How skin is built, and how it actually works.
All 56 entries →SYNC Beauty
Skin Encyclopedia
An evidence-based skincare reference by SYNC Beauty — clear, science-checked answers on ingredients, skin types and daily routines.
931 entries · 12 categories · reviewed by the SYNC editorial team
Identify your type — and what it genuinely needs.
All 46 entries →Acne, pigmentation, redness, texture, ageing.
All 96 entries →What each active does, how fast, and for whom.
All 148 entries →Cleansers, serums, moisturisers, sunscreens.
All 76 entries →What to layer together, and what to keep apart.
All 62 entries →The mechanisms, explained properly.
All 45 entries →AM and PM structures for every skin and age.
All 54 entries →Head-to-head, with a clear verdict.
All 63 entries →What is true, what is marketing.
All 45 entries →Direct answers to the questions people ask.
All 92 entries →Plain-language definitions, A to Z.
All 148 entries →A
- A Barrier-Safe Minimal Active Routine Active Combinations
- Acid Mantle Glossary
- Acne Scarring Skin Concerns
- Acne-Prone Skin Skin Types
- Acne: Causes, Types and Treatment Skin Concerns
- Actinic Keratosis Skin Concerns
- Actives Glossary
- Actives Booster Product Types
- Adapalene Ingredients
- Adapalene vs Tretinoin Comparisons
- Adult Acne Skin Concerns
- Age Spots on Hands Skin Concerns
- AGEs (Advanced Glycation End Products) Glossary
- AHA (Alpha Hydroxy Acid) Glossary
- AHA + BHA Active Combinations
- AHA + PHA Active Combinations
- AHA vs BHA Comparisons
- Allantoin Ingredients
- Allantoin and Soothing Actives Ingredients
- Allergic Reactions and Hives Skin Concerns
- Allergy-Prone Skin Skin Types
- Aloe Vera Ingredients
- Alpha Arbutin Ingredients
- Alpha Arbutin + Vitamin C Active Combinations
- Alpha-Lipoic Acid Ingredients
- Alternating Retinol and Acids Active Combinations
- Amino Acids in Skincare Ingredients
- Ampoule Product Types
- Ampoule vs Serum Comparisons
- Androgens and Sebum Production Foundations
- Anti-Inflammatory (Skincare) Glossary
- Antioxidant Glossary
- Antioxidant Defense in Skin Foundations
- Antioxidant Network Glossary
- Antioxidant Stability Glossary
- Arbutin Ingredients
- Are Blackheads Trapped Dirt? Myths & Misconceptions
- Are Copper Peptides Worth It? Frequently Asked Questions
- Are Parabens Dangerous? Myths & Misconceptions
- Argan Oil Ingredients
- Arginine and Skin Ingredients
- Argireline (Acetyl Hexapeptide-8) Ingredients
- Ascorbyl Glucoside Ingredients
- Asiaticoside Ingredients
- Astaxanthin Ingredients
- Athlete's Skin Skin Types
- Atrophic Acne Scars Skin Concerns
- Azelaic Acid Ingredients
- Azelaic Acid + Salicylic Acid Active Combinations
- Azelaic Acid + Vitamin C Active Combinations
- Azelaic Acid vs Salicylic Acid Comparisons
- Azelaicin Derivatives Ingredients
B
- Back Acne (Bacne) Skin Concerns
- Bakuchi Oil Ingredients
- Bakuchiol Ingredients
- Bakuchiol + Retinol Active Combinations
- Bakuchiol + Vitamin C Active Combinations
- Bakuchiol vs Peptides Comparisons
- Bakuchiol vs Retinol Actives Ingredients
- Balm Cleanser Product Types
- Barrier Damage and Over-Exfoliation Skin Concerns
- Barrier Function Glossary
- Barrier Lipids Glossary
- Barrier Repair Glossary
- Barrier Repair Cream Product Types
- Beginner Skincare Routine Routines
- Benzoyl Peroxide Ingredients
- Benzoyl Peroxide + Adapalene Active Combinations
- Beta-Carotene Ingredients
- Beta-Glucan Ingredients
- Betaine Ingredients
- BHA (Beta Hydroxy Acid) Glossary
- BHA + PHA Active Combinations
- Bioavailability Glossary
- Biomimetic Glossary
- Bisabolol Ingredients
- Black Skin Care Fundamentals Skin Types
- Blackheads Skin Concerns
- Blocked Sebaceous Glands Skin Concerns
- Blood Supply to the Skin Foundations
- Body Acne Skin Concerns
- Body Butter Product Types
- Body Lotion Product Types
- Body Odor and Skin Skin Concerns
- Body Oil Product Types
- Body Wash Product Types
- Brightening Agent Glossary
- Broad-Spectrum Glossary
- Broad-Spectrum SPF (Term) Glossary
- Broad-Spectrum vs Standard Sunscreen Comparisons
- Broken Capillaries and Telangiectasia Skin Concerns
- Brow Gel Product Types
- Brow Gel vs Brow Pomade Comparisons
- Brow Serum Product Types
- Buffered Acid Glossary
- Buffering (Skincare) Glossary
- Buffering Actives to Reduce Irritation Active Combinations
- Building a Brightening Active Stack Active Combinations
- Building an Acne Active Stack Active Combinations
- Building an Anti-Aging Active Stack Active Combinations
C
- Caffeine in Skincare Ingredients
- Can Chocolate Cause Acne? Myths & Misconceptions
- Can Diet Alone Clear Acne? Myths & Misconceptions
- Can I Exfoliate After Retinol? Frequently Asked Questions
- Can I Exfoliate Sensitive Skin? Frequently Asked Questions
- Can I Layer Two Moisturizers? Frequently Asked Questions
- Can I Mix Different Acids? Frequently Asked Questions
