Sea, Safe and Sun: Sun Safety Demystified
Although my sunblock bar works for me, it is not a beginner DIY project. Guaranteeing it's efficacy relies on knowing and clinically testing the following factors on humans, amongst other things:UNEVEN DISPERSION = UNEVEN COVERAGE
Even dispersion of protective inorganic minerals like zinc oxide and titanium dioxide in an emulsion, can be tricky to achieve in a formula. Minerals can sink to the bottom of a lotion if not properly mixed in and/ settle to the bottom of a cream over time and clump/fluctuate with heat variations when not properly formulated, thus not guaranteeing even coverage. Testing dispersion and protection of a sunscreen, is paramount to guaranteeing it's safeguarding of skin.
To prevent clumping in a cream and an opaque white, ashy looking skin finish, minerals like Zinc oxide and Titanium dioxide, which are used to make white paints and cosmetics, are super-refined: first cleaned of potential contaminants and toxins and ground up incredibly fine into nanoparticle size (GRAS but problematic) and then coated with chemicals that make them easier to spread and ensure that they're non-photocatalytic- don't break down into free radicals. The refining and the coating are not the most DIY friendly or easy processes and recent studies have brought the photo stability, safety and effectiveness of zinc oxide in sunscreen into question, as it has been shown to degrade in UV light after two hours and cause environmental damage when introduced into aquatic ecosystems. (source)
STABILITY TESTING & EFFICACY
Clinically testing a DIY sunblock's photo-stability on a large enough sample size of people over an adequate amount of time to prove it protects from burns and skin cancers, is a huge responsibility that most non-chemists and DIY enthusiasts, can simply not afford to undertake. Until I can do proper clinical trials, I am testing my sunbars on friends and family. (Sorry and thank you friends and family! ;)
What is light? Baby don't hurt me!
When looking for non-toxic sun protection, understanding what it is protecting you from, is important. There are a large number of organic 'chemical' sunscreens and inorganic or ‘mineral’/ 'physical' sunscreens' out there that protect the skin against different kinds of ultraviolet light ray damage, like UVA and UVB.
Before discovering how all these chemicals work, let’s first find out what ultra-violet light is and why we should care to block it.
Ultraviolet light describes different kinds of electromagnetic radiation (or light rays) emitted by the sun. Often these light rays are divided into two types, that are of concern to those worried about skin damage and skin cancer:
Type 1: UV-A
Has a lower energy and a longer wavelength (320-360/400nm)
Is not absorbed by the ozone layer.
AGES the skin: UV-A accelerates visible signs of aging by damaging collagen (connective tissue) and blood vessels, causing free radicals and aging effects such as wrinkled skin.
Type 2: UV-B
Has a higher energy and a shorter wavelength (280-320nm)
Shorter wavelengths mean higher energies. So the shorter rays of UV-B light or radiation, are more damaging than UV-A.
Is partially absorbed by the ozone layer
Damages skin by UVB -burning it.
UV-C is the shortest wavelength but is effectively screened out by the ozone layer. A broad spectrum sunscreen/sunblock, means the protection will protect against both UVA and UVB rays.*
Myth busting Organic/ '“Chemical” vs. Inorganic / “Physical” sunscreen/ sunblock ideas..
Sun protection products are often classified as 'Chemical' or 'Physical' (aka 'mineral') according to their active ingredients. These are inaccurate names, because everything in the universe, whether natural or manmade, consists of chemicals and chemicals are physical- they have mass and take up space! Both 'chemical' and 'physical' sunscreens are in fact, chemical sunscreens. Titanium dioxide and zinc oxide are also chemicals, found on the periodic table, so they are both chemical and physical. Easy peasy!
That said, the differences can be named by their more accurate, scientific appellations: 'organic' (a.k.a 'chemical) - made with substances based on carbon chains to block UVA and UVB rays and 'inorganic' (a.k.a "physical")- made with ionic compounds (no carbon chains) or minerals that block UVA and UVB rays.
Inorganic/ 'physical' sunblock, is understood to be minerals that contain no carbon, only metal and oxygen ie: zinc + 1 oxygen = zinc oxide, titanium + 2 oxides = titinium dioxide.., ' while 'chemical' sunscreens are understood as the chemistry of compounds that contain carbon.
