A simple guide to skincare ingredients, product labels, routine steps, and skin concerns.
Clear definitions for 104 skincare ingredients, product labels, routine steps, and skin concerns. Use the A–Z index to jump to a letter, compare related terms, and follow the shopping links to relevant Skin Source MNL products and collections.
Last updated: September 8, 2026
| Compare | First term | Second term |
|---|---|---|
| Dry skin vs dehydrated skin | Skin type with less oil | Temporary lack of water that can affect any skin type |
| AHAs vs BHAs | Water-soluble surface exfoliants | Oil-soluble exfoliants often chosen for clogged pores |
| Mineral vs chemical sunscreen | Zinc oxide and/or titanium dioxide filters | Organic UV filters such as avobenzone or octocrylene |
| Retinol vs retinoid | One over-the-counter retinoid | The full vitamin A ingredient family |
| Humectant vs emollient | Attracts water | Softens and smooths the surface |
Azelaic acid is used for blemish-prone skin, visible redness, uneven tone, and marks left after breakouts. It is different from a scrub because it works as a leave-on active. Start slowly if your routine already contains retinoids or exfoliating acids. See also Salicylic acid.
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Acne-prone skin develops blackheads, whiteheads, pimples, or deeper blemishes more easily. It can still be dry or sensitive. A practical routine usually starts with a gentle cleanser, non-comedogenic moisturizer, sunscreen, and one suitable acne active. See also Non-comedogenic.
Alpha hydroxy acids, or AHAs, are water-soluble exfoliating acids. Glycolic, lactic, and mandelic acid belong to this group. They mainly work at the skin's surface and are commonly chosen for dullness, rough texture, and uneven-looking tone. See also Glycolic acid.
Allantoin is a soothing skin-conditioning ingredient found in cleansers, serums, and moisturizers. It is often included in formulas for dry or sensitive skin because it helps soften rough-feeling areas without acting as a strong exfoliant. See also Panthenol.
The skin barrier is the outer layer that limits water loss and helps keep irritants out. Tightness, flaking, and increased sensitivity can appear when it is disrupted. Gentle cleansing and a moisturizer containing humectants, emollients, or occlusives can support recovery. See also Ceramides.
Benzoyl peroxide is an acne medicine that reduces acne-causing bacteria. It is sold in washes and leave-on treatments and may cause dryness or bleach towels and clothing. Persistent or severe acne should be assessed by a dermatologist. See also Salicylic acid.
Beta hydroxy acids, or BHAs, are oil-soluble exfoliants. Salicylic acid is the BHA most shoppers encounter. Because it can work within oily pores, it is commonly selected for blackheads, congestion, and oily areas. See also Salicylic acid.
Broad-spectrum sunscreen is tested to protect against both UVA and UVB radiation. SPF mainly describes sunburn protection, so the broad-spectrum label matters. For daily use, dermatologists commonly recommend broad-spectrum SPF 30 or higher. See also SPF.
Ceramides are lipids naturally present in the skin barrier. Skincare formulas use them to help reduce moisture loss and support a smoother, less dry surface. They are common in cleansers, lotions, creams, and barrier balms. See also Skin barrier.
Chemical sunscreen is the common retail name for sunscreen made with organic UV filters such as avobenzone or octocrylene. The category does not automatically indicate better or worse protection. Choose a broad-spectrum formula you can apply generously and reapply. See also Mineral sunscreen.
Comedogenic describes an ingredient or formula with the potential to contribute to clogged pores. The effect depends on the full formulation and the individual using it. A comedogenicity rating cannot guarantee how a finished product will behave on your skin. See also Non-comedogenic.
A cleansing balm is a solid or buttery oil-based cleanser that melts makeup, sunscreen, and excess sebum. It is usually massaged onto dry skin and emulsified with water before rinsing. Some people follow it with a water-based cleanser. See also Double cleansing.
Double cleansing uses an oil-based cleanser first and a water-based cleanser second. The first step loosens makeup and water-resistant sunscreen; the second removes remaining residue. It is optional and may be unnecessary when one gentle cleanser cleans effectively. See also Oil cleanser.
Dehydrated skin lacks water and may feel tight while still producing oil. It is a temporary condition rather than a fixed skin type. Humectants, moisturizer, less aggressive cleansing, and fewer exfoliating steps can help improve comfort. See also Hyaluronic acid.
