Without a doubt the most popular skin care products are those which use Vitamin C, also known as L-ascorbic acid.

In this post I will write about Cellex C and Skinceuticals C E Ferulic, two popular anti aging skin care products that use Vitamin C as their main active ingredients.

I will also discuss the problems with using Vitamin C in anti ageing skin care products and some other the alternatives that are available in the form of Vitamin C derivatives.

In the next post I will be giving some examples on how we can make our own DIY Cellex C and DIY Skinceuticals C E Ferulic products.

Vitamin C and anti-aging skin care

Vitamin C is one of the most popular ingredients in anti aging skin care products. Vitamin C can benefit the skin in two ways. First it can increase collagen production, and second as an antioxidant it can reduce and prevent skin damage caused by free radicals.

Vitamin C is also one of the most studied active ingredients in anti aging skin care. These studies examined the various ways in which Vitamin C increases collagen synthesis, and the way in which vitamin C prevents free radical damage, as well as UVB damage.

For more details about these studies, please look at this list of abstracts.

Cellex C

Commercial skin care products with vitamin C started with Cellex C. Developed by Lorraine Meisner , who is a cell biologist at UW-Madison, Cellex-C was quite revolutionary. There is an interesting article about her here.

From a DIY skin care point of view Cellex C is not very practical.  The three main ingredients are: L-ascorbic acid, the mineral zinc and the amino acid tyrosin.

Tyrosin has poor solubility in water and alcohol, and requires the use of some very professional (and dangerous) solvents.

Also, L-ascorbic acid is unstable, and this is what the main problem is.

Unstable L-ascorbic Acid

It is well known that L ascorbic acid is unstable.  It reacts with water and air, and will easily oxidize. Oxidized Vitamin C is not good for the skin, instead of an antioxidant, it becomes a pro-oxidant. This means that it will increase the formation of free radicals, instead of doing what it is supped to do and decrease free radicals in the skin.

Vitamin C derivatives

Many efforts have been made to use Vitamin C in skin care products. Most of these efforts have involved developing Vitamin C derivatives. For example, products such as: Ascorbyl palmitate, Magnesium ascorbyl phosphate, and Ascorbyl Tetraisopalmitate (also known as Tetrahexyldecyl Ascorbate).

Magnesium ascorbyl phosphate and Ascorbyl Tetraisopalmitate / Tetrahexyldecyl Ascorbate, have shown to increase collagen production, and they are good stable alternatives to L-ascorbic acid. However, it would be nice if we could still use the real deal.

Stable L-ascorbic acid in skin care products

Two other solutions have been developed. One is the L-ascorbic acid in silicone. I blogged about this recently, and you can read all about it here.

The other solution was offered by Pinnel and others in their paper “Ferulic Acid Stabilizes a Solution of Vitamins C and E and Doubles its Photoprotection of Skin”.

L-ascorbic acid with Ferulic acid

The Pinnell paper proposes that:

“Ferulic acid is a potent ubiquitous plant antioxidant. Its incorporation into a topical solution of 15% L-ascorbic acid and 1% tocopherol improved chemical stability of the vitamins (C+E) and doubled photoprotection to solar-simulated irradiation of skin from 4-fold to approximately 8-fold as measured by both erythema and sunburn cell formation. Inhibition of apoptosis was associated with reduced induction of caspase-3 and caspase-7. This antioxidant formulation efficiently reduced thymine dimer formation. This combination of pure natural low molecular weight antioxidants provides meaningful synergistic protection against oxidative stress in skin and should be useful for protection against photoaging and skin cancer.”

This study (and the patent) led to the Skinceuticals C E + Ferulic product. The Skinceuticals skin care product is certainly very popular and many people swear by it.

However, is it really stable?

This sentence “Ferulic acid is a potent ubiquitous plant antioxidant. Its incorporation into a topical solution of 15% L-ascorbic acid and 1% tocopherol improved chemical stability of the vitamins (C+E)” would suggest it is.

However, some forum members have commented that their product is colored orange, and an orange product with L-ascorbic acid means that the asacorbic acid has oxidized.

Did the Pinnell study also look at for how long Ferulic acid can stabilize a solution of Vitamin C and Vitamin E?

I don’t know, and it really does not matter, because this product is something that we can DIY ourselves.

The advantage of making your own version of Skinceuticals C+E+Ferulic is that it can be made fresh every week, so it will never oxidize.

In my next post I will discuss various DIY recipes for the SkinCeuticals product.  In the meantime there are already some recipes available on our website:  ce ferulic 1 and ce ferulic 2

Active ingredients for DIY Skinceuticals CE + Ferulic

http://www.bulkactives.com/ascorbicacid.htm

http://www.bulkactives.com/ferulicacidnatural.htm

http://www.bulkactives.com/dpanthenol.htm

http://www.bulkactives.com/nah.htm

Recent posts on various DIY skin care forums have discussed the issue of the penetration of L-ascorbic acid suspended in a silicone base into the skin.