Using the terms 'organic' and 'inorganic' is more accurate, and denotes the chemistry of compounds in most sunscreens containing carbon, and titanium dioxide and zinc, which contain no carbon.
REFLECTING the light- 'Physical' inorganic sunblocks like Zinc and Titanium Dioxide do this- scattering light waves away from the skin.
ABSORBING the light- 'Chemical' organic sunscreens do this- absorbing and transforming the energy of UV and UVB into less harmful forms of energy.
MYTH: It is a misconception that sunlight is ONLY reflected or ONLY absorbed via minerals. The facts are that "physical' inroganic sunblocks only refract 5% of light, while absorbing 95% of it like 'chemical' organic sunscreens. (source) That is only a 5% difference between 'chemical' organic sunscreens, which absorb 100% of light and inorganic sunscreen which absorb 95% while refracting the rest. (source)
Just give me the light! How sunblocks work:
The law of conservation of energy, states that energy cannot be destroyed, only transformed.* Organic (chemical) and Inorganic (physical) sunblocks, both function by absorbing and transforming UV light waves (energy) via electron delocalisation (in conjugated, carbon based structures), to a safer form of energy: longer wavelength photon chains-ie: heat and/ lower light wavelengths, that won't destroy your skin and accelerate aging. (source)
Inorganic ('physical') sunblocks, also refract and scatter ~5% of UV light and absorb and transform 95% of UV light.* (source)
Added sunscreen chemicals and the pH (acidic or basic) of a formula, can also affect how they work- by either shortening or lengthening the carbon chain and resonance of different 'active' molecules. (source)
Feel the Burn: The top 5 sunscreen toxins to avoid:
Knowing that altered chemicals can increase the efficacy of sunscreens, chemists design molecules to alter their resonance structures, so that they can be as broad spectrum (protective) as possible.
OXYBENZONE: One such molecule is benzophenone, and a derivative called benzophenone-3, also known as Oxybenzone. "The most common sunscreen chemical, Oxybenzone, was found in the bloodstream of 96% of the population by a recent study by the CDC (Center for Disease Control and Prevention).
EFFECTS ON HUMANS & THE ENVIRONMENT:
Studies have shown that oxybenzone may affect thyroid hormone, testosterone level, kidney function, and pubertal timing (breast development and onset of menses).* It has also been shown to contribute to the killing of coral reefs in the ocean. As a result, Key West, FL and Hawaii have banned the sale of sunscreens containing oxybenzone and octinoxate starting in 2021 because of the threat they pose on marine ecosystems.*
OCTINOXATE: Octinoxate poses high toxicity concerns as a skin allergen and hormone disruptor.*
HOMOSALATE: Homosalate poses a moderate toxicity risk for hormone disruption.*
OCTISALATE and OCTOCRYLENE: Octisalate and octocrylene pose a moderate toxicity risk for skin allergy.*
AVOBENZONE: Avobenzone also displays lower toxicity, but if it breaks down it poses a relatively high risk of skin allergic response. *
Size matters! Nanoparticles & toxicity
As if worrying about the safety of chemicals like oxybenzone and octinoxate weren't enough, the size of the chemical particles may also be cause for worry.
Invisible to the human eye, nanoparticles, are micronized particles that can bioaccumulate in the environment and in humans cells, in organs like the lungs, liver, spleen, brain, heart and foetus in pregnant women, potentially causing inflammation and oxidative stress.*
Black Like Me: Do people of colour need sunscreen? And why nanoparticles?
“In the cosmetics industry, mineral nanoparticles – such as titanium oxide – are used in sunscreen, due to the poor stability that conventional chemical UV protection offers in the long-term. Titanium oxide nanoparticles are able to provide improved UV protection while also having the added advantage of removing the cosmetically unappealing whitening associated with sunscreen in their non-nano-form."*
"Because powders of inorganic zinc oxide (ZnO) and titanium dioxide (TiO2) are very effective at blocking UV-light, these are largely used in sunblocks. However, the fact that their common forms (i.e. particles in the micrometre range) have a white colour, this makes them less appealing to customers for application on skin, especially since they can cause an 'ashy' or gray cast look on darker skin tones.