Dermatologist-tested means a product was tested under a dermatologist's supervision, but the phrase does not describe the study size, method, or result. Check the ingredient list and product directions instead of treating the claim as a guarantee for sensitive skin. See also Ingredient list.
Dry skin produces less oil and often feels rough, flaky, or tight. It differs from dehydration, which is a lack of water that can affect any skin type. Creams and balms usually suit dry skin better than very light gels. See also Dehydrated skin.
Exfoliation removes or loosens dead cells from the skin's surface. Chemical exfoliants use acids or enzymes, while physical exfoliants use friction. More frequent exfoliation is not always better; stinging, persistent redness, and tightness are signs to scale back. See also Over-exfoliation.
An emollient softens and smooths skin by filling gaps between surface cells. Squalane, fatty alcohols, and many plant oils can work as emollients. Moisturizers often combine them with humectants and occlusives. See also Occlusive.
An essence is a lightweight hydrating step used after cleansing and before thicker serums or creams. The name describes a product format, not a required routine stage. Its value depends on the ingredients and whether it adds something your other products lack. See also Toner.
Eczema-prone skin is easily affected by dryness, itching, and inflammation. Fragrance-free cleansers and rich moisturizers may feel more comfortable, but an eczema flare is a medical condition. A dermatologist can help identify triggers and appropriate treatment. See also Fragrance-free.
Fragrance-free means fragrance ingredients were not added to create a scent. It does not always mean the product has no smell because raw ingredients can have their own odor. Sensitive shoppers should also distinguish fragrance-free from unscented. See also Irritation.
A facial cleanser removes sweat, excess oil, sunscreen, makeup, and daily debris. A cleanser should leave skin clean without prolonged tightness or burning. Gel, cream, foaming, and oil-based formulas suit different preferences and routines. See also Gel cleanser.
Ferulic acid is a plant-derived antioxidant used in some vitamin C and vitamin E serums. It can help stabilize an antioxidant formula. Packaging and storage matter because light, air, and heat can affect many antioxidant products. See also Vitamin C.
Fungal acne is a popular name for Malassezia folliculitis, which can resemble acne but has a different cause. The bumps are often small and itchy. Because ordinary acne products may not address it, a clinician should confirm the diagnosis. See also Inflamed acne.
Glycolic acid is an AHA that exfoliates the skin's surface. It is commonly used for dullness, rough texture, and uneven-looking tone. Its small molecular size can make it effective, but it may also feel more irritating than gentler acids. See also Lactic acid.
Glycerin is a humectant that attracts water into the outer layer of skin. It appears in cleansers, serums, lotions, and creams and works across skin types. It is often paired with emollients or occlusives to reduce water loss. See also Humectant.
A gel cleanser has a light, water-based texture and often rinses clean without a creamy residue. Some gel formulas foam and others do not. Judge the cleanser by how skin feels afterward, since a gel texture does not guarantee gentleness. See also Facial cleanser.
Gluconolactone is a polyhydroxy acid, or PHA, used for gentle surface exfoliation and hydration. Its larger molecular structure generally limits how quickly it penetrates compared with glycolic acid, which may suit people who find stronger acids uncomfortable. See also AHAs.
Hyaluronic acid is a humectant that attracts and holds water near the skin's surface. Despite its name, it is used for hydration rather than exfoliation. Apply it under moisturizer, particularly when air-conditioning or low humidity leaves skin feeling tight. See also Humectant.
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A humectant attracts and retains water in the outer skin layer. Glycerin, hyaluronic acid, panthenol, and urea can serve this role. Humectants often work best within a moisturizer that also contains ingredients that soften skin or slow water loss. See also Glycerin.
Hyperpigmentation is an area of skin that appears darker because of increased pigment. Sun exposure, inflammation, acne, and hormonal changes can contribute. Daily sunscreen matters because ultraviolet and visible light can deepen some forms of discoloration. See also Post-inflammatory hyperpigmentation.
Hydroquinone is a pigment-reducing medicine used for certain forms of hyperpigmentation. Rules and availability differ by country, and incorrect use can cause irritation or uncommon complications. It is best used with guidance from a qualified clinician. See also Hyperpigmentation.