- Can I Mix Niacinamide and Salicylic Acid? Frequently Asked Questions
- Can I Skip Moisturizer if I Have Oily Skin? Frequently Asked Questions
- Can I Sleep With a Sleeping Mask On? Frequently Asked Questions
- Can I Use a Sheet Mask Every Day? Frequently Asked Questions
- Can I Use Actives on My Body? Frequently Asked Questions
- Can I Use AHA and Retinol on the Same Night? Frequently Asked Questions
- Can I Use Azelaic Acid Twice a Day? Frequently Asked Questions
- Can I Use Benzoyl Peroxide Every Day? Frequently Asked Questions
- Can I Use Body Sunscreen on My Face? Frequently Asked Questions
- Can I Use Expired Skincare? Frequently Asked Questions
- Can I Use Face Oil in the Morning? Frequently Asked Questions
- Can I Use Hyaluronic Acid in a Dry Climate? Frequently Asked Questions
- Can I Use Niacinamide With Vitamin C? Frequently Asked Questions
- Can I Use Physical and Chemical Exfoliants Together? Frequently Asked Questions
- Can I Use Retinol After Waxing? Frequently Asked Questions
- Can I Use Retinol and Benzoyl Peroxide Together? Frequently Asked Questions
- Can I Use Retinol and Niacinamide Together? Frequently Asked Questions
- Can I Use Retinol Around My Eyes? Frequently Asked Questions
- Can I Use Retinol Every Day? Frequently Asked Questions
- Can I Use Retinol Every Night From the Start? Frequently Asked Questions
- Can I Use Retinol in Summer? Frequently Asked Questions
- Can I Use Retinol on My Neck? Frequently Asked Questions
- Can I Use Retinol While Pregnant? Frequently Asked Questions
- Can I Use Retinol With Hyaluronic Acid? Frequently Asked Questions
- Can I Use Salicylic Acid Every Day? Frequently Asked Questions
- Can I Use Tranexamic Acid Every Day? Frequently Asked Questions
- Can I Use Two Serums at Once? Frequently Asked Questions
- Can I Use Vitamin C at Night? Frequently Asked Questions
- Can I Use Vitamin C Every Day? Frequently Asked Questions
- Can I Use Vitamin C for Dark Spots? Frequently Asked Questions
- Can I Use Vitamin C Under Sunscreen? Frequently Asked Questions
- Can I Wear Vitamin C and SPF Together? Frequently Asked Questions
- Can Lemon Juice Brighten Skin Safely? Myths & Misconceptions
- Can Makeup Replace Sunscreen? Frequently Asked Questions
- Can Niacinamide Cause Purging? Frequently Asked Questions
- Can Sunscreen Cause Vitamin D Deficiency? Myths & Misconceptions
- Can Teenagers Use Retinol? Frequently Asked Questions
- Can Toothpaste Cure a Pimple? Myths & Misconceptions
- Can You Detox Your Skin? Myths & Misconceptions
- Can You Repair Sun Damage Completely? Myths & Misconceptions
- Can You Shrink Your Pores Permanently? Myths & Misconceptions
- Can You Use Retinol Only in Winter? Myths & Misconceptions
- Can You Use Vitamin C and Retinol Together? Frequently Asked Questions
- Carrier Peptides Ingredients
- Cell Turnover Foundations
- Cell Turnover Glossary
- Cellulite Skin Concerns
- Centella Asiatica (Cica) Ingredients
- Ceramide Glossary
- Ceramide NP, AP and EOP Ingredients
- Ceramide Ratio Glossary
- Ceramides Ingredients
- Ceramides + Hyaluronic Acid Active Combinations
- Ceramides + Niacinamide Active Combinations
- Ceramides + Retinol Active Combinations
- Ceramides in the Skin Barrier Foundations
- Ceramides vs Hyaluronic Acid Comparisons
- Chapped and Dry Lips Skin Concerns
- Chelating Agent Glossary
- Chemical Exfoliant Product Types
- Chemical Exfoliation (Term) Glossary
- Chemical Peel vs At-Home Exfoliation Comparisons
- Chemical Sunscreen Product Types
- Chemical vs Physical Exfoliation Comparisons
- Chest Acne Skin Concerns
- Chest and Décolletage Aging Skin Concerns
- Chlorella and Algae Extracts Ingredients
- Cholesterol (Skin) Glossary
- Cholesterol and Fatty Acids in Skin Foundations
- Cholesterol in Skincare Ingredients
- Cholesteryl Esters Ingredients
- Cica Cream Product Types
- Citric Acid Ingredients
- Clay Mask Product Types
- Clean Beauty (Term) Glossary
- Cleanser Product Types
- Cleansing Oil vs Balm Overview Product Types
- Cleansing Wipes Product Types
- Closed Comedones Skin Concerns
- Cocoa Butter Ingredients
- Coconut Oil in Skincare Ingredients
- Coenzyme Q10 (Ubiquinone) Ingredients
- Collagen Foundations
- Collagen Glossary
- Colloidal Oatmeal Ingredients
- Combination Skin Skin Types
- Combination-Dry Skin Skin Types
- Combination-Oily Skin Skin Types
- Combination-Skin Concerns Skin Concerns
- Comedogenesis Glossary
- Comedogenic Glossary
- Comedonal Acne Skin Concerns
- Comedone Glossary
- Compedogenicity Rating Glossary
- Compromised Barrier Skin Skin Types
- Congested Skin Skin Types
- Congested Skin and Clogged Pores Skin Concerns
- Contact Dermatitis Skin Concerns
- Contact-Dermatitis-Prone Skin Skin Types
- Copper and Skin Ingredients
- Copper Peptides (GHK-Cu) Ingredients
- Copper Peptides + AHA Active Combinations
