Round Lab
Birch Juice Mild-Up UV Lock Sunscreen
Round Lab Birch Juice Mild-Up UV Lock Sunscreen (50 ml) is a sunscreen for anyone who wants a lighter, cosmetically elegant sunscreen texture, used last.
No reviews yet50 ml
$30.58 per 100 ml
- Korean-market formula
- Ships from California or direct from Korea
- Korean barcode and batch code intact
- Suited to
- Normal skinDry skinCombination skinOily skin
- Helps with
- The final leave-on step of a morning routineA lighter, cosmetically elegant texture than many US sunscreen formulasWear under makeup without pilling
In stock. Arrives in 3 to 7 business days
We accept
You’re $100.00 away from free US shipping.
- 30-day returns
- Free US shipping on orders of $100 or more
- Tracked delivery to your door
How it works
Round Lab Birch Juice Mild-Up UV Lock Sunscreen is built as a sunscreen, so its texture and finish are designed around one specific place in a routine rather than several. Round Lab, TIRTIR and Torriden formulate this kind of sunscreen to feel consistent with the rest of the brand's line, so the texture and absorption speed match what the format is meant to do. The texture is built for use last, as the final step of your morning routine, before makeup, which is why it behaves differently on skin than a product meant for a different point in a routine. This is the Korean-market formula of the birch juice mild-up uv lock sunscreen, the version sold on shelves in Korea rather than a formula reworked for a different market.
Key benefits
- Birch Juice Mild-Up UV Lock Sunscreen is Round Lab's sunscreen, sourced for the Korean market rather than reformulated for US shelves.
- Carries Zinc Oxide, which is a mineral UV filter, the reflective, physical-sunscreen ingredient in this formula.
- Carries Sodium Hyaluronate, which is a salt-form humectant from the hyaluronan family, smaller and faster-absorbing than the parent molecule, and a staple of Korean hydration formulas.
- Carries Hyaluronic Acid, which is the water-binding polymer most Korean hydration formulas are built around.
- Ships with the Korean-market barcode and batch code intact, the same box sold on Korean shelves rather than a US repack.
- Suited to shoppers targeting dehydration and a compromised moisture barrier.
Inside the formula
Inside the formula
Is this the same formula sold in Korea, or a version made for the US market?
This is the Korean-market formula, the same one sold on shelves in Korea, not a separate version reformulated for US retail. The pack you open matches what a shopper in Seoul buys.
Where does this step go in a routine?
It belongs last, as the final step of your morning routine, before makeup. Placing it earlier or later than that changes how it feels going on and how well the steps after it absorb, so keeping it in that order is worth doing even on a simplified routine.
Can I use this if my skin runs sensitive?
This sunscreen is formulated with skin types like normal skin, dry skin in mind, but any new product is worth a patch test first if your skin reacts easily. A short patch test on the inside of your arm or behind an ear is worth doing with any new product before it goes on your face, and that goes for sensitive skin most of all.
How long before I will know if this is right for my skin?
Give it a full week or two of consistent use before judging, since a single use rarely tells you much either way. Watch for how skin feels rather than for any specific number, and stop use if you notice ongoing irritation.
Not on the ingredient list below: fragrance or parfum, denatured or SD alcohol, parabens, sulfate surfactants, mineral oil or petrolatum and added color.
Full INCI (35): Water, Zinc Oxide, Cyclohexasiloxane, Butyloctyl Salicylate, Propanediol, Propylheptyl Caprylate, Isododecane, Caprylyl Methicone, Lauryl Polyglyceryl-3 Polydimethylsiloxyethyl Dimethicone, Methyl Methacrylate Crosspolymer, Methyl Trimethicone, Adansonia Digitata Seed Extract(1,045ppm), Cryptomeria Japonica Leaf Extract, Nelumbo Nucifera Leaf Extract, Saccharomyces Ferment Filtrate, Glyceryl Glucoside, Sodium Hyaluronate, Hyaluronic Acid, Glycerin, Butylene Glycol, Triethoxycaprylylsilane, Artemisia Annua Extract, Anthemis Nobilis Flower Oil, Pinus Sylvestris Leaf Oil, Ethylhexylglycerin, Ascorbic Acid, Tocopherol, Glyceryl Caprylate, Caprylyl Glycol, Polymethylsilsesquioxane, Lauryl Polyglyceryl-3 Polydimethylsiloxyethyl Dimethicone, 1,2-Hexanediol, Polyglyceryl-2 Dipolyhydroxystearate, Disteardimonium Hectorite, Magnesium Sulfate
Ingredient list read from jolse.com on 10 September 2026.
33 of 35 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.
- Cyclohexasiloxane silicone
- Cyclohexasiloxane is a volatile silicone used for a light, fast-spreading feel that leaves nothing behind.
- Butyloctyl Salicylate emollient
- Butyloctyl Salicylate is an ester used as a solvent and emollient, particularly for dissolving powdered ingredients evenly. Despite the salicylate name it is not an exfoliant.
- 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.
- Propylheptyl Caprylate emollient
- A branched ester with a notably dry, silky slip. It is one of the standard silicone replacements when a formula needs a non-greasy finish.
- Isododecane solvent
- Isododecane is a light, volatile hydrocarbon. It carries pigments and film formers on smoothly and then evaporates, leaving the film behind and nothing oily.
- Caprylyl Methicone silicone
- Caprylyl Methicone is a silicone with a fatty tail, so it mixes with plant oils as well as with silicones. It gives a dry slip and helps disperse powders.
- Lauryl Polyglyceryl-3 Polydimethylsiloxyethyl Dimethicone emulsifier
- This is a silicone emulsifier that holds water inside an oil or silicone base. It is why a long-wear or water-resistant texture stays put.