An ingredient list identifies a formula's contents using standardized cosmetic names. Ingredients usually appear in descending order until low concentrations, where listing rules can vary. The list helps check allergens and actives, but it cannot reveal texture or performance by itself. See also Dermatologist-tested.
Irritation can look or feel like burning, stinging, redness, tightness, or peeling. It may follow over-cleansing, excessive exfoliation, or a poorly tolerated product. Stop the likely trigger and simplify the routine if symptoms are persistent or worsening. See also Over-exfoliation.
Inflamed acne includes red, swollen papules, pustules, nodules, or cysts. Picking can increase the chance of marks and scarring. Painful, widespread, or deep acne deserves early dermatology care rather than repeated experimentation with strong products. See also Acne-prone skin.
An ingrown hair curves back or grows sideways into skin, causing a bump that can become inflamed. Shaving technique, friction, and tightly curled hair can contribute. Avoid digging at the bump, which can lead to infection or discoloration. See also Exfoliation.
Jojoba oil is technically a liquid wax used as an emollient. It helps soften skin and reduce a rough feel without functioning as an exfoliant. Its presence does not determine whether a complete formula will suit acne-prone skin. See also Emollient.
A jelly cleanser has a bouncy gel texture that spreads easily and rinses with water. The term describes texture rather than cleansing strength. Check surfactants, fragrance, and how your skin feels after rinsing to judge the formula. See also Gel cleanser.
Japanese skincare refers broadly to products and routines developed for the Japanese market. Common themes include gentle cleansing, light hydrating layers, and daily UV protection, but there is no single Japanese routine. Product type and ingredients matter more than country-of-origin shorthand. See also Essence.
Jowl lines describe folds or shadows that form around the lower cheeks and jaw as facial volume, skin elasticity, and underlying support change. Moisturizer can soften the look of dryness, but topical skincare cannot reposition sagging tissue. See also Wrinkles.
Keratosis pilaris causes small rough bumps, often on the upper arms or thighs, when keratin collects around hair follicles. Moisturizers containing urea, lactic acid, or salicylic acid may smooth the feel. Scrubbing hard can increase irritation. See also Urea.
Kojic acid is used in brightening products to reduce the appearance of uneven pigmentation. It can irritate sensitive skin, so introduce it gradually and pair the routine with sunscreen. Persistent pigmentation may need professional assessment. See also Hyperpigmentation.
K-beauty is a broad label for skincare associated with South Korea. It includes many textures and product types, from essences to sunscreens. A long multi-step routine is optional; choose products that fill a real need instead of copying every step. See also Essence.
Kaolin is an absorbent clay used in masks and cleansers to reduce surface oil temporarily. It does not permanently shrink pores or stop oil production. Frequent use can feel drying, especially on already dehydrated skin. See also Oily skin.
Lactic acid is an AHA that exfoliates the skin's surface and also has humectant properties. It is commonly used for dullness and rough texture. Some people find it gentler than glycolic acid, though concentration and formula still determine tolerance. See also Glycolic acid.
The lipid barrier is the mixture of ceramides, cholesterol, and fatty acids surrounding cells in the outer skin layer. These lipids help limit water loss. Harsh cleansing and over-exfoliation can disturb this organized barrier. See also Ceramides.
Licorice root extract is a plant-derived ingredient used in soothing and brightening formulas. It may help improve the look of uneven tone, but results depend on the extract and finished product. Sunscreen remains central to a discoloration routine. See also Vitamin C.
A lotion is an emulsion with a lighter texture than most creams or balms. It spreads easily and can suit humid weather, larger body areas, or oily skin. Texture names are not standardized, so compare the actual ingredient list and feel. See also Moisturizer.
Mineral sunscreen uses zinc oxide, titanium dioxide, or both as active UV filters. Look for broad-spectrum protection and SPF 30 or higher. Finish and white cast vary widely, so the best daily option is one you can apply in a sufficient amount. See also Zinc oxide.
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A moisturizer combines ingredients that add water, soften the surface, or reduce water loss. Gel, lotion, cream, and balm textures suit different preferences. Even oily or acne-prone skin may benefit from a non-comedogenic moisturizer when treatment causes dryness. See also Humectant.
