Glossier Zit Stick Review

There’s really no need to go into great detail about this very basic component. Oddly enough, applying massive amounts of water onto the skin surface doesn’t actually hydrate – contrary to popular belief. It is that magical balance when hydrating components seeps under the skin’s surface is when we start to see benefits.

The other important thing to note is – when a product’s main or initial components tend to be water – there can be issues of bacterial contamination or growth. Unless there is some ingredient that may counter this within the formulation stability – such as a chelating agent.

And behold!  This formulation does, in fact, have chelating agents: citric acid and disodium EDTA.

Bottom line: Water is neither here nor there. But if this product is predominantly WATER with a tiny bit of ACTUAL ingredient – well then are we truly getting the most bang for our buck?

Dimethyl Isosorbide functions as a pharmaceutical vehicle and drug permeation enhancer.  Apparently, dimethyl isosorbide combined with water makes for a very good solvent or cosolvent.

In a 2008 study, hydroquinone, salicylic acid and octadecenedioic acid with different lipophilicities were used to investigate the effect of dimethyl isosorbide as a solubility modifier relative to dermal and transdermal delivery.  Unfortunately, the study concluded that 10% dimethyl isosorbide was unable to increase skin accumulation of transdermal delivery of hydroquinone, salicylic acid, and octadecenedioic acid.

Bottom line:   Dimethyl Isosorbide functions as a drug permeation enhancer and combined with water makes for a very good solvent or cosolvent.

Glycerin (or glycerol) is one of the oldest humectant agent (water attracting) ingredients used to assist in hydrating and moisturizing the skin surface. The idea of moisturizers and emollients are not only used to smooth the skin but to provide a defined supple appearance after repeated use.

A 1993 study evaluated the influence of glycerin, water, and various other skin mechanics to clarify the effects of short-term influence. The study showed that utilization of these skin mechanics induced significant changes in the mechanical properties of human skin in vivo even AFTER 10 minutes of application.   

Wow!

However, a 2001 study evaluated the influence of a cream containing 20% glycerin and whether it affected the skin barrier function during repeat application. Yet, the study failed to show an influence of glycerin on human skin with respect to TEWL (transepidermal water loss) and skin sensitivity.

Yet, time and time again, glycerol has been evaluated for its role in skin hydration, cutaneous elasticity, and epidermal barrier repair. In fact, glycerol has a tendency to accumulate within the entire thickness of the stratum corneum. A review in 2008 concluded that glycerol’s three hydrophilic hydroxyl groups have the ability to bind and retain water, thus providing enhanced skin hydration.

Bottom line:   Glycerin is a humectant agent. Historically used for over 50 years in cosmetics to provide hydration and moisture to the skin.

Acrylamide/Sodium Acryloyldimethyltaurate copolymer function as a dispersing agent, emulsion stabilizer, opacifying agent, and viscosity increasing agent.

I could not find any specific data or research that would correlate the benefits of this component added to the formulation relative to the overall effects on its claims.  And that may or may not be a good thing. Nevertheless, the CIR deemed acryloyldimethyltaurate polymers to be safe based on their assessment.

Bottom line:  For now, this functions as a dispersing agent, emulsion stabilizer, opacifying agent, and viscosity increasing agent.

Propanediol is corn-derived and exists in two forms: 1,2-propanediol (propylene glycol or PPG) and 1,3-propanediol.  This ingredient is often used as a moisturizing agent or humectant. Since the ingredient list does not mention which particular form is used within the formulation – I’ll go ahead and supply information for both.

First, 1,2-propanediol (propylene glycol) has been flagged for a number of safety issues – with the most common being skin irritations and even carcinogenic but somehow does not fall under the scary toxic category of no-nos.

Similarly, its other form, 1,3-propanediol, has been flagged for a number of skin irritating issues yet is still frequently used within the industry.

However, both ingredients can be used safely at low dosage/concentration levels.  But since the list does not indicate the actual concentration of propanediol (nor its actual true form) – I would keep this in mind in terms of caution.