- Copper Peptides + Retinol Active Combinations
- Copper Peptides + Vitamin C (Why to Separate) Active Combinations
- Copper Peptides vs Retinol Comparisons
- Corneocyte Glossary
- Cortisol and the Skin Foundations
- Cosmeceutical Glossary
- Cream Product Types
- Cream Cleanser Product Types
- Cream Mask Product Types
- Cream vs Lotion Comparisons
- Crepey Skin Skin Concerns
- Crow's Feet Skin Concerns
- Cruelty-Free Glossary
- Cypress and Botanical Astringents Ingredients
- Cyst Glossary
- Cystic Acne Skin Concerns
D
- Dark Circles Under the Eyes Skin Concerns
- Dark Spots Skin Concerns
- Day Cream Product Types
- Day Cream vs Night Cream Comparisons
- Day vs Night Routine Differences Routines
- Dehydrated Skin Skin Types
- Depigmenting Agent Glossary
- Derivative (Actives) Glossary
- Dermis Glossary
- Desmosome Glossary
- Desquamation Foundations
- Desquamation Glossary
- Dimethicone and Silicones Ingredients
- Do Anti-Aging Creams Erase Wrinkles? Myths & Misconceptions
- Do Collagen Creams Boost Collagen? Myths & Misconceptions
- Do Expensive Products Work Better? Myths & Misconceptions
- Do I Apply Moisturizer to Damp or Dry Skin? Frequently Asked Questions
- Do I Need an Essence? Frequently Asked Questions
- Do I Need an Eye Cream? Frequently Asked Questions
- Do I Need to Wait for Vitamin C to Dry? Frequently Asked Questions
- Do Peptides Really Work? Frequently Asked Questions
- Do Pores Open and Close? Myths & Misconceptions
- Do Silicones Clog Pores? Myths & Misconceptions
- Do You Need a 10-Step Routine? Myths & Misconceptions
- Do You Need Separate Day and Night Moisturizers? Myths & Misconceptions
- Do You Need to Wear SPF Indoors? Myths & Misconceptions
- Does a Higher SPF Mean You Can Reapply Less? Myths & Misconceptions
- Does Coconut Oil Fix Everything? Myths & Misconceptions
- Does Cold Water Close Pores? Myths & Misconceptions
- Does Drinking Water Hydrate Your Skin? Myths & Misconceptions
- Does Eating Collagen Improve Skin? Myths & Misconceptions
- Does More Product Mean Better Results? Myths & Misconceptions
- Does Natural Always Mean Safer? Myths & Misconceptions
- Does Non-Comedogenic Guarantee No Breakouts? Myths & Misconceptions
- Does Oily Skin Need Moisturizer? Myths & Misconceptions
- Does Retinol Thin the Skin? Myths & Misconceptions
- Does Skin Get Addicted to Moisturizer? Myths & Misconceptions
- Does Sweat Detox the Skin? Myths & Misconceptions
- Does the Order of Acids Matter? Frequently Asked Questions
- Does Toothpaste Whiten Dark Spots? Myths & Misconceptions
- Does Vitamin C Make Skin Sun-Sensitive? Myths & Misconceptions
- Double Cleansing Product Types
- Double Cleansing vs Single Cleansing Comparisons
- Drugstore vs Luxury Skincare Comparisons
- Dry Patches on the Face Skin Concerns
- Dry Skin Skin Types
- Dry-Climate Routine Routines
- Dull and Tired-Looking Skin Skin Concerns
- Dull Skin Skin Types
E
- East Asian Skin Skin Types
- Ectoin Ingredients
- Ectoin and Osmolytes Ingredients
- Eczema (Atopic Dermatitis) Skin Concerns
- Eczema-Prone Skin Skin Types
- Elastin Foundations
- Elastin Glossary
- Emollient Glossary
- Emulsifier Glossary
- Emulsion Product Types
- Emulsion Glossary
- Encapsulated Retinol Ingredients
- Encapsulation Glossary
- Enlarged Pores Skin Concerns
- Enzymatic Exfoliation (Term) Glossary
- Enzyme Exfoliant Product Types
- Enzyme-Inhibitor Peptides Ingredients
- Epidermal Turnover Glossary
- Epidermis Glossary
- Ergothioneine Ingredients
- Erythema Glossary
- Essence Product Types
- Essence vs Serum Comparisons
- Essence vs Toner Comparisons
- Essential Oil Glossary
- Ester (Skincare) Glossary
- Estrogen and Skin Foundations
- Ethylated Ascorbic Acid Ingredients
- Excess Oil and Shine Skin Concerns
- Exfoliant Glossary
- Exfoliating Cleanser Product Types
- Exfoliating Toner Product Types
- Exosomes in Skincare Ingredients
- Extracellular Matrix Glossary
- Eye Cream Product Types
- Eye Cream vs Face Moisturizer Comparisons
- Eye Mask (Patches) Product Types
- Eye Serum Product Types
- Eyelid Skin Concerns Skin Concerns
F
- Face Mist Product Types
- Face Oil Product Types
- Face Oil vs Moisturizer Comparisons
- Facial in a Bottle Product Types
- Facial Redness and Flushing Skin Concerns
- Fair and Freckled Skin Skin Types
- Fatty Acid Glossary
- Fatty Acids in Skincare Ingredients
- Fermented Ingredients (Galactomyces, Bifida) Ingredients
- Ferulic Acid Ingredients
- Fibroblast Glossary
- Fibroblasts Foundations
- Fine Lines Skin Concerns
- First Treatment Essence Product Types
- Flaky and Peeling Skin Skin Concerns
- Foaming Cleanser Product Types
- Foaming vs Cream Cleanser Comparisons
- Folliculitis Skin Concerns
- Foot Cream Product Types
- Forehead Lines Skin Concerns
- Fragrance (Parfum) Glossary
- Fragrance vs Fragrance-Free Comparisons
- Freckles Skin Concerns