Micellar water contains mild cleansing agents arranged in structures called micelles. It can remove light makeup and surface debris with a cotton pad. Some formulas can remain on skin, while others feel better rinsed off depending on sensitivity and residue. See also Double cleansing.
Mandelic acid is an AHA with a larger molecular structure than glycolic acid. It exfoliates the surface and is often chosen by people easing into acids. Gentle does not mean irritation-proof, so frequency still matters. See also AHAs.
Niacinamide is a form of vitamin B3 used to support the skin barrier and improve the appearance of oiliness, redness, and uneven tone. It appears in many product types. Higher percentages are not automatically more effective and may feel irritating. See also Ceramides.
Non-comedogenic means a product is formulated or tested to be less likely to clog pores. The claim is useful for acne-prone shoppers, but it is not a guarantee because individual reactions and testing methods differ. See also Comedogenic.
Normal skin is a practical category for skin that is neither persistently oily nor dry and has few ongoing sensitivity concerns. Its needs can still change with weather, hormones, medication, and product use. A basic cleanser, moisturizer, and sunscreen may be enough. See also Skin barrier.
Nano zinc oxide refers to zinc oxide particles engineered at very small sizes to improve sunscreen transparency and texture. The word nano does not describe SPF or UVA protection. Use the complete sunscreen label and local regulatory standards to assess a product. See also Zinc oxide.
An occlusive forms a surface layer that slows water evaporation. Petrolatum, mineral oil, and dimethicone are common examples. Occlusives are useful for very dry areas, though heavier textures may feel uncomfortable on oily skin or in humid weather. See also Emollient.
An oil cleanser dissolves makeup, sebum, and water-resistant sunscreen and then emulsifies with water. It can be used alone or as the first step of double cleansing. A well-rinsing formula should not require harsh rubbing. See also Cleansing balm.
Oily skin produces more sebum and may look shiny or develop congestion. It can also become dehydrated from aggressive cleansing. Lightweight moisturizer and sunscreen can still belong in an oily-skin routine. See also Dehydrated skin.
Over-exfoliation happens when acids, scrubs, retinoids, or cleansing remove more than skin comfortably tolerates. Common signs include stinging, tightness, redness, and sudden sensitivity. Pause exfoliants and use a simpler cleanser-moisturizer-sunscreen routine while skin settles. See also Irritation.
Panthenol is provitamin B5, a moisturizing and soothing ingredient used in serums, creams, and repair balms. It acts as a humectant and helps dry or uncomfortable skin feel softer. Rich panthenol balms can be used on targeted areas. See also Humectant.
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Peptides are short chains of amino acids used in skincare for conditioning and age-support claims. Different peptides have different functions, so the category name alone says little about results. Formula stability and consistent use matter. See also Vitamin C.
Patch testing means trying a small amount of a new product on a limited area before wider use. It can reveal obvious irritation or allergy, but it cannot guarantee that long-term facial use will be trouble-free. See also Irritation.
Post-inflammatory hyperpigmentation, or PIH, is a flat dark mark left after acne, irritation, or injury heals. It is not an acne scar. Sunscreen and ingredients such as azelaic acid may help, while picking can make marks more persistent. See also Azelaic acid.
Coenzyme Q10, also called ubiquinone, is an antioxidant used in some serums and moisturizers. It helps formulas address oxidative stress, but cosmetic claims vary with concentration and stability. It does not replace sunscreen. See also Vitamin E.
Quick-absorbing skincare is a texture claim for products that leave little residue soon after application. It does not measure effectiveness. Humidity, applied amount, and the products layered underneath can change how quickly a formula seems to absorb. See also Gel cleanser.
Quercetin is a plant flavonoid with antioxidant properties used in some cosmetic formulas. Evidence for a finished product depends on concentration, delivery, and stability. Treat it as a supporting ingredient rather than a substitute for proven sun protection. See also Ferulic acid.
Quaternium compounds are a broad family used for different cosmetic functions. Quaternium-15 is a specific preservative and formaldehyde releaser that can trigger contact allergy in sensitized people. Read the exact ingredient name rather than treating every quaternium compound as identical. See also Ingredient list.
