerb has the most affordable prices by far when it comes to online household and supplement shopping. There are numerous natural mineral-based sunscreens available on iHerb including but not limited to; Badger Company, Mad Hippie, and Thinksport. Badger Company has SPF 30 and 40 formulas available for babies, kids, and adults. Thinksport has SPF 50+ formulas available for babies, kids, and adults.
References
1.) Breast Cancer Prevention Partners. (2019). Sunscreens (UV Filters). Retrieved from Breast Cancer Prevention Partners: https://www.bcpp.org/resource/uv-filters/
2.) Breast Cancer.org. (2020,09 11). Exposure to Chemicals in Sunscreen. Retrieved from Breast Cancer.org: https://www.breastcancer.org/risk/factors/sunscreen
3.) Deep Kaur, C., & Saraf, S. (2010). In vitro sun protection factor determination of herbal oils used in cosmetics. Pharmacognosy Research, 22-25.
4.) Gabros, S., Nessel, T. A., & Zito., P. M. (2020, 09 29). Sunscreens And Photoprotection. Retrieved from StatPearls : https://www.ncbi.nlm.nih.gov/books/NBK537164/
5.) Hao, I. T., Qi, J. L., & Yeh, C. H. (2017). Comparative Sun Protection Factors of Essential Oils in Formulation of Natural Sunscreens. Retrieved from http://ircset.org/anand/2017papers/IRC-SET_2017_paper_S3-3.pdf
6.) Israel, M. O. (2014). Effects of topical and dietary use of shea butter on animals. American Journal of Life Sciences, 303-307.
7.) Kelly, J. (2019, 05 06). FDA Finds High Systemic Absorption of Sunscreen Ingredients. Retrieved from Medscape: https://www.medscape.com/viewarticle/912651
8.) Matta, P. M., Zusterzeel, M. P., Pilli, P. N., & al et. (2019, 05 06). Effect of Sunscreen Application Under Maximal Use Conditions on Plasma Concentration of Sunscreen Active Ingredients. Retrieved from JAMA Network: https://jamanetwork.com/journals/jama/fullarticle/2733085
9.) Oomaha, D., Bussonb, M., & Godfreya, D. V. (2002). Characteristics of hemp (Cannabis sativa L.) seed oil. Food Chemistry, 33-43.
10.) Oomaha, D., Ladetb, S., & Godfreya, D. V. (2000). Characteristics of raspberry (Rubus idaeus L.) seed oil. Food Chemistry, 187-193. Retrieved from https://www.berrybeautiful.us/assets/characteristics-of-raspberry-(rubus-idaeus-l.)-seed-oil.pdf
11.) Raghavamma, S., Anjali, M., Amrutha, N., Hemalatha, T., & Nadendla, R. R. (2016). Assessment of Efficacy and Safety of Newly Formulated Natural Sun Protective Cream. IOSR Journal of Pharmacy and Biological Sciences, 119-124.
12.) Suryawanshi, J. A. (2016). In-Vitro Determination of Sun Protection Factor and Evaluation of Herbal Oils. International Journal of Pharmacology Research, 37-43.
13.) Woodcock, J., & Michele, T. (2019, 05 06). Shedding New Light on Sunscreen Absorption. Retrieved from U.S. Food & Drug Administration: https://www.fda.gov/news-events/fda-voices/shedding-new-light-sunscreen-absorption#2
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