Product

ROUND LAB Birch Juice Moisturizing Sunscreen

A Korean sunscreen with an exceptional texture, sold in the US through importers. Two different products share this name — and only one is legal to sell here as a sunscreen.
At a Glance
Mixed

Korea allows newer UV filters that the US does not. The original Korean SPF 50+ formula uses several of them, which give a light feel but are not FDA-approved, so it cannot be sold legally as a sunscreen in the US. It reaches US buyers only through importers.

Round Lab also sells a different US formula, SPF 45, made with avobenzone, homosalate, and octisalate. Same brand and name, different chemistry. Neither is wrong to buy, but it helps to know which one you have.

A note on imports: filters degrade with heat and age. When you buy through unofficial sellers, you cannot verify storage, authenticity, or expiry. Buying the US version from Round Lab's own site avoids that.

Key facts

Key activeDepends on the version — US SPF 45 uses avobenzone, homosalate, octisalate; Korean SPF 50+ uses filters not approved in the US
TextureLightweight, creamy lotion
Best forDry, sensitive skin; anyone who hates how sunscreen feels
Approximate price$16–20

How it works

Korean sunscreens have a real advantage, and it is not marketing. Korea permits UV filters the US does not — newer filters like Tinosorb M and Uvinul A Plus that give strong UVA protection with far better texture. The result is sunscreens that feel like nothing, which is why people who have tried one rarely go back.

This one is genuinely well liked — lightweight, fast-absorbing, no white cast, with birch sap, niacinamide, and hyaluronic acid for hydration. An independent Korean lab tested it above its label claim.

But you need to know which product you are actually buying, because the answer changes everything below.

Everyday habits

How to use it
  • When: Every morning, as the last step in your skincare.How much: About 1/4 teaspoon for the face. Most people use too little. Where: Face, ears, neck, and hairline. Reapply: Every 2 hours outdoors, and after sweating or swimming. Texture note: This is a chemical sunscreen and leaves no white cast on any skin tone.
Who should be careful+

There are two different sunscreens with nearly this name, and they are not the same product.

The Korean SPF 50+ formula uses Tinosorb M, Uvinul A Plus, Uvinul T and Uvasorb HEB — none of which are FDA-approved. It cannot legally be sold in the US as a sunscreen. It reaches American buyers only through importers and resellers, which means no guarantee of storage conditions, authenticity, or expiry dates. This is a grey market, not a regulated one.

The US formula, sold by Round Lab directly, is a different sunscreen — SPF 45, using avobenzone, homosalate and octisalate. Reformulated for the American market. Same brand, same name, different chemistry.

Neither is wrong to buy — but know which you have. If you want the famous Korean texture, you are buying an unregulated import. If you want an FDA-regulated product, buy from Round Lab's US site and accept it is a different formula.

Korean SPF labels have a credibility history. In 2021, independent testing found several Korean sunscreens tested far below their labeled SPF, traced to contract manufacturers reusing old test data. Reports conflict on whether this brand was affected — we could not resolve it, and we will not guess.

Questions people ask+
Is this mineral or chemical?Chemical, in both versions.
Will it leave a white cast?No.
Which version should I buy?For an FDA-regulated product, buy the US SPF 45 from Round Lab directly. The Korean SPF 50+ is an unregulated import.
Is it fragrance-free?The formula contains botanical oils, so treat it as scented and check the label.
What SPF is it?SPF 45 in the US version; SPF 50+ in the Korean version.
Full ingredient list+

Water, Dibutyl Adipate, Propanediol, Diethylamino Hydroxybenzoyl Hexyl Benzoate, Polymethylsilsesquioxane, Ethylhexyl Triazone, Niacinamide, Methylene Bis-Benzotriazolyl Tetramethylbutylphenol, Coco-Caprylate/Caprate, Caprylyl Methicone, Diethylhexyl Butamido Triazone, Glycerin, 1,2-Hexanediol, Butylene Glycol, Betula Platyphylla Japonica Juice, Sodium Hyaluronate, Hyaluronic Acid, Glyceryl Glucoside, Dipotassium Glycyrrhizate, Allantoin, Portulaca Oleracea Extract, Artemisia Annua Extract, Pinus Sylvestris Leaf Oil, Anthemis Nobilis Flower Oil, Acrylates/C10-30 Alkyl Acrylate Crosspolymer, Sodium Stearoyl Glutamate, Polyacrylate Crosspolymer-6, Ethylhexylglycerin, Ascorbic Acid, Adenosine, Pentylene Glycol, Behenyl Alcohol, Poly C10-30 Alkyl Acrylate, Polyglyceryl-3 Methylglucose Distearate, Decyl Glucoside, Tromethamine, Xanthan Gum, T-Butyl Alcohol, Tocopherol, Carbomer

References+

1. Positive patch- and photopatch-test reactions to methylene bis-benzotriazolyl tetramethylbutylphenol in patients with both atopic dermatitis and chronic actinic dermatitis (https://pubmed.ncbi.nlm.nih.gov/21504696/) — Confirms bisoctrizole (Tinosorb M) is a newer class of UV filter that is not available on the US market but is widely available in Europe, South America, and Asia, backing the claim that Korea/other markets permit UV filters the US does not. 2. Evaluation of nanostructured lipid carriers (NLC) and nanoemulsions as carriers for UV-filters: characterization, in vitro penetration and photostability studies (https://pubmed.ncbi.nlm.nih.gov/24157543/) — Shows diethylamino hydroxybenzoyl hexyl benzoate (DHHB / Uvinul A Plus) and bemotrizinol (Tinosorb) are UVA-range sun filters that retain photostability, backing the claim that these newer filters provide strong, stable UVA protection. 3. Efficacy of cream-based novel formulations of hyaluronic acid of different molecular weights in anti-wrinkle treatment (https://pubmed.ncbi.nlm.nih.gov/22052267/) — Randomized vehicle-controlled trial showing topical hyaluronic acid formulations significantly improve skin hydration (and elasticity), backing the hyaluronic acid hydration claim. 4. Moisturizing at a molecular level - The basis of Corneocare (https://pubmed.ncbi.nlm.nih.gov/36453857/) — Peer-reviewed review identifying niacinamide and humectants as treatment ingredients for dry skin and stratum corneum moisturization, backing the niacinamide-for-hydration claim.