Product

ROUND LAB Birch Juice Sun Cushion

A zinc oxide sunscreen in a cushion compact. Made for reapplying over makeup — and unlike much of the K-beauty sunscreen market, this one is sold in the US by the brand itself.

At a Glance

Mixed

A sun cushion beats a sunscreen powder in one important way. A cushion presses a real film of product onto the skin, while a powder only dusts on a fraction of what you need. Both are easier to reapply over makeup than a lotion, but the cushion puts down meaningfully more protection. It is not as good as a lotion, but it is a real step up from a powder.

Reapplication is where almost everyone fails, mostly because of makeup, so a format you will actually use during the day has real value. Start with a proper sunscreen in the morning and use this to top up.

It is zinc oxide only, fragrance-free, with a light tone-up effect. Round Lab sells it directly in the US, which matters, since much of the K-beauty sunscreen market runs through grey-market resellers.

Key facts

Key active	Zinc oxide 22% (SPF 50+)
Texture	SPF 50+ cushion compact
Best for	Reapplying sun protection over makeup; dry to normal skin
Approximate price	$24–30
Fragrance	Fragrance free

How it works

The reapplication problem again — and a cushion is a good answer to it. You pat it on over makeup, it deposits real product, and it takes ten seconds.

A cushion deposits considerably more product than a powder does. That matters: the whole weakness of powder sunscreens is that a dusting is nowhere near a protective layer. A cushion press puts down a real film. It is not as good as a lotion, but it is a meaningful step up from a powder.

Zinc oxide 22%, mineral-only, fragrance-free, with a light tone-up effect and no reported white cast.

Round Lab sells this one directly in the US, from a US warehouse. Given how much of the K-beauty sunscreen market runs through grey-market resellers, that traceability is worth something real.

Everyday habits

How to use it

When: Over a sunscreen you already applied, as a top-up during the day.How much: Press on an even layer with the puff. Cushions go on thinner than a lotion, so build up enough. Where: Face, focusing on areas that get direct sun. Reapply: Every 2 hours outdoors, and after sweating or swimming. Best use: Use a real sunscreen in the morning; use this to reapply. It can still cast on deep skin, so treat no-cast claims as unverified there.

Who should be careful+

It is still not your primary sunscreen. Any compact format gets applied more thinly than a lotion. Use a real sunscreen in the morning; use this to reapply.

15 g is a small amount for a product you are meant to use throughout the day.

It frequently sells out on the official site, which pushes people toward third-party sellers where authenticity and storage are not guaranteed. Buy from the brand if you can.

Zinc-only formulas can still cast, and "no white cast" claims tend to be tested on lighter skin. Deep skin tones should treat this as unverified.

Questions people ask+

Is this mineral or chemical?Mineral. The only active is zinc oxide.

Can I use it as my only sunscreen?No. Use a lotion in the morning and this to reapply.

Is it better than a powder?Yes. A cushion deposits more product than a powder does.

Can I reapply it over makeup?Yes. That is its main use.

Is it fragrance-free?Yes.

What SPF is it?SPF 50+.

Full ingredient list+

Active ingredients: Zinc Oxide 22%

Inactive ingredients: Water, Butyloctyl Salicylate, Caprytyl Methicone, Methyl Trimethicone, Ethylhexyl Isononanoate, Butylene Glycol Dicaprylate/Dicaprate, Pro-panecio, Polyglypery -4 Disostearate/Polyhydroxystearate/Sebacate, Ethylhexyl Methoxycrylene, Alcohol Denat., Methyl Methacrylate Cross-polymer, Polyglycery -6 Polyricinoleate, Triethoxycaprylyisilane, Magnesium Sulfate, 1,2- Hexanediol, Distearimonium Hectorite, Polyglyceryl-6 Polyhydroxystearate, Hydroxy-acetophenone, Artemisia Annua Extract, Polyglyperin-6, Pinus Sylvestris Leaf Oil, Anthemis Nobils Flower Oil, Dipotassium Glycyrrhizate, Allantoin, Glyceryl Glucaside, Butyiene Glycol Glycerin, Tocopherol, Ascorbyl Palmitate, Betula Platyphylla Japonica Juice, Umus Davidiana Root Extract, Aloe Barbadensis Leaf Extract, Dioscorea Japonica Root Extract, Viola Mandshurica Flower Extract, Laminaria Japonica Extract, Glyceryl Caprylate, Sodium Hyaluronate Hyaluronic Acid, Ascorbic Acid

References+

1. Sunscreen Drug Products for Over-the-Counter Human Use (Proposed Rule) (https://www.federalregister.gov/documents/2019/02/26/2019-03019/sunscreen-drug-products-for-over-the-counter-human-use) — FDA proposes zinc oxide (and titanium dioxide) as GRASE (Category I) mineral UV filters at concentrations up to 25%, supporting the safety and effectiveness of the product's zinc oxide 22% mineral-only formula. 2. ROUND LAB BIRCH JUICE MOISTURIZING UVLOCK SUN CUSHION - zinc oxide sponge (Drug Label) (https://fda.report/DailyMed/26407b83-b417-6450-e063-6294a90ad2b1) — The official OTC drug facts label confirms the exact active ingredient formulation: Zinc Oxide 22%, broad spectrum SPF 50+. 3. Birch Moisturizing Sun Cushion SPF 50+, PA++++ | Round Lab (https://roundlab.com/products/birch-moisturizing-sun-cushion) — Round Lab sells the cushion directly in the US with fast shipping from a US warehouse, confirming the page's US-warehouse and direct-sale claim. 4. ROUND LAB Birch Juice Moisturizing Sun Cushion 0.52 oz.(15g) | OLIVE YOUNG US (https://us.oliveyoung.com/products/UA87927457) — A major retailer listing confirms US availability and the mineral zinc oxide active (listed as Zinc Oxide 22.28%) of the cushion. 5. Does Powder Sunscreen Actually Work? | Cleveland Clinic (https://health.clevelandclinic.org/powder-sunscreen) — A dermatologist explains that a light dusting of powder sunscreen is not a protective layer — a thick layer is needed to reach adequate protection and people rarely apply enough — supporting the claim that powder is the weakest reapplication format. 6. Photoprotection according to skin phototype and dermatoses: practical recommendations from an expert panel (https://pmc.ncbi.nlm.nih.gov/articles/PMC8252523/) — Expert-panel recommendations stress that applying an adequate quantity of sunscreen (the ~2 mg/cm2 target) and reapplying are essential for real protection, supporting the page's emphasis on reapplication and depositing real product.