More precisely, a few posters have started promoting the idea that L-ascorbic acid cannot penetrate into the skin, because silicone forms a barrier on the skin.

I would like to address this issue in more detail.

Background: Stable L-ascorbic acid products for skin care

The DIY skin care community has long struggled with the formulation of a stable L-ascorbic acid skin care product. In fact, professional skin care companies and formulators have also struggled with the same problem.

Some attempts have been made by professionals to develop a stable vitamin C skin care product.  The best example of this is the Skinceuticals C+E+Ferulic product.  This is based on the 2006 study “Ferulic acid stabilizes a solution of vitamins C and E and doubles its photoprotection of skin” by Pinnel and others.

This study claimed that

“Ferulic acid is a potent ubiquitous plant antioxidant. Its incorporation into a topical solution of 15% L-ascorbic acid and 1% tocopherol improved chemical stability of the vitamins (C+E) and doubled photoprotection to solar-simulated irradiation of skin from 4-fold to approximately 8-fold as measured by both erythema and sunburn cell formation.” http://www.nature.com/jid/journal/v125/n4/full/5603565a.html

However, consumers have found that skinceuticals C E ferulic product is often orange tinted.  This color usually indicates that the L ascorbic acid has oxidized, thus making it pro-oxidant.  So, even though Ferulic acid may stabilize l ascorbic acid in the lab, in practicality there appear to be some serious issues that have not been addressed.

DIY skin care formulators are able to work around this.  By making a CE Ferulic product at home, it is possible to have a fresh supply every week, thus reducing (but not eliminating) the amount of vitamin C oxidization.

Solution: The Fitzpatrick study

Another study of interest is the 2002 “Double-blind, half-face study comparing topical vitamin C and vehicle for rejuvenation of photodamage” by Fitzpatrick.

Even though this study predates the CE+Ferulic study, it did not start getting discussed on the DIY skin care forums until quite recently.

Fitzpatrick’s method was as follows:

“Ten patients having facial photodamage were recruited for a double-blind pilot study of a newly formulated vitamin C complex having 10% ascorbic acid, a water soluble acid, and 7% tetrahexyldecyl ascorbate, a lipid soluble analog.

Both of these are combined in an anhydrous polysilicone gel base, which acts as a ‘dermal patch,’ releasing the water soluble acid slowly and the lipid soluble analog rapidly. The active vitamin C complex was applied to one side of the face and the inactive placebo base was applied to the opposite side of the face once a day.” http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=pubmed&cmd=Retrieve&dopt=AbstractPlus&list_uids=11896774&query_hl=7&itool=pubmed_ExternalLink

Now, this is where a very few posters start having some issues.  The base used is an anhydrous silicone gel, and the doubt seems to be in the fact that a very few posters believe that silicone forms a barrier and therefore hinders the absorption of active ingredients.

However, let’s look at the next part of Fitzpatrick’s study:

“Biopsies showed increased Grenz zone collagen, as well as increased staining for mRNA for type I collagen. This formulation of vitamin C results in clinically visible and statistically significant improvement in wrinkling when used topically for 12 weeks. This clinical improvement correlates with biopsy evidence of new collagen formation.”

Now, if silicone prevents the absorption of active ingredients, than there would not have been an increase collagen.

So, this should put to rest the claims that using silicone as a base prevents the absorption of active ingredients.

Flawed study

There is one troubling aspect about the Fitzpatrick study.  The study did not test the use of each key ingredient separately.

The two key ingredients in the anhydrous C product are L-ascorbic acid (which is water soluble), and Ascorbyl Tetraisopalmitate (also known as Tetrahexyldecyl Ascorbate ) which is oil soluble.

So, even though the study shows that the combination the two active ingredients in a silicone base led to an increase of collagen, we do not know if this was caused by the Tetrahexyldecyl Ascorbate, the Vitamin C, or the combination of the two.

This brings us back full circle to the original problem! We do not know which active is responsible for the increase in collagen. So it is possible to claim that the L-ascorbic acid is in fact not absorbed by the skin, and that the increase of collagen is cause by the Tetrahexyldecyl Ascorbate.

The blame for this confusion can be put purely with Fitzpatrick. It seems a simple matter to have tested the activity of both l-ascorbic and Tetrahexyldecyl Ascorbate in anhydrous silicone, separately. However, he chose not to do this.

So, we remain with his original statement.

“Both of these are combined in an anhydrous polysilicone gel base, which acts as a ‘dermal patch,’ releasing the water soluble acid slowly and the lipid soluble analog rapidly.”

To me the dermal patch idea makes sense, and I personally put more trust in this than the doubt caused by a very few (but very ‘vocal’) posters on skin care forums.

In the end the choice is yours.