Bottom line:   Moisturizing agent but may cause skin irritations depending on the concentration level – which is unknown.

What can I say about niacinamide?  There just seems to be so much information out there – that it often becomes quite overwhelming.  

But to try to summarize it briefly, niacinamide (or nicotinamide) is an amide of vitamin B3 (niacin or nicotinic acid).  It has been extensively researched and shown to have sufficient bioavailability – with antimicrobial, photoprotective, sebostatic (anti-acne), skin conditioning, and lightening effects depending on its concentration.

In fact, varying studies have found the following:

• A 2002 study investigated the effects of niacinamide on melanogenesis in vitro and on facial hyperpigmentation and skin color in vivo in Japanese women.  The study found that niacinamide significantly decreased hyperpigmentation and increased skin lightness.
• A 2004 study found topical application of niacinamide had a stabilizing effect on epidermal barrier function, seen as a reduction in transepidermal water loss, an increase in protein synthesis (e.g. keratin), stimulating effect on ceramide synthesis, speeds up the differentiation of keratinocytes, and raises intracellular NADP levels, improves the surface structure, smoothes out wrinkles and inhibits photocarcinogenesis.
• A 2005 study found significant skin appearance improvement effects for topical niacinamide: reductions in fine lines and wrinkles, hyperpigmented spots, red blotchiness, skin sallowness (yellowing), and elasticity was improved.
• A 2011 clinical study evaluated the therapeutic effect of topical niacinamide versus hydroquinone (HQ) in melasma patients.  All patients showed pigment improvement – with niacinamide inducing a decrease in pigmentation, inflammatory infiltrate, and solar elastosis.

Bottom line:   Niacinamide is an effective skin-conditioning agent, with antimicrobial, photoprotective, sebostatic (anti-acne), and lightening effects.  Helps in improving pigmentation, skin sallowness, elasticity and wrinkles, and increases skin lightness.

Capryloyl salicylic acid (2-hydroxyl-5-octanoyl benzoic acid) is a lipophilized derivative of salicylic acid and has been shown to be an effective exfoliating agent due to its reduced penetration in the skin compared to traditional salicylic acid with a similar profile to glycolic acid.

And as we all know, salicylic acid is another member of the hydroxy acid group – beta hydroxy acid (BHA), to be exact.  Salicylic acid (SA) is best marketed as an anti-acne and anti-aging treatment but it also functions as a denaturant, hair-conditioning, and skin-conditioning agent.  Either way, SA are lipid (fat) soluble compounds that are effective at reducing the appearance of fine lines, wrinkles, and improving skin texture – with mild skin irritation.  SA also decreases the secretion of sebum in patients with acne, which adds to its therapeutic effect in these patients.

Since its early development, many studies have propped up evaluating capryloyl salicylic acid:

• A 1999 study compared 10% glycolic acid, 2% capryloyl salicylic acid, and 0.05% all-trans-retinoic acid and found that capryloyl salicylic acid increase cell renewal.
• A 2002 study evaluated its dermal stimulatory effects and found it to be equivalent to that of tretinoin.
• A 2008 study evaluated clinical tolerance and efficacy of capryloyl salicylic acid peel compared to a glycolic acid peel in subjects with fine lines/wrinkles and hyperpigmented skin.  The results concluded the following:
  • 5- 10% concentration of a capryloyl salicylic acid peel is generally safe and as effective as a 20–50% concentration glycolic peel in reducing facial hyperpigmentation and fine lines/wrinkles.
  • 41% of capryloyl salicylic acid-treated and 30% of glycolic acid-treated subjects demonstrated a significant reduction of fine lines/wrinkles compared to baseline.
  • 46% of capryloyl salicylic acid-treated subjects and 34% of glycolic-treated subjects showed significant reduction of hyperpigmentation compared to baseline.

