07.05.08
Posted in Facts About UV Protection, nanotechnology, skin care news at 4:40 pm by Administrator
While I am happy about the recent attention that has been paid to our sunscreen products (M V Sun Serum was rated in the top 10 for saftey and effectiveness by EWG) I still have a little bone to pick. This is on the subject of nanoparticles in sunscreens. Evidently The EWG does not have separate categories for micronized zinc oxide and non-micronized zinc oxide. Until nanoparticles have been adeqautely studies I don’t believe we can deem them safe for use, especially on children.
I have written about the need for studies in this area. While the jury is out, Marie Veronique will not use micronized zinc oxide in its sunscreen. Making our sun serum and crme de jour, arguably, the safest you can buy.
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Posted in Facts About UV Protection, nanotechnology, skin care news at 4:33 pm by Administrator
Link to CNN story on safe sunscreens http://www.cnn.com/2008/HEALTH/07/01/sunscreen.study/?iref=mpstoryview
link to
Comment by Sonya Lunder, senior analyst, EWG
As CNN reported, sunscreens over promise and under-deliver. At Environmental Working Group, we analyzed product efficacy and possible health hazards for over 900 commercial sunscreens. We found that 85% of available products don’t measure up: they either fail to block the full range of UV rays or they contain ingredients linked to health hazards. Only 1 of the 144 products from market leaders Coppertone, Banana Boat and Neutrogena is recommended by EWG.
Why is this the case? For starters, FDA has not finalized the comprehensive safety standards for sunscreen they began drafting 30 years ago. Instead, they have delayed many times at the request of the sunscreen industry.
In the absence of a final rule, FDA requests that sunscreen companies comply with their draft guidance. Our analysis suggests that this voluntary system leaves consumers with products that do not meet the claims that are printed on the label, including more than 1 in 10 products marketed as “broad spectrum” that aren’t, and 40% of products that make claims FDA considers misleading, like “all day” or “instant” protection.
In the absence of standards, we publish ratings for nearly 1,000 sunscreens to help consumers find products that provide broad spectrum and contain few if any ingredients with significant safety concerns at .
How to Choose Sunscreen
• The active ingredient is at least 7% zinc oxide or titanium dioxide, not oxybenzone or benzophenone-3.
• Opt for a formula that doesn’t contain bug repellent. Ingredients in sunscreen can make more of the pesticide absorb into the skin.
• Avoid spray-on or powder forms, because those forms are too easy to inhale, which creates further potential hazards.
• Also note that fewer than 5% of 100+ products from market leaders Coppertone, Neutrogena and Banana Boat are recommended by EWG.
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Posted in Facts About UV Protection, nanotechnology, skin care news at 4:20 pm by Administrator
The Environmental working group did a piece about safe sunscreens that appeared as a news item on CNN.
http://www.informify.com/top-stories/48-health/283-sunscreens-not-as-safe-effective-as-you-might-think
We are pleased that we are rated in the top 10 picks for best sunscreens by the EWG.
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06.15.08
Posted in Facts About UV Protection, skin care news at 8:58 pm by Administrator
A natural sun defense pill is being released by a Florida-based company. The dietary supplement is designed to protect the skin against UVA and UVB damage. Not intended to replace sunscreen lotions, its purpose is to provide an extra layer of protection internally.
The SunPill’s two active ingredients are astaxanthin (a carotenoid found in microalgae) and polypodium leucotomos (a fern extract).
Another biotech company is on the verge of releasing a pill containing lycopene, yet another high-powered beta carotene with significant anti-oxidant properties. This company is also promoting its supplement as providing an additional level rather than acting as a replacement.
Whether one decides to go the extra mile or not with dietary supplementation bear in mind that these anti-oxidants and beta carotenes also provide protection when applied topically, though studies are unclear on exactly how much protection is provided whether taken internally or applied externally, or even if the user does both.