People of all skin tones can benefit from sheer sun protection without worrying about an ashy cast, thanks to tinted and sheer and effective sunscreen formulas. Though melanin protects the skin from burning as quickly, it can still burn and is susceptible to sun damage, aging and basal cell carcinomas (skin cancer).*
However, when they are in the form of nanoparticles (NPs), they become transparent, keep their UV absorption properties when exposed to UV for long periods of time, which enhances the stability of sunscreens and their ability to protect the skin from ultraviolet light, therefore making sunscreens one of the applications where the emerging nanotechnologies have been developed.
Dangers of Nano-particles:
“The present Literature review (*7) showed that there is evidence that:
- In the presence of UV light, ZnO and TiO2 nanoparticles can produce reactive oxygen species (a type of oxygen that can damage DNA) and be carcinogenic if they enter into the body;
- This toxicity and genotoxicity of ZnO and TiO2 nanoparticles have been demonstrated in a wide range of cell types;
- A diversity of other potential negative health effects observed in laboratory animals upon administration of ZnO and TiO2 nanoparticles.
Nano minerals in sunblock, are non-toxic:
However, the majority of experimental studies have shown that both ZnO and TiO2 nanoparticles either do not penetrate or minimally penetrate through the outer layers of skin and blood stream, and suggest that the absorption of nanoparticles into the body, and the accompanying toxicity, is highly unlikely.
In addition, neither TiO2 nor ZnO NPs when used in sunscreens on humans in the absence of UV or non-UV light were found to possess notable skin irritation (reversible skin damage), corrosion (irreversible necrotic damage extending into the dermis), or sensitisation properties.
Nano mitigation: Coating and dispersion
How can the potential toxic effects of titanium dioxide and zinc oxide nanoparticles be reduced in sunscreen products? In order to reduce their potential to generate reactive oxygen species (ROS), even after UV exposure, which largely mediate their toxicity for cells and genotoxicity, the surface of nanoparticles can be modified by coating them with aluminium hydroxide, polymers or inert oxides of silica.
"Anti-oxidant compounds (such as vitamins A, E or C) can also be added to the sunscreen formulation. Dispersing ZnO particles in some kinds of triglycerides was shown also experimentally to reduce ROS formation.
However, it has been shown that the integrity of the coating layer can be disrupted and the NP coating be stripped under certain circumstances, principally by calcium and hypochlorite ions, which, for example are present in swimming pool water."
Based on the current evidence, the report concluded that neither titanium dioxide nor zinc oxide nanoparticles in the way they are used as coated ingredients in sunscreens, are likely to cause harm.
On the contrary, the report underlined that the current state of knowledge strongly indicated that the minor risks potentially associated with nanoparticles in sunscreens are vastly outweighed by the benefits that nanoparticles containing sunscreens afford against skin damage and, importantly, skin cancer.
The report also mentioned that, in 2012, the Scientific Committee on Consumer Safety (SCCS) of the European Commission concluded that in sunscreens, zinc oxide nanoparticles can be considered to not pose any risk of adverse effects in humans after application on healthy, intact or sunburnt skin. A similar position was upheld in their review of TiO2 nanoparticles2.” *
In summary, it is more cautious to avoid ‘chemical’ sunscreens and opt for mineral based ‘physical’ sunblocks but make sure to choose broad spectrum sunblocks, which can sometime be a combination of organic and inorganic chemicals. Whether or not you choose to use a nano-particle or non-nano particle zinc oxide or titanium dioxide (mineral) based sunblock, is up to you.
It's Not Right, But it's Okay: Other ingredients to watch out for in Sunscreens/sunblocks:
ALUMINUM HYDROXIDE: NOT ALL ALUMINUM IS THE SAME, OR IS IT?
Another super common ingredient in ‘clean’ and ‘safe’ sunblock formulations is aluminum hydroxide. It is used to coat Titanium Dioxide and prevent it from clumping and allows for an even application.
Rather than penetrating the skin, it forms a refractive layer that helps reflect and scatter UV rays away from the skin. In fact, an aluminum coating is recommended in the Guidelines for Natural Cosmetics of the BDIH. *(source)
Aluminum hydroxide is not to be confused with the controversial Aluminum Chlorohydrate, which is believed by many to cause cancer and Alzheimer's disease. Yet it should be noted that both ingredients comprise of Aluminum, a proven neurotoxin.” (source)
“Skin is permeable to aluminum salts when, for example, they are topically applied. According to researchers at Keele University “It will accumulate in the skin and be transported to sites throughout the body. It is highly likely that the everyday use of sunscreens/sunblocks is an hitherto unrecognised contributor of aluminium to the human body burden of this non-essential (to human bodies!) metal. Perhaps of immediate significance is the potential for aluminium in the skin to act as a pro-oxidant." (source)
Since fragrance ingredients are protected under proprietary trade secret laws, and perfumers don’t have to divulge them, it's anybody’s guess as to what's in them.