I will continue to use the anhydrous C product as my number one weapon in anti aging skin care.  Why? Because no matter which active did the job, somehow this product has improved my skin and that is ultimately what I want.

http://www.bulkactives.com/siliconegel.htm

http://www.bulkactives.com/ascorbicacid.htm

http://www.bulkactives.com/ascorbyltetraisopalmitate.htm

It is a well-known fact of life that exposure to UV light, especially the UVA component, festers skin disorders like melanoma and non-melanoma skin cancers. Superficial remedies such as sunscreens are effective only to a limited extent. This realization has led to investigation of new methods to protect the skin from photo-damaging effects of solar UV radiation, or “photo-carcinogenesis” as it is called. Recent years have seen considerable interest in identifying naturally-occurring botanicals with anti-oxidant and anti-inflammatory properties, and which exhibit anti-carcinogenic and anti-mutagenic functionality.

It is in this light that the medicinal benefits of milk thistle have been a subject of intense research by scientists. Though its value as a medicine for a host of health conditions, including dermatological, has been known for over 2,000 years, it is only now that science has seriously begun looking at the role played by milk thistle and “Silymarin”, its active compound, in treating skin damage.

In an experiment conducted at Palacky University in Czechoslovakia (1), researchers studied the impact of two components of Silybum marianum (technical name for milk thistle) as both a preventative as well as treatment intervention for skin damage against UVA exposure. Their findings were positive, in that it was discovered that these two components – collectively known as “flavonolignans” – perform a host of functions, such as increasing the viability of keratinocytes in irradiated cells, inhibiting the production of ROS, stopping further depletion of ATP and GSH taking place at intracellular level, and halting the peroxidation of membrane lipids. Further, the activation of caspases-3 process that UVA exposure initiates gets halted and reversed when the two components of Silybum marianum are applied. The overall picture that emerges, therefore, is that Silybum marianum is a good candidate to be considered for inhibiting UV damage.

An interesting experiment conducted on mice at the University of Alabama in Birmingham has been reported in the March-April 2008 issue of Photochem Photobiology journal (2). Two observations from this research are of special relevance to us here. One, it is the CD11b+ cells, which are the major source of oxidative stress in UV-irradiated skin, were inhibited by Silymarin. The flavonoid also suppresses the infiltration of leukocytes that UV exposure had induced. The second important observation is that Silymarin not only halts UV damage, it also acts as a preventive measure. Another researcher has gone one step ahead with the identification of yet another reversal that this chemical performs to UV action: it reduces the volume of H2O2-producing and cytokine interleukin-10 producing cells, both of whose generation is activated by UV (6).

Nearly the same conclusion has been arrived at by researchers working in the Department of Pharmaceutical Sciences at the University of Colorado (3). Their research has shown a positive effect of Silibinin on the repair of UVB-induced DNA damage. Another experiment conducted at the Department of Dermatology of the University of Alabama has observed the inhibition affect that the flavonoid has on tumor promoters such as 12-O-tetradecanoylphorbol-13-acetate, mezerein, benzoyal peroxide and okadaic acid (4).

Topical application of Silibinin prior to, or immediately after, UV irradiation has been found to inhibit thymine dimer positive cell generation that UV induces in the epidermis (5). This research has also shown that terminal sunburn cell formation that is again induced by UV is inhibited too, when Silibinin is applied.

A strong case for Silymarin being a very effective agent in inhibiting and reversing carcinogen and tumor-promoter-induced cancers is made by two independent researches. In both the experiments (7), (8), it has been reported that Silibinin inhibits cancer-causing cells (ERK1/2 activation) and promotes benign cells (JNK1/2, p38), making it an effective cancer-intervention agent for cancer.

A paper published in the journal “Cancer Research” details yet another in-depth investigation carried out on the efficacy of Silymarin as a possible intervention agent against Stage I and Stage II tumors (9). The paper reports that the milk thistle extract has been found to be especially useful in Stage I tumor suppression, and inhibits edema, hyperplasia, proliferation index and oxidant state which take place due to UV irradiation. This same result has been arrived by an independent group of researchers, who used a different chemical to induce skin edema in mice (10).

From the above researches being conducted around the world, it may safely be concluded that Silymarin is proving to be very effective in inhibiting UV-induced skin damage, and the day may not be far when milk thistle becomes one of the major ingredients in sunscreen lotions.

References

Svobodová A, Zdarilová A, Walterová D, and Vostálová J. Flavonolignans from Silybum marianum moderate UVA-induced oxidative damage to HaCaT keratinocytes. J Dermatol Sci. 2007 Dec;48(3):213-24. Epub 2007 Aug 3.

Katiyar SK, Meleth S, and Sharma SD. Silymarin, a flavonoid from milk thistle (Silybum marianum L.) inhibits UV-induced oxidative stress through targeting infiltrating CD11b+ cells in mouse skin. Photochem Photobiol. 2008 Mar-Apr;84(2):266-71. Epub 2007 Nov 28.

