Triethanolamine (TEA) is a pH adjusting agent and surfactant used in cosmetics to balance acidity and help mix oil and water-based ingredients. It's been used in skincare and makeup formulations for decades to improve product stability and texture.
Benefits
Neutralizes acidic ingredients to achieve optimal skin pH
Helps create stable, uniform product textures
Allows better mixing of different ingredient types
Potential concerns
May cause skin irritation or sensitization in sensitive individuals
Can form potentially harmful nitrosamines when combined with certain preservatives
Classified as a potential carcinogen in some recent literature reviews, though regulatory bodies consider it safe at approved concentrations
Science: A 2013 expert panel safety assessment by the Cosmetic Ingredient Review concluded TEA is safe as used in cosmetics. However, a 2023 analysis of commercial products identified TEA and its derivatives as potential carcinogens present in most facial makeup cosmetics tested, highlighting the need for longer-term safety studies on cumulative exposure.
Stearic acid is a naturally occurring fatty acid commonly derived from plant or animal sources. In skincare products, it functions as an emollient and emulsifier, helping to soften skin, improve product texture, and stabilize formulations by allowing oil and water to mix together.
Benefits
Softens and moisturizes skin by forming a protective barrier
Improves product texture and stability
Helps other active ingredients penetrate the skin more effectively
Potential concerns
May cause mild irritation or sensitivity in people with very sensitive skin
Can leave a slight waxy residue if used in high concentrations
Science: Research indicates stearic acid acts as a permeation enhancer, potentially improving how active ingredients cross the skin barrier. It is well-established in cosmetic formulation design and has a strong safety history in topical products.
Cetearyl alcohol is a waxy, fatty alcohol derived from vegetable or petroleum sources that acts as an emulsifier and thickener in skincare products. It helps blend oil and water-based ingredients together and gives creams and lotions their smooth, spreadable texture.
Benefits
Stabilizes emulsions to prevent separation of oil and water
Thickens and improves texture of creams and lotions
Creates a smooth, non-greasy feel on skin
Potential concerns
Rare allergic contact dermatitis reported in sensitive individuals
May cause localized irritation or allergic reactions in patch-tested cases
Science: Cetearyl alcohol is widely used as an emulsifier in topical formulations and generally has a good safety profile. However, multiple case reports document allergic contact dermatitis in susceptible individuals, suggesting it can act as a contact allergen in rare cases. It does not significantly penetrate skin and primarily remains in the formulation.
Coumarin is a naturally occurring compound found in plants like vanilla, cinnamon, and citrus fruits. In skincare, coumarin derivatives are studied for their potential anti-inflammatory benefits and are being researched for their ability to help calm irritated or sensitive skin.
Benefits
May help reduce skin inflammation and redness associated with conditions like atopic dermatitis
Naturally derived from common plant sources
Being actively researched for skincare applications
Potential concerns
Some coumarin derivatives (particularly furocoumarins) can increase skin photosensitivity and cause reactions when exposed to sunlight
In medical contexts, coumarin compounds have been associated with rare but serious allergic skin reactions and skin sensitivity
Limited safety data available for cosmetic use in skincare products
Science: Recent research (2025) shows coumarin derivatives can reduce inflammatory skin symptoms in atopic dermatitis models. However, earlier medical literature documents that certain coumarin compounds can trigger allergic reactions and photosensitivity, particularly furocoumarin derivatives. More long-term cosmetic safety data is needed for topical skincare applications.
Sodium cocoamphoacetate is a mild surfactant derived from coconut oil that helps cleanse skin by removing dirt and oil. It's commonly used in gentle cleansers and makeup removers because it's less harsh than traditional soap-based surfactants.
Benefits
Effective at removing makeup and impurities
Gentler than stronger surfactants like sodium lauryl sulfate
Well-tolerated by most skin types, including sensitive skin
Potential concerns
Can cause mild irritation at higher concentrations (10%+), though typically at lower irritation levels than harsher surfactants
Rare contact allergy reported in isolated cases
May cause dryness or transepidermal water loss with prolonged or repeated exposure at high concentrations
Science: Research shows sodium cocoamphoacetate induces lower irritation compared to stronger surfactants like sodium lauryl sulfate and benzalkonium chloride. Patch testing studies indicate it causes minimal irritant responses even in people with pre-existing dermatitis, eczema, or atopic conditions, supporting its use as a gentle cleanser ingredient.
Methylparaben is a preservative used in skincare and cosmetic products to prevent bacterial and fungal growth, extending shelf life. It's one of the most commonly used preservatives in the beauty industry and has been approved for use in cosmetics across most regulatory regions.
Benefits
Prevents microbial contamination and product spoilage
Allows products to remain safe and effective throughout their shelf life
Cost-effective preservation at low concentrations
Potential concerns
Classified as a potential carcinogen in recent literature reviews; however, regulatory bodies consider approved concentrations safe
Some studies suggest parabens may have weak estrogenic activity, though real-world risk at cosmetic-use levels remains debated
May cause contact sensitivity or allergic reactions in individuals with paraben sensitivity
Science: A 2023 review identified methylparaben among potential carcinogenic substances in analyzed cosmetics, though the authors note these are used 'within allowable range of established concentrations.' Current EU and regulatory approval suggests approved concentrations are considered safe for consumers, but long-term exposure studies at cosmetic levels remain limited.
Propylparaben is a preservative used in skincare products to prevent bacterial and fungal growth, extending shelf life. It's one of several paraben preservatives commonly found in cosmetics and personal care products.
Benefits
Prevents microbial contamination
Extends product shelf life
Cost-effective preservation
Potential concerns
Potential endocrine-disrupting properties at high concentrations
Detectable in human urine, suggesting systemic absorption from cosmetic use
May reduce fecundity in animal models at very high exposures
Science: Research in Drosophila models shows propylparaben has estrogenic properties and can reduce fecundity at high concentrations (200 mM), though typical cosmetic use involves much lower levels. Human biomonitoring studies confirm paraben absorption through skincare products, but long-term health effects at cosmetic exposure levels remain understudied in humans.
