Glossier Stretch Concealer Review

Octyldodecanol is a long-chain saturated fatty alcohol.  Fatty alcohols occur in components of wax esters in plants and animals and are often used as emulsifiers, emollients, antifoaming agents, and surfactants.  

In general, Octyldodecanol spreads easily when applied to the skin – leaving no visible trace of greasiness.  It is used as a carrier or vehicle and is sometimes a coupling agent for waxes. In this particular case, that seems to align with the ingredient list as Glossier includes beeswax and microcrystalline wax.

In fact, a study published in 2007, examined the lipophilic character of five vehicles (which included octyldodecanol) and eight botanical oils (aloe vera oil, coconut oil, olive oil, grape leaf oil, hazelnut oil, jojoba oil, and safflower oil).  

Lipophilic effect or lipophilicity is a compound’s ability to dissolve in fats, oils, and lipids.  What they discovered was that the most lipophilic effects were observed with octyldodecanol and oleyl alcohol as vehicles coupled with coconut oil, jojoba oil, and safflower oil as botanical oils – suggesting that these specific combinations could be effective dermal permeation enhancers.  

And what do ya know?  There happens to be jojoba oil in this product!

Bottom line:  Octyldodecanol is a carrier or vehicle with lipophilic (fat dissolving) properties coupled with specific botanical oils.  Octyldodecanol was ultimately observed as a potential dermal permeation enhancer.

I searched far and wide for research-based information regarding this ingredient – but came up empty-handed.  This seems to be a blended ingredient likely manufactured by Ikeda Corporation of America. This is a mixture of fatty acids – often used as a substitute for lanolin.  Ikeda even states that their proprietary blend claims to have superior oxidative stability as compared to lanolin.  

The company claims that the product has “good water-holding capacity” – recommending formulating this raw material in lipsticks, creams, and hair products. 

Bottom line:  This is a blend of fatty acids and is likely used as an emollient substitute for lanolin.  Less able to oxidize when exposed to normal environmental conditions. It is important to note, that there are no scientific publications (to date) outside of the manufacturer’s claims to prove these points.

Polyethylene (PE) is a polymer or ethylene monomers – basically many monomers which are molecules that can be linked together.  As a result, it is generally a large molecule with a fairly large molecular weight on average.

It is the most commonly used plastic and is historically used in packaging and manufacturing (such as plastic bags, plastic film, bottles, etc).  According to a 2007 safety assessment published by the Cosmetic Ingredient Review, in cosmetics; polyethylene is often used as an abrasive, adhesive, binder, emulsion stabilizer and nonaqueous viscosity-increasing agent.

The 2007 assessment concluded, that cosmetic-grade polyethylene used at targeted concentrations – did not contain any harmful toxins.  Since specific concentration and formulation is generally proprietary unless released by the individual company, we can only assume that compliance with these particular targets has been established.  Additionally, the panel also concluded that dermal absorption of any expected impurities due to reactants was insignificant due to the large molecular size of polyethylene. Therefore, it is concluded as safe.

Bottom line:   If used in cosmetics, Polyethylene often functions as emulsifying stabilizers.  Although classified as “safe”, it still warrants observation. How are we sure whether the polyethylene concentration in this formulation is set at a “safe” level?

Beeswax is a structure that forms out of honeycomb.  Bees secrete this waxy material to build their lovely honeycomb hive in order to protect and store honey.  Therefore, it makes sense that beeswax itself is rich in hydrophobic protective properties – more specifically, hydrocarbons, free fatty acids, esters of fatty acids & alcohols, and various exogenous substances.  

In the past, the pharmaceutical industry has used beeswax as a key ingredient to prepare ointments and creams to soothe wounds.  This really hasn’t changed much even with present-day modernization. However, scientists and researchers have discovered the antimicrobial benefits and properties of beeswax.  Providing a good alternative to harsher synthetic chemicals that thwart microbial growth in formulations and products.  Even determining that not only is beeswax helpful as an anti-inflammatory source but when coupled with olive oil has been proven to be effective for the treatment of atopic dermatitis and psoriasis.  

Bottom line:   Beeswax is a natural material with protective strength from its fatty acids and hydrophobic properties.  Creating an amazing moisturizing material. Plus it is a good natural alternative for its anti-inflammatory and antimicrobial properties!

Certified Organic

Cacao, one of the top raw material sources for a multibillion-dollar food industry.  Whether you are a chocoholic or not – cacao and its derivatives have long been used in various foods.  

The pulp of the fruit of the Theobroma cacao tree is the source of cocoa butter (or cupuacu butter)– a natural lipid rich in saturated fatty acids that are stored in the form of triacylglycerides.  In fact, scientists have determined with its abundant polyphenol and flavonol composition – cacao seed butter may influence healing properties –improving dermal blood flow, increasing photoprotection and ultimately contributing to the maintenance of skin health!

In fact, we are just scratching the surface of its neuroprotective benefits as well as its antioxidant properties – which all began from the Aztec and Mayan civilizations!  Nowadays, it is considered a modern plant-based alternative to lanolin, which can often be a sensitizer and allergen.

