Chemical (Or group)	Source	Simplify
Alpha hydroxy acid(AHAs)	FDA NIH	Plant-based, water-soluble, chemical exfoliants. Often used to treat acne, wrinkles, and uneven skin texture by "peeling"("AHAs diminish corneocyte cohesion immediately above the granular layer by detaching and desquamating the stratum corneum" - Tang SC, Yang JH.). They're classified as organic acids, the possible side-effects depending on the concentration of the solution.
Amino Acids	FDA NIH	Broad term used to describe several different peptides, FDA does not label synthetic peptides as amino acids and only has a few allowed peptides. Certain peptides are used to improve signs of aging such as acne and loss of skin elasticity. While certain amino acids can be absorbed through the skin, it is more common to see them ingested.
Allantoin	CC FDA	Found naturally in the body, but when used in products often derived from plants like comfrey. It is used as a moisturizer as well as an anti-inflammatory. “It increases the water content of the skin, which means it helps to hydrate and moisturize.” - Dr. Bergfeld shares.
Aloe vera	Dermnet NIH	Naturally derived straight from the source often, used for anti-inflammatory purposes as well as to cool and aid with burns. The plant itself has a mix of many amino acids and beneficial acids, adding to it's soothing properties.
Apple cider vinegar	NIH NIH	Although there are many claims on anti-bacterial nature or anti-fungal properties, studies have shown simple rinses with ACV do no change the bacterial content of the skin. Despite this, some people still use it to remove excess oil or prevent harmful bacteria from hurting their skin barrier.
Avocado oil	Researchnet NIH	Used both on the skin and ingested for results, suggested to promote collagen production and skin firmness. Most ofted used as an anti-aging product.
Beta hydroxy acids (BHAs)	FDA WebMD	A group of chemical exfoliants much like AHA's, however with the adeded benefit of anti-aging properties. They help by removing dead skin cells that sit on top of the skin and remove unwanted sebaceous filaments. Due to the similiarites of the two, sometimes BHAs and AHAs get mixed up in classification. "safe as used when formulated to avoid irritation and when formulated to avoid increased sun sensitivity." - FDA
Beeswax	NIH CC	Beeswax acts as a protective barrier that locks in moisture and shields skin from environmental stressors without clogging pores. It is rich in Vitamin A, which supports cell regeneration and helps repair damaged or chapped skin. Additionally, its natural anti-inflammatory and antimicrobial properties make it effective at soothing conditions like eczema and minor irritations
Benzoyl peroxide	NIH Mayo Clinic	Benzoyl peroxide is a potent antibacterial and anti-inflammatory agent primarily used to treat mild-to-moderate acne by killing C. acnes bacteria and unclogging pores through mild exfoliation. It is scientifically proven to be highly effective and, unlike some antibiotics, does not cause bacterial resistance, though it can cause temporary dryness, irritation, or skin peeling.
Benzenes	AAD Yale med	Benzene is not an intentional ingredient in skincare; it is a known human carcinogen that has no skin benefits and is strictly prohibited or restricted by global regulatory bodies. Its presence in products like sunscreens, dry shampoos, and acne treatments is typically due to unintentional contamination from raw materials, aerosol propellants, or the chemical breakdown of active ingredients like benzoyl peroxide over time.
Bithionol	FDA CFR	Bithionol was formerly used as an antibacterial and antiseptic agent in products like soaps, shampoos, and blemish-hiding creams to reduce odors and treat acne. However, it is now strictly prohibited in cosmetics by the FDA because it is a potent photosensitizer that can cause severe, long-lasting skin disorders and extreme sensitivity to sunlight.
Biotin	NIH CC	Biotin (Vitamin B7) is primarily used in skincare as a moisturizing and smoothing agent that supports the production of fatty acids essential for maintaining a healthy skin barrier. While it is scientifically proven to reverse specific skin rashes and scaly dermatitis caused by a biotin deficiency, there is limited evidence that it provides additional benefits for individuals with normal levels.
Petroleum jelly	NIH Harvard Med	Petroleum jelly (Petrolatum) is a highly effective occlusive that creates a physical barrier on the skin, reducing transepidermal water loss by over 98% to lock in deep moisture. It is widely used to protect and heal dry cracked skin by providing a clean, moist environment for the skin to repair itself.
Butylene glycol	FDA NIH	Butylene glycol is a versatile humectant and solvent that pulls moisture into the skin while thinning out thick formulas to help other active ingredients penetrate more deeply. It is widely considered safe and non-irritating for most skin types, often serving as a gentler alternative to propylene glycol in sensitive skin products.