In addition, formulating with traditional SA is often recommended to cosmetic products at concentrations <3% based on a 2009 study.  Interestingly enough, the FDA indicates that OTC topical acne products with single active ingredients containing salicylic acid must be in the concentration range of 0.5-2%.  However, according to the label, this salicylic acid derivative is under “inactive ingredients”.  So, since the folks at Glossier have not indicated the % concentration of this salicylic acid derivative (capryloyl salicylic acid) — we are left wondering whether this meets the recommended concentration levels from either study (2008 and 2009) or the FDA.

Overall, the CIR Panel also recommends that effects on skin sensitivity to sunlight be considered in the formulation and use of products containing SA and salicylates.  In the past, the salicylates were often used in treating fever, pain, and inflammation. Salicylate is a natural salt or ester of salicylic acid – a famous component in various cosmetic/skincare products.

Standard chemical peel procedure studies have indicated that SA may be used at 20-30% in an ethanol base with interval peels of 2-4 weeks.  Various side effects based on patient sensitivity have been reported but may be managed with topical moisturizers.  

Bottom line:   Anti-aging, anti-acne, antioxidant, and anti-inflammatory capabilities with studies which provide statistically significant anti-aging changes to reduce hyperpigmentation and fine line/wrinkles.

Butylene Glycol (or 1,3-Butylene glycol) is widely used in cosmetics as a low-irritant humectant in skincare products and topical products compared to propylene glycol. However, there have been various reported cases of allergic contact dermatitis and contact eczema caused by butylene glycol.

One of the reasons this ingredient has been included in cosmetic formulations is due to its moisturizing properties and its antimicrobial capabilities. But most importantly glycol is most widely used as a vehicle to deliver the beneficial goodness of key ingredients.

Bottom line: Used in cosmetics as a low-irritant humectant compared to propylene glycol with antimicrobial capabilities. Cases of contact dermatitis and eczema have been reported.

Melaleuca Alternifolia Leaf Oil or also known as tea tree oil (TTO), has been around for decades.  You’ve likely come across it in aromatherapy, cleaning supplies, as a pure essential oil, and of course skincare and beauty products.  Overall, tea tree oil is largely used for its antimicrobial, anti-inflammatory, and antioxidant properties with studies pointing to its historical treatment of infections.

TTO is composed of terpene hydrocarbons (mainly monoterpenes, sesquiterpenes, and their associated alcohols).  Monoterpenes are dietary compounds that are found in the essential oils of many fruits, vegetables, and herbs. These compounds are widely used as flavorings and fragrances in both food and cosmetic industries, and as active ingredients in many pharmaceutical products due to their therapeutic and healing properties.

But what are terpenes?

Terpenes and sesquiterpenes have been suggested as promising non-toxic, non-irritating transdermal penetration enhancers. A 2007 study examined the effect of terpene concentration in skin penetration. Sadly, this study found no direct relationship between terpene concentration and skin penetration rate.

Although, it is considered an essential oil – it is definitely one that is not immune to questions of its toxicity and sensitivities due to the actual amount used.  More specifically, whether TTO is used in its neat (pure) form.

And, of course, environmental factors (light, heat, exposure to air, and moisture) play a role to affect oil stability.  Tea tree oil kept in varying containers may still undergo photo-oxidation starting from manufacturer to storage — the result may lead to TTO degradation and therefore, allergic sensitization issues.  Therefore, TTO should always be stored in dark, cool, dry conditions; preferably in a vessel that contains little air.

Interesting enough, a 1990 clinical study compared the efficacy of 5% tea tree oil to 5% benzoyl peroxide (like in the Zit Stick formulation) in the treatment of acne. The study found that both treatments reduced the numbers of inflamed lesions – with BPO performing significantly better than TTO and significantly fewer side effects reported by the TTO group than by the BPO group.

Bottom line:   Melaleuca alternifolia leaf oil or tea tree oil is often used for its used for its antimicrobial, anti-inflammatory, and antioxidant properties.  Some allergic sensitivities may arise as a result of photo-oxidation and degradation.

