Round Lab Sunscreen, Birch Sap and the Brand from Chuncheon

Round Lab is a Korean brand from the company Seorin, founded in 2017 and based in Chuncheon, in Gangwon-do. Co-founders are reported to be Lee Young-hak and Jung Seo-rin. The brand's slogan is Better Skin, Better Round, and I could not find anyone who explains what the name means, so I will not guess.

What I can tell you is where the ingredients come from. The Birch Juice line uses birch sap from the forests of Inje, and the Round Lab sunscreen range is built around that sap for a moisturizer-like feel. Goodai Global, the parent of Beauty of Joseon, acquired Seorin in 2025, which tells you how much attention Korean sunscreen is getting.

There is a fun detail in the range too. The 1025 in 1025 Dokdo Toner is October 25, Dokdo Day in Korea, and the toner uses deep sea water from those waters.

The first grid is the brand itself, from sunscreens in a cream, a serum, a stick and a cushion to the toner and moisturizer it is known for. The second is other Korean sunscreens, the ones I would set beside it.

Here is a test I like: wear a sunscreen for a full day under your usual makeup and look at your face at 3 p.m. If it has pilled, gone greasy or turned grey, it is not your formula, no matter how many people love it.

The two hero Round Lab sunscreens are the Birch Moisturizing Sunscreen, SPF 45, and the Birch Mild-Up, SPF 50. The listing calls the first Korea's number one sunscreen with more than 20 million sold worldwide, with birch sap and hyaluronic acid and no white cast. Mild-Up is a mineral formula with zinc oxide and titanium dioxide, described as fragrance-free and made for sensitive skin.

If you want a different format, the Birch Juice Sun Serum is an SPF 50 serum with 73 percent hydrating essence and vegan PDRN, made to layer under makeup. The Sun Cushion is a mineral SPF 50 in cushion form with birch sap, aloe, artemisia and allantoin, so it can be reapplied on the go. The Sun Stick is SPF 50 with birch sap from Inje and a peptide complex, unscented. The Pine Calming Cica Primer is an SPF 50 primer with niacinamide and madecassoside that the brand says controls sebum.

Then the two that are not sunscreen. The 1025 Dokdo Toner is a watery, unscented toner that exfoliates dead skin cells while it hydrates, and the brand says it was voted best toner in South Korea for three years running. The Birch Moisturizing Cream is a light cream with birch juice and hyaluronic acid.

Start with the sunscreen you will wear daily, then add the stick for reapplying over makeup.

What I would skip: buying the toner and the cream first. Get the sunscreen first, since that is the step that matters.

Dr. Jart+ has three. The Every Sun Day Mineral is a matte SPF 50+ with zinc oxide and titanium dioxide. The Fluid is a liquid SPF 50+ with a radiant finish and no white cast, and the Invisible Stick is SPF 40, with hyaluronic acid and a powder-like, pore-blurring finish. Beauty of Joseon's Day Dew is a lightweight, water-resistant SPF 50 with hyaluronic acid, niacinamide and panthenol for a dewy finish.

belif has two. The True Cream Aqua Bomb is a two-in-one moisturizer and SPF 45 for skin that wants hydration first. The Aqua Bomb Glow Sunstick is a gel stick with SPF 50+ and niacinamide, for top ups. innisfree's Invisible Barrier is a sunscreen serum, SPF 47 with Jeju green tea and hyaluronic acid capsules, and the brand calls it friendly to sensitive skin. Its Daily UV Invisible Stick is SPF 50+, water-resistant, with green tea and cica, and it works on the face and the body.

If you cannot decide, choose by format. Liquid or serum for mornings, stick for the afternoon.

Here is a trick I like: apply the stick over a lightly moisturized cheek, not over a bare one, and it glides instead of dragging.

What I would skip: a mineral formula if you want a totally clear finish. Choose the serum or fluid instead.

I think the best Korean sunscreen is the one that lets you forget the sunscreen. That means picking a finish you like, whether that is dewy or matte, and then reapplying it.

My rule: a serum or cream in the morning, a stick in the bag. I would start with the Round Lab Birch Moisturizing one, give it a week under makeup, and compare it with whichever second grid pick caught your eye. Sunscreen is a habit, and the one you like touching is the one you will actually use. If you want to keep browsing, I also put together Strawberry Perfume Is Mostly a Lab Trick and Clinique and the White Lab Coat.