- Free Acid Value Glossary
- Free Radical Glossary
- Free Radical Scavenger Glossary
- Free Radicals and Reactive Oxygen Species Foundations
- Free-From (Term) Glossary
- Fungal Acne (Malassezia Folliculitis) Skin Concerns
G
- Gel Cleanser Product Types
- Gel Moisturizer Product Types
- Gel vs Cream Moisturizer Comparisons
- Gel-Cream Product Types
- Ginseng Extract Ingredients
- Gluconolactone Ingredients
- Glutathione Ingredients
- Glycation Glossary
- Glycation and Skin Aging Foundations
- Glycerin Ingredients
- Glycolic Acid Ingredients
- Glycolic Acid + Salicylic Acid Active Combinations
- Glycolic Acid vs Lactic Acid Comparisons
- Glycosaminoglycan Glossary
- Glycosaminoglycans Foundations
- Grapeseed Oil Ingredients
- Green Tea Extract (EGCG) Ingredients
- Growth Factors in Skincare Ingredients
- Gym and Post-Workout Routine Routines
H
- Hair Follicles and the Pilosebaceous Unit Foundations
- Hand Cream Product Types
- Heartleaf (Houttuynia Cordata) Ingredients
- Honey in Skincare Ingredients
- Hormonal Acne Skin Concerns
- Hormonal Skin Skin Types
- Hormone-Related Pigmentation Skin Concerns
- Hormones and Skin Health Foundations
- How Acne Develops Scientific Guides
- How AHAs Exfoliate Scientific Guides
- How Alpha Arbutin Inhibits Tyrosinase Scientific Guides
- How Antioxidants Neutralize Free Radicals Scientific Guides
- How Azelaic Acid Works Scientific Guides
- How Benzoyl Peroxide Kills Acne Bacteria Scientific Guides
- How BHAs Work in Pores Scientific Guides
- How Blue Light Affects Skin Scientific Guides
- How Broad-Spectrum Protection Works Scientific Guides
- How Ceramides Repair the Barrier Scientific Guides
- How Chemical vs Mineral Filters Work Scientific Guides
- How Collagen Is Made and Lost Scientific Guides
- How Do I Choose a Moisturizer for Oily Skin? Frequently Asked Questions
- How Do I Choose Sunscreen for Dark Skin? Frequently Asked Questions
- How Do I Fade Melasma Safely? Frequently Asked Questions
- How Do I Fade Post-Acne Marks? Frequently Asked Questions
- How Do I Fix Over-Exfoliated Skin? Frequently Asked Questions
- How Do I Introduce a New Active? Frequently Asked Questions
- How Do I Know if a Product Is Working? Frequently Asked Questions
- How Do I Layer SPF Over Moisturizer? Frequently Asked Questions
- How Do I Prevent Sunscreen Pilling? Frequently Asked Questions
- How Do I Stop Retinol Peeling? Frequently Asked Questions
- How Do I Treat a Damaged Skin Barrier? Frequently Asked Questions
- How Elastin Degrades Scientific Guides
- How Encapsulation Improves Actives Scientific Guides
- How Exfoliation Renews Skin Scientific Guides
- How Glycation Stiffens Collagen Scientific Guides
- How Humectants, Emollients and Occlusives Work Scientific Guides
- How Hyaluronic Acid Hydrates Skin Scientific Guides
- How Hydration Differs From Moisturization Scientific Guides
- How Hyperpigmentation Forms Scientific Guides
- How Inflammation Drives Skin Damage Scientific Guides
- How Long a Routine Takes to Show Results Routines
- How Long Before Retinol Shows Results? Frequently Asked Questions
- How Long Do Sheet Masks Take to Work? Frequently Asked Questions
- How Long Does Purging Last? Frequently Asked Questions
- How Long Does the Skin Barrier Take to Heal? Frequently Asked Questions
- How Long Should I Wait Between Skincare Steps? Frequently Asked Questions
- How Long to Wait Between Active Layers Active Combinations
- How Long Until Azelaic Acid Works? Frequently Asked Questions
- How Melanin Is Produced Scientific Guides
- How Moisturizers Hydrate Skin Scientific Guides
- How Much Sunscreen Should I Use on My Face? Frequently Asked Questions
- How Niacinamide Works Scientific Guides
- How Often Should I Exfoliate? Frequently Asked Questions
- How Often Should I Reapply Sunscreen? Frequently Asked Questions
- How Penetration Enhancers Work Scientific Guides
- How Peptides Signal the Skin Scientific Guides
- How pH Affects Ingredient Performance Scientific Guides
- How PHAs Differ Mechanistically Scientific Guides
- How Retinoids Regulate Gene Expression Scientific Guides
- How Retinol Works in the Skin Scientific Guides
- How Scars Form Scientific Guides
- How Sebum Is Produced and Regulated Scientific Guides
- How Should I Store Vitamin C? Frequently Asked Questions
- How Skin Absorbs Ingredients Scientific Guides
- How Skin Ages (Intrinsic and Extrinsic) Scientific Guides
- How Skin Heals and Repairs Wounds Scientific Guides
- How Skin Type Changes With Age Skin Types
- How Skin Works Foundations
- How Soon Can I Wear Makeup After Skincare? Frequently Asked Questions
- How SPF Numbers Are Calculated Scientific Guides
- How Sunscreen Protects the Skin Scientific Guides
- How the Microbiome Protects Skin Scientific Guides
- How the Skin Barrier Loses Water Scientific Guides
- How to Build a Skincare Routine Routines
