SKIN1004 Hyalu-Cica Sun Serum: SPF 50+ PA++++ and UV Filters

SKIN1004 Hyalu-Cica Water-Fit Sun Serum 50ml sells for USD 17.10 (checked 2026-10-06), and its Korean-market label states SPF50+ PA++++, described on SKIN1004's own product page as a chemical sunscreen with UVA and UVB protection. SPF is a measured UVB result from a standardized in-vivo test under ISO 24444, and PA is a measured UVA result derived from the Persistent Pigment Darkening test under ISO 24442, so the question behind any SPF50+ PA++++ label claim is whether a dated lab number sits behind each grade rather than a maker's own adjective. That is the axis this Hyalu-Cica sunscreen settles: SKIN1004 attaches named ISO test reports, subject counts and dates to its SPF and PA figures on its own product documentation. Two other SPF50+ PA++++ facial sunscreens, Beauty of Joseon's Relief Sun: Rice + Probiotics and ANESSA's Perfect UV Sunscreen Skincare Milk NA, post the same four-plus-sign label and are read against that same documentation standard below.

SKIN1004 Hyalu-Cica Water-Fit Sun Serum 50ml

SKIN1004 Hyalu-Cica Water-Fit Sun Serum 50ml is sold under the GB-market SKU name "Hyalu-Cica Water-Fit Sun Serum SPF50+ PA++++," described on SKIN1004's own page as a chemical sunscreen offering UVA and UVB protection. An in-vivo SPF test under ISO 24444:2019, run 2021-11-24 to 2021-12-24 on ten adult subjects, returned 50.5±7.1, and a matching in-vivo PFA/PPD reading under the 2011 protocol of ISO 24442, from the same subject panel and window, returned 16.56±2.69, both of which clear the respective 50 and 16 thresholds that the SPF50+ and PA++++ grades require. The GB-market SKU is also sold in 15ml, Twin Pack (50ml x2) and 100ml Mega Size formats alongside the 50ml bottle, and SKIN1004's Korean domestic listing offers the 50ml, 100ml Mega Size and Twin Pack (50ml x2) sizes under the same SPF50+ PA++++ label.

• In-vitro UVA-PF (ISO 24443), run 2026-05-06 on four PMMA plates at 1.2mg/cm²: 14.9 (SD 0.4), critical wavelength 376.0nm (SD 0.0).
• In-vivo UVA-PF/PPD (ISO 24442:2022, EU protocol), ten subjects aged 40-60, skin types II-III, window 2025-04-10 to 2025-05-09: mean 17.3.
• In-vivo PFA (ISO 24442:2011 protocol), ten subjects, window 2021-11-24 to 2021-12-24: 16.56±2.69.
• In-vivo SPF (ISO 24444:2019), same subject panel and window: 50.5±7.1.

This GB-market SKU's four UV filters are named on its own ingredient list: Diethylamino Hydroxybenzoyl Hexyl Benzoate, Ethylhexyl Triazone, Methylene Bis-Benzotriazolyl Tetramethylbutylphenol and Diethylhexyl Butamido Triazone. SKIN1004's stated directions are to apply it as the last step of a basic skincare routine, evenly over the face, neck, arms and legs. The same formula is registered with the Philippines FDA as Madagascar Centella Hyalu-Cica Water-Fit Sun Serum SPF50+ PA++++ under notification NN-1000013572210, issued 2025-09-22 and set to expire 2026-09-22.

SKIN1004 (SKIN1004) is a Korean skincare brand built on a Madagascar-sourced Centella Asiatica Extract, and this Hyalu-Cica line pairs that extract with hyaluronic acid across the serum, a toner and a cream. A reader who searches for a 1004 sunscreen with its lab numbers on record finds them on this product's own documentation, where the SPF and PPD results above are dated and sourced to named test reports. SKIN1004 lists the full GB-market range, including the 15ml, 50ml, Twin Pack and 100ml sizes, on its own product page, where each figure above can be checked against its original report.

