The primary purpose of sunscreen products is to protect the body from dangerous sun irradiation. With an aim to block the harmful rays, these products must adhere to the skin, making it imperative to include certain penetration enhancers. The role of these enhancers is to take the sunscreen through the skin pores through absorption and penetration. As sunscreens can penetrate into the skin, the ingredients must not cause any internal harm. Careful analysis and thoughtful consideration of these factors can aid us in making the right decision.

Though direct exposure to sun rays can cause harm to our body, complete avoidance of the sun can be equally dangerous too.  Exposure to sunlight and penetration through the skin is the primary source of vitamin D intake, especially since food sources do not provide us with adequate amounts. According to doctors and medical studies all around the globe, exposure to direct sunlight for few minutes or hours in the early morning can be beneficial to our body. Contact between pigments under our skin and ultraviolet B form of radiation from the sun combine together to produce multiple units of Vitamin D. As one of the most essential vitamins for the body, Vitamin D is essential for calcium absorption, which strengthens bones and teeth. In addition, vitamin D plays a role in  healthy growth in children, boosts immunity in adults and assists in the overall functioning of the body.

While direct contact with sunlight can be beneficial for the vitamin D absorption, over exposure to harmful UV radiation or continuous contact with the sun can be dangerous. This makes it essential to protect the skin with the correct sunscreen product that can help instead of causing harm.

Every sunscreen product on the market involves an active ingredient. By filtering the harmful radiations from the sun, these ingredients act as the primary source of protection. These active ingredients can either be physical (mineral) filters or chemical based filters. While deciding the right choice of sunscreen from the wide array of advertisements, it is important to understand the consequences of both these physical and chemical products. Several studies and research have been carried out in this direction to know about the after effects of these ingredients.

Physical sunscreens: Physical barriers or mineral based barriers make use of zinc oxide or titanium dioxide nanoparticles to block the UV radiation. As these nanoparticles are inert and unable to penetrate or interfere with the cells of the skin, they do not cause any harm to the skin layers. Physical sunscreens have not demonstrated any significant impact over skin allergies or hormonal changes. According to a comparative report on harmful effects of the active ingredients, published by Environmental working group (EWG); physical sunscreens containing zinc oxide showed less than 0.01% skin penetration in human volunteers, with no evidence of skin allergies or hormonal imbalance. As physical sunscreens do not show any influential hazard to the skin, they were categorized under low toxicity group in the study.

These reports point to the harmless impact of physical sunscreens. With their inert components and beneficial effects, physical sunscreens can protect us from the harmful UV radiations without causing any harm in the long run.

Chemical sunscreens: involve chemicals such as oxybenzone, avobenzone, octisalate, octocrylene, homosalate and octinoxate. These chemicals can be either used alone or in combination of 2 or 3 depending on the formulation of the product. The chemical active ingredients in these sunscreens can pave way towards harmful effects. Though their primary aim is to block UV radiations from the sun, these chemicals are able to penetrate into the skin leading to skin damage, mutations, allergies and hormonal imbalances. With 1-9% cases of skin penetration, these chemicals were detected in body fluids such as breast milk. Presence in mother’s milk increases the risk factor of these chemicals as they can cause permanent damages to the nursing child too.

A case study published in the Journal of Allergy and Clinical Immunology points to the various adverse effects of oxybenzone. Oxybenzone can induce reactions such as skin irritation, phototoxicity, allergic contact dermatitis that may or may not require exposure to light to develop. The report also demonstrates the role of oxybenzone in eliciting life threatening systemic reactions in the form of anaphylaxis in susceptible individuals. The study concludes that increasing use of oxybenzone based sunscreens can lead to allergic reactions to the compound, harming the skin with adverse effects.

According to a case study published in the Journal of Skin Pharmacology and Physiology, penetration of sunscreens can lead to interference with cells of the lower epidermis. This interference can result into loss of cell proliferation, cell damage or mutations. The study concluded that the chemicals in most of the sunscreens can easily penetrate into the layers of the skin, with oxybenzone showing maximum absorption within the epidermal membranes. Though the skin penetration can result in harmful effects, the study did not point towards toxicity due to this rising concentration of chemicals.

A research paper published in Free Radical Biology and Medicine explores the role of chemical filters such as benzophenone, octocrylene, oxybenzone in skin cancers and mutations. According to the study, highly reactive oxygen species (ROS) are generated within the skin as a result of penetration by these harmful chemicals. As these reactive species can interact with cell proliferation in the skin, there can be probable effects such as mutations and skin cancer.

