PHA 15% Serum 30ml
PHA 15% Serum, TIRTIR's gentle chemical exfoliant serum built on Gluconolactone rather than glycolic acid. It is part of TIRTIR's Korean-market skincare lineup.
No reviews yet30 ml
$166.67 per 100 ml
- Korean-market formula
- Ships from California or direct from Korea
- Korean barcode and batch code intact
- Suited to
- Skin looking to add a targeted treatment step to an existing routineDehydrated or tired-looking skin needing a hydration boostSkin new to the specific active this serum is built around
- Helps with
- Skin new to chemical exfoliation or sensitive to AHA/BHAA gentler nighttime exfoliating stepDull, uneven texture that wants smoothing without irritation
In stock. Arrives in 3 to 7 business days
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How it works
Gluconolactone is a polyhydroxy acid, a gentler cousin of the AHA family that exfoliates with a larger molecule size than the smaller-molecule AHAs it does not contain, which is why PHA formulas are the usual starting point for exfoliation-sensitive skin. Squalane and Adenosine sit in the base to keep the exfoliating serum from feeling stripping, and a run of fruit and root extracts, including Vaccinium Myrtillus (bilberry), sugarcane and lemon, rounds out a formula built around gentle acid exfoliation rather than one active alone. It is meant to follow toner and precede a moisturizer, applied to skin that is still slightly damp so the actives have a receptive surface to absorb into. This particular listing is the 30ml size TIRTIR sells for the line, packaged and formulated for the Korean market rather than a separate US release.
Key benefits
- Gluconolactone (PHA), rather than a smaller-molecule AHA, for gentler exfoliation
- Squalane and Adenosine to offset stripping
- Bilberry, sugarcane and citrus fruit extracts in the base
- Built for exfoliation-sensitive skin starting out with acids
- Sold as TIRTIR's authentic Korean-market formula, the same version sold through Korean retail rather than a US-reformulated substitute
How to use
- Apply to clean, dry skin at night, starting two to three times a week rather than daily until skin has adjusted. Follow with a moisturizer, and always use daytime sun protection separately since any acid exfoliant increases sun sensitivity.
Is PHA gentler than a standard AHA exfoliant?
Yes. Rather than a smaller-molecule AHA, Gluconolactone's larger molecule size means it exfoliates the skin's surface more gradually, which is why PHA formulas are typically recommended for sensitive or acid-new skin.
How often should I use this?
Start two to three nights a week and increase only if skin tolerates it well, the same introduction pace recommended for any new exfoliating acid. This is general guidance rather than a fixed rule, so adjust it based on how your own skin or the product itself responds.
Do I need sunscreen when using this?
Yes, every day this is in the routine. Any exfoliating acid increases how easily skin sunburns, so daytime sun protection is a separate, necessary step. This is general guidance rather than a fixed rule, so adjust it based on how your own skin or the product itself responds.
Is this the same formula sold in Korea, or a version made for the US market?
This is TIRTIR's Korean-market formula, sourced and shipped with its original Korean-market packaging and batch coding rather than a separate US-reformulated version. Korean Pharmacy stocks the exact SKU sold through Korean retail rather than a substitute built for US shelves, which is the point of buying from a specialist rather than a general beauty retailer.
How should I store this to keep it in good condition?
Keep the cap or compact closed between uses and store it away from direct sunlight and heat, the same way you would any cosmetic. A cool, dry spot such as a drawer or cabinet keeps the texture and finish consistent for longer than leaving it exposed on a warm windowsill or in a hot car.
Not on the ingredient list below: fragrance or parfum, denatured or SD alcohol, essential oils, silicones, parabens, sulfate surfactants, mineral oil or petrolatum and added color.
Full INCI (27): Water, Gluconolactone, C9-12 Alkane, Propanediol, Butylene Glycol, 1,2-Hexanediol, Tromethamine, Sodium Hydroxide, Sodium Citrate, Citric Acid, Ethylhexylglycerin, Vaccinium Myrtillus Fruit Extract, Adenosine, Disodium Edta, Saccharum Officinarum (Sugarcane) Extract, Squalane, Citrus Aurantium Dulcis (Orange) Fruit Extract, Citrus Limon (Lemon) Fruit Extract, Acer Saccharum (Sugar Maple) Extract, Dioscorea Japonica Root Extract, Tocopherol, Corchorus Olitorius Leaf Extract, Nelumbo Nucifera Root Extract, Hibiscus Esculentus Fruit Extract, Angelica Keiskei Extract, Capryloyl Salicylic Acid, Hippophae Rhamnoides Fruit Oil
Ingredient list read from tirtir.global on 10 September 2026.