Singh RP, and Agarwal R. Mechanisms and preclinical efficacy of silibinin in preventing skin cancer. Eur J Cancer. 2005 Sep;41(13):1969-79.

Katiyar SK. Silymarin and skin cancer prevention: anti-inflammatory, antioxidant and immunomodulatory effects. Int J Oncol. 2005 Jan;26(1):169-76.

Dhanalakshmi S, Mallikarjuna GU, Singh RP, and Agarwal R. Silibinin prevents ultraviolet radiation-caused skin damages in SKH-1 hairless mice via a decrease in thymine dimer positive cells and an up-regulation of p53-p21/Cip1 in epidermis. Carcinogenesis. 2004 Aug;25(8):1459-65. Epub 2004 Mar 19.

Katiyar SK. Treatment of Silymarin, a plant flavonoid, prevents ultraviolet light-induced immune suppression and oxidative stress in mouse skin. Int J Oncol. 2002 Dec;21(6):1213-22.

Singh RP, Tyagi AK, Zhao J, and Agarwal R. Silymarin inhibits growth and causes regression of established skin tumors in SENCAR mice via modulation of mitogen-activated protein kinases and induction of apoptosis. Carcinogenesis. 2002 Mar;23(3):499-510.

Jifu Zhao, Moushumi Lahiri-Chatterjee, Yogesh Sharma and Rajesh Agarwal. Inhibitory effect of a flavonoid antioxidant Silymarin on benzoyl peroxide-induced tumor promotion, oxidative stress and inflammatory responses in SENCAR mouse skin. Carcinogenesis, Vol. 21, No. 4, 811-816, April 2000.

Lahiri-Chatterjee M, Katiyar SK, Mohan RR, and Agarwal R. A flavonoid antioxidant, Silymarin, affords exceptionally high protection against tumor promotion in the SENCAR mouse skin tumorigenesis model. Cancer Res. 1999 Feb 1;59(3):622-32.

Zhao J, Sharma Y, and Agarwal R. Significant inhibition by the flavonoid antioxidant Silymarin against 12-O-tetradecanoylphorbol 13-acetate-caused modulation of antioxidant and inflammatory enzymes, and cyclo-oxygenase-2 and interleukin-1-alpha expression in SENCAR mouse epidermis: implications in the prevention of Stage I tumor production. Mol Carcinog. 1999 Dec;26(4):321-33.

In the last two articles we have covered the types of UV damage, and looked at the current range of common ingredients. With that out of the way, it is time to cover botanical sun care.

The simple truth is that, with the issues surrounding some of the chemical UV protection ingredients, you may not always want to lather up. When it comes to those days that you will spend hours out in the sun, the benefits outweigh the risks, and you should protect yourself from the suns damage.

For the days that you won’t be in the sun for long periods of time, though, it is better to use botanical products. Many botanical ingredients provide anti-oxidant protection, have anti-inflammatory properties, and have been shown to be able to repair the suns effects.

The advantage to using botanical sun products is that you aren’t covering your body in harmful chemicals. For the times that you are using the chemical products, a good botanical antioxidant can also provide protection against the damaging effects of the sunscreen itself.

Botanical Sun Care Ingredients

Studies are currently being done into botanical ingredients that provide UV protection. Some of the ingredients that I have listed do provide mild UVB protection, but they aren’t adequate for long term exposure. What you really want when you start to make a sun care product, from botanicals, are ingredients that provide antioxidant protection, and ingredients that help to repair the suns damage.

With that let’s look at some botanical ingredients that work well for sun care. The idea that some ingredients are better than others does hold true here, and I have tried to indicate the best ingredients for the job.