Cucumis sativus (cucumber) fruit extract functions as a skin-conditioning agent in cosmetics.  But we all know what a cucumber is, right?!  We’ve had it in foods, our cocktails, and even our quintessential spa treatments – cucumber eyes!

Overall composition of the cucumber consists of ~96% moisture, ~0.4% proteins, ~0.1% fats, ~2.8%  carbohydrates, and trace minerals. Interestingly enough, cucumber contains a good amount of vitamins, phenolic acids, fatty acids, trace essential oils, and flavonoids – which happen to play a considerable amount of importance to its free-radical scavenging and antioxidant properties.

Its therapeutic potential seems to be unlimited – in its clarifying and detoxifying capabilities, and its soothing and emollient effect.

Bottom line:   Cucumbers function as a skin-conditioning agent in cosmetics with antioxidant and free-radical scavenging properties.

According to a CIR assessment, isohexadecane is an isoparaffin or paraffin often used as an emollient in cosmetics.

It’s important to note that a 2-week study evaluating the safety of a tan-enhancing spray containing 42% isohexadecane in 30 volunteers, found the following adverse reactions:

• Mild itching of the forehead (in 1 out of 4 participants)
• Burning sensation in the left eye (in 1 out of 4 participants)
• Mild tingling and itching of arms, chest, shoulders, and face (in 1 out of 4 participants)
• Mild tingling of cheeks (in 1 out of 4 participants)

However, in this study, the changes observed in participants tested were deemed to be not clinically significant.

But overall, limited relevant peer-reviewed publications were found or available.  Hence, much of the information seemed to stem from specific vendors synthesizing isohexadecane – most referencing to it as a clear, colorless, and odorless liquid providing high emolliency, ease of spreadability and moisturizing properties.

Bottom line:   Overall, the CIR panel has deemed isohexadecane as safe to be used as an emollient or skin-conditioning agent.

Ok, first – what is this?  I reviewed the CIR and found absolutely nothing with respect to this compound.  There were NO studies or reputable published research – with only “fluff” pieces posted randomly on the interwebs.  

So what gives, Glossier?

My only conclusion is that saccharide isomerate is a trademarked proprietary ingredient of some sort.  But again, not much could be found to saccharide isomerate ONLY. The closest I could find were the following compounds and their benefits as listed on each vendor’s websites:

• Lipotec’s  CELLYNKAGE™ marine ingredient [propanediol (and) water (and) saccharide isomerate]
  • “Enhances intercellular communication to improve skin functioning offering a rejuvenating effect for mature skin.  Complete menopausal skin rejuvenation: improved skin thickness, collagen density and microrelief structure as well as increased skin surface smoothness (56 days, 2%).”
• DSM Nutritional’s PENTAVITIN®️ [saccharide isomerate (and) aqua (and) citric acid (and) sodium citrate]
  • “100% natural and plant derived.  Unique skin identical carbohydrate complex.  Deep hydration for up to 72 hours. Strengthens skin barrier function.”

So, at this point, all we know is that saccharide isomerate is plant-derived.

In addition, since saccharide isomerate is listed as a singular entity in Glossier’s Zit Stick and NOT similarly to either Lipotec or DSM’s trademarked products above; we have to assume that it was formulated differently.  Therefore, not much can be said with respect to saccharide isomerate alone and any claims associated with the formulation.

Bottom line:   Not much can be said about saccharide isomerate other than that it is plant-derived and use of trademarked blends may “assist in skin hydration”.

So what is this Xanthan Gum? It is essentially a microbial polysaccharide gum made of monosaccharide components (glucose, glucuronic acid, 6-acetulmannoe, and 4,6-pyruvylated mannose). It is often used as a skin-conditioning agent, emulsifying agent, and binder.