Two other SPF50+ PA++++ facial sunscreens post the same label question in this comparison. Beauty of Joseon's Relief Sun: Rice + Probiotics lists the identical four organic filters on its own EU product page, though the 52.5±5.8 and 63.1±0.6 SPF readings attributed to it by a Korean lab and a Spanish lab appear only on retailer listings, not on that EU page itself.

What SPF 50+ and PA++++ Grades Mean by Market

SPF50+ is the Korean and EU labelling convention for any measured SPF result of 60 or higher; the raw number is capped and displayed as "50+" instead of printed in full. PA (Protection Grade of UVA) is the matching Korean and Japanese UVA scale, run off the PPD test under ISO 24442, with four tiers from PA+ to PA++++. Neither label is a marketing phrase on its own; both are shorthand for a measured result that a brand can choose to publish in full or leave as the plus signs.

• PA+: PPD (UVA protection factor) of 2 to under 4.
• PA++: PPD of 4 to under 8.
• PA+++: PPD of 8 to under 16.
• PA++++: PPD of 16 or above.

The United States does not use the PA scale at all. SKIN1004 sells a second SKU of the same line, Hyalu-Cica Water-Fit Sun Serum UV, through its US storefront, and its Drug Facts panel, filed with the US National Library of Medicine's DailyMed registry under NDC 85796-2805, states "SPF50, Broad Spectrum" instead of SPF50+ PA++++. Broad Spectrum is a pass or fail US test for critical wavelength of 370nm or above, a different measure from the PPD number that PA++++ represents.

The same product line is sold under two different regulatory labels depending on where it is bought: a Korean SPF50+ PA++++ grade on the GB-market SKU, and a US SPF50 Broad Spectrum grade, filed under a formal OTC drug listing, on the US-market SKU. A shopper comparing the two labels side by side is comparing two different test systems, not two different protection levels on the same scale.

Documented UV Filters Behind the Same Product Line

The GB-market Hyalu-Cica Water-Fit Sun Serum states four UV filters on its own ingredient list: Diethylamino Hydroxybenzoyl Hexyl Benzoate, Ethylhexyl Triazone, Methylene Bis-Benzotriazolyl Tetramethylbutylphenol and Diethylhexyl Butamido Triazone, all organic, carbon-based filters.

The US-market Hyalu-Cica Water-Fit Sun Serum UV states a different set on its federally filed Drug Facts panel: Avobenzone 2.7%, Homosalate 13.6%, Octisalate 4.5% and Octocrylene 9%, matching the percentages recorded on DailyMed under NDC 85796-2805. A shopper avoiding a specific filter, such as avobenzone or octocrylene, needs to check which regional SKU of this line they are actually buying, since the two formulas do not share an active-ingredient list even though they share a product name.

SKIN1004's own ingredient pages separate this filter list from the line's other stated ingredients: Centella Asiatica Extract and hyaluronic acid appear in the cosmetic ingredient section of both SKUs' pages, not in the sunscreen active-ingredient or Drug Facts panel, so the moisturizing claims attached to this serum sit apart from its SPF and PA claims, in a separate section of the same page.

Use Directions and Warnings Across the Two SKUs

SKIN1004's GB-market page gives one instruction for the Hyalu-Cica Water-Fit Sun Serum: apply it as the last step of a basic skincare routine, evenly over the face, neck, arms and legs. No reapplication interval is stated on that page.

The US-market Hyalu-Cica Water-Fit Sun Serum UV states a fuller Drug Facts panel, filed with DailyMed: apply liberally 15 minutes before sun exposure, and reapply at least every 2 hours. The same panel adds standard US sun-protection measures, including limiting time in the sun between 10am and 2pm and wearing protective clothing, and notes that children under 6 months should be checked with a doctor first.

That Drug Facts panel also warns against applying the product to damaged or broken skin and against letting it contact the eyes without rinsing with water; it tells users to stop use and ask a doctor if a rash develops, and to contact a Poison Control Center if the product is swallowed. These are the only documented warnings found on either SKU's primary page, and they sit on the US label specifically, not on the GB-market page.