- How to Choose a Cleanser Product Types
- How to Determine Your Skin Type Skin Types
- How to Introduce Exfoliating Acids Routines
- How to Introduce Retinol Into a Routine Routines
- How to Introduce Vitamin C Routines
- How to Layer Active Ingredients Safely Active Combinations
- How to Patch Test New Products Routines
- How to Simplify an Overloaded Routine Routines
- How Tranexamic Acid Reduces Pigment Scientific Guides
- How UV Radiation Damages Skin Scientific Guides
- How UVA and UVB Differ Scientific Guides
- How Vitamin C Is Stabilized in Formulas Scientific Guides
- How Vitamin C Works Scientific Guides
- How Wrinkles Form Scientific Guides
- Humectant Glossary
- Humectant Magnet Effect Glossary
- Humectant vs Occlusive Comparisons
- Humid-Climate Routine Routines
- Hyaluronic Acid Ingredients
- Hyaluronic Acid (Term) Glossary
- Hyaluronic Acid + Glycerin Active Combinations
- Hyaluronic Acid in the Skin Foundations
- Hyaluronic Acid vs Glycerin Comparisons
- Hyaluronic Acid vs Polyglutamic Acid Comparisons
- Hydrating Mist Product Types
- Hydrating Toner Product Types
- Hydration vs Moisturization Comparisons
- Hydrolyzed Hyaluronic Acid Ingredients
- Hydroquinone Ingredients
- Hydroquinone vs Alpha Arbutin Comparisons
- Hydroxypinacolone Retinoate (Granactive Retinoid) Ingredients
- Hyperhidrosis (Excessive Sweating) Skin Concerns
- Hyperpigmentation (Term) Glossary
- Hyperpigmentation Explained Skin Concerns
- Hypertrophic and Keloid Scars Skin Concerns
- Hypoallergenic Glossary
- Hypodermis Glossary
I
- INCI (International Nomenclature of Cosmetic Ingredients) Glossary
- Inflammation (Term) Glossary
- Inflammation in Skin Foundations
- Ingredients You Should Not Mix Active Combinations
- Ingrown Hairs Skin Concerns
- Inorganic UV Filter Glossary
- Intrinsic vs Extrinsic Skin Aging Foundations
- Is 10% Vitamin C Enough? Frequently Asked Questions
- Is a Skin Tingle a Sign It's Working? Myths & Misconceptions
- Is Alcohol in Skincare Always Bad? Myths & Misconceptions
- Is Baking Soda a Good Exfoliant? Myths & Misconceptions
- Is Double Cleansing Necessary? Frequently Asked Questions
- Is Fragrance Always an Irritant? Myths & Misconceptions
- Is Hypoallergenic a Regulated Term? Myths & Misconceptions
- Is It Normal for Retinol to Cause Redness? Frequently Asked Questions
- Is It Okay to Use Retinol With Moisturizer? Frequently Asked Questions
- Is Micellar Water Enough to Cleanse? Myths & Misconceptions
- Is Popping Pimples Ever Okay? Myths & Misconceptions
- Is Rubbing Ice on Your Face Good for Skin? Myths & Misconceptions
- Is SPF 100 Worth It? Frequently Asked Questions
- Is Sunscreen Bad for You? Myths & Misconceptions
- Is Tanning Ever 'Healthy'? Myths & Misconceptions
- Isotonic Glossary
J
- Jojoba Oil Ingredients
K
- K-Beauty vs Western Skincare Comparisons
- Keratinization Glossary
- Keratinocyte Glossary
- Keratinocytes Foundations
- Keratolytic Glossary
- Keratosis Pilaris Skin Concerns
- Kojic Acid Ingredients
- Kojic Acid + Vitamin C Active Combinations
L
- L-Ascorbic Acid Ingredients
- L-Ascorbic Acid vs Vitamin C Derivatives Comparisons
- Lactic Acid Ingredients
- Lactic Acid + Hyaluronic Acid Active Combinations
- Lactobionic Acid Ingredients
- Lamellar Structure Glossary
- Langerhans Cells Foundations
- Layering Glossary
- Lecithin and Phospholipids Ingredients
- Licorice Root Extract (Glabridin) Ingredients
- Linoleic Acid Ingredients
- Lip Balm Product Types
- Lip Balm vs Lip Oil Comparisons
- Lip Mask Product Types
- Lip Oil Product Types
- Lip Pigmentation Skin Concerns
- Lip Scrub Product Types
- Lip Treatment (SPF) Product Types
- Lipid Glossary
- Long-Haul Flight Skincare Routines
- Loss of Firmness and Elasticity Skin Concerns
- Lotion (Face) Product Types
M
- Madecassic Acid Ingredients
- Madecassoside Ingredients
- Magnesium Ascorbyl Phosphate Ingredients
- Malic Acid Ingredients
- Mandelic Acid Ingredients
- Mandelic Acid + Niacinamide Active Combinations
- Mandelic Acid vs Glycolic Acid Comparisons
- Mango Seed Butter Ingredients
- Manuka Honey Ingredients
- Marula Oil Ingredients
- Maskne (Mask-Related Acne) Skin Concerns
- Matrixyl (Palmitoyl Pentapeptide) Ingredients
- Mature Skin Skin Types
- Mediterranean and Middle Eastern Skin Skin Types
- Melanin (Term) Glossary
- Melanin and Skin Pigmentation Foundations
- Melanocyte Glossary
- Melanocytes Foundations
- Melanogenesis Foundations
- Melanogenesis Glossary
- Melasma Skin Concerns
- Men's Skin Skin Types
- Menopausal Skin Skin Types
- Menopause Skincare Routine Routines
- Micellar Water Product Types
- Micellar Water vs Cleansing Balm Comparisons
- Micelle Glossary
- Micro-Needling Serum (At-Home) Product Types
- Microbiome Glossary
- Microneedling vs Retinol for Collagen Comparisons
- Milia Skin Concerns
- Mineral Oil and Petrolatum Ingredients