26 of 27 explained
- Water solvent
- Water is the base almost every serum, toner and cream is built on. It dissolves the water-loving ingredients and sets how light the finished texture feels. On an INCI list it is usually first, which only means it is the largest single ingredient by weight.
- Gluconolactone exfoliant
- Gluconolactone is a PHA, the gentlest exfoliant class. Its molecule is too large to penetrate quickly, so it smooths the surface without the sting of an AHA, and it is a humectant at the same time.
- C9-12 Alkane solvent
- A light plant-derived hydrocarbon that evaporates off skin, used in place of a volatile silicone. It carries other ingredients and then leaves.
- Propanediol humectant
- Propanediol is a plant-derived glycol used in place of propylene glycol. It hydrates, carries actives into solution, and gives a lighter, less sticky slip than glycerin at the same strength.
- Butylene Glycol humectant
- Butylene Glycol is a small glycol that does two jobs at once: it holds water in the top layer of skin and it dissolves plant extracts and actives that plain water cannot. It also thins a formula, which is why watery Korean essences lean on it.
- 1,2-Hexanediol humectant
- 1,2-Hexanediol is a glycol used for two reasons: it holds water like glycerin, and it makes a formula harder for microbes to live in, so less traditional preservative is needed. Korean formulas use it heavily for that second reason.
- Tromethamine pH adjuster
- Tromethamine neutralises acidic thickeners such as carbomer so they gel, and holds a formula near skin-friendly pH. It is used at a fraction of a percent.
- Sodium Hydroxide pH adjuster
- Sodium Hydroxide is a strong base used in traces to bring an acidic formula up to skin-friendly pH. None of it remains as itself once the formula is neutralised.
- Sodium Citrate pH adjuster
- Sodium Citrate is the salt of citric acid, used as a buffer: it holds a formula at a steady pH rather than pushing it in one direction. It is also a mild chelator.
- Citric Acid pH adjuster
- Citric Acid is used in tiny amounts to bring a formula to the pH its actives need, not as an exfoliant at that level. It is an AHA, so at much higher concentrations it can also exfoliate.
- Ethylhexylglycerin preservative booster
- Ethylhexylglycerin softens skin and boosts a preservative system, which is why it is nearly always sitting beside phenoxyethanol or 1,2-hexanediol. It also cuts down the odour bacteria produce, so it turns up in deodorising products.
- Vaccinium Myrtillus Fruit Extract plant extract
- Bilberry fruit extract, the European relative of the blueberry and one of the richest anthocyanin sources. It is used as a plant antioxidant.
14 more explained
- Adenosine active
- Adenosine is a nucleoside that Korea's own cosmetic authority recognises as a wrinkle-care functional ingredient, which is why it appears on so many Korean lists at a low level. It is used for the look of fine lines and is stable and well tolerated.
- Disodium Edta chelator
- EDTA is a chelator: it locks up trace metal ions from water and packaging that would otherwise turn a formula cloudy, off-colour or rancid. It does nothing to skin and appears at a fraction of a percent.
- Saccharum Officinarum (Sugarcane) Extract plant extract
- Sugarcane Extract carries natural glycolic acid and sugars. In cosmetics it is used as a humectant; the acid content is far too low to work as an exfoliant.
- Squalane emollient
- Squalane is the stable, saturated version of squalene, a lipid human skin already makes. It is a light emollient that absorbs quickly, does not oxidise, and is one of the few oils widely considered safe for blemish-prone skin. Most cosmetic squalane is now from sugarcane or olive rather than shark.
- Citrus Aurantium Dulcis (Orange) Fruit Extract plant extract
- Sweet orange fruit extract, carrying fruit acids, sugars and flavonoids. It is used as a conditioning extract.
- Citrus Limon (Lemon) Fruit Extract plant extract
- Lemon fruit extract, carrying citric acid, sugars and flavonoids. It is the water-based fruit extract rather than the peel oil, so it brings the fruit acids without the aromatic terpenes.