But the most interesting part of polysaccharides is their anti-oxidative capacity as potential lipid protectors for topical administration, which was examined in a 2005 study.  What this means is this ingredient helps in the protection of human skin against UV-induced damage.

Who doesn’t love that?

Bottom line: It is a skin-conditioning agent, emulsifying agent, and binder – with a strong antioxidative capacity to thwart UV damage to the skin.

Polysorbate 80 mostly function as a surfactant and emulsifying ingredient in cosmetics and are classified as safe.  Surfactants have been found to have effects on the permeability characteristics of several biological membranes including the skin.  In fact, they have the potential to solubilize lipids within the stratum corneum. More specifically, surfactants are able to emulsify sebum, thereby enhancing the thermodynamic coefficient of drugs and allowing it to penetrate into the cells more effectively.

Polysorbates aren’t new with respect to being a solubilizing agent.  However, in a 2005 study, polysorbate 80 was evaluated and found to cause severe nonimmunologic anaphylactoid reactions (such as flushing and itching).  

Yikes!

Bottom line:   Surfactant, emulsifying, solubilizing agent, and penetration enhancer which may cause severe nonimmunologic anaphylactoid reactions.

Polyglyceryl-2 isostearate is a fatty acid ester and function as skin-conditioning, emollient agents, and/or surfactants in cosmetics.  

In a 1997 clinical study, 7% polyglyceryl-2 isostearate elicited slight irritation in a 24-hour patch test was performed.  In addition, polyglyceryl-2 isostearate was found to be significantly less irritating than a positive control (0.3% sodium lauryl sulfate) and significantly more irritating than a negative control (deionized water).

Bottom line:  Polyglyceryl-2 isostearate is an emollient agent with skin-conditioning properties.  Depending on the particular vendor, specific properties of the ingredient may be further observed.

Hydroxyacetophenone baffles me.  Literally. So what is this, Glossier?  And why are you including this in your product?  Is it an endocrine disruptor as it was listed in a 2012 review of drinking water? If so, I’m a little concerned!

The ONLY information I was able to find was from the following vendor:

• Symrise which manufactures hydroxyacetophenone (SymSave® H) and lists the following benefits:
  • “Multifunctional stabilizer for cosmetic products.  Enables mild formulations for better skin compatibility.  Combines antioxidant, soothing, emulsion stabilizing and preservative boosting properties.  Helps enhance the efficacy of a wide range of preservatives and protect a whole range of formulations.”

As you can see, not much could be extracted.  And I wouldn’t be doing my job to just take this vendor’s “claims” as its word with respect to hydroxyacetophenone.  

For now, I would say hydroxyacetophenone is not high on my list of compounds to include due to its mysterious and unidentifiable benefits.

Bottom line:   The vendor states that it “combines antioxidant, soothing, emulsion stabilizing and preservative boosting properties” but I was not able to provide any justification to their claims.  For now, be cautious!

1,2-Hexanediol is a 1,2-alkanediols and often used as a solvent or preservative with antimicrobial activity with skin conditioning properties.

Bottom line:  1,2-Hexanediol is likely used as a preservative (with conditioning properties) to thwart microbial issues within the formulation.

Caprylyl Glycol is often used as skin and hair conditioning agents, viscosity agents and preservatives in cosmetic products.  We know that this product seems to have a slew of naturally derived ingredients which often come with microbial issues.

And nobody wants microbes or bacteria in their product — am I right?!

Therefore, the use of caprylyl glycol as a preservative with conditioning properties doesn’t seem far-fetched.

And in a study published in 2016, researchers evaluated the synergy behind antimicrobial activity effectiveness and particle size (of the droplets) of combining caprylyl glycol and various other preservatives.  What researchers ultimately discovered, was the results showed a positive correlation between the antimicrobial activity of the preservative and the particle size of the emulsion droplets in the range of 100-900 nm.

Bottom line:   Caprylyl Glycol is likely used as a preservative (with conditioning properties) to thwart microbial issues within the formulation.