- Mineral Sunscreen Product Types
- Mineral vs Chemical Sunscreen Comparisons
- Minimalist Skincare Routine Routines
- Moisturizer Product Types
- Molecular Weight (Skincare) Glossary
- Morning Skincare Routine Routines
- Morning vs Night Active Scheduling Active Combinations
- Morning vs Night Vitamin C Comparisons
- Mugwort (Artemisia) Ingredients
N
- N-Acetylglucosamine Ingredients
- Nano vs Non-Nano Glossary
- Nanoparticle Glossary
- Nasolabial Folds Skin Concerns
- Natural Moisturizing Factor (NMF) Foundations
- Natural Moisturizing Factor (NMF) Glossary
- Natural vs Synthetic Skincare Comparisons
- Neck Aging and Tech Neck Skin Concerns
- Neck Cream Product Types
- Nerve Endings and Skin Sensation Foundations
- Neutralized Acid Glossary
- Niacinamide (Vitamin B3) Ingredients
- Niacinamide + Azelaic Acid Active Combinations
- Niacinamide + Hyaluronic Acid Active Combinations
- Niacinamide + Peptides Active Combinations
- Niacinamide + Salicylic Acid Active Combinations
- Niacinamide + Zinc Active Combinations
- Niacinamide vs Azelaic Acid Comparisons
- Night Cream Product Types
- Night Skincare Routine Routines
- Nodule Glossary
- Non-Comedogenic Glossary
- Normal Skin Skin Types
O
- Occlusion Glossary
- Occlusive Glossary
- Occlusive Film Glossary
- Oil Cleanser Product Types
- Oil Cleanser vs Balm Cleanser Comparisons
- Oily Skin Skin Types
- Oily T-Zone Skin Concerns
- Oleic Acid Ingredients
- Organic UV Filter Glossary
- Osmolyte Glossary
- Over-Exfoliated Skin Skin Types
- Overnight Mask Product Types
- Oxidative Stress Foundations
- Oxidative Stress (Term) Glossary
P
- PA Rating Glossary
- Panthenol Ingredients
- Panthenol vs Allantoin Overview Ingredients
- Papule Glossary
- Patch Test Glossary
- PCA and Sodium PCA Ingredients
- Peel-Off Mask Product Types
- Peeling Solution Product Types
- Penetration Enhancer Glossary
- Peptide Complexes and Botox-Alternatives Ingredients
- Peptide vs Retinol Actives Ingredients
- Peptides + Hyaluronic Acid Active Combinations
- Peptides + Niacinamide Active Combinations
- Peptides + Vitamin C Active Combinations
- Peptides in Skincare Ingredients
- Percutaneous Absorption Glossary
- Perioral Dermatitis Skin Concerns
- Periorbital Hyperpigmentation Skin Concerns
- pH Glossary
- pH-Dependent Actives and Layer Order Active Combinations
- PHA (Polyhydroxy Acid) Glossary
- PHA vs AHA Comparisons
- Photoaging Glossary
- Photodamage and Photoaging Skin Concerns
- Photolyase Glossary
- Photoprotection Glossary
- Photosensitivity Glossary
- Photostability Glossary
- Physical Exfoliant (Scrub) Product Types
- Physical Exfoliation (Term) Glossary
- Physical Scrub vs Enzyme Exfoliant Comparisons
- Phytosphingosine Ingredients
- Pimple Patch Product Types
- Polyglutamic Acid Ingredients
- Polyhydroxy Acids (PHA) Ingredients
- Post-Acne Marks (PIE and PIH) Skin Concerns
- Post-Inflammatory Erythema (PIE) Glossary
- Post-Inflammatory Hyperpigmentation Skin Concerns
- Post-Inflammatory Hyperpigmentation (PIH) Glossary
- Postpartum Routine Routines
- Postpartum Skin Skin Types
- Powder Cleanser Product Types
- Prebiotics for Skin Ingredients
- Pregnancy Skin Skin Types
- Pregnancy-Safe Routine Routines
- Preservative Glossary
- Prickly Pear Seed Oil Ingredients
- Probiotics and Postbiotics Ingredients
- Proline and Collagen Synthesis Ingredients
- Propolis Ingredients
- Provitamin Glossary
- Psoriasis Skin Concerns
- Purging Glossary
- Pustule Glossary
R
- Razor Burn and Shaving Irritation Skin Concerns
- Reactive Oxygen Species Glossary
- Reactive Skin Skin Types
- Redness After Exfoliation Skin Concerns
- Redness-Prone Skin Skin Types
- Reef-Safe (Term) Glossary
- Resveratrol Ingredients
- Retinal (Retinaldehyde) Ingredients
- Retinaldehyde (Term) Glossary
- Retinization Glossary
- Retinoid Glossary
- Retinoid Boosters and Adjuncts Ingredients
- Retinoid Esters Overview Ingredients
- Retinoid Purging Skin Concerns
- Retinoids + Exfoliating Acids Timing Active Combinations
- Retinol + AHA Active Combinations
- Retinol + Azelaic Acid Active Combinations
- Retinol + Benzoyl Peroxide Active Combinations
- Retinol + BHA Active Combinations
- Retinol + Ceramides Active Combinations
- Retinol + Hyaluronic Acid Active Combinations
- Retinol + Niacinamide Active Combinations
- Retinol + Peptides Active Combinations
- Retinol + SPF Active Combinations
- Retinol + Vitamin C Active Combinations
- Retinol Cream Product Types
- Retinol vs Bakuchiol Comparisons
- Retinol vs Peptides Comparisons
- Retinol vs Retinal: Which Is Right for You Comparisons
- Retinol vs Retinyl Palmitate Comparisons
- Retinol vs Tretinoin Comparisons
- Retinol: The Complete Guide Ingredients
- Retinyl Palmitate Ingredients
- Retinyl Retinoate Ingredients
- Rice Extract Ingredients
- Rich Cream Product Types
- Rosacea Skin Concerns