- Dioscorea Japonica Root Extract plant extract
- Dioscorea Japonica is Japanese wild yam, whose root is naturally slippery with mucilage. Its extract hydrates and leaves a cushioned feel.
- Tocopherol antioxidant
- Tocopherol is vitamin E. It is an oil-soluble antioxidant that protects the oils in a formula from going rancid and works on skin as an emollient, and it is regularly paired with vitamin C because each keeps the other going for longer.
- Corchorus Olitorius Leaf Extract plant extract
- Jute mallow leaf extract. The leaf is notably mucilaginous, so the extract holds water and gives a slippery feel.
- Nelumbo Nucifera Root Extract plant extract
- Lotus root extract. The root is starchy and mucilaginous, so the extract hydrates and leaves a soft, cushioned feel.
- Hibiscus Esculentus Fruit Extract plant extract
- Hibiscus Esculentus is okra, whose fruit is thick with mucilage. Its extract hydrates and gives a cushioned, slippery feel.
- Angelica Keiskei Extract plant extract
- Ashitaba extract, a Japanese angelica relative rich in chalcones. It is used as an antioxidant conditioning extract.
- Capryloyl Salicylic Acid exfoliant
- Capryloyl Salicylic Acid is salicylic acid with a fatty tail, sometimes sold as LHA. It stays nearer the surface than salicylic acid and works at a higher pH, so it exfoliates more evenly and more gently.
- Hippophae Rhamnoides Fruit Oil emollient
- Oil from the pulp of the sea buckthorn berry rather than from its seed. The pulp oil is the richer and more strongly coloured of the two.
- Market
- Korean market, the version sold in Korea
- EAN (barcode)
- 8809928135373
- Made in
- Republic of Korea
- Volume
- 30 ml
- Category
- Serum & Ampoule
- Actives
- Adenosine, Salicylic Acid, Sea Buckthorn, Squalane
- Ships from
- California or Korea
Orders ship from California or direct from Korea with tracked delivery to your door, and both routes carry the same Korean-market release. Shipping is free on orders of $100 or more. Returns are accepted for 30 days, by mail.
We split shipments free, so one out-of-stock item never holds up the rest of your order.
Where this unit came from
- 1Seoul
Bought as Korean-market stock - 2Barcode
Listed against the Korean barcode on its box - 3California or Korea
Ships to you from either, as the same Korean-market release
We stock the version of a formula that is sold in Korea, not the release a brand prepares for another market under the same name. The barcode in the specification above is the Korean-market one and it is printed on the box you receive.
Every unit keeps its original barcode and batch code intact, so the unit in your hands can be checked against the brand’s own records.
Every order ships from California or direct from Korea, and returns run for 30 days.
Every claim on this page traces to the unit in the box, the barcode, the batch code and the price you can read for yourself.
Inside the formula
Inside the formula
Worth knowing
- Introduce any new active serum gradually, a few nights a week at first, rather than daily right away.
- Follow an exfoliating or retinoid-containing serum with daytime sun protection the next morning as a separate step.
Complete the routine
- This itemTIRTIR PHA 15% Serum 30ml$50.00
- Cleanse first, so the next step meets bare skinTIRTIR Milk Creamy Foam Cleanser 90g$42.50
- The treatment step of this routineTIRTIR ICE-COOLING WATER DROP SERUM 30ml$57.50
Total for 3 items$150.00
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TIRTIR PHA 15% Serum 30ml
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TIRTIR, Korean-market original
Exfoliation, without the sting of a smaller-molecule acid.
Verify your unit when it arrives
Verify your unit when it arrives
Korean-market stock with the original barcode and batch code intact, exactly as it left Korea.
On the unit itself
- The Korean-market barcode, unaltered from the retail package.
- The manufacturer’s batch code, exactly as the maker printed it.
정품Genuine article, Korean-market stock
What professionals say
What professionals say
What skin-care professionals say about skin care, quoted from the medical sources linked beside each.
Your skin barrier is basically your outer layer of the skin.
Melissa Piliang, MDDermatologist, Cleveland Clinic Pretty much every step of a Korean skin care routine is going to have some component of hydration.
Alok Vij, MDDermatologist, Cleveland Clinic
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