Sodium citrate is the trisodium salt of citric acid.

Bottom line:   Mild exfoliant, skin conditioning agent, and pH adjuster in cosmetic products.  Has been shown to increase elastic fibers, density of collagen, and skin thickness.

Citric acid is a naturally-occurring organic acid (alpha hydroxy acid to be exact) present in many foods.  

Citric acid often functions as a chelating agent, pH adjuster, moisturizing agent, mild exfoliant, and fragrance ingredient in cosmetic formulations.  In a 1988 study, citric acid was found to increase skin renewal rate and treat sun-damaged skin.  

But just to drive the point further home, regarding citric acid, varying studies found the following:

• A 1996 study evaluated the effects of AHAs on photoaged human skin through clinical and microanalytic means.  Patients applied a lotion containing 25% glycolic, lactic, or citric acid (like what is included in this formulation? shocking!) to one forearm and a placebo lotion to the opposite forearm for an average of 6 months.  Treatment with AHAs caused an approximate 25% increase in skin thickness with improved quality of elastic fibers and increased density of collagen.
• A 1997 study examined the effect of 20% citric acid lotion, as compared with vehicle alone, on skin thickness and viable epidermal thickness.  Topical citric acid produces changes similar to those observed in response to glycolic acid, ammonium lactate, and retinoic acid including increases in epidermal thickness.

Bottom line:   Mild exfoliant, skin conditioning agent, chelating agent, and pH adjuster in cosmetic products.  Has been shown to increase elastic fibers, density of collagen, and skin thickness.

And ANOTHER preservative!  However, ethylhexylglycerin (an alkyl glyceryl ether) has additional functionalities as a surfactant, emollient, and skin-conditioning agent – in addition to its antimicrobial properties.

Ethylhexylglycerin is a multifunctional additive for cosmetics and is used as a potentiating agent in combination with 2-phenoxyethanol (another preservative) to obtain better protection against microbial growth.  A 2016 study investigated the mechanisms behind potentiation of the bactericidal effect of 2-phenoxyethanol, by ethylhexylglycerin.  The study concluded that the synergy of ethylhexylglycerin and 2-phenoxyethanol led to rapid killing of E. coli – thereby providing microbial protection.  

At the present moment, there have only been a few cases where contact allergy to ethylhexylglycerin have been published.  In fact, a 2016 study evaluated 13 patients who reported allergic contact dermatitis caused by ethylhexylglycerin.  The study was performed at two Belgian university patch test clinics during the period 1990–2015.  The study identified ethylhexylglycerin as a cosmetic sensitizer even in those products advertised to be safe for consumers.   

Bottom line:   Ethylhexylglycerin is likely used as a preservative to thwart microbial issues within the formulation – but may also function as a surfactant, emollient, and skin-conditioning agent.  As in many preservatives, ethylhexylglycerin may provide an allergic response to more sensitive consumers.

Disodium EDTA is the sodium salt of EDTA (ethylenediaminetetraacetic acid) which functions as a permeating agent, sensitizing agent, and chelating agent in cosmetic formulations.  In fact, historically speaking, EDTA was often used as a chelating agent to treat patients who were poisoned with heavy metals (such as lead or zinc).  

Chelating agents often play a role in stabilizing a product from metallic impurities.  Metallic impurities can come from many different sources, primarily from the ingredients themselves.  Often times, impurities are naturally derived, such as water in this case. Chelating agents prevent deterioration and overall oxidation by binding and inactivating metallic ions.

This specific chelating agent is biodegradable and is selective towards problematic transition metals such as copper and iron compared to calcium and magnesium.

In addition, EDTA has also been found to control microorganisms in combination with other actives such as citric acid and surfactants – which this product contains!

Bottom line:   Disodium EDTA functions as a sensitizing agent and chelating agent with antimicrobial properties.

Diethylhexyl sodium sulfosuccinate is a dialkyl sulfosuccinate salt which functions as a surfactant and solubilizer in cosmetics.

