Some ingredients shouldn’t be used together at the same time. Here you’ll find what conflicts with what and how to avoid it, per dermatologist guidance. Red = best not to combine · Yellow = be careful if your skin is sensitive. Tap any card for details.
Retinol + benzoyl peroxide Don’t combine
Benzoyl peroxide can oxidize some forms of retinol and weaken it. Don’t combine them at the same time — one in the AM and the other in the PM (or on alternating days).
Vitamin C + benzoyl peroxide Don’t combine
Benzoyl peroxide oxidizes vitamin C and weakens it. Don’t use them together at the same time — separate AM/PM.
Benzoyl peroxide + alpha acid (AHA) Don’t combine
Benzoyl peroxide with an exfoliating acid (AHA) can cause dryness, over-flaking and irritation. Don’t combine them — alternate on different days.
Benzoyl peroxide + beta acid (BHA / salicylic) Don’t combine
Benzoyl peroxide with an exfoliating acid (BHA) can cause dryness and excess irritation. Don’t combine them — alternate on different days.
Alpha acid (AHA) + beta acid (BHA / salicylic) Don’t combine
Two exfoliating acids together (AHA and BHA) can over-exfoliate and weaken the skin barrier. Use only one per session.
Retinol + alpha acid (AHA) Caution
Gentle note: the idea that acids “deactivate” retinol is a myth with no research behind it. The only caveat is that using them together may increase irritation for sensitive skin. If your skin is sensitive, give each its own night; otherwise there’s no problem.
Retinol + beta acid (BHA / salicylic) Caution
Gentle note: there’s no real conflict between retinol and BHA, but combining them may increase irritation for sensitive skin. If you start to feel dryness, separate them onto different nights.
Retinol + vitamin C Caution
Gentle note: they can be used safely in the same routine, and may even complement each other. The most common order for comfort: vitamin C in the AM (with sunscreen) and retinol in the PM — that’s a choice, not a conflict.
Vitamin C + alpha acid (AHA) Caution
Vitamin C with an exfoliating acid (AHA) — both are acidic and may cause stinging and irritation for sensitive skin. Easiest: vitamin C in the AM and the acid in the PM.
Vitamin C + beta acid (BHA / salicylic) Caution
Vitamin C with an exfoliating acid (BHA) may irritate sensitive skin. Easiest: vitamin C in the AM and the acid in the PM.
Azelaic acid + retinol Caution
Gentle note: azelaic and retinol are an excellent duo for spots and acne, but combining them on the same night may increase dryness and irritation — especially in the first 4–8 weeks of retinol. Easiest: azelaic in the AM and retinol in the PM.
Azelaic acid + benzoyl peroxide Caution
Azelaic with benzoyl peroxide may cause dryness and excess irritation when combined at the same time. Separate them AM/PM for comfort.
Each ingredient and what it does for your skin, the right concentration, and key notes — with a scientific source for every point. Filter by goal or see the products that contain it.
Retinol / Retinoid
20 products| Use | Acne, wrinkles, cell renewal |
| Concentration | 0.025–1% (OTC) |
| Notes | PM only, introduce gradually. Off-limits in pregnancy/breastfeeding. Increases sun sensitivity. |
Azelaic acid
5 products| Use | Acne, rosacea, post-inflammatory pigmentation |
| Concentration | 10% OTC / 15–20% prescription |
| Notes | Safe in pregnancy. Gentle on sensitive skin. 20% ≈ 4% hydroquinone for melasma. |
Benzoyl peroxide
3 products| Use | Inflammatory acne (antibacterial) |
| Concentration | 2.5–10% |
| Notes | 2.5–5% is effective with the least irritation. Bleaches fabric. Don’t combine with retinol/vitamin C. |
Salicylic acid (BHA)
15 products| Use | Pores, blackheads, oily skin |
| Concentration | 0.5–2% |
| Notes | Penetrates the oil inside pores. Ideal for oily skin. |
Alpha acids (AHA)
11 products| Use | Surface exfoliation, pigmentation, texture |
| Concentration | Glycolic 5–10% |
| Notes | Exfoliates the surface. Increases sun sensitivity — sunscreen is essential. |
Tranexamic acid
4 products| Use | Melasma and stubborn pigmentation |
| Concentration | 2–5% topical |
| Notes | Effective for melasma, especially with niacinamide. A good option for darker skin. |
Kojic acid
4 products| Use | Fading spots and melasma |
| Concentration | 1–4% |
| Notes | Inhibits tyrosinase. Stronger with arbutin and niacinamide. Oxidizes easily (yellows). Best at pH 4–5. |
Alpha-arbutin
2 products| Use | Fading spots, evening tone |
| Concentration | 1–2% |
| Notes | A gentler derivative of hydroquinone. Inhibits tyrosinase. |
Licorice extract