Retinol is an over-the-counter retinoid used for uneven texture, fine lines, and some forms of acne. It can cause dryness and irritation, especially at first. Start with a low frequency, moisturize, and use sunscreen every morning. See also Retinoid.
Retinoid is the umbrella term for vitamin A derivatives used in skincare and medicine. Retinol is one type; adapalene and tretinoin are others. Strength, evidence, and prescription status vary, so the terms are not interchangeable. See also Tretinoin.
Redness can follow heat, friction, irritation, acne, allergy, or an underlying skin condition. A bland routine may help temporary irritation, but persistent redness, visible vessels, swelling, or discomfort deserves professional assessment. See also Rosacea-prone skin.
Rosacea-prone skin may flush easily and develop persistent redness, bumps, or visible blood vessels. Rosacea is a medical condition with several patterns. Gentle, fragrance-conscious skincare and sunscreen may support comfort, while treatment should come from a clinician. See also Redness.
Salicylic acid is an oil-soluble BHA that exfoliates inside pores and at the surface. It is commonly used for blackheads, whiteheads, congestion, and excess oil. Begin a leave-on product a few nights per week if your skin is new to it. See also BHAs.
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SPF is a standardized measure of sunscreen protection against sunburn, which is driven mainly by UVB. It does not tell the whole UVA story. Look for broad-spectrum SPF 30 or higher and apply enough to cover exposed skin evenly. See also Broad-spectrum sunscreen.
Sensitive skin reacts easily with stinging, burning, redness, or itching. Triggers differ, so a short routine and one new product at a time make patterns easier to identify. Fragrance-free does not guarantee that every formula will suit everyone. See also Patch testing.
Skin cycling is a routine pattern that alternates exfoliation, retinoid use, and recovery nights. It can help some people avoid stacking irritating actives, but the schedule is not a medical requirement. Frequency should follow skin tolerance and product directions. See also Over-exfoliation.
Topical tranexamic acid is used in brightening formulas for uneven pigmentation. It is different from prescription oral tranexamic acid. Results depend on the formulation, and daily sunscreen remains necessary in a discoloration routine. See also Hyperpigmentation.
A toner is a liquid step used after cleansing. Modern toners may hydrate, soothe, or exfoliate, so the label alone does not reveal the function. Choose one by ingredients and routine need rather than treating toner as mandatory. See also Essence.
Titanium dioxide is a mineral UV filter used in sunscreens, often alongside zinc oxide. It can also add opacity or color to cosmetics. Protection depends on the finished sunscreen's testing, not the ingredient name alone. See also Mineral sunscreen.
Tretinoin is a prescription retinoid used for acne and photoaged skin. Dryness, peeling, and irritation are common during adjustment. It should be used according to a clinician's instructions, with daily sun protection. See also Retinoid.
UVA radiation penetrates more deeply than UVB and contributes to tanning, pigmentation, photoaging, and skin cancer risk. UVA is present throughout daylight and can pass through window glass. Broad-spectrum sunscreen covers UVA as well as UVB. See also Broad-spectrum sunscreen.
UVB radiation is a major cause of sunburn and also contributes to skin cancer. Its intensity changes with time, season, altitude, and location. SPF testing mainly measures protection from UVB-driven redness. See also SPF.
Ultraviolet protection combines sunscreen with shade, clothing, hats, and sensible timing around strong sun. Sunscreen is one part of that approach. Reapplication matters during extended outdoor exposure, swimming, or heavy sweating. See also Water-resistant sunscreen.
Urea is both a humectant and, at higher concentrations, a keratolytic that helps soften thick or scaly skin. It is common in body moisturizers. Urea may sting on cracked or freshly irritated skin. See also Keratosis pilaris.
Vitamin C is an antioxidant used to brighten uneven-looking tone and support protection from environmental oxidative stress. Ascorbic acid is the best-known form, while derivatives differ in stability and evidence. Vitamin C complements sunscreen but does not replace it. See also Ferulic acid.
Vitamin E refers to antioxidant compounds such as tocopherol and tocopheryl acetate used in skincare. It can support formula stability and skin conditioning. People with a known contact allergy should check the exact form on the ingredient list. See also Coenzyme Q10.
Vegan skincare is made without animal-derived ingredients according to the brand's standard. The claim does not indicate whether a product is fragrance-free, cruelty-free, organic, or suitable for sensitive skin. Check each label for the attributes that matter to you. See also Ingredient list.