Why anti-oxidants protect
UV radiation can lead to photochemical reactions, and the photochemical reaction products then intervene in skin metabolism. Such photochemical reaction products are chiefly free-radical compounds, for example hydroxyl radicals. Undefined free-radical photo-products which are formed in the skin itself can also show uncontrolled secondary reactions because of their high reactivity. UV radiation is furthermore counted among ionizing radiation. There is therefore the risk of ionic species also being formed during UV exposure, which then in turn are capable of intervening oxidatively in biochemical processes. Anti-oxidants scoop up these free radicals, thus preventing skin damage at the level of biochemical activity..
Sun protection at the surface
UVA rays can cause reactions on photosensitive skin. It has been proven that UVA radiation leads to damage to the elastic and collagenic fibres of connective tissue, which causes the skin to age prematurely, and that it is to be regarded as a cause of numerous phototoxic and photo-allergic reactions. The damaging influence of UVB radiation may be intensified by UVA radiation. The best way to protect against this type of damage is with a mineral sunblock that reflects the UVA rays at the surface of the skin, before they can penetrate and do damage. Chemical sunscreens may actually generate free radicals upon exposure to UV, which rather defeats the purpose of wearing sunscreen. Zinc oxide is safe and non-reactive and your best bet.
For total protection
Clearly, sun protection should be undertaken on two fronts. The best way to ensure as much protection as possible is to use a product containing effective anti-oxidants like Vitamin C and the beta-carotenes, in conjunction with a zinc oxide based product. Marie-Veronique uses the anti-oxidants Polypodium leucomotos, lycopene and astaxanthin as well as Vitamin C, emu oil, marula oil and red raspberry oil in order to provide a full panoply of natural and powerful anti-oxidant sun protection agents. But for complete protection MV also uses zinc oxide, for many tests exist to show that it is safe and non-reactive. It is also the only natural sunblock agent to provide complete UVA protection up to 400 nm.
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05.28.08
Posted in Facts About UV Protection, Skin Aging Facts, hyperpigmentation at 11:25 pm by Administrator
Skin color is influenced by melanin, and variation in skin pigmentation is attributed to the levels of melanin produced and the number of melanocytes present. Fair and darker skinned people may have the same number of melanocytes, but darker tones obtain where melanin production is higher. In addition, the rate of degradation of melanin in the epidermal layers of darker skin is lower.
Melanogenesis (melanin biosynthesis) is influenced by genetics, environmental factors, diet and medication. Many people want to use a skin lightening product to address irregular pigmentation issues including malasma, age spots (Lentigus senilis) or liver spots (associated with sun damage or aging sometimes appearing as raised spots Seborrheic keratoses) and freckles (Lentigo aestiva). Unfortunately many products on the market are either dangerous, as in the case of hydroquinone (see “about hydroquinone” below), or they don’t seem to have much effect. The good news is that you can get excellent results with a product containing safe ingredients. The bad news is that you won’t see changes overnight, so patience is required. Remember to use an effective sunblock every day whether you are on a skin brightening program or not; it is your first line of defense against further skin damage.
Many studies indicate that natural agents can help to lighten skin gradually, over time. Let’s take a look at how and why they work.
Melanogenesis
The production of melanin by specialized cells called melanocytes occurs through the action of the enzyme tyrosinase. The rate-limiting step in melanogenesis is the conversion of L-tyrosinase to melanin, through the action of tyrosinase. Controlling melanin synthesis is usually accomplished at the first step of the melanogensis process by inhibiting tyrosinase, though other products/ingredients may affect other stages of the process: physical sunscreens block UVA rays which initiate tyrosinase activity, anti-oxidants chelate metal ions like copper which catalyze tyrosinase activity, and anti-inflammatories control inflammation which can often induce hyperpigmentation because it affects proliferation and functioning of melanocytes.
We can look at melanogenesis as a three-step process, as diagrammed below:
TYROSINE
I
I ———UV light
I
I ——-tyrosinase
v
L-DOPA
I
I —Cu+
I —tyrosinase
I
v
DOPA QUINONE
I I
I I
v v
Eumelanin Pheomelanin (reddish-brown)
(brown-black)
There are many natural ingredients that work well to control melanogenesis at the first stage by inhibiting tyrosinase. These ingredients are better tolerated than hydroquinone, which has been banned for use in Europe and Japan.