0 products| Use | Brightening, calming redness, anti-inflammatory |
| Concentration | — |
| Notes | Glabridin inhibits tyrosinase; licochalcone calms inflammation. Gentle and suited to sensitive, rosacea-prone skin. |
Hyaluronic acid
102 products| Use | Hydration, radiance, plumping |
| Concentration | 0.1–2% |
| Notes | Draws water into the skin. Apply to damp skin then seal with a moisturizer. |
Collagen
18 products| Use | Hydration and a surface-plumped look |
| Concentration | — |
| Notes | Topically it hydrates and plumps temporarily (the molecule is too large to penetrate deeply). |
Panthenol (provitamin B5)
15 products| Use | Hydration, soothing, healing |
| Concentration | 1–5% |
| Notes | A gentle soother and repairer. Excellent after procedures or for irritated skin. |
Ceramides
14 products| Use | Barrier repair, dryness, eczema |
| Concentration | — |
| Notes | Essential for dry/sensitive skin and a weak barrier. Works in synergy with cholesterol and fatty acids. |
Squalane
10 products| Use | Emollient moisturizer, barrier, non-comedogenic |
| Concentration | Up to 100% |
| Notes | A light emollient similar to the skin’s own oils, non-comedogenic. Excellent for dry, sensitive and even oily skin. |
Urea
6 products| Use | Hydration (low %) and exfoliation (high %) |
| Concentration | 5–10% hydrating / 20–40% exfoliating |
| Notes | A natural component of the skin barrier (NMF). 5–10% hydrates, 20–40% exfoliates and softens thick skin. Excellent for severe dryness, eczema and cracked feet. |
Centella / Cica
41 products| Use | Soothing, redness, repair, sensitive skin |
| Concentration | — |
| Notes | A plant anti-inflammatory. Excellent for rosacea, redness and reactive skin. |
Beta-glucan
1 product| Use | Deep hydration, soothing, repair |
| Concentration | — |
| Notes | Hydrates, soothes and supports healing; a molecule that locks in water sometimes deeper than hyaluronic acid. Gentle for reactive skin. |
Allantoin
0 products| Use | Soothing, healing, gentle hydration |
| Concentration | 0.1–2% |
| Notes | Soothes and speeds skin healing, safe even for very sensitive skin. Common in soothing and repair products. |
Vitamin C
22 products| Use | Antioxidant, pigmentation, glow |
| Concentration | L-AA 10–20% |
| Notes | AM under sunscreen. Store away from light/air. |
Green tea (EGCG)
2 products| Use | Antioxidant, soothing, oil |
| Concentration | — |
| Notes | Anti-inflammatory and antioxidant. Helpful for oily, irritated skin. |
Vitamin E
1 product| Use | Antioxidant, hydration, protection |
| Concentration | — |
| Notes | Synergizes with vitamin C. Protects lipids from oxidation. |
Ferulic acid
1 product| Use | Antioxidant, stabilizes vitamin C/E, sun protection |
| Concentration | 0.5–1% |
| Notes | Doubles the stability and effect of vitamins C and E and protects from UV damage. Oxidizes easily, so the formula matters. |
PDRN (polynucleotide)
16 products| Use | Renewal, healing, radiance |
| Concentration | — |
| Notes | Stimulates tissue repair. Common in modern K-beauty products. |
Bakuchiol
5 products| Use | Plant retinol alternative — wrinkles, pigmentation, acne |
| Concentration | 0.5–2% |
| Notes | Stimulates collagen I/III and a strong antioxidant, with results close to retinol and better tolerance for sensitive skin. Relatively safe in pregnancy (consultation preferred). |
Adenosine
2 products| Use | Wrinkles, collagen stimulation, soothing |
| Concentration | 0.04–0.1% (approved) |
| Notes | An approved anti-wrinkle ingredient; stimulates fibroblasts and collagen production. Safe for all skin types and non-irritating. |
Peptides
1 product| Use | Collagen stimulation, lines, elasticity |
| Concentration | — |
| Notes | Signals that stimulate collagen. Gentle and combine with most ingredients. |
Niacinamide (B3)
28 products| Use | Pores, redness, barrier, pigmentation |
| Concentration | 2–10% |
| Notes | Tolerated by almost everyone. Doesn’t conflict with vitamin C (a myth). |
Caffeine
4 products| Use | Puffiness and the look of dark circles |
| Concentration | — |
| Notes | Temporarily constricts vessels to reduce puffiness. Common in eye creams. |
Zinc
5 products| Use | Oil control, soothing, protection |
| Concentration | — |
| Notes | Zinc PCA controls oil; zinc oxide is a physical sunscreen for sensitive skin. |
Sunscreen
40 products| Use | The most important prevention — protection and preventing pigmentation |
| Concentration | SPF 30 (~97%) / 50 (~98%) |
| Notes | Reapply every two hours when exposed. The foundational step in any routine. |
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