Peptide Skincare & BeautySkin science and ingredient guides

Ingredient or product comparison

Paula's Choice Resist Youth-Extending Daily Hydrating Fluid SPF 50 Versus Round Lab Birch Moisturizing Sunscreen SPF 50+ PA++++

Paula's Choice Resist Youth-Extending Daily Hydrating Fluid SPF 50 Versus Round Lab Birch Moisturizing Sunscreen SPF 50+ PA++++ Detailed comparison of Paula's Choice Resist Youth-Extending Daily Hydrating Fluid SPF 50 versus Round Lab Birch Moisturizing Sunscr

This source-based comparison does not add ratings or recommend a winner.

Paula's Choice Resist Youth-Extending Daily Hydrating Fluid SPF 50 Versus Round Lab Birch Moisturizing Sunscreen SPF 50+ PA++++ Detailed comparison of Paula's Choice Resist Youth-Extending Daily Hydrating Fluid SPF 50 versus Round Lab Birch Moisturizing Sunscreen SPF 50+ PA++++. This hybrid sunscreen covers the full UV range and blocks ~98% of UVB at SPF 50. This chemical sunscreen covers the full UV range and blocks ~98% of UVB at SPF 50. Butyl Methoxydibenzoylmethane 2% Ethylhexyl Methoxycinnamate 7.5% Ethylhexyl Salicylate 5% Octocrylene 2% Water Glycerin Silica Dimethicone Tocopherol Chamomilla Recutita Flower Extract Vitis Vinifera Seed Extract Camellia Sinensis Leaf Extract Camellia Oleifera Leaf Extract Peucedanum Graveolens Extract Sambucus Nigra Fruit Extract Avena Sativa Bran Extract Punica Granatum Extract Lycium Barbarum Fruit Extract Hydrogenated Lecithin Titanium Dioxide Dimethicone/Vinyl Dimethicone Crosspolymer Diethylhexyl Syringylidenemalonate Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer Xanthan Gum Sodium Carbomer Benzyl Alcohol Sodium Benzoate Potassium Sorbate Phenoxyethanol Butyl Methoxydibenzoylmethane 2%, Ethylhexyl Methoxycinnamate 7.5%, Ethylhexyl Salicylate 5%, Octocrylene 2%, Water, Glycerin, Silica, Dimethicone, Tocopherol, Chamomilla Recutita Flower Extract, Vitis Vinifera Seed Extract, Camellia Sinensis Leaf Extract, Camellia Oleifera Leaf Extract, Peucedanum Graveolens Extract, Sambucus Nigra Fruit Extract, Avena Sativa Bran Extract, Punica Granatum Extract, Lycium Barbarum Fruit Extract, Hydrogenated Lecithin, Titanium Dioxide, Dimethicone/Vinyl Dimethicone Crosspolymer, Diethylhexyl Syringylidenemalonate, Hydroxyethyl Acrylate/Sodium Acryloyldimethyl Taurate Copolymer, Xanthan Gum, Sodium Carbomer, Benzyl Alcohol, Sodium Benzoate, Potassium Sorbate, Phenoxyethanol Dibutyl Adipate Propanediol Diethylamino Hydroxybenzoyl Hexyl Benzoate Polymethylsilsesquioxane Ethylhexyl Triazone Niacinamide Methylene Bis-Benzotriazolyl Tetramethylbutylphenol Coco-Caprylate/Caprate Caprylyl Methicone Diethylhexyl Butamido Triazone 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 T-Butyl Alcohol Carbomer 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 Methylglu These ingredients are found in both products. Ingredients higher up in an ingredient list are typically present in a larger amount. Glycerin (or glycerol) is a compound naturally found in your skin. It's a powerhouse humectant that pulls water into the stratum corneum. Topically, glycerin does several things at once: Your skin makes glycerin on its own (mostly from sebaceous oil breakdown) and shuttles it to your outermost layer of skin, or your epidermis, via aquaporin-3. Aquaporin-3 is a transporter that is essential for normal skin hydration, elasticity, and repair. Interestingly, mice lacking in AQP3 have dry and less elastic skin that can be fully corrected with glycerin. This ingredient is non-irritating, plays well with almost every ingredient, and works across all skin types. Typical use is anywhere between 3-10% but can go up to 79% in some leave-on products. Just know very high concentrations (>40%) can feel tacky in low humidity. Glycerin is the name for this ingredient in American English. British English uses Glycerol/Glycerine. Tocopherol is a fat-soluble antioxidant known as Vitamin E. You'll find this ingredient in the vast majority of skincare (for good reason). It works to neutralize free radicals, or unstable molecules generated by UV exposure, pollution, and other environmental stressors, before they can cause oxidative damage to your skin cells. Topically applied tocopherol has been shown to protect against UV damage by ramping up the skin's own natural defense enzymes. It also acts as a skin conditioning agent; some studies show that regular topical use can improve the skin's water-binding capacity over 2-4 weeks. This ingredient is especially loved for being a team player. When combined with Vitamin C, the photoprotective effect of both ingredients roughly doubles and the combo also helps reduce UV-induced DNA damage. This ingredient has some brightening potential but it's more of a prevention ingredient than spot-fader. Cell studies show it can slow down melanin production but it's worth noting that it's not the most powerful brightener out there. In formulations, it also serves as a stabilizer that helps protect other oxidation-prone ingredients from degrading. Concentrations usually range from 0.1-1% in most leave-on products. Water. It's the most common cosmetic ingredient of all. You'll usually see it at the top of ingredient lists, meaning that it makes up the largest part of the product. So why is it so popular? Water most often acts as a solvent - this means that it helps dissolve other ingredients into the formulation. You'll also recognize water as that liquid we all need to stay alive. If you see this, drink a glass of water. Remember to stay hydrated! Xanthan gum is used as a stabilizer and thickener within cosmetic products. It helps give products a sticky, thick feeling - preventing them from being too runny. On the technical side of things, xanthan gum is a polysaccharide - a combination consisting of multipl