STEP ONE: Arbutin from the leaves of the common bearberry (Arctophylos uva ursi), glabridin from licorice (Glycrrhiza glabra roots), catechins from green tea, paper mulberry (Brouzzometria kazinoki + B. papyrifera), Sophora flavescens (ku shen), lactic acid and ascorbic acid all work at the first stage by inhibiting tyrosinase activity.
STEP TWO: Kojic acid (a bacterial carbohydrate metabolite) works by chelating copper ions from the active site of the enzyme. Other chelators include other antioxidants and rice.
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05.27.08
Posted in Facts About UV Protection at 8:56 pm by Administrator
There are some misconceptions about sun protection and the role afforded by sunscreens that I think are important to clear up. Here’s a test to see how sun savvy you are:
Answer true or false:
1) An SPF of 45 gives me all-day protection
2) An SPF of 30 gives me all the protection I need
3) Mexoryl is the only way I can get UVA protection
4) If I am in Australia I need to stay out of the sun during certain hours
5) SPF protection is proportional
6) UVC rays are blocked by the ozone layer
7) Zinc oxide does not protect as well as micronized zinc oxide
Zinc oxide provides more protection than titanium dioxide
9) If I don’t care about getting wrinkles I don’t need to wear a sunscreen
10) You need a chemical sunscreen to get the best protection
1) False: SPF provides a rough estimate for the length of time you can stay in the sun without burning, but it depends on the individual’s burning time. Starting with a baseline of SPF 15 sun protective agents are double in concentration, so 15 to 30 is a doubled concentration while 15 to 45 triples it without providing much more protection (from about 93.3% protection in SPF 15 to 96.6% in SPF 30. If you are a “burner” you are better off applying SPF 15 every hour than SPF 30 every 2 hours.)
2) False: SPF ratings refer to amount of UVB protection only. Some sunscreens will say “full-spectrum UVB/UVB protection” but you need to look at the ingredients to make sure you are getting complete UVA protection.
3) False: Mexoryl is a chemical sunscreen that protects up to 380 nm. The UVA range is actually 320 to 400 nm.
4) True: The ozone layer is thinning in some places on the planet, and no sunscreen protects against UVC rays. UVC rays pose a very serious risk for skin damage in some areas, and your best bet is to wear clothing and stay in the shade, especially during peak burning hours.
5) False: SPF protection goes up incrementally as concentrations of active ingredients double. SPF 8 = 87% protection, SPF 15=93.3%, SPF 30=97.7%. SPF ratings beyond 30 are fairly meaningless.
6) False: this is a qualified false and borders on opinion on my part. Some scientists insist ozone absorbs all the UVC rays, while some suggest that in places where the ozone layer is thinning there might be a risk. I believe in erring on the side of caution. In any case, fair-skinned people should limit their amount of beach time during peak burning times no matter where they are—reflections from water (and snow) increase UVB and UVA exposure.
7) False: Zinc oxide in larger particles (100 microns and larger) provides better protection because it works by reflecting or scattering UVA/UVB rays. In addition, nanoparticles may be absorbed by the skin and even enter the bloodstream, and the repercussions there are unknown. But that’s another story.
True: Zinc oxide protects in the 280 to 400 nm range, so provides full-spectrum UVB/UVA protection. Titanium dioxide protects from 280 to 360 nm. Micronized versions probably provide less protection, but no studies have been done in this area.
9) False: Again, I kind of sit on the fence about this one. UVB rays have been linked to squamous cell and basal cell carcinomas, and most scientists accept that more than 90% of skin cancers are the result of sun exposure. However, no link has been established between deadly melanomas and sun exposure, so if you don’t care about wrinkles, sun spots, premature aging and possibly getting a basal cell lesion then fine, don’t wear sun screen. I have noticed that men more than women fall into this category (no, really?) and to them I just provide one cautionary note—if you’re bald wear a hat to prevent painful sunburn. And to avoid lesions on the most susceptible part of your face, your poor little nose, at the very least slap some zinc oxide on your schnozz while you’re at the beach or skiing.