Botanical Antioxidants and Sun Care Ingredients

Ingredient	Properties Useful for Sun Care	Notes
Ginkgo Biloba	Mild UVB Protection Powerful Antioxidant Cancer Preventative Repairs Damage Already Done	Along with mild UVB inhibition, Ginkgo Biloba is one of the better ingredients for sun care. It works to prevent the formation of cancer-causing free radicals. It is also effective in reducing the damage done by oxidization.
Grape Seed Proanthocyanidins	Antioxidant Prevent Free Radical Formation Healing Effects Promotes Cells Natural Defenses Inhibits Tumor Formation Anti-Aging Properties	Grape seed is an ingredient that not only works to prevent and repair sun damage, it also promotes healing, and increases skin elasticity. When all of its properties are combined is becomes an excellent choice for sun care.
Green Tea EGCG	Antioxidant Broad Spectrum UV Repair Anti-Inflammatory Mild UVB Protection Tumor Prevention	Green tea EGCG is an excellent ingredient choice for skin products that will be applied before exposure to UV. It provides mild UVB protection, and prevents free radical formation, and oxidization by both UVB and UVA rays. In other words it helps to stop the damage before it occurs.
Gynostemma extract 95% (Jiaogulan extract )	Poweful Antioxidant Aptogenic (increases the bodies resistance to stress).	Gystoemma is an antioxidant that may be used for sun care.
Liquid Lecithin	Prevents UV Induced Collagen Reduction Increases the skins resistance to UV damage.	Lecithin is actually an emulsifying ingredient. Since it has advantages for sun care, it should be the emulsifier of choice for sun care products.
Yeast Beta 1-3 Glucan	Anti-Inflammatory Healing Properties	For after sun exposure, Yeast Beta Glucan can help to promote healing and to reduce inflammation from sunburns. It is more often used in anti-aging formulations, but sun damage and anti-aging products often go hand in hand (since UV promotes aging).
Pine Bark Proanthocyanidins	Antioxidant Healing Reduces Free Radical Production Reduces Pigmentation caused by UV Promotes Healing Overall Reduces signs of aging caused by UV exposure	Pine bark can also be an excellent antioxidant. With its other qualities is another great choice for sun care formulations. There is also research being done that suggests pine bark may be a good UVB and UVA filter.
Pomegranate extract	Powerful Antioxidant Anti-Tumor Properties Promotes Healing Helps to prevent cancerous changes	Pomegrante is another ingredient that can be a good choice for both before and after UV exposure. It has powerful antioxidant properties, and has been shown to reduce cancerous changes after over exposure to the sun.
Quercetin	Antioxidant Prevents Free Radical Formation	Quercetin is used as an antioxidant in sun care products.
Silymarin (milk thistle extract)	Powerful Antioxidant Prevents Free Radical Formation Promotes Healing After UV Exposure Signifigantly Reduces DNA Damage	Silmarin is one of the best antioxidants for sun care. Along with properties that help to prevent sun damage, it has even been shown to reduce, and even reverse tumor growth in mice.
Soy Isoflavones	Antioxidant Reduces Sunspots Promotes Healing of UV Induced Damage.	Since soy isoflavone has color corrective properties, along with antioxidant properties, it is a good choice for after UV exposure.

Conclusion – Protect Yourself

With the last three article we have covered UV damage, and how to protect yourself. You should now have a good knowledge of ingredients that can be harmful, and those that work for you. With this last article you also have a good guide to ingredients to use in your botanical sun care products.  When it comes to sun protection and to DIY skin care, choosing the right ingredients for the job is important to ensuring your skin’s health!

In our last article, we discussed the different types of UV radiation, and talked about their effects on your skin. With that knowledge in hand, it is now time to discuss protection from the sun’s harmful rays. In may seem like a simple thing, but when you begin to look closer, choosing the right sun protection can be quite difficult.

Protecting yourself from all of the sun’s damaging effects is important, but it isn’t just sunburn from UVB rays, or long-term damage from UVA, that you have to worry about. In almost every product there is at least one ingredient that is unstable, ineffective, or downright dangerous.  There used to be some concern that the use of certain UV filers led to an increase in melanoma. This is still a somewhat controversial issue, but it appears to have been debunked(3).

However, there is plenty of evidence that numerous chemical UV filters have the potential to increase cancer-causing free radicals (6).  Others may have possible estrogenic and other adverse effects, and another is actually systemically absorbed and excreted in urine at a much higher rate than any other sunscreen filter (4,5)

The topic of sun protection could (and actually has been) covered in an entire book. We will do our best to cover everything here.

First let’s cover the wrong way to do it. Although there is some controversy surrounding the issue, studies have shown that some chemical products actually promote free radical production, thus causing more damage than they prevent! In brief “photo-unstable sunscreens may damage your skin.”

The Wrong Way to Protect Against UV

The topic of how not to protect against UV damage could actually be quite a lengthy one. For the purpose of this article we will just discuss some of the more damaging effects of sunscreens. In particular the chemical sunscreens that we buy in the stores can have adverse effects to the skin.

Simply applying a sunscreen with ingredients like avobenzone, bemotrizinol, or benzophenone-3 (Oxybenzone) isn’t enough. In fact, when used by themselves, some studies show that they do as much harm as good. There are a number of problems with using a commercials sunscreen alone. These include:

• Not all ingredients are created equal: It is important to be aware that not all ingredients are created equal. Some UV blockers work better than others, some are more stable and last longer, and each protects against only a certain range of UV wavelengths.
• Some ingredients cause harm: There are ingredients that are easily absorbed by the skin, and can cause damage. Oxybenzone for example, which is a very common ingredient in commercial sunscreens, has been shown to promote the production of free radicals.
• Some stabilizers cause damage: With ingredients that degrade, stabilizers are often used to make them last longer. This can lead to other problems. For example, in a sunscreen that uses avobenzone as a UV blocker, it may have octocrylene as a stabilizer. This increases the risk of irritation and adds to the low-level toxicity of the product.
• Constant chemical use on the skin has shown negative effects: Some studies have shown that the repeated use of chemical UV blockers can have negative effects; especially in those that promote free radical production.
• Micronized Ingredients are being found to cause problems. With physical UV blocks (the ones that look white on your skin) some companies have created micronized version of these products to make them more cosmetically elegant. Studies are showing that the micronized particles of zinc or titanium can actually be absorbed by the skin, and cause further problems.