Caffeine	NIH CC	Caffeine is primarily used as a vasoconstrictor and antioxidant to temporarily reduce puffiness and dark circles by shrinking blood vessels and stimulating circulation. It is scientifically proven to protect skin cells against UV-induced damage and can improve the appearance of cellulite by stimulating the breakdown of fats (lipolysis).
Calcium bentonite clay	NIH Mayo Clinic	Calcium bentonite clay is a highly absorbent mineral used as a detoxifying mask to pull excess oils, toxins, and impurities from deep within the pores. It is scientifically proven to have antibacterial and anti-inflammatory properties, making it an effective treatment for oily and acne-prone skin by reducing sebum and soothing irritation.
Castor oil	FDA WebMD	Castor oil is a thick emollient rich in ricinoleic acid, which acts as a humectant to deeply moisturize and soothe dry or irritated skin. It is scientifically proven to have antimicrobial and anti-inflammatory properties, making it helpful for reducing acne-causing bacteria and speeding up the healing of minor skin wounds.
CBD oil (Cannabidiol)	FDA CFR	CBD oil is used as a potent anti-inflammatory and antioxidant agent that interacts with the skin’s endocannabinoid system to regulate oil production and calm irritation. It is scientifically recognized for its potential to treat inflammatory conditions like acne, eczema, and psoriasis by reducing excess sebum and neutralizing free radicals that cause premature aging.
Calamine lotion	Dermnet NIH	Calamine lotion is a topical astringent and protectant composed of zinc oxide and iron oxide, used primarily to dry out oozing skin lesions and relieve itching. It is scientifically proven to soothe minor skin irritations caused by poison ivy, insect bites, and sunburns by providing a cooling sensation as it evaporates.
Carrier oil	NIH Mayo Clinic	Carrier oils are neutral vegetable oils used to dilute potent essential oils and "carry" them into the skin, preventing irritation while providing their own nourishing fatty acids. They are scientifically proven to enhance the absorption of active ingredients and strengthen the skin's natural lipid barrier to prevent moisture loss.
Ceramides	NIH Mayo Clinic	Ceramides are lipid molecules that make up over 50% of the skin’s natural composition, acting as the "glue" that holds skin cells together to maintain a strong, healthy moisture barrier. They are scientifically proven to restore hydration and protect against environmental damage by preventing transepidermal water loss, making them essential for treating dry or compromised skin.
Citric acid	FDA WebMD	Citric acid is an alpha-hydroxy acid (AHA) used to exfoliate the skin's surface, promoting cell turnover and brightening the complexion by fading dark spots. It is scientifically proven to regulate the pH of skincare products, ensuring they remain stable and effective while providing mild antioxidant benefits against environmental damage.
Charcoal	NIH Mayo Clinic	Charcoal (specifically activated charcoal) is used as a powerful adsorbent to draw out excess oil, dirt, and micro-particles from the pores, helping to clarify the skin. It is scientifically recognized for its ability to bind to toxins, making it highly effective for treating oily and acne-prone skin by reducing surface impurities. While it is excellent for deep cleaning, claims that it can "detox" the bloodstream or remove systemic toxins through the skin are scientifically unproven, as its effects are strictly limited to the skin's surface.
Chia seed oil	FDA CFR	Chia seed oil is a nutrient-dense emollient primarily used to strengthen the skin's moisture barrier and provide intense hydration for dry or aging skin. It is scientifically proven to be one of the richest botanical sources of omega-3 fatty acids (alpha-linolenic acid), which help calm inflammation and have been shown in clinical studies to significantly reduce itching and dryness.
Chlorofluorocarbon propellants (CFCs)	Dermnet NIH	Chlorofluorocarbon propellants (CFCs) were once used in aerosol skincare products like sunscreens and hairsprays to deliver a fine mist, but they provide no direct benefit to the skin and are strictly prohibited. They are scientifically proven to be primary drivers of stratospheric ozone depletion, leading to increased UV radiation exposure which significantly raises the risk of skin cancer and premature aging.
Coconut oil	FDA CFR	Coconut oil is a versatile emollient primarily used to strengthen the skin's barrier and provide deep hydration by reducing transepidermal water loss. It is scientifically proven to possess antimicrobial and anti-inflammatory properties, largely due to its high lauric acid content, making it effective for soothing conditions like eczema and minor wounds.
Collagen	NIH Mayo Clinic	Topical collagen is primarily used as a powerful humectant that sits on the skin's surface to provide intense hydration and a temporary smoothing effect. While it is scientifically proven to improve skin moisture and texture, the common claim that it can penetrate deep enough to "rebuild" your skin’s structural collagen is false because the molecules are too large to pass through the dermis.