On the other hand, a study published in Islas labs showed a reduction in ROS effects upon the reapplication of chemical based sunscreens after every 20 minutes. The study showed that after 20 minutes of application, oxybenzone reduced the release of ROS, preventing any radiation or harmful effects on cell proliferation.

What can we use instead?

Even with weak clinical data, chemical based sunscreens are a cause for concern, at least in theory. By penetrating the skin layers and interacting with skin cells, sunscreens with chemical components can pose harm to the skin in the long run. That said, there are alternatives that are a lot safer. For instance, the inert nature of physical components doesn’t seem to pose similar threats to skin.

INORGANIC SUNSCREENS OR PHYSICAL BLOCKERS

Choosing mineral based physical sunscreens is one of the best options to block UV radiation. Opaque formulations of sunscreens with inorganic components were widely used to scatter or reflect the UV radiation. However, low cosmetic acceptability resulted in the failure of these sunscreens. Newer trends have paved way for micro-sized forms also termed as inorganic particular sunscreens. These sunscreens contain inorganic minerals such as titanium dioxide or zinc oxide that can scatter the UV radiation. Since these inorganic particles prevent the harmful UV radiation by means of a physical barrier, they do not enter into the layers of skin, dispelling any major concerns.

→ Some examples of mineral based sunscreen: Kiss my face SPF 30, 100% Pure Organic Pomegranate Antioxidant Hydration Lotion and Goddess Garden Kids SPF 30 Sunscreen Lotion.

SECONDARY PHOTOPROTECTION

Secondary photo protection involves use of agents that can block the DNA damage to skin cells. Most of this damage originates from the reactive oxygen species (ROS) produced due to UV radiation. While the enzymes, antioxidants, osmolytes, vitamins in our body can fight against the building of these reactive species, their effect cannot handle all the stress from the UV radiation and environmental pollutants. This makes it essential to make use of sunscreens that contain non-enzymatic or enzymatic antioxidants (AO). The following topical agents are used in external formulations in order to penetrate into the skin layers and exhibit their valuable effects.

• Antioxidants such as Silymarin derived from the milk thistle plant, Silybum marianum, is a flavonoid that can prevent harmful effect of ROS and prevent lipid oxidation. It has shown effects against the UV-B induced sunburn and UV-B induced tumors in mice. Water soluble vitamin C and fat soluble vitamin E also act as excellent antioxidants for the skin. Application of L-ascorbic acid and α-tocopherol has shown reduction in skin burning, photoaging, photocarcinogenesis and immunosuppression.
  • Green tea polyphenols possess anti-oxidation properties that are more effective than vitamin C or E. They are effective against singlet oxygen radicals, reactive oxygen species, hydrogen peroxide etc. besides possessing anti-inflammatory and anti-carcinogenic effects.
• Many sunscreens contain osmolytes such as taurine and ectione that show effects against UV radiation. These molecules regulate the cellular environment by means of hydration in response to stress or unusual environmental activities.

INTERNAL AGENTS OF PHOTO-PROTECTION

Besides external agents, internal dietary needs can also be altered for the benefits in skin care. Consuming a diet that is rich in antioxidants can do wonders for protection against skin cancers. An article ’10 ways to eat your sunscreen’ explores these options:

• Green leafy vegetables like spinach, kale, broccoli, cilantro, leeks, artichokes, parsley can prevent sun damage.
• Watermelon, papaya, apricots, pink grapefruits, tomato and all red fruits contain antioxidant ‘lycopene’ that can work against free radicals in the skin. Healthy women between 21-47 years who consumed 16 mg of lycopene through tomato paste and puree for 12 weeks showed significant effects against acute sun damage.
• Dark chocolate and cocoa contains phenols and catechins as antioxidants.
• Omega 3 fatty acids in salmon, sardines, mackerel, herring, sea weed, algae, flax, chia and hemp seeds can protect against sunburns and cancers.
• Pomegranate seeds, juice or supplements can also work against skin cancers protecting the layers of skin.
• Vitamin E in almonds, asparagus and pumpkin seeds.
• Beta carotene in carrots and red bell peppers.
• Catechins in green tea are some of the ideal contents to be incorporated in our diet for healthy skin.

ESSENTIAL OILS

Along with these commonly used contents in the diet, topical agents with antioxidant properties have been explored as sunscreen agents.

