Three sunscreens, three different filter mixes. That's the difference to shop on.
Search for Round Lab Birch Juice and you’ll find two separate sunscreens: the UV LOCK SPF 45, here as a two-pack, and the Moisturizing Sun Serum SPF 50. They don’t share a formula. SKIN1004’s Hyalu-Cica Water-Fit Sun Serum SPF 50 is the rival both get compared to.
SKIN1004 is the best pick for most people: avobenzone plus octocrylene for SPF 50, a panthenol and centella base, and no essential oils. UV LOCK also uses avobenzone, adds niacinamide and costs the least per tube, but carries chamomile and pine oils. Round Lab’s Sun Serum is the most hydrating of the three and skips avobenzone, so it suits dry skin on ordinary days more than long hours outside.
Which sunscreen should you buy?
| Daily two-pack ROUND LAB Birch Juice UV LOCK Two-Pack | VS | Best overall SKIN1004 Hyalu-Cica Water-Fit SPF 50 Sun Serum |
|---|---|---|
45 broad spectrum | SPF |
50 broad spectrum |
Avobenzone 2.7%, homosalate 13.5%, octisalate 4.5% | UV filters |
Four filters, incl. avobenzone 2.7%, homosalate 13.6%, octocrylene 9% |
Niacinamide, birch juice, allantoin | Key extras |
Panthenol, centella, hyaluronic acid |
Chamomile and pine leaf oil | Essential oils |
None |
Two tubes | Pack |
One 1.69 fl oz tube |
No | Water resistant |
No |
| View | View |
Round Lab UV LOCK SPF 45: the two-pack for daily wear
Two SPF 45 tubes with avobenzone and niacinamide.
UV LOCK’s filters are avobenzone 2.7%, homosalate 13.5% and octisalate 4.5%, for SPF 45 broad spectrum. Avobenzone covers the long UVA rays, so on filters it sits close to SKIN1004, one step down on SPF.
The extras set it apart. Niacinamide is listed ahead of glycerin, a bonus if your skin runs oily or your tone is uneven. Birch juice, allantoin, sodium hyaluronate and vitamin E add light hydration.
This pack holds two tubes, so per tube it costs about the same as one SKIN1004 and less than Round Lab’s Sun Serum. It also contains chamomile flower oil and pine leaf oil. If essential oils make your skin sting or break out, go with SKIN1004.
- Two tubes per pack, the lowest cost per tube here
- Avobenzone 2.7% with homosalate and octisalate
- Niacinamide listed ahead of glycerin
- Birch juice, allantoin and hyaluronic acid for light hydration
- SPF 45, the lowest of the three
- Contains chamomile flower oil and pine leaf oil
- Not water resistant
- Two tubes is a lot if you only wear sunscreen on weekends
SKIN1004 Hyalu-Cica: the best all-rounder
Four-filter SPF 50 with panthenol and centella, no essential oils.
SKIN1004 uses four filters, including avobenzone 2.7%, homosalate 13.6% and octocrylene 9%, for SPF 50 broad spectrum. It’s the only sunscreen here with both avobenzone and octocrylene, and octocrylene helps keep avobenzone stable in sunlight.
The base is built to calm and hydrate. Panthenol sits high on the list, followed by centella asiatica extract, several forms of hyaluronic acid, glycerin, and extracts of green tea, rice, oat and soybean.
There’s no added fragrance and no essential oils. That’s the main reason it beats both Round Lab formulas for sensitive skin, and why it’s the one to buy if you’re not sure what your skin will tolerate.
- Avobenzone, homosalate and octocrylene for SPF 50 broad spectrum
- Panthenol, centella and hyaluronic acid in the base
- No added fragrance and no essential oils
- Lowest cost of the single tubes
- One 1.69 fl oz tube, no multipack
- Less hydrating than Round Lab’s Sun Serum for very dry skin
- Not water resistant
Round Lab Birch Juice Sun Serum SPF 50: the hydrating option
Hydration-first SPF 50 for dry skin.
This is a different formula from UV LOCK, not just a higher SPF. Its filters are ensulizole 2.5%, homosalate 5%, octisalate 4.5% and octocrylene 6%, for SPF 50 broad spectrum. There’s no avobenzone, the filter most US chemical sunscreens rely on for long UVA rays. For long hours outside, SKIN1004 and UV LOCK have the stronger UVA filter.
Where this one wins is hydration. Birch juice, panthenol, glycerin and eight forms of hyaluronic acid run through the list, along with sodium DNA (PDRN) and extracts of aloe and kelp. It’s the best of the three for skin that feels tight by midday.
The formula has no added fragrance, but it does contain chamomile flower oil and pine leaf oil, the same two oils as UV LOCK. If essential oils make your skin sting, skip both Round Lab sunscreens.
- Most hydrating of the three: birch juice, panthenol and eight forms of hyaluronic acid
- Adds sodium DNA (PDRN) plus aloe and kelp extracts
- SPF 50 broad spectrum in a single tube
- No avobenzone, the main long-UVA filter in US chemical sunscreens
- Contains chamomile flower oil and pine leaf oil
- Costs more than SKIN1004 for the same size tube
How much sunscreen to apply
A serum texture is not a reason to use less. Light sunscreens spread easily, which makes it easy to under-apply. Use about two finger lengths for your face and neck, and make it the last step of your morning routine.
Moisturizer is a separate call. If your skin is oily or combination, SKIN1004 or UV LOCK can be enough on their own in the morning. If your skin is dry, Round Lab's Sun Serum gives you the most hydration, but on flaky days put a moisturizer under it and let it set for a minute first.
Reapply every two hours when you're outdoors, and right after swimming or heavy sweating. A higher SPF doesn't stretch that window. SPF 50 blocks slightly more UVB than SPF 45, but the gap is far smaller than the gap between a full layer and a thin one.
These are everyday sunscreens. For the pool, the beach or a hard workout, wear one labeled water resistant (40 or 80 minutes) and reapply on the schedule printed on it.
Choose SKIN1004 Hyalu-Cica if you want one sunscreen that suits most skin. It pairs avobenzone with homosalate and octocrylene for SPF 50, adds panthenol, centella and hyaluronic acid, and skips the essential oils both Round Lab formulas carry.
Choose the Round Lab UV LOCK two-pack if you wear sunscreen every day and like niacinamide. Avobenzone, homosalate and octisalate give SPF 45, and two tubes per pack keeps the per-tube cost low. Skip it if chamomile or pine oil bothers your skin.
Choose Round Lab’s Sun Serum SPF 50 if your skin is dry and hydration comes first. Birch juice, panthenol and eight forms of hyaluronic acid make it the most moisturizing of the three. It has no avobenzone, so for long days outside, take SKIN1004 instead.
Whichever you pick, apply a full layer, about two finger lengths for face and neck, and reapply every two hours outdoors.
