Medik8 C-Tetra® Luxe Lipid Vitamin C Enhanced Radiance Serum Versus Dr. Barbara Sturm The Good C Vitamin C Serum

Because it’s oil-soluble, THD dives deep into your skin’s fatty layers (think ceramides and cholesterol) to fight off the kind of free radicals that mess with your skin barrier. This makes it a great pair with water-based vitamin C (ascorbic acid) that mainly works on the surface.

Even at just 0.1%, THD is already showing great antioxidant activity. When used up to 2%, it helps keep your skin happy and calm, especially when it’s stressed from pollution or sun.

Want to fade dark spots or tackle hyperpigmentation? You’ll want 5% or more. Pairing it with brightening buddies like niacinamide or licorice root gives even better results. One study even used 30% THD with other brighteners and saw real results on stubborn discoloration, even in melasma-prone skin.

A note on THD: It’s has a slightly silky, oily texture and usually shows up colorless or pale yellow (though the exact shade can vary by supplier).

While you can sneak it into water-based formulas, it really shines when paired with silicones or oils, which help your skin soak it up better.

THD is pretty stable, but it’s still vulnerable to degradation like ascorbic acid. Too much light or heat (above 113°F / 45°C) can break it down over time. Go for dark and opaque packaging that keeps it safe and shady!

Read more about other types of Vitamin C:

These fatty acids help the skin create ceramides. Ceramides play a role in repairing the skin barrier.

Helianthus Annuus Seed Oil helps moisturize the skin. This in turn helps the skin look more rejuvenated and smoother.

Sunflowers are rich in vitamin E.

Historians believe Indigenous cultures of North America domesticated sunflowers before corn. Thus they relied on sunflower oil for a variety of uses. One such use is moisturizing skin and hair.

Sunflower seed oil may not be fungal acne safe. We recommend speaking with a professional if you have any concerns.

This ngredient also has antioxidant properties from Vitamins A, C, and E. Antioxidants help fight free-radicals. Free-radicals are molecules that may damage your skin cells. Besides being antioxidants, these vitamins provide plenty of skin benefits as well.