10) False: chemical sunscreens may irritate skin at higher concentrations, and about 15% of the population will break out from a chemical ingredient in a sunscreen product. The following ingredients have been linked to increasing free radical generation upon exposure to UV:
• octocrylene
• octylmethoxycinnimate
• benzophenone-3
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Posted in Facts About UV Protection at 8:53 pm by Administrator
We’ve talked a lot about the different wave-lengths of UV light, in particular UVA and UVB and how they affect the skin: UVB=burning, UVA=aging.
The discussion hasn’t touched on UVC for two reasons; 1) UVC rays are prevented from reaching the earth by the ozone layer, for the most part, and 2) I don’t want to be the one to sound alarm bells. However, so much misinformation abounds surrounding the complicated topic of sun protection that I feel I must take up the torch once again. This time the discussion will be around UV light and its relationship to skin cancer.
UVB: The UVB rays are the burning rays. They:
• Penetrate the epidermis
• Are present from 10AM to 4 PM
• Reflect off shiny surfaces
• are linked to squamous and basal cell carcinomas, damage DNA
• are 1000x stronger than UVA
• stimulate melanin biosynthesis and keratinocyte production
UVA: The long wavelength, low energy UVA rays are the aging rays. They:
• penetrate glass and clouds, penetrate to the dermis (Only 10% of UVB rays reach the dermis, about 50% of UVA rays do)
• present from sun up to sundown
• cross-link collagen and elastin
• damage DNA, carcinogenic (though the least associated with skin cancer)
• destroy langerhans cells and immune function
• turn melanin darker
• 1000x more prevalent than UVB
• cause hyper-hypo-pigmentation and broken capillaries
UVC: The short wavelength, high energy UVC rays. They are:
• the most carcinogenic
• sterilizing rays used to kill small organisms
• mostly absorbed by the ozone layer, sunscreens provide NO protection
Skin cancer facts
When it comes to skin cancer, we know that more than 90% are the result of sun exposure, with over 1 million new cases being reported each year. One of three fair-skinned people will develop a skin cancer, and one out of five of the general population will do the same. However, while the link between the UVB rays (and to a lesser extent UVA rays) and squamous and basal cell carcinomas has been established, the link between deadly melanomas and sun exposure is less sure. Knowing the facts will help you make an informed choice about the degree of protection you want for yourself. Here are some things to look at before coming to a decision:
Cosmetic
If you want to avoid premature wrinkling or sunspots use full-spectrum UVA/UVB protection. Recommended: Zinc oxide at 20% concentration.
If you don’t care about any of these issues (and many men I have encountered fall in this category though few women, what a surprise) then wear a hat to protect your bald spot and put sunblock on your nose at the beach to protect against basal cell lesions and you’ll probably be fine.
Safety
Squamous and basal cell carcinoma risks are reduced with full-spectrum UVA/UVB protection. Zinc oxide at 20% concentration is your best protection. At least be aware of UVC risks, and if you are in Australia limit your sun exposure. During peak burning hours ANYWHERE where burning is a problem, at high altitudes, at the beach, in the water or skiing, you are better off to stay in the shade as much as possible.
Children
Children are looking at 100 years of sun exposure, and these days also at 100 years of exposure to ingredients in sunscreens. You have to balance for yourself which is ultimately more lethal. But here is my take on it.