With that in mind, it begins to become apparent that simply lathering up with chemical sunscreens each time you go out in the sun isn’t enough. To protect yourself, the right way, requires some special considerations.

The Right Way: Protection Against UVA, UVB, and Antioxidant Protection

To ensure that you have the best protection actually requires choosing the right product for the job. How much time will you be spending in the sun? Is it a cloudy day, or will you be out in the dead-heat of the midday sun? When you begin to look at the answers to these questions you can begin to choose the right product(s) to protect yourself. You also need to consider photo-stability of ingredients, the cosmetic elegance of the product, and whether to choose physical or chemical blockers. You also need to ensure that along with UV filters, you always have an antioxidant to reduce the production of free radicals.

Photo-stability of UV filters

The first thing to consider is the photo-stability of the ingredients. A sunscreen filter is photo-stable if it does not degrade in sunlight. Photo-unstable filters may lose their protective effect. The rate of degradation can be reduced by stabilizers. However, photo-stabilizers may increase the risk of irritation.

In practice, the most photo-unstable filter is avobenzone. Octyl methoxycinnamate is also photo-unstable but it does not degrade quite as quickly. However, the combination of avobenzone and octinoxate degrades faster than either alone (1).  Oxybenzone (benzophenone-3) is also photo-unstable.

List of Common UV filters and blockers

Chemical name: zinc oxide
UV spectrum: UVA-1 , UVA-2, UVB
type :physical
stability: stable
irritation : none
Pros: broad range protection, safe, anti-irritant
cons: white residue

Chemical name: titanium dioxide
UV spectrum: UVA-1, UVB
type: physical
stability: unstable
irritation: none
Pros: none
cons: insufficient protection against UVA-2, may generate free radicals, white residue

Chemical name: phenylbenzimidazole sulfonic acid  (ensulizole
UV spectrum: UVB
type: chemical
stability: stable
irritation: low
Pros: may stabilize other chemicals, water soluble in salt form
cons: No UVA protection

Chemical name: homosalate
UV spectrum: UVB
type: chemical
stability: unstable
irritation: low
Pros: none
cons: No UVA protection, Poor range of UVB protection

Chemical name: octyl methoxycinnamate (octinoxate)
UV spectrum: UVB
type: chemical
stability: unstable (partially stabilized by bemotrizinol/ Tinosorb M)
irritation: potential high risk
Pros: none
cons: risk of possible estrogenic and other adverse effects

Chemical name: octyl salicylate (octisalate)
UV spectrum: UVB
type: chemical
stability: unstable
irritation: low
Pros: none
cons: Poor range of  UVB  protection

Chemical name: octocrylene
UV spectrum: UVB, UVA-2
type: chemical
stability: very stable,sStabilizes other UV filters
irritation: low
Pros: very stable, stabilizes other UV filters
cons: weak, cannot be used alone

Chemical name: Benzophenone-3 (Oxybenzone)
UV spectrum: UVB, UVA-2
type: chemical
stability: unstable
irritation: high risk
Pros: none
cons: weak, cannot be used alone, promotes generation of free radicals, systemically absorbed and excreted in urine at a much higher rate than other sunscreen filters.

Chemical name: Avobenzone ( butyl methoxydibenzoylmethane, Parsol 1789, Eusolex 9020, Escalol 51)
UV spectrum: UVA-1, UVA-2
type: chemical
stability: unstable (Octocrylene, increases stability. Zinc oxide and titanium dioxide reduce stability)
irritation: low
Pros: Full UVA protection
cons: loses effectiveness over time,             may produce low-level toxicity with long-term use

Chemical name: 4-Methylbenzylidene camphor , 4-MBC, 3-(4-Methylbenzylidene) bornan-2-one , 3-(4-Methylbenzylidene)-dl-camphor
UV spectrum: UVB
type: chemical
stability: unstable
irritation: potential high risk
Pros: Stabilizes Avobenzone
cons:risk of possible estrogenic and other adverse effects, not approved in the USA

Chemical name: Ecamsule/terephthalylidene dicamphor sulfonic acid  (Mexoryl SX and XL)
UV spectrum: UVA-1, UVA-2
type: chemical
stability: stable
irritation: low
Pros: Ecamsule is acidic, the alkaline base used for neutralizing may cause irritation for some people.
cons: Full UVA protection, photo-stable, expensive -patented by L’Oreal

Chemical name: Bisoctrizole/methylene bis-benzotriazolyl tetramethylbutylphenol  (Tinosorb M, S)
UV spectrum: UVA-1, UVA-2, UVB
type: Chemical and Physical
stability: stable
irritation: low
Pros: Full UVA protection, photo-stable,pPartially stabilizes octinoxate
cons: Not approved in the USA

Stabilized Avobenzone

Due to the stability issues of avobenzone companies developed stabilized formulations.