A water absorption study was performed with each of the following: cupuacu, shea butter, and lanolin (stirring until separation was observed). The study concluded that cupuacu could support 440% of its weight in water, which means that 1 kg of cupuacu butter could absorb 4.4 kg of water; therefore, allowing it to function much more effectively as a skin hydrator and plumper.

In 2003, the chemical composition of cupuacu butter was evaluated and found to be rich in:

• Phytosterols (or plant sterols) which combat free radicals; to benefit dry, damaged skin and
• Polyphenols to combat free radical damage
• Fatty acids to protect and moisturize the skin
  • 18.8 % Oleic acid (Omega-9)
  • 55.2% Palmitic acid
  • 3.1% Linoleic acid (Omega-6)
  • 18.0% Linolenic acid (Omega-3)

Bottom line:  Provides photo-protective, helps to improve dermal blood flow, maintain overall skin health, skin hydrator and plumper.

A 1991 study, evaluated the effects of various avocado oils on collagen metabolism in skin whereby growing rats were fed diets containing 10% (w/w) of the tested oils. What was discovered was that rats fed with unrefined avocado oil showed significant increases in soluble collagen content in skin.

Bottom line: Avocado oil is a carrier oil and is often used in collaboration with other essential oils to carry prominent micronutrients and antioxidants deeper into the skin - such as vitamin A, E, and D.

This is a wax derived from petroleum and characterized by the fineness of its crystals in contrast to the larger crystals of paraffin wax.  Waxes are often used in skin and lip care cosmetic products due to their excellent skin tolerance as well as their high protecting and cleansing performance and broad viscosity options.  

In fact, a review published in 2017, evaluated 13 in vivo (human and animal) and in vitro studies investigating overall dermal penetration of mineral oil and waxes.  The review concluded that mineral oils and waxes are 1) absorbed to the upper layer of the skin (stratum corneum), 2) minor fraction is actually absorbed deep within the skin layer, 3) there is no evidence that its percutaneously absorbed (organ absorbed), and 4) cosmetic use is unlikely to represent a systematic human health risk after long-term exposure.  

Another important detail is that the average molecular weight of microcrystalline wax ranges between 500-800 g/Mol (Da).  This is important due to the 500 Dalton rule – which I will go into further detail in another post.  But briefly, based on an article published in 2000; under the 500 Da rule, it is thought that all common contact allergens are under 500 Da and larger molecules (greater than 500 Da) are typically non-irritating.  Of course, this would be a difficult rule to test out entirely – as all compounds can’t possibly be categorized based on molecular weight and tested for specific dermal sensitivities.  But for the most part, this a good rule to start with when trying to determine the formulation of products.  In essence, a larger sized molecule allows a product to penetrate the skin more slowly which in turn makes it very gentle and suitable for all skin types including the most sensitive skin.  

Bottom line:  So based on this review, how are waxes beneficial to this formulation? If we take into account that it provides a nice protective shield (as waxes tend to do) and is relatively safe based on reviews and research — then it does make sense as to why Glossier would include wax.  However, this type of wax is certainly up for discussion as I could not find finite published benefits.

Jojoba esters are the hydrogenation or interesterification product of Jojoba oil.  The name of this has always made me laugh. In fact, a childhood friend of mine and I would always chuckle at the sound of this ingredient in products.  Was it “ho-ho-ba” or was it “joe-joe-ba”? However you pronounce it, it’s a functional vehicle for providing natural hydration, moisturizing, and firming capabilities synergistically with other key extracts and essential oils.  A number of reviews from scientific sources suggest that jojoba has anti-inflammatory effects and can be used on a variety of skin conditions including skin infections, skin aging, as well as wound healing.

In fact, a 2010 study assessed the hydration and viscoelastic effect of moisturizers containing different herbal ingredients (including jojoba oil) – after 3 weeks of topical application to the skin.  The study found that there was a significant increase in skin viscoelasticity (90-95%) and increase in water content of the stratum corneum (upper layer of the skin) by 60-70%.

Bottom line: Bottom line, this funny-sounding oil enhances the penetration of whatever is synergistically formulated into the product.  It also provides hydration and promotion of skin elasticity!

Again, I searched for research-based information regarding this ingredient – but came up empty-handed.  Based on my search, this is likely manufactured by Givaudan Active Beauty which they have stated is an alkylated vinylpyrrolidone copolymer – often used for the purpose as a sensory agent, sun protection, and film-forming agent.  Givaudan Active Beauty claims that this ingredient is easily soluble in cosmetic lipids such as mineral oil and ester oils.  

Givaudan Active Beauty also lists the following properties of VP/Hexadecene Copolymer as follows:

• Pigment dispersant and film-forming agent.
• Stabilizes the pigment dispersion and gives gloss and shine to colors.
• Additive for all types of face care and body care products.
• Form moisture balancing water resistance films on the skin.
• Not sticky and have no occlusive effects.
• Emollient with skin protecting properties.
• Non-toxic and not skin irritating.

