Double cleanse
Korean skincare, in order
Apply Korean skincare from the thinnest texture to the thickest: oil cleanse, water cleanse, toner, essence, serum, moisturiser, and SPF last in the morning. The full template is numbered as ten steps, and this guide shows where each active fits and what the label numbers actually mean.
Double cleanse
The serum slot
Sheet mask rules
SPF is always last
Percentages that matter
Count the plus signs
Thinnest to thickest: oil cleanse, water cleanse, toner, essence, serum, moisturiser, then SPF in the morning.
The logic is texture: each layer should be thinner than the one that follows it, so light watery products absorb before heavier creams seal them in. Numbered as a full template, the routine runs to ten steps, and the first two are the double cleanse — an oil or balm cleanser to dissolve sunscreen and sebum, then a water-based cleanser to lift sweat and water-soluble dirt.
Not every step happens every day. Exfoliating acids sit at step 3 but only two or three nights a week, and the sheet mask at step 7 is a single-use extra worn for 10-20 minutes — most packs say 15 — on mask days. The skeleton that repeats daily is cleanse, toner, serum, moisturiser, and sunscreen.
Timing matters at the ends of the sequence. Sunscreen is always the last morning step, and in sun it is reapplied every 2 hours. Retinol, when it appears at the serum step, belongs to the evening, and starters should expect about 12 weeks of nightly use before judging it.
Skin sits at pH 4.5-5.5, and a cleanser above pH 7 works against it.
Healthy skin surface sits at pH 4.5-5.5, kept there by the acid mantle — the thin film that holds moisture in and irritants out. Cleansers formulated above pH 7 push against that acidity, disrupt the mantle and slow the barrier's recovery after washing.
The practical symptom is the 'squeaky clean' feeling: tight, dry skin within minutes of washing. That tightness is not cleanliness; it is a stripped barrier, and every product applied afterwards has to work harder on compromised skin.
The double cleanse exists partly to solve this. Because the oil or balm step does the heavy lifting on sunscreen and makeup, the water-based second cleanse can be a gentle low-pH formula that finishes the job without dragging the surface out of its 4.5-5.5 comfort zone.
The serum slot — step 6 — is where every active in this guide is applied.
Vitamin C as L-ascorbic acid is typically dosed at 10-20% and performs best in formulas below pH 3.5, which is why it goes onto freshly cleansed skin in the serum slot — most people give it the morning, where it sits under sunscreen.
Niacinamide is the flexible one: serums commonly run 2-5%, with stronger leave-on products at 10%, and it layers in either the morning or evening slot. Retinol is the evening specialist — starters use 0.25-0.5%, step up to 1% only when tolerated, and allow about 12 weeks of nightly use before judging results.
BHA (salicylic acid) works one step earlier, at the exfoliant slot: leave-on products are formulated at 0.5-2%, while rinse-off washes run milder at 0.5-1%. Two or three nights a week is the standard cadence, and retinol nights and BHA nights are best alternated rather than stacked.
Six cards covering the steps people most often get wrong.
SPF grades UVB protection; the PA plus signs grade UVA protection via PPD values.
SPF and PA measure different things. The SPF number grades protection against UVB — the burning rays — while the PA plus signs grade UVA protection, the rays behind tanning and deeper pigmentation. PA is derived from PPD (persistent pigment darkening) testing.
The conversion is fixed: PA+ corresponds to PPD 2-4, PA++ to 4-8, PA+++ to 8-16 and PA++++ to 16 or above. A Korean sunscreen carrying PA++++ is certifying the strongest UVA grade the system has.
Whatever the label says, the clock resets in the sun: reapply every 2 hours. Water-resistance claims are narrower than they sound — in the US, labels are only permitted at 40 or 80 minutes, so swimming or sweating shortens the interval sharply. Set the reapply timer before you need it.
| Product or label | Typical strength or value | How it is used | Worth knowing |
|---|---|---|---|
| Niacinamide serum | 2-5% | Leave-on, morning or night | Stronger leave-on products run at 10% |
| Vitamin C (L-ascorbic acid) | 10-20% | Leave-on, morning serum slot | Works best formulated below pH 3.5 |
| Retinol (starter) | 0.25-0.5% | Leave-on, nights only | Step up to 1%; judge after about 12 weeks |
| Salicylic acid (BHA) | 0.5-2% | Leave-on exfoliant, 2-3 nights a week | Rinse-off washes run milder at 0.5-1% |
| Sheet mask | 10-20 minutes | Single use, on mask days | Pack directions commonly say 15 minutes |
| Sunscreen reapplication | Every 2 hours | Whenever you are in sun | US water-resistance labels only at 40 or 80 minutes |
| PA++++ (UVA grade) | PPD 16 or above | Read on the sunscreen label | PA+ starts at PPD 2-4 |
The figures reflect widely published dermatology guidance, pack directions and sunscreen labelling rules rather than any single brand's claims.