- Rosacea-Prone Skin Skin Types
- Rosehip Oil Ingredients
- Rough Skin Skin Concerns
- Routine After a Chemical Peel Routines
- Routine After Laser Treatment Routines
- Routine After Microneedling Routines
- Routine After Retinoid Irritation Routines
- Routine for a Damaged Barrier Routines
- Routine for Acne Routines
- Routine for Anti-Aging Routines
- Routine for Brightening Routines
- Routine for Combination Skin Routines
- Routine for Dehydrated Skin Routines
- Routine for Dry Skin Routines
- Routine for Dull Skin Routines
- Routine for Eczema-Prone Skin Routines
- Routine for Firming and Elasticity Routines
- Routine for Hormonal Acne Routines
- Routine for Hyperpigmentation Routines
- Routine for Large Pores Routines
- Routine for Melasma Routines
- Routine for Men Routines
- Routine for Oily Skin Routines
- Routine for Redness-Prone Skin Routines
- Routine for Rosacea Routines
- Routine for Sensitive Skin Routines
- Routine for Teens Routines
- Routine for Textured Skin Routines
- Routine in Your 20s Routines
- Routine in Your 30s Routines
- Routine in Your 40s Routines
- Routine in Your 50s Routines
- Routine in Your 60s and Beyond Routines
S
- Sagging Skin Skin Concerns
- Salicylate Derivatives (LHA) Ingredients
- Salicylic Acid (BHA) Ingredients
- Salicylic Acid + Benzoyl Peroxide Active Combinations
- Salicylic Acid vs Benzoyl Peroxide Comparisons
- Salicylic Acid vs Glycolic Acid Comparisons
- Salix (Natural BHA) Ingredients
- Sallow and Yellow-Toned Skin Skin Concerns
- Sandwich Method Glossary
- Sandwiching Retinol for Sensitive Skin Active Combinations
- Sea Buckthorn Oil Ingredients
- Seasonal Changes in Skin Type Skin Types
- Sebaceous Filament Glossary
- Sebaceous Filaments Skin Concerns
- Sebocyte Glossary
- Seborrheic Dermatitis Skin Concerns
- Sebum Glossary
- Sebum and the Sebaceous Glands Foundations
- Selenium and Skin Ingredients
- Sensitive Skin Skin Types
- Serum Product Types
- Serum vs Moisturizer Comparisons
- Setting Mist Product Types
- Shea Butter Ingredients
- Sheet Mask Product Types
- Sheet Mask vs Clay Mask Comparisons
- Should Face Oil Go Before or After Moisturizer? Frequently Asked Questions
- Should I Apply Sunscreen as the Last Step? Frequently Asked Questions
- Should I Cleanse Twice a Day? Frequently Asked Questions
- Should I Patch Test Every Product? Frequently Asked Questions
- Should I Use a Different Routine in Winter? Frequently Asked Questions
- Should I Use SPF on Cloudy Days? Frequently Asked Questions
- Should I Use Toner Before or After Serum? Frequently Asked Questions
- Should Men Use Different Skincare? Frequently Asked Questions
- Should You Exfoliate Every Day? Myths & Misconceptions
- Should You Let Skin 'Breathe' by Skipping Products? Myths & Misconceptions
- Signal Peptides Ingredients
- Skin Anatomy Foundations
- Skin Barrier Itch Skin Concerns
- Skin Changes in Menopause Skin Concerns
- Skin Changes in Pregnancy Skin Concerns
- Skin Cycling Glossary
- Skin Dehydration Skin Concerns
- Skin Density and Thickness Foundations
- Skin Elasticity and Firmness Foundations
- Skin Flora Glossary
- Skin Hydration and Water Content Foundations
- Skin Identical Ingredient Glossary
- Skin in Your 20s Skin Types
- Skin in Your 30s Skin Types
- Skin in Your 40s Skin Types
- Skin in Your 50s Skin Types
- Skin in Your 60s and Beyond Skin Types
- Skin Laxity Skin Concerns
- Skin Layers Foundations
- Skin Lipids Foundations
- Skin of Color Skin Types
- Skin pH Foundations
- Skin Purging vs Breaking Out Skin Concerns
- Skin Sensitivity and Stinging Skin Concerns
- Skin Tone and Undertone Foundations
- Sleeping Mask Product Types
- Sleeping Mask vs Night Cream Comparisons
- Slugging Glossary
- Smoker's Skin Skin Types
- Snail Mucin (Snail Secretion Filtrate) Ingredients
- Snail Mucin vs Hyaluronic Acid Comparisons
- Snow Mushroom Extract Ingredients
- Sodium Ascorbyl Phosphate Ingredients
- Sodium Hyaluronate Ingredients
- Sodium Lactate Ingredients
- Soothing Agent Glossary
- South Asian Skin Skin Types
- Sparse and Thinning Brows Skin Concerns
- SPF (Sun Protection Factor) Glossary
- SPF + Antioxidants Active Combinations
- SPF 30 vs SPF 50 Comparisons
- SPF Booster Glossary
- SPF Powder Product Types
- Spot Treatment Product Types
- Squalane Ingredients
- Squalane vs Plant Oils Overview Ingredients
- Squalane vs Rosehip Oil Comparisons
- Squalene Ingredients
- Stratum Corneum Glossary
- Stretch Marks Skin Concerns
- Sulfur in Skincare Ingredients
- Summer Breakouts Skin Concerns
- Summer Skincare Routine Routines
- Sun Spots and Solar Lentigines Skin Concerns
- Sun-Damaged Skin Skin Types
- Sunburn Skin Concerns
- Sunflower Seed Oil Ingredients
- Sunscreen (SPF) Product Types
- Surfactant Glossary
- Sweat Glands and Thermoregulation Foundations
- Sweat-Related Breakouts Skin Concerns
T