For the first five years you can depend on a child’s natural protection to do the job for the most part. At the beach wear hats, clothing and slather them with diaper cream or 20% zinc oxide from a safe product. At other times, and if your child burns easily, look at using Vitamin C directly on the skin. Wet it with green tea to get more natural protection. Overture also contains astaxanthin to protect against burning naturally. Neither of these will interfere with Vitamin D synthesis. My recommendations for children 5 and under:
1) Vitamin C
2) Astaxanthin
3) For serious sun, zinc oxide from diaper rash cream or Sun Serum
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Posted in Facts About UV Protection, skin care news at 4:31 pm by Administrator
The nanoparticle controversy brings up the all-important question of testing. What do we know, what tests are presently available, and what is on the horizon? I talked to Dr. Jay L. Nadeau, professor of bio-medical engineering at McGill University, who heads a nanotechnology research group funded under EPA’s STAR (Science and Technology to Achieve Results) program. One of the results of their research has been the publication of a quantitative test of free-radical generation from nanoparticles in solution.
I described to her the difficulties associated with testing levels of UVA protection in sunscreen. Testing protection against longer UV wavelengths (from 330 to 400+ nanomaters) is not as intuitive as UVB testing, which simply tests for protection against the immediately visible effects of burning. UVA rays don’t burn you, they age you, so it makes sense that these longer-term effects would be harder to measure. However, one test that has been adopted by Japan and Europe, called Persistent Pigment Darkening, (PPD), uses essentially the same methodology as is used in SPF testing. L’Oreal Research presented such a PPD test model in their recent study.
In the L’Oreal study human volunteers were exposed to 330-440 nm of light 3 times a week for 4 weeks. Exposed sites were compared with nonexposed sites, exposed sites protected with a broad UVA absorber, and exposed sites to which a sunscreen vehicle had been applied. Various parameters related to early photoaging due to UVA exposure, including pigment darkening, stratum corneum thickening and changes in elasticity, were measured.
This is a clumsy testing method to say the least, especially as it requires the use of human volunteers who must be subjected to potentially harmful UV rays. Dr. Nadeau suggests that “absorbance spectroscopy and fluorescence-based assays can also quantify UVA absorption.” (see “Photosynthesis of dopamine-modified quantum dots and effects on biological systems,” Clarke, Hollmann, Zhang, Suffern, Bradforth, Dmitrijevic, Minarik and Nadeau, Nature Materials 5(5): 409-17 (2006).
In other words, nanoparticles may be instrumental in resolving issues around nanoparticle safety, which certainly makes for an elegant solution. I am very hopeful that we will soon be seeing less invasive and more reliable testing coming from the nanotechnology community.
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Posted in Facts About UV Protection, skin care news at 4:25 pm by Administrator
In the event that there are potential risks associated with nanoparticle use, Friends of the Earth has recently begun a campaign advising the public to avoid using products that contain them. Their argument is that since the physics of nanoparticles is different we can’t predict their behaviour. They quote a 2004 report by the United Kingdom’s Royal Society, which recommends that “ingredients in the form of nanoparticles should undergo a full safety assessment by the relevant scientific advisory body before they are permitted for use in products.”
(Please see Friends of the Earth press release at this link for more details) http://www.foe.org/new/releases/may2006/nanorelease5162006.html
FOE points out that many companies continue to use nanoparticles in the absence of independent safety testing, and advise a moratorium on their use until studies can demonstrate their safety.
Companies use nanoparticles for different reasons. Many are using them as delivery systems in anti-aging creams, arguing that nanoparticles will drive other anti-aging ingredients (specifically anti-oxidants) into the dermis where they will promote collagen production and prevent cell damage. FOE points out, and rightly, that if they do indeed drive other ingredients into the skin then the risk of doing damage would correlate to how many harmful ingredients contained in the product are also being carried to the dermis, notably parabens, other preservatives and fragrances. However, as we do not really know whether nanoparticles penetrate intact skin, or whether they act as uptake for other ingredients, it’s at best an academic argument and at worst unduly alarmist. As an anti-aging mechanism nanoparticles show promise, but we are a long way from knowing whether they are creating more damage than they are delivering benefits.
Many companies are adding micronized mineral particles to their sunscreens, and FOE adds a caveat about this practice: “Nanoparticles of titanium dioxide and zinc oxide-used in large numbers of cosmetics, sunscreens and personal care products-have been shown to be photoactive, producing free radicals and causing DNA damage to skin cells when exposed to UV light.” This is a large claim, and while perhaps sounding a warning klaxon a bit on the side of shrill, it does underline the crying need for more testing of this new technology.