Visible light is the portion of light people can see. It may contribute to persistent pigmentation, especially in deeper skin tones. Tinted sunscreens containing iron oxides can add visible-light coverage beyond ordinary untinted formulas. See also Hyperpigmentation.
Water-resistant sunscreen is tested to maintain its labeled SPF for either 40 or 80 minutes of swimming or sweating, as stated on the label. It is not waterproof. Reapply after the tested interval, toweling off, or heavy sweating. See also SPF.
White cast is the pale or gray film some sunscreens leave on skin. Mineral filters and the way particles are dispersed can affect it, though modern formulas vary. Testing the correct application amount is more useful than judging a tiny swatch. See also Zero-white-cast sunscreen.
A water-based moisturizer lists water as a major ingredient and often has a gel or lotion texture. It can feel comfortable on oily skin or in humid weather. It may still contain oils, silicones, or fatty alcohols as part of the emulsion. See also Lotion.
Wrinkles are lines and folds influenced by age, repeated movement, sun exposure, smoking, genetics, and skin dryness. Moisturizer can temporarily soften their appearance. Sunscreen and retinoids have stronger evidence for prevention or improvement than most trend ingredients. See also Retinol.
Xerosis is the medical term for abnormally dry skin. It can cause roughness, scaling, itching, or small cracks. Gentle washing and regular emollient or occlusive moisturizer often help, while persistent or severe cases need clinical evaluation. See also Dry skin.
Xanthan gum is a thickener and stabilizer used to keep skincare formulas evenly mixed and pleasant to apply. It is not an exfoliating gum and is usually present for texture rather than as the product's main active ingredient. See also Ingredient list.
Xylitol is a sugar alcohol used as a humectant or skin-conditioning ingredient in some formulas. Its role is usually supportive. A product's overall moisturizing performance depends on the full mix of humectants, emollients, and occlusives. See also Humectant.
Xanthophylls are yellow plant pigments in the carotenoid family with antioxidant properties. They may appear in botanical extracts or specialty formulas. Evidence for a finished cosmetic cannot be inferred from the pigment name alone. See also Quercetin.
Yeast extract is a fermented ingredient used for skin conditioning, hydration, or antioxidant support. Composition varies by source and manufacturing method. People with sensitive skin should judge the finished formula rather than assuming every fermented product behaves the same way. See also Essence.
A yellow undertone is a warm or olive cast beneath the skin's surface color. Undertone helps with shade matching for tinted sunscreen, concealer, and foundation. It is different from temporary yellowing or a sudden color change that may need medical attention. See also Visible light.
Ylang-ylang oil is a fragrant essential oil used to scent cosmetics. Natural origin does not make it irritation-proof, and fragrance-sensitive shoppers may prefer products without it. Check the ingredient list when scent is a concern. See also Fragrance-free.
Youthful-looking skin is a marketing phrase rather than a medical or measurable skin type. Brands may use it to describe smoother, brighter, or more hydrated skin. Look for the specific outcome and evidence behind the product instead of relying on the phrase. See also Wrinkles.
Zinc oxide is a mineral UV filter that can provide broad UVA and UVB protection in a properly tested sunscreen. It may leave a visible cast depending on particle size, tint, and formulation. The finished product's SPF and broad-spectrum label determine protection. See also Mineral sunscreen.
Zinc PCA combines zinc with pyrrolidone carboxylic acid and is used in formulas for oily or blemish-prone skin. It may support oil control and skin conditioning. It is not the same ingredient as sunscreen-grade zinc oxide. See also Niacinamide.
Zit is an informal word for a pimple. A pimple forms when a clogged pore becomes inflamed. Picking or squeezing can increase swelling, discoloration, and scarring, especially when the blemish is deep. See also Inflamed acne.
Zero-white-cast sunscreen is a finish claim meaning the product is designed to avoid a pale residue. Results vary by skin tone and application amount. Tinted mineral formulas and transparent organic-filter sunscreens are common approaches. See also White cast.
Definitions are written for general shopping education and checked against dermatology and regulatory references. Prescription medicines and diagnosed skin conditions need guidance from a qualified clinician.
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