Paula's Choice BOOST C15 Super Booster Vitamin — 30% Off

Paula’s Choice BOOST C15 is the brand’s high-strength vitamin C super booster, formulated with 15% pure L-ascorbic acid plus vitamin E and ferulic acid — the same antioxidant pairing used in clinical vitamin C serums at three to four times the price (e.g., SkinCeuticals C E Ferulic). The “booster” format is the differentiator: it’s designed to be mixed into a moisturizer or serum at home rather than applied as a standalone, letting users dial concentration up or down based on tolerance and avoid the irritation that 15% L-AA serums often cause on sensitive skin. Vitamin C at this strength is the daytime workhorse most dermatologist routines pair with sunscreen for free-radical defense and the brightening, even-tone effects that build over an 8-to-12-week routine. Paula’s Choice publishes full ingredient rationales for each formula, which is why it remains a recommended brand in evidence-leaning skincare communities. With 3,142 ratings averaging 4.2 stars (the lower rating reflects the unfortunate reality that 15% L-AA destabilizes over time — buy fresh stock), feedback is solid for the active strength. At $38.50 — 30% off the $55.00 list — this is one of the few times the booster bottle dips below $42.