Stable daily Vitamin C. Freshly activated Vitamin C. One clean, clinical system. No fillers. No irritants. No compromise. Real Results. Real People. 8 Weeks. Wendy · Advanced THD Vitamin C Serum · 8 weeks · No filters Dale · Advanced THD Vitamin C Serum · Week 6 · No filters Trial Participant · Advanced Vitamin C System · 8 weeks · No filters Trial Results 8-week independent trial What This System Does The Intrinsic Advanced Vitamin C System combines two forms of Vitamin C into one integrated daily protocol — stable THD Ascorbate for consistent daily protection, and freshly activated L-Ascorbic Acid for periodic potency. The result is brighter, smoother, more even-looking skin without a single ingredient you would want to avoid. What Our Trial Participants Said "Brighter and smoother — my skin tone is so much more even and calmer. The redness I'd had for years just settled down."WendyAdvanced Vitamin C System · 8 weeks "Reduced sunspots, skin feels smoother. Very happy — easy to use, and some visible results."DaleAdvanced Vitamin C System · Week 6 (still using at Week 10) "Fine lines have softened — jaw and neck lines have improved."Trial ParticipantAdvanced Vitamin C System · 8 weeks What's Included Advanced THD Vitamin C Serum — daily stable Vitamin C in a water-free oil base Vitamin C Activation Booster — the lightweight vehicle for fresh activation Vitamin C Activation Powder — 100% L-Ascorbic Acid, kept dry until the moment of use Why This System Is Different Most Vitamin C serums ask you to choose between stability and potency. L-Ascorbic Acid is the most researched form but degrades the moment it is mixed with water. Stable alternatives like THD are gentler and longer-lasting but traditionally lack the clinical backing of L-Ascorbic Acid. The Intrinsic system does not make you choose. The THD Serum gives you stable daily Vitamin C that works with your skin barrier. The Activation System gives you freshly mixed L-Ascorbic Acid — at full potency, every time — when your skin needs more. Two forms. One clean system. No compromise. WHAT YOUR SKIN WILL FEEL Brighter and more even-looking skin tone Smoother skin texture from consistent use Softer appearance of fine lines over time Daily antioxidant protection against environmental stressors Confident that your Vitamin C is stable, clean and actually working THIS IS FOR YOU IF: You want Vitamin C that doesn't oxidise in the bottle You have ingredient-conscious skin and won't compromise on what you apply You want visible results without aggressive formulations You prefer clean, clinical skincare that works progressively over time You want a complete Vitamin C protocol, not just another serum WHY THD OVER TRADITIONAL VITAMIN C? L-Ascorbic Acid is the most extensively studied form of Vitamin C in skincare — but it is notoriously unstable in water-based formulas. The moment it is mixed with water, it begins to oxidise and lose potency. Many serums are already significantly degraded by the time they reach your skin. Tetrahexyldecyl Ascorbate (THD) is oil-soluble, highly stable and able to penetrate into the skin's lipid layers where it converts to active Vitamin C. It does not oxidise, does not irritate and does not turn orange in the bottle. The Activation Powder addresses the potency question by keeping 100% pure L-Ascorbic Acid completely dry until the moment of application — delivering Vitamin C at full potency, every time. Two forms. One clean system. No compromise.