Neutrogena Sunblock, Ultra Sheer Dry-Touch SPF uses Helioplex (a formulation containing avobenzone and oxybenzone). Banana Boat offers ‘AvoTriplex’, a formulation containg: avobenzone 3% , homosalate 8.78% , octinoxate 5% , octisalate 5% , octocrylene 2.5% , and oxybenzone 5%.

The problem with these products is the use of oxybenzone, which is a high-risk product.

European UVA filters

Until recently the only UVA filter available in the USA was Avobenzone. Sun-savvy consumers would therefore buy and import their sun protection products from abroad.  The most popular of these products was L’Oreal La Roche-Posay, which is formulated with Mexoryl SX and XL

In 2006 the FDA approved the sales of sun protection product containing Mexoryl SX and XL. It is now possible to buy L’Oreal La Roche-Posay products, as well as cheaper products made by their umbrella companies (Vichy Capital Soleil, L’Oreal Solar Expertise and Garnier Ambre Solaire).

Tinosorb (S and M) is an amazing hybrid filter and we will discuss it more, later in this article. At the time of this writing it is still not approved by the FDA. Those who are seriously committed to maintaining excellent skin health are still forced to import this product from the European Union or Canada.

Cosmetic elegance

Next we need to consider the cosmetic elegance of the sun screen. This is a concern to many.

Due to the nature of the UV filters, it is actually not easy to manufacture and effective UVA/UVB sun protection products which are also cosmetically elegant.  High oil content and excessive alcohol use are a problem for those with sensitive skin.  Excessive shininess (as opposed to the preferred matt look) and balling (when the product ends up forming little ‘balls’) are also a problem for those who have to look presentable during the day.

Physical and Chemical UV Protection

When prolonged exposure to the sun is planned, the best UV protection is offered by new the UV filters Mexoryl SX and XL. These new filters offer outstanding protection against the entire UVA range, they are photo-stable, non-irritating and have no reported toxicity concerns.

Physical protection (UV blocking) used to be only available with Zinc Oxide and Titanium dioxide.  Although Zinc Oxide has a good safety profile, there are numerous concerns about Titanium dioxide. However, non-micronized zinc keeps out both UVA, and UVB rays and is a good alternative for those with extremely sensitive skin.

With the absence of easily absorbed chemicals there isn’t a lot of damage that can be done by the sunscreen itself. The problem with these particular products is that they leave the skin white, which may not always be the look you want for that day on the beach.

It is worth noting that some products contain Zinc Oxide with the chemical Avobenzone, this combination should really be avoided as the already unstable Avobenzone can be degraded even more by Zinc Oxide.

An excellent alternative to the purely physical blockers is the new hybrid (chemical and physical blocker) Tinosorb (S and M). This insoluble powder is usually added to the water phase of a product, and it acts as both a chemical UVA filter AND a UVA reflector. In addition it partially stabilizes the commonly used UVB filter Octinoxate.

When a more cosmetically elegant sunscreen is required, a chemical sunscreen can be used with the antioxidant. What is important to ensure is that you choose one with ingredients that don’t generally have harmful effects, and that protect from both UVA and UVB rays. It is also quite important to understand that with some ingredients there isn’t a lot of studies that look at the long term effects or repeated use. For this reason chemical sunscreens should not be over used.

Anti-Oxidant Protection to Prevent Free Radical Production

Whenever you go plan to expose yourself to the sun (and even when you aren’t using a sunscreen) you should be using an antioxidant. The process is known as layering, and the antioxidant always goes on first. This works to counter the free radical production that comes both from sun exposure, and from the use of chemical UV blockers.

What do I use?

Sun protection for my face, daily use during the summer:

Last year I was using Anthelios XL Fluide Extreme from La Roche-Posay line. However, with the release of the tinosorbs I was ready for a change, so this year I am trying RoC Minesol protect SPF 60 spray-on .  I am not too happy with the formulation, although it is an elegant product, and the next sunscreen I will try is one of the Bioderma ones, also with the Tinysorbs.

I will write another post soon, with a detailed analysis of these sunscreens, and others!

All over body protection for when I am at the beach.

I used to use Ultra Sunscreen SPF 30+ made by the Australian Cancer Council. I especially loved their spray on, which was quick and effective on the beach. However, since learning more about sun protection I realized that this is really quite a bad formulation. In fact, I have given up on body sunscreens all together.

Most of my sun exposure occurs when I am windsurfing, sailing, kayaking or snorkeling.  I have had some nasty burns, and I have too many moles on my body. So, now I use a nice pair of UV protection swim shirts (SPF 50), and swim tights.  It may look silly, but I love being active on the beach and on the water, and there is no point taking risks.

