Some By Mi AHA BHA PHA 30 Days Miracle Serum
The serum in the brand's best-known range: three acid families at cosmetic levels alongside tea tree water, aimed at oily and congested skin. The three-acid approach is more about covering different solubilities than about strength — the AHA works on the surface, the BHA is oil-soluble enough to get into a pore, the PHA is the gentlest of the set. The whole line is built around the same promise and sold as a set.
What it is built around
Who it suits
Oily, combination and congested skin that wants a mild everyday exfoliating step rather than a weekly strong one. Reasonable for the look of rough texture and visible pores. Dry, sensitive or barrier-compromised skin should stay away, and so should anyone already using a nightly retinoid. If you have inflamed cystic breakouts, this is not the product and a clinician is the better call.
How to use it
Evening, after toner, before moisturiser. Start twice a week and build slowly, watching for tightness or stinging. Follow with a plain moisturiser and use sunscreen daily — exfoliating acids make that non-negotiable. Do not run the toner, cleanser and serum from this line all at once; pick one exfoliating step and keep the rest bland.
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🙋 People also ask
What is the difference between AHA and BHA?
AHAs like glycolic and lactic acid are water-soluble and work on the skin's surface to brighten and smooth, while BHA like salicylic acid is oil-soluble and gets into pores. In Korean skincare both are used sparingly, a few times weekly, always with daily sun protection.
What is the difference between essence and serum?
In Korean skincare, essence is typically a thinner, hydration-focused layer that preps skin, while serum is more concentrated with targeted actives like vitamin C or niacinamide. Essence usually comes first; serum follows. The line between them blurs, and not every routine needs both.
What is BHA and what does it do?
BHA, usually salicylic acid, is an oil-soluble exfoliant that can penetrate pores to dissolve oil and dead skin, helping refine the look of texture and blemish-prone skin. In Korean routines it's used a few times weekly, with sunscreen by day, to avoid over-exfoliating.
What is the difference between essence, serum and ampoule?
Essence is the lightest and most hydration-focused, serum is more concentrated and targeted, and ampoule is the most concentrated of the three. The boundaries are marketing convention, not regulated definitions.
✍️ Written & reviewed by the KoreaPlus Editorial team — dermatologist-informed, cosmetic-science researched & source-cited. Last reviewed: 2026-08-23.
General educational information using cosmetic structure-function wording — not medical advice. Always patch-test new actives. © KoreaPlus.