Other than this was a surfactant or wetting agent, not much was found with respect to its benefits or lack thereof.

Currently, there seem to be a few diethylhexyl sodium sulfosuccinate trademarked products from the following vendors: Evonik, Spectrum Chemical, Miwon Commercial, Pilot Chemical, and Innospec.

All of the above reported varying benefits specific to each trademarked product of this ingredient.  And of course, since there wasn’t much publicly available; we were left (again) realizing not much could be concluded regarding benefits or problematic issues.

Bottom line:   Not much can be said other than diethylhexyl sodium sulfosuccinate is a surfactant and is assessed as safe.

Carbomers are high-molecular polymers based on acrylic acid and often function as emulsifiers, gel-forming substances, stabilizers of suspensions, thickening agents, and viscosity-increasing agents.

A 2015 study, evaluated 8 hydrogels formulated using a primary and secondary polymer (carbomer) relative to use in cosmetic applications.  Using caffeine as their active ingredient, the study determined that formulations which combined the primary carbomer with xanthan gum or with the secondary carbomer were the most promising for bioadhesive skin products.   

Bottom line:   For now, this functions as an emulsifier, gel-forming substance, stabilizer of suspensions, thickening agent, and viscosity-increasing agent.

Sodium hydroxide (SH) function primarily as denaturants and pH adjusters in cosmetics (used to raise pH values if need be).  

But be forewarned, in my experience with this corrosive material — it can be quite irritating as it is a very strong base.  And little does go a long way! You never want to have a strong percentage of sodium hydroxide anywhere near your skin.

In fact, in humans, SH was irritating at concentrations as low as 0.5%.  And depending on the concentration, SH can produce immediate coagulative necrosis resulting in considerable tissue damage with ulceration and sloughing.

In an efficacy study of skin protective creams, 20 human subjects were tested with 0.5% SH in aqueous solution.  The results yielded expected irritation. In a human repeat insult patch test (HRIPT), SH was not sensitizing when induced at up to 1.0% and challenged at 0.125%, but irritation was observed.

Bottom line:   Sodium hydroxide is a denaturant and pH adjuster with possible skin sensitivity and irritations.

Dimethicone (also called polydimethylsiloxane) is a type of silicone oil with properties that make it a useful ingredient in many skincare (and haircare) products. This silicone with two methyl group compound is extremely resistant to water; yet, still flexible and provides ideal properties as a lubricant.

The CIR panel assessed that dimethicone is poorly absorbed into the skin due to its large molecular weight. Therefore, when applied to the skin it prevents water loss and penetration of exogenous substances, thus acting as a skin protector. Sounds good to me!

Overall, the CIR panel has assessed dimethicone as safe when used at concentrations of 0.0000014-85% in cosmetic products.  However, it is important to note that the allowable active ingredient concentration of use of dimethicone in the formulation of skin protectant drug products for over-the-counter human use is 1 – 30%.

Bottom line: Dimethicone functions as a skin and hair conditioning agent, occlusive, solvent, and anti-foaming agent. Poorly absorbed itself but effective in allowing the active ingredient of choice to penetrate quickly.

Sorbitan stearate is a sorbitan ester and function as surfactants and emulsifying agents in cosmetics.   

A 1985 report evaluated by the CIR panel, found 4% sorbitan stearate to be non-sensitizing in 420 subjects.

Bottom line:   Sorbitan isostearate is a surfactant and emulsifying agent and is considered safe based on a CIR panel assessment.  Not much to be said here.

Peg-100 Stearate is a polyethylene glycol (PEG) ester of stearic acid – also known as PEG stearates.  Overall, PEG stearates are soft waxy solids. They are nonionic surfactants and emulsifiers used in cosmetic products.  Nonionic surfactants are recognized as penetration enhancers due to their ability in modifying the permeability of several biological membranes, such as skin.