- Tartaric Acid Ingredients
- Tazarotene Ingredients
- Tea Tree Oil Ingredients
- Teen Skin Skin Types
- Teenage Acne Skin Concerns
- Telangiectasia Glossary
- Tetrahexyldecyl Ascorbate Ingredients
- TEWL (Transepidermal Water Loss) Glossary
- Textured Skin Skin Types
- The Acid Mantle Foundations
- The Circadian Rhythm of Skin Foundations
- The Correct Order to Apply Skincare Routines
- The Dermis Foundations
- The Endocrine System and Skin Foundations
- The Epidermis Foundations
- The Extracellular Matrix Foundations
- The Fitzpatrick Skin Types Foundations
- The Hypodermis (Subcutaneous Layer) Foundations
- The Lipid Bilayer of the Stratum Corneum Foundations
- The Nail Unit Foundations
- The Skin Barrier Explained Foundations
- The Skin Immune System Foundations
- The Skin Microbiome Foundations
- The Skin Renewal Cycle Foundations
- The Stratum Corneum Foundations
- Tight Junction Glossary
- Tightness and Discomfort Skin Concerns
- Time-Release Actives Ingredients
- Tinted Brow Gel Product Types
- Tinted Sunscreen Product Types
- Tinted vs Clear Brow Gel Comparisons
- Tinted vs Untinted Sunscreen Comparisons
- Titanium Dioxide Ingredients
- Toner Product Types
- Toner vs Micellar Water Comparisons
- Tranexamic Acid Ingredients
- Tranexamic Acid + Niacinamide Active Combinations
- Tranexamic Acid + Vitamin C Active Combinations
- Tranexamic Acid vs Hydroquinone Comparisons
- Trans-Epidermal Delivery Glossary
- Transdermal Glossary
- Transepidermal Water Loss (TEWL) Foundations
- Travel Skincare Routine Routines
- Trehalose Ingredients
- Tretinoin (Retinoic Acid) Ingredients
- Turmeric (Curcumin) Ingredients
- Types of Collagen in Skin Foundations
- Tyrosinase Glossary
U
- Under-Eye Bags and Puffiness Skin Concerns
- Under-Eye Fine Lines Skin Concerns
- Understanding Sensitive Skin Skin Types
- Understanding Serums Product Types
- Uneven Skin Texture Skin Concerns
- Uneven Skin Tone Skin Concerns
- Urea Ingredients
- UV Filter Glossary
- UV Index Glossary
- UVA Glossary
- UVB Glossary
V
- Vegan Skincare Glossary
- Very Dry (Xerotic) Skin Skin Types
- Viscosity Glossary
- Vitamin A Overview Ingredients
- Vitamin B12 in Skincare Ingredients
- Vitamin B5 (Panthenol) Ingredients
- Vitamin C + AHA/BHA Active Combinations
- Vitamin C + Ferulic Acid + Vitamin E Active Combinations
- Vitamin C + Hyaluronic Acid Active Combinations
- Vitamin C + Niacinamide Active Combinations
- Vitamin C + Retinol Active Combinations
- Vitamin C + SPF Active Combinations
- Vitamin C in Skincare Ingredients
- Vitamin C Serum (Format Guide) Product Types
- Vitamin C vs Alpha Arbutin Comparisons
- Vitamin C vs Niacinamide Comparisons
- Vitamin C vs Retinol Comparisons
- Vitamin C vs Vitamin E Comparisons
- Vitamin E (Tocopherol) Ingredients
- Vitamin F (Essential Fatty Acids) Ingredients
- Vitamin K in Skincare Ingredients
- Volume Loss and Facial Aging Skin Concerns
W
- Water Resistance (SPF) Glossary
- Water-Based vs Oil-Based Layer Order Active Combinations
- Weekly Treatment Schedule Routines
- What Goes First, Serum or Moisturizer? Frequently Asked Questions
- What Is a Humectant? Glossary
- What Is the Skin Barrier? Glossary
- What Percentage of Retinol Should a Beginner Use? Frequently Asked Questions
- What SPF Do I Need for Daily Use? Frequently Asked Questions
- Which Actives Are Safe in Pregnancy? Frequently Asked Questions
- Which Comes First, Vitamin C or Niacinamide? Frequently Asked Questions
- Whiteheads Skin Concerns
- Whitening and Brightening Concerns Skin Concerns
- Why Did My Vitamin C Turn Orange? Frequently Asked Questions
- Why Does Hyaluronic Acid Sometimes Dry My Skin? Frequently Asked Questions
- Why Does My Skin Sting When I Apply Products? Frequently Asked Questions
- Why Does My Sunscreen Leave a White Cast? Frequently Asked Questions
- Why Is My Skin Purging? Frequently Asked Questions
- Willow Bark Extract Ingredients
- Windburn and Cold-Weather Damage Skin Concerns
- Winter Skin Skin Concerns
- Winter Skincare Routine Routines
- Wrinkles Skin Concerns
Z
- Zinc Oxide Ingredients
- Zinc Oxide vs Titanium Dioxide Comparisons
- Zinc PCA Ingredients
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Open dataset
The Encyclopedia as a dataset
All 931 entries in a single file: title, category, link, the opening definition exactly as published, and all 5,233 citations with the publisher of each. Free to reuse with attribution, for anyone who would rather read the corpus than crawl it.
Open data, CC BY 4.0 · JSON · CSV, entries · CSV, citations
Reference table
Active ingredient compatibility
All 49 documented pairs of actives in one table: which can share a routine, which are worth introducing slowly, and which are better applied at different times of day. Each verdict is quoted from the entry it comes from, and every row links back to that entry.