Dimethicone	NIH Mayo Clinic	Dimethicone is a widely used silicone-based occlusive that creates a silky, breathable film on the skin to lock in moisture and smooth out uneven texture. It is scientifically proven to be an effective skin protectant, frequently used in clinical settings to treat diaper rash and dermatitis by shielding the skin from environmental irritants.
Emollients	Dermnet NIH	Emollients are moisturizing agents that fill the micro-cracks between skin cells with lipids and oils, resulting in a smoother, softer surface. They are scientifically proven to repair the skin barrier and soothe inflammatory conditions like eczema or psoriasis by providing immediate relief from dryness.
Ferulic acid	NIH Mayo Clinic	Ferulic acid is a potent plant-based antioxidant used to neutralize free radicals and protect the skin from environmental stressors like UV radiation and pollution. It is scientifically proven to double the photoprotective power of Vitamins C and E, making it a critical stabilizing agent in high-performance brightening serums.
Formaldehyde	FDA CFR	Formaldehyde is a potent preservative and disinfectant used to prevent the growth of harmful bacteria and mold in water-based cosmetic products. It is scientifically proven to be a human carcinogen and a major skin allergen, leading to its strict regulation or ban in many countries due to risks associated with inhalation and prolonged skin contact. While "pure" formaldehyde is rarely added directly today, many products contain formaldehyde-releasing agents (like DMDM hydantoin) that slowly dispense small amounts of the chemical to maintain shelf life.
Glycerin (glycerol)	FDA WebMD	Glycerin is a powerful humectant that draws moisture from the environment and deeper skin layers into the surface to provide immediate, deep hydration. It is scientifically proven to strengthen the skin barrier and improve its elasticity by mimicking the skin's natural moisturizing factor (NMF). While some fear it can "dry out" skin in arid climates by pulling water from the dermis, it is effectively self-correcting when formulated in modern moisturizers alongside occlusive ingredients like petrolatum or dimethicone.
Glycolic acid	FDA CFR	Glycolic acid is an Alpha Hydroxy Acid (AHA) with the smallest molecular size, allowing it to penetrate deeply to dissolve the "glue" holding dead skin cells together for effective exfoliation. It is scientifically proven to stimulate collagen production and fade hyperpigmentation, resulting in a brighter, firmer, and more even skin tone. While highly effective, it can increase sun sensitivity and cause irritation if used in high concentrations, making daily sunscreen use and gradual introduction essential for safety
Goat milk	NIH Mayo Clinic	Goat milk is primarily used as a gentle emollient and exfoliant because it contains lactic acid (an AHA) that helps break down dead skin cells while nourishing the lipid barrier. It is scientifically proven to benefit sensitive or dry skin due to its high concentration of fatty acids and Vitamin A, which help restore the skin's natural pH and reduce inflammation. While some claim it can "cure" chronic eczema, the truth is that it acts as a soothing supportive treatment.
Green tea	Dermnet NIH	Green oil (specifically Green Tea Extract) is a potent antioxidant and anti-inflammatory agent used to protect the skin from UV-induced damage and reduce redness. It is scientifically proven to contain EGCG, a polyphenol that can reduce sebum production and fight acne-causing bacteria by inhibiting certain androgen receptors in the skin. While it is highly effective at soothing and protecting, the claim that it can "permanently" shrink pores is false, as it only temporarily tightens their appearance through its natural astringent properties.
Halogenated salicylanilides	FDA CFR	Halogenated salicylanilides were formerly used as antibacterial and antifungal agents in soaps and creams to prevent body odor and treat minor infections. However, they are now strictly prohibited in cosmetics by the FDA because they are potent photosensitizers that can cause severe, permanent light sensitivity and chronic skin inflammation.
Hexachlorophene	NIH Mayo Clinic	Hexachlorophene is a potent antibacterial agent formerly used in soaps and cleansers to treat acne and reduce skin infections. It is scientifically proven to cause severe neurotoxicity and brain damage if absorbed through the skin in significant amounts, leading the FDA to restrict its use to prescription-only products at concentrations below 0.75%. While it was once a common household disinfectant, it is now strictly prohibited in general cosmetics due to these extreme safety risks, particularly for infants and children.
Hyaluronic acid	FDA CFR	Hyaluronic acid is a powerful humectant that can hold up to 1,000 times its weight in water, pulling moisture into the skin to provide immediate plumping and hydration. It is scientifically proven to smooth fine lines and improve skin elasticity by replenishing the moisture naturally lost due to aging and environmental stressors. While often marketed as a "deep" repair agent, topical hyaluronic acid primarily hydrates the surface layers of the skin unless formulated with specific low-molecular weights designed for deeper penetration.