However, a 2000 study evaluated skin penetration enhancers relative to the permeability of ketoprofen (an anti-inflammatory drug),  The study concluded that the surfactant with the largest polar head, PEG-40 stearate, was ineffective in enhancing skin permeation of ketoprofen.  And therefore, absorption enhancing capability of PEG derivatives (such as PEG-40 stearate) appeared to relate to the vehicle other as opposed to the number of chain groups.

Bottom line:   Is a nonionic surfactant and emulsifier used in cosmetic products.

Phenoxyethanol is a preservative used to inhibit the growth of microorganisms in cosmetic products.  Generally, a product formulated with high water content (is in this situation) is prone to the growth of microorganisms unless certain precautions or ingredients are added to thwart such problems.

However, overuse of preservatives within a formulation has also been shown to lead to increased incidences of contact allergy.  Therefore, adding these ingredients poses the question of whether it is truly worth it.

Current concentration use in cosmetics based on a CIR assessment has indicated that phenoxyethanol may be used at a range of ≤ 0.0002% to 1%.

Bottom line:   A preservative used to thwart the growth of microorganisms in high water content formulated products.  No real benefit to claims with potential for skin irritations.

Silica is abundant and makes up of 26% of the Earth’s crust by weight.  It is found primarily in rocks, sand, and clay. Sounds a lot like Mica, huh?  In fact, mica is a form of silica! Along with clay (as mentioned before), quartz, emerald, talc, glass, etc.

In its purest form – silica is unable to exist in its natural state due to its propensity to react with the atmosphere (i.e. Oxygen).  Therefore silica – is actually silicon dioxide.  And generally speaking, there are two forms of silica – crystalline and amorphous.  At present, the amorphous form processed synthetically; is traditionally used in cosmetics as an absorbent, anti-caking agent, and suspending agent.

Did you know that it is the third most abundant trace element in the human body?  And silicon has been suggested that to improve skin strength and elasticity and pivotal in collagen synthesis?  And it is suggested that a higher silicon content in the hair results in a lower rate of hair loss and increased brightness.  Well, now you do!

In fact, in a study of women aged 40 to 65 with typical signs of photoaging — intake of a bioavailable form of silicon supplements saw a significant improvement after 20 weeks in skin surface characteristics and in its mechanical properties.  The study also observed significant improvement in the fragility of nails and hair compared to the placebo group after a nine-month period.

Bottom line:  Silica (or silicon) is safe as it is clearly an abundant element within nature AND your body.  And with studies pointing to its positive effects on skin elasticity and improvement in photo-aged skin — this is certainly a win!

Tocopherol is the most prevalent form of vitamin E in plant seeds and products derived from corn, sesame seed, sunflower, olive oils, and a plethora of nuts.

Most of the tocopherols are reported to function in cosmetics as antioxidants or skin conditioning agents. In fact, a 2003 study, evaluated whether the combination of topical vitamin C and E was better for UV protection to the skin than an equivalent concentration of each – alone. The study concluded that each (in their own right) were significant antioxidants in the protection from skin damage. However, the combination of both C and E provided superior synergy against the likes of skin cancer and photo-aging. Further detailed information regarding tocopherol as a major lipid-soluble chain-breaking antioxidant of membranes and an important cellular protectant against oxidative damage was provided in a 2014 safety assessment.

It is also interesting to note that in 1999, a study found that topical vitamin E applied on scars provided no benefit (in 90% of the cases) to the cosmetic outcome of scars after skin surgery.  And it even noticed that 33% of the patients treated, developed contact dermatitis to the vitamin E.

Overall, tocopherol is the predominant form of vitamin E in human and animal tissues, and it has a high bioavailability. The safety assessment recognized that tocopherol has some absorption in the UV range. However, it was noted that according to animal and clinical testing, tocopheryl acetate was not photo-allergenic or phototoxic.

Bottom line: Strong antioxidant capacity. Best if formulated with vitamin C ingredients but may be a potential for dermatitis.