Bottom line:  This is a specific copolymer (chain of monomers) and is likely used as a pigment dispersion agent, film-foaming agent, and emollient with skin-protecting properties.  It is important to note, that there are no scientific publications (to date) outside of the manufacturer’s claims to prove these points.

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.

Lecithin is often the trade name for a mixture of phosphatides (or phospholipids) typically used in the food and cosmetic industry.  Lecithin is the gummy material contained in crude vegetable oils and removed by degumming.

Most commonly seen such as “soybean lecithin or soy lecithin”.  I’ve astutely become aware of this ingredient as it is generally a major component in most chocolates.  Soybeans are the most commercially sourced in order to create the lecithin by-product.

Now back to why this is used.  

In a study published in 2010, a lecithin nanoemulsion (or fancy term for small-scale formulated mixture) which consisted of snake oil (yikes!), soybean lecithin, glycerol, and water were evaluated for its topical delivery effectiveness.  The study observed that the mixture improved skin hydration capacity significantly by 2.5 fold – inhibiting water evaporation from the skin.  The study further attributed the increase in skin hydration due to the nanoemulsion (mixture) barrier.

However, it is important to note that according to an assessment by the Cosmetic Ingredient Review panel, clinical irritation studies were performed and 65% of the cosmetic formulations containing 0.3-3% lecithin were generally non-irritating.

Bottom line:  Overall, lecithin often functions as skin and hair conditioning agents, emulsifiers and surfactants in cosmetics.  It is effective in providing superior skin hydration and helpful for improving permeation effects.

Phenoxyethanol is a preservative used to inhibit the growth of microorganisms in cosmetic products. Generally, a product formulated with high water content (like 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.

Tocopheryl acetate is also known as Tocopherol – which 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 photoaging.  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 photoallergenic or phototoxic.

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

But what is this high chroma business, you ask?  To put it simply, the 2008 study observed that the chroma in aged skin decreased, while youthful skin maintained high chroma levels.  Yet the study did not reference or indicate how it determined chroma levels. And during my search – I was not able to find any linked studies, which correlate chroma levels relative to skin and aging.  So until I find additional information to link that correlation, I am taking it with a grain of salt.

However, since this product includes all three ingredients (mica, iron oxide AND titanium dioxide) – it would certainly explain its slightly pearlescent sheen when used.  Giving you that lit from within glow!

Bottom line:  Overall Mica is safe and has been historically used for various purposes.  The only concern with this particular form of mica is not necessarily knowing whether it was naturally sourced or synthetic.  However, with trifecta ingredients of mica+iron oxide+titanium dioxide, we know that Glossier was certainly looking at maximizing some sort of pearlescent result; likely attributing to its brightening claims.

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 photoaged skin — this is certainly a win-win!

CI 77491 (Red iron oxide), CI 77492 (Yellow iron oxide), CI 77499 (Black iron oxide)

Iron oxides are naturally sourced but synthetically processed.  Therefore, most “natural” marketed beauty companies tend to utilize iron oxides in their formulations due to this “naturally” derived colorant source.  Depending on the type of iron oxide, some varieties may have varying trace metals. Due to heavy regulations imposed by the FDA, iron oxides are generally safe as the trace amounts of metal are likely low.

Bottom line:  Synthetically processed but naturally sourced ingredient used as a colorant or pigment in cosmetics.  Although they do contain trace metals, due to heavy FDA regulations, the amount of allowable iron oxides in products is safe for consumers.

To reiterate what I said earlier regarding mica, I believe titanium dioxide and iron oxides were layered in this formulation to take advantage of the 2008 technique of sandwiching mica+iron oxides+titanium dioxides to create a high chroma pearlescent pigment.

Titanium Dioxide is an inert, semiconducting material, which often exhibits photocatalytic activity in the presence of light.  

English, please?

Basically, it’s considered to be a “natural” material which can scatter UV and visible radiation – yet what is also astonishing is that titanium dioxide can also be absorbed at certain levels.  Absorption can often lead to adverse effects such as oxidative stress, cell damage, inflammatory responses, and genotoxic effects. Yikes! However, the effects are strongly mediated and dependent on chemical and physical characteristics of titanium dioxide – such as size, purity, solubility, etc.  Since we as consumers are not privy to exact chemical amount/concentration/size that is generally formulated in products we purchase – this is certainly concerning!

Bottom line:  Overall titanium dioxide has been used in sunscreens since 1952.  However, the FDA has only recently approved its use in sunscreens since 1999.  So at this point, Glossier is likely using these three ingredients of mica+iron oxide+titanium dioxide; with the intention of maximizing some sort of pearlescent results.  Therefore, attributing to its dewy and glowing claims.

Just dyes/pigments – nothing much to discuss here.  Is approved per the Personal Care Products Council and the FDA in the US.

Just dyes/pigments – nothing much to discuss here.  Is approved per the Personal Care Products Council and the FDA in the US.