• Myrrh, an essential oil resin, has shown beneficial properties in protecting against skin cancers and promote healthy skin.
• Carrot seed essential oil is a rich source of antioxidants that has been shown to protect skin layers against free radicals.

PHOTOPROTECTION BY CLOTHING AND SUNGLASSES

It is important to use sun protective clothing that can leave less scope for exposure. Proper clothes and hats play an important role in preventing direct exposure to sunlight, limiting the damage to skin cells. As these are physical elements of protection, they do not lead to any hazards. Loose-fitting colored fabrics or white colored cotton clothes are the best ways to protect from the harmful radiation of the sun. Fabrics are evaluated on the basis of UV protection factor (UPF) which aims to determine the transmission of UV radiation with and without clothes. Fabrics with UPF value 40-50 are considered to be the best, while those within 15-27 are of an acceptable range.

Importantly, the eyes can also be protected from harmful UV rays by wearing sunglasses or other protective eye wear. Sunglasses can protect up to 99% of UV radiation. This property depends on the size, make, quality and thickness of the glass.

Newer trends in sunscreen Nanotechnology

With advent of nanotechnology and nanoparticles, several changes have been observed in the sunscreen products too. As nanoparticles are extremely thin particles with size less than 100nm, these particles have been used in physical sunscreens to block the effect of UV radiation.

Sunscreens with titanium dioxide and zinc oxide are now produced in a nanoform, increasing the cosmetic value of these products. As these particles are very small in size, they are unable to penetrate into the skin layers through the pores, preventing any interference with the skin cells.

Sunspheres: Besides the nanoparticles used in commercial sunscreens, sunspheres made up of styrene/acrylate polymers have entered into the market. These spheres are filled with water,  which escapes upon skin contact, leaving behind shells that can scatter the UV light. The sunspheres are able to increase surface area for more contact between UV filters and radiation.

With so many factors to consider regarding sun protection, choosing an appropriate sunscreen can be confusing and overwhelming. Not only should we consider adequate protection from sun rays, the sunscreen of choice should not cause irreparable skin damage. Cosmetic and aesthetic factors also influence our product selection. The safest approach is to stay out of the sun during the most heated hours (12-3pm), hydration, antioxidant intake, wearing protective head covering and clothing, and using physical sunblock whenever possible. This approach will also save your skin from dehydration and wrinkling prematurely.  As for vitamin D intake, getting 15-30 minutes of sun in the daytime or evening is the best method for safe sun exposure.

Works Cited: 

1. “EWG’s 10th Annual Guide to Safer Sunscreens.” The Trouble with Oxybenzone and Other Sunscreen Chemicals. N.p., n.d. Web.
2. Hayden, C.g.j., S.e. Cross, C. Anderson, N.a. Saunders, and M.s. Roberts. “Sunscreen Penetration of Human Skin and Related Keratinocyte Toxicity after Topical Application.” Skin Pharmacol Physiol Skin Pharmacology and Physiology18.4 (2005): 170-74. Web.
3. Emonet, Stéphane, Florence Pasche-Koo, Marie-Jole Perin-Minisini, and Conrad Hauser. “Anaphylaxis to Oxybenzone, a Frequent Constituent of Sunscreens.”Journal of Allergy and Clinical Immunology 107.3 (2001): 556-57. Web.
4. Hanson, Kerry M., Enrico Gratton, and Christopher J. Bardeen. “Sunscreen Enhancement of UV-induced Reactive Oxygen Species in the Skin.” Free Radical Biology and Medicine 41.8 (2006): 1205-212. Web.
5. “The Cancer Causing Potential of Sunscreen Ingredients.” IslasLab -. N.p., n.d. Web. 
6. Rai, Reena, Sekar C. Shanmuga, and CR Srinivas. “Update on Photoprotection” Indian Journal of Dermatology. Medknow Publications & Media Pvt Ltd, 2012. Web. 
7. “75% of Sunscreens Are Toxic: What to Do Instead – DrAxe.com.” Dr Axe. N.p., 2012. Web. 
8. “10 Ways to Eat Your Sunscreen.” Gaia. N.p., n.d. Web.
9. “10 Proven Myrrh Oil Benefits & Uses.” Dr Axe. N.p., n.d.
10. “Health Benefits of Carrot Seed Essential Oil | Organic Facts.” Organic Facts. N.p., 2008. Web.