UVA Protection-We know we need it, but do we know to get it?
Aside from the question of whether nanoparticles generate free radicals, there is another problem associated with micronized sun protection products that we can state unequivocally: the smaller the particle, the less effective the UVA protection. This is because mineral sunblocks work differently than chemical sunscreens, which absorb UV rays, lowering energy levels and releasing energy as heat. Mineral sunblocks reflect or scatter energy rays, and for this reason are non-irritating, unlike chemical sunscreens which may cause skin irritations and even rashes, especially at higher concentrations. Micronized minerals are not as efficient at the physical process of scattering rays, so the question arises–we may have a product that disappears on the skin that people will wear, but how much protection are they actually getting?
The temporary answer, at least until such time as we know more about the effects of nanoparticles, lies in using a product that contains a high concentration of non-micronized zinc oxide. FOE lists companies that do not use nanoparticles in their sunscreens/blocks, and there are other small companies not listed that also do not use nanoparticles. Marie-Veronique Skin Therapy is one of them–though FOE did not list our company as one of the “good ones”, rest assured that we are waiting for more information about nanoparticle safety before we use them. There are also several good diaper rash creams on the market that contain high concentrations of zinc oxide in all-natural formulas. You may mix them with your daily sunscreen to ensure that you are getting adequate protection.
Sunscreens and skin cancer
On another note. A new sunblock has come out on the market that is a micronized zinc oxide at 16% concentration. It claims that it gives UVC protection. UVC are the very short wave-lengths of light that do not enter the atmosphere as they are blocked by the ozone layer. Clearly in areas where the ozone layer is thin or absent (like Australia) UVC is a problem. It is said that everybody over 40 in Australia has skin cancer (usually of the basal cell carcinoma type, where lesions are slow-growing and require removal by a physician, but are not life-threatening). However UVC exposure is a potential and very real hazard. No sunscreen or sunblock protects against UVC rays—so if you live in a high-risk area you should limit your sun exposure and wear clothing and hats. As much as I admire zinc oxide for its great benefits I know it doesn’t protect against UVC rays. Beware sunblocks or sunscreens that claim they offer UVC protection—it’s not true, and it is extremely irresponsible, bordering on criminal in my opinion, for companies to be making such a claim.
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04.14.08
Posted in Facts About UV Protection, Skin Aging Facts at 10:34 pm by Administrator
The Future of Sun Protection
Sun protection has become a more complicated affair than simply smearing on the stuff made famous by a pig-tailed little girl. In fact, our then-adorable beach baby could probably be a poster model today, only now her leathery, wrinkled skin dotted with precancerous lesions would serve as a warning to us all of the long-term effects of too much sun-time. Being tan used to equate with being healthy, but this perception is gradually changing as we learn more about the long term effects of too much sun exposure. Especially for those who are interested in preserving our skins against the ravages of time any outdoor activity isn’t the same care-free pleasure it used to be. An overview of that day at the beach from the perspective of UV exposure will help us understand just why this is so.
Ultra Violet Light
The sun emits light at all different wavelengths in the electromagnetic spectrum, but the UV (ultraviolet) range is responsible for skin changes and aging.
Though some ultraviolet waves from the sun penetrate earth’s atmosphere, most of them, especially the short-length UVC rays, are blocked from entering by various gases like ozone. UV penetration fluctuates on a daily basis, with more ultraviolet waves getting through our atmosphere on some days than others. However, as the ozone layer thins we can count on more frequent and prolonged penetration of UVC rays.
The graph below describes the range we are talking about.