Botanical Protection From UV

For the days when only a short time will be spent in the sun (quick trip to work, working in a windowless office), botanical protection may be a good choice. An effective antioxidant serum can be made using ingredients that have been proven to prevent UVB damage, reduce free radical activity and even reverse sun damage.  Using natural ingredients ensures that you’re not exposing your body to chemicals, and that you still have basic protection from the sun.

No matter what, a good antioxidant serum is essential to maintaining skin health, and should always be layered under your chemical or physical sun protection product. This will actually be the topic of the next article in this series of 3 on sun protection.

References

1.  Maier H, Schauberger G, Brunnhofer K, HoÈnigsmann H. Change of Ultraviolet Absorbance of Sunscreens by Exposureto Solar-Simulated Radiation. Division of Special and Environmental Dermatology, University of Vienna Medical School, Vienna, Austria; Institute of Medical Physics and Biostatistics, University of Veterinary Medicine Vienna, Vienna, Austria; Austrian Consumers’ Association, Vienna, Austria

2. Dr. G. Todorov. Sun Blocks/Sun Screens – an  online resource. Various pages used in researching chemical skin care ingredients. Accessed July 20, 2008 from http://www.smartskincare.com/skinprotection/sunblocks/

3.  Sunscreen use and the risk for melanoma: a quantitative review. Dennis LK, Beane Freeman LE, VanBeek MJ. College of Public Health and College of Medicine, University of Iowa, Iowa City, Iowa 52242, USA. leslie-dennis@uiowa.edu

4. mSarveiya V, Risk S, Benson HA. Liquid chromatographic assay for common sunscreen agents: application to in vivo assessment of skin penetration and systemic absorption in human volunteers. Faculty of Pharmacy, University of Manitoba, Winnipeg, Man., Canada.

5.   Janjua NR, Mogensen B, Andersson AM, Petersen JH, Henriksen M, Skakkebaek NE, Wulf HC. Systemic absorption of the sunscreens benzophenone-3, octyl-methoxycinnamate, and 3-(4-methyl-benzylidene) camphor after whole-body topical application and reproductive hormone levels in humans.

6.  Schallreuter KU, Wood JM, Farwell DW, Moore J, Edwards HG. Oxybenzone oxidation following solar irradiation of skin: photoprotection versus antioxidant inactivation. Department of Dermatology, University of Hamburg, Germany.

7.    Negishi, K; Higashi, S; Nakamura, T; Otsuka, C; Watanbe , M; Negishi, T. (2007) Oxidative DNA Damage Induced by 364-nm UVA Laser in Yeast Cells. Originally published by the Japanese Environmental Mutagen Society. Accessed online July 16th 2008 from http://www.jstage.jst.go.jp/article/jemsge/28/2/74/_pdf

8.   Brannon, Heather MD. (March 23, 2008). Effects of Sun on the Skin: Cellular Skin Changes Caused by UV Radiation. Article hosted on about.com. Accessed July 16th, 2008 from http://dermatology.about.com/cs/beauty/a/suneffect.htm

9.   Hugget, J. (June 28, 2005) Less Than Full Protection: Most Sunscreens Do Only Half the Job, Blocking Unsafe UVB Rays But Not Skin-Damaging UVA. Can We Get Better Cover. Washington Post. Accessed July 16th 2008 from http://www.washingtonpost.com/wp-dyn/content/article/2005/06/27/AR2005062701099.html

10. Eldich, R Dr. and Various other Authors (2004) Photoprotection by Sunscreens with Topical Antioxidants and Systemic Antioxidants to Reduce Sun Exposure.  Journal of Long-Term Effects of Medical Implants. Begal House Inc. Accessed July 16th 2008 from http://www.pacificcenterplasticsurgery.com/articles/Photoprotection-by-Sunscreens.pdf

11.  Reinheckel, Thomas,  Bohne, Marisela,  Halangk, Walter,  Augustin, Wolfgang,  Gollnick, Harald. Evaluation of UVA-mediated oxidative damage to proteins and lipids in extracorporeal photoimmunotherapy. A Study hosted on findarticles.com Accessed July 16th 2008 from http://findarticles.com/p/articles/mi_qa3931/is_199905/ai_n8838478

12. Columbia-Presbyterian Medical Center, no author listed. Two Cancer Studies: Tomatoes, Green Tea, and Cancer. Originally published in the P&S Journal: Fall 1997, Vol.17, No.3 Research Reports. Accessed July 16th 2008 from http://cpmcnet.columbia.edu/news/journal/journal-o/archives/jour_v17n03_0009.html

13. MakeupAlley, no author listed. List of UVA-Protective Sunscreens. Accessed July 20th 2008 from http://www.makeupalley.com/user/notepad/sunscreens

14. MakeupAlley, no author listed. Information and frequently asked questions about sunscreen. Accessed July 20th 2008 from http://makeupalley.com/account/vn.asp?u=sunscreenFAQ