- Methyl Methacrylate Crosspolymer absorbent
- Methyl Methacrylate Crosspolymer is a polymer in fine sphere form. It absorbs oil, soft-focuses the look of texture and gives a powdery slip.
- Methyl Trimethicone silicone
- Methyl Trimethicone is a light, volatile silicone chosen for a notably dry finish. It thins a formula and disperses powders evenly.
- Adansonia Digitata Seed Extract(1,045ppm) plant extract
- Baobab seed extract, from the African tree whose seed oil appears on the same lists. The extract is used as a conditioning, hydrating ingredient.
- Cryptomeria Japonica Leaf Extract plant extract
- Cryptomeria Japonica is Japanese cedar. Its leaf extract is used as an aromatic antioxidant plant extract.
21 more explained
- Nelumbo Nucifera Leaf Extract plant extract
- Nelumbo Nucifera is the sacred lotus. Its leaf extract carries flavonoids and is used as a conditioning antioxidant extract.
- Saccharomyces Ferment Filtrate ferment
- Saccharomyces Ferment Filtrate is a brewers yeast ferment filtered clear. It supplies amino acids, B vitamins and sugars, and it is one of the ferments the Korean essence category was built on.
- Glyceryl Glucoside humectant
- Glyceryl Glucoside is glycerin bound to glucose, from the resurrection plant. It is a humectant that holds water in the outer layer of skin.
- Sodium Hyaluronate humectant
- Sodium Hyaluronate is the salt of hyaluronic acid, and it is what most products labelled hyaluronic actually contain. The salt dissolves more readily and the molecule is smaller, so it sits in the outer layer of skin rather than only on top of it.
- Hyaluronic Acid humectant
- Hyaluronic Acid is a sugar chain the body already makes, and one gram of it can hold several litres of water. In a formula it is a humectant that pulls water to the surface of skin and holds it in a film, which is what makes skin look plumper while it is there.
- Glycerin humectant
- Glycerin is the most used humectant in skincare. It draws water into the outer layer of skin and holds it there, and it is one of the very few ingredients whose hydrating effect is settled science rather than marketing. Higher amounts feel tacky, which is why it is usually blended.
- 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.
- Triethoxycaprylylsilane silicone
- Triethoxycaprylylsilane is a coating applied to mineral powders so they disperse evenly and resist water rather than clumping.
- Artemisia Annua Extract plant extract
- Artemisia Annua is sweet wormwood, a mugwort relative. Its extract is used in Korean formulas for the look of reactive skin.
- Anthemis Nobilis Flower Oil fragrance component
- Anthemis Nobilis is Roman chamomile. The flower oil is an essential oil, so it scents a formula as well as conditioning it, and essential oils are the class most likely to bother reactive skin.
- Pinus Sylvestris Leaf Oil fragrance component
- Scots Pine Leaf Oil is a conifer essential oil used to scent a formula.
- 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.
- Ascorbic Acid antioxidant
- Ascorbic Acid is pure vitamin C, the most researched form and also the least stable: it needs a low pH and airtight packaging to stay active. It is an antioxidant used for the look of dullness and uneven tone.
- 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.
- Glyceryl Caprylate emulsifier
- Glyceryl Caprylate is a mild emulsifier that also makes a formula less hospitable to microbes, so it is often part of a preservative-free system.
- Caprylyl Glycol preservative booster
- Caprylyl Glycol is a glycol that conditions skin and, more importantly, strengthens a preservative system so less of the traditional preservative is needed. It appears in most modern formulas built without parabens.
- Polymethylsilsesquioxane silicone
- Polymethylsilsesquioxane is a silicone resin in fine sphere form. It soft-focuses the look of pores and lines and gives a smooth, powdery finish.
- 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.
- Polyglyceryl-2 Dipolyhydroxystearate emulsifier
- A water-in-oil emulsifier used in sticks and high-oil formulas, where it keeps the water phase in fine droplets so the texture stays smooth.
- Disteardimonium Hectorite thickener
- Disteardimonium Hectorite is a modified clay used to thicken the oil phase and stop pigments settling to the bottom of the bottle.
- Magnesium Sulfate mineral
- Magnesium Sulfate is Epsom salt, used as a mineral salt in the water phase. Despite the name it is not a cleansing sulfate and does not foam.
- Market
- Korean market, the version sold in Korea
- EAN (barcode)
- 8809962541215
- Made in
- Republic of Korea
- Volume
- 50 ml
- Category
- Sun Care
- Actives
- Hyaluronic Acid, Sodium Hyaluronate, Vitamin C
- 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.
How to use
- Use the Birch Juice Mild-Up UV Lock Sunscreen as the last step of the morning routine, over moisturizer and under makeup.
- Apply it at the last stage of skincare routine 15 minutes before heading out. Gently massage for better absorption.
- Nothing skincare goes over it. It is the last thing on in the morning, and it is never mixed into the moisturizer underneath it.
- Every morning, and again through the day as the instruction on the pack directs. Do not stir it into your moisturizer to save a step.
Worth knowing
- Let it absorb fully before layering makeup over it, since a still-wet sunscreen is what causes pilling underneath foundation.
Complete the routine
- This itemRound Lab Birch Juice Mild-Up UV Lock Sunscreen$15.29
- Seal the routine in as the last stepRound Lab Dokdo Lotion 400ml$32.50
- Cleanse first, so the next step meets bare skinRound Lab Birch Juice Cleansing Pad 60Pads$27.50
Total for 3 items$75.29
Reviews
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Round Lab Birch Juice Mild-Up UV Lock Sunscreen
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Round Lab, Korean-market original
Birch Juice Mild-Up UV Lock Sunscreen, Round Lab's sunscreen in its authentic Korean-market formula.
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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