UV light
UVC—————-UVB———–UVA——-visible light
_________________________________________________
200-290 nm 290-320 nm 320-400nm 400-700nm
short waves/high energy <-------------> long waves/low energy
nm=nanometers (1 nanometer = 1 billionth of a meter)
The ABC’s of UV
UV C rays are the shortest, highest energy ultra violet light and are the closest to x rays on the scale (moving left). These are sterilizing rays that kill small organisms and are the most carcinogenic. Sunscreens provide no protection.
UV B rays are the burning rays, which penetrate to the epidermis and are present from 10 AM to 4PM. They are 1000 times stronger than UVA, stimulate melanin biosynthesis, and are linked to squamous cell carcinomas. They cause all the nasty symptoms of sunburn; edema, redness, and itching. They can also contribute to cataracts.
UVA, the long wave, low energy waves, are present from sunrise to sunset, enter the dermis and are 1000 times more prevalent than UVB rays. For low-energy waves they have a long list of inimical effects: they cross-link collagen and elastin, damage DNA, destroy langerhans cells and immune function, turn melanin darker and cause hyper, hypo-pigmentation and broken capillaries.
A good mnemonic is UVA = aging, UVB = burning and UVC = carcinoma
Aging Rays
Up until the present, more attention has been paid to the shorter wave-lengths, the UVB rays which measure from 290 to 320 nm. The reason for this is simply because their effects are rapidly obvious. When we are over-exposed we burn. Most sunscreens on the market concern themselves with protection in this range, and in fact, an SPF rating is an indication of how much protection you are getting, over a duration of time, from the burning rays. So an SPF rating of 2 would indicate that, if you can stay out in the sun for ten minutes without burning, you would be able to stay out for 20 minutes without burning wearing your SPF 2 protection. The testing for SPF is simply a matter of measuring duration of non-burning time on human skin, where the parameters are known.
This is a relatively easy test to perform, and one can understand why FDA requirements vis a vis testing are only concerned with UVB protection. However, an aging population has begun to pay attention to the UVA part of the spectrum, and for an overwhelmingly obvious reason. The UVA rays are the aging rays, responsible for hyperpigmentation, sun spots, redness and (shudder) wrinkles. UVA rays are different from UVB rays in other ways—they penetrate to the dermis rather than the epidermis where they may do longer-lasting damage, they are present from sun-up to sun-down and they go through clouds and glass. Because their effects are insidious damage testing is not as easy as it is with UVB–with UVA one doesn’t burn, one ages.
Unfortunately it is not safe to make the assumption that because one is wearing a sunscreen with a high SPF rating one is automatically protected against UVA rays. Remember, an SPF rating refers only to the UVB range. Indeed, the typical sunscreen which contains the most commonly used chemicals does NOT protect against UVA rays. For example, benzophenone -3 protects from 290-360 nm, while octyl methoxycinnimate protects in the 290 to 320 range.
Three ingredients commonly used by sunscreen manufacturers provide protection for the longer UV wave-lengths: Avobenzone, 310-400 nm, Titanium dioxide, 290 to 360 nm, and Zinc oxide, 290-400 nm. Avobenzone looks like a good bet, but unfortunately it degrades after 30 minutes in the sun, so sunscreens including avobenzone as an active ingredient must be applied very frequently if one is to receive adequate protection.
Range of Protection of Common Sun Protective Agents
UVC UVB UVA
200nm—–290nm——- 320nm—————-400nm _________________________________________________
200 245 290 300 310 320 330340350360370380390
PABA ————————–
Avobenzone (Parsol 178) ———————–
————Octyl methoxycinnimate
Octyl salicylate————
Oxybenzone————————————-
(Benzophenone-3)
Zinc oxide —————————————
Titanium dioxide —————————-
This leaves zinc oxide, an excellent choice as it is inert, anti-inflammatory and provides superior, full-spectrum protection. However, it has not been popular with the public as it tends to leave a white, greasy film on the skin. Since UVA protection is an everyday affair (this means EVERY day, not just when it’s sunny, but even on those cloudy days when you don’t plan on going outside) sunscreen formulation has become more and more the purlieu of the cosmetic chemist, who is faced with the challenge of formulating a product that is both protective and light enough for people to wear.
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