Furthermore, language is not regulated, so terms like 'natural' and 'herbal' or 'fragrance oils' or 'essences' when applied to fragrance and personal care products in general, are generally meaningless.
We do know that pthalates are a class of toxins found in most synthetically created fragrances and that they are major hormone/endocrine system disruptors.* So look for 'pthalate-free' or best yet 'fragrance-free' or scented with organic and sustainable essential oils. Sniff. Adieu old sunscreen smell of my youth!
Smelling like vanilla (one of the most expensive non-synthetic scents!), coconut and ‘sunscreen’ to the detriment of ones’ health or the well being of your neighbor at the beach, is unnecessary. Seeking clean options with no fragrance or ‘natural fragrances’ like Kavana's Sunflower bar with 20% Zinc oxide may one day be the best option for the scent-sitive amongst us.
SKIP THE CITRUS:
Since citrus essential oils can be photo-sensitizing, negatively reacting with light waves on the skin, look for ‘bergaptene-free’ bergamot or non-citrus (orange, grapefruit and lemon) scented sunscreens and fragrances/perfumes, especially in the summer months.
So what to use?! Ultimately, it’s up to you to find a texture and formula you like for your skin type and consider safe and effective enough for you. Hopefully this blog will help inform you to make a wise and safe choice.
Here are some I recommend that are non-nano, zinc and/ or titanium dioxide based, non-chalky or thick and greasy, silicone and aluminum free and synthetic-fragrance-free too!
RECOMMENDED, NON-TOXIC, REEF SAFE, PROUDLY CANADIAN BRANDS OF SUNBLOCK (Waterproof and regular, adult and child friendly):
Consonant Sunblock (@well.ca and etiket and Shoppers Drug Mart)
Green Beaver SPF 40 (@Well.ca)
WHAT ABOUT SPRAY SUNSCREENS?
I have not listed any spray sunscreens for a few reasons. They're flammable, inhaling the stuff makes me feel sick, the propellants and other toxic chemicals in these formats are bad for the environment and potentially for lungs.
Staying out of the sun altogether during the hottest hours (11:30AM-4pm) paired with wearing protective white coloured clothing to help reflect the light - like sunhats, umbrellas and long sleeves, increasingly available in an array of SPF-savvy, eco-friendly materials, are still necessary options along with sunscreen protection.
Whatever you use, try and make sure to apply a nice even coating of it, and if you are a fan of spray for squirmy kids, try to apply it over top of a lotion, to be sure you are getting full coverage.
WHEN TO APPLY?
All sunscreens work immediately- there is no need to wait 20 minutes before leaving the house after application. "The reason why a wait time can be suggested in the application instructions is to allow the sunscreen formula time to dry and form a film on the skin. This makes it harder for it to be wiped off and it also means it can dry to as even of a film on the skin as possible." (source) The more evenly you spred sunscreen on your skin, the more evenly it will protect you from UV light.
Reapplying is always wise, especially since we likely don't pply enough-2 milligrams per square centimetre of skin is recommended. Swimming, sweating, removing clothes, even using cell phones, can remove sunscreen from our skin. Re-application is also wise after drying off and a hat is always a good idea, even with sunscreen on.
If you wear makeup, don't rely on the sunblock in makeup (ie: foundation or powders) for adequate coverage. Simply apply your sunblock first and then your makeup! This will allow a uniform film offering broad spectrum protection, to cover skin and protect from aging and harmful UV rays.
If you are having photos taken for a graduation or wedding event outdoors, and are concerned about a glare in photos because of the light reflecting properties of sunblock, these are quite minimal (~5%). Instead of getting too hot or looking flushed sans sunscreen, it's best to stay safe and apply it well. When it comes to sun protection, an ounce of prevention is still worth a pound of cure, so choose wisely and apply consistently!