Hydrocortisone	NIH Mayo Clinic	Hydrocortisone is a mild corticosteroid used to reduce swelling, redness, and intense itching by suppressing the skin's immune response to irritants. It is scientifically proven to treat inflammatory conditions like eczema, dermatitis, and insect bites by mimicking the body's natural anti-inflammatory hormones. While highly effective for short-term relief, claims that it is safe for long-term daily use are false, as prolonged application can lead to permanent skin thinning (atrophy), discoloration, and "steroid withdrawal" rashes.
Hydrogen peroxide	NIH Mayo Clinic	Hydrogen peroxide is an antiseptic and oxidizing agent traditionally used to clean minor wounds and whiten surfaces by releasing oxygen that creates a visible foaming action to remove debris. It is scientifically proven to kill a broad spectrum of bacteria, fungi, and viruses; however, modern dermatological consensus has shifted against its use for skin as it is directly cytotoxic to healthy cells, which delays wound healing and can increase scarring.
Hydroquinone	NIH Mayo Clinic	Hydroquinone is a potent skin-lightening agent used to treat hyperpigmentation, melasma, and age spots by inhibiting the enzyme tyrosinase, which produces melanin. It is scientifically proven to be one of the most effective treatments for fading dark spots, showing significant results within 4 to 12 weeks of consistent use.
Jojoba oil	FDA WebMD	Jojoba oil is a liquid wax ester that closely mimics the skin’s natural sebum, allowing it to deeply moisturize and balance oil production without clogging pores. It is scientifically proven to provide anti-inflammatory and antioxidant benefits through its high Vitamin E and mineral content, which helps soothe conditions like eczema, psoriasis, and sunburn.
Keratin	FDA CFR	Topical keratin is primarily used as a skin-conditioning agent that forms a thin, protective film on the surface to temporarily smooth texture and increase hydration. It is scientifically proven to improve skin elasticity and moisture levels by mimicking the proteins naturally found in the skin's outer layer, helping to strengthen the barrier against environmental damage. While highly effective as a moisturizer, claims that topical keratin can "rebuild" the deep structural proteins of your skin are largely false, as the molecules are generally too large to penetrate past the epidermis.
Kojic acid	NIH Mayo Clinic	Kojic acid is a powerful skin-lightening agent derived from fungi that works by inhibiting tyrosinase, the enzyme responsible for melanin production. It is scientifically proven to fade hyper-pigmentation, sun damage, and melasma, offering a more natural alternative to harsher chemicals like hydroquinone. While highly effective for brightening, it is a known sensitizer that can cause contact dermatitis or increased sun sensitivity, making daily SPF use and careful patch testing essential.
Lactic acid	NIH Mayo Clinic	Lactic acid is a gentle Alpha Hydroxy Acid that exfoliates the surface of the skin by dissolving the bonds between dead cells to reveal a smoother, brighter complexion. It is scientifically unique because it also acts as a natural humectant, meaning it pulls moisture into the skin while it exfoliates, making it the preferred AHA for dry or sensitive skin types.
Magnesium oil	NIH Mayo Clinic	Magnesium oil—a concentrated solution of magnesium chloride and water—is primarily used as a topical calming agent to reduce skin redness, inflammation, and oiliness while supporting the skin's barrier function. It is scientifically proven to act as a humectant that improves skin hydration and may alleviate symptoms of inflammatory conditions like eczema and psoriasis by regulating cellular processes.
Niacinamide	FDA CFR	Niacinamide (Vitamin B3) is a versatile barrier-repair agent that stimulates ceramide production to lock in moisture and protect against environmental damage. It is scientifically proven to regulate oil production, minimize the appearance of enlarged pores, and fade hyperpigmentation through its potent anti-inflammatory properties.
Mineral oil	FDA WebMD	Mineral oil is a highly refined occlusive and emollient that forms a breathable protective film on the skin's surface to lock in moisture and soften the texture. It is scientifically proven to be non-comedogenic (it does not clog pores) and hypoallergenic, making it exceptionally safe for sensitive or dry skin and conditions like eczema.
Milk thistle	NIH Mayo Clinic	Milk thistle is primarily used in skincare for its active compound, silymarin, a powerful antioxidant that protects the skin from environmental free radicals and UV-induced oxidative stress. It is scientifically proven to reduce inflammation and balance oil production, making it highly effective for calming acne-prone skin and reducing the severity of inflammatory lesions.
Polyhydroxy acids (PHAs)	FDA CFR	Polyhydroxy acids (PHAs) are next-generation chemical exfoliants that gently dissolve dead skin cells on the surface to improve texture and tone. They are scientifically proven to be significantly less irritating than AHAs because their larger molecular size prevents deep penetration, making them the ideal choice for sensitive skin, rosacea, or eczema.