Vitamin C is a truly fantastic antioxidant that should not only be a staple in your diet but also regularly appear in your skincare routine (with one exception, more on that below).
However, when it comes to products with Vitamin C, you have to be careful. Vitamin C is a water-soluble vitamin and needs to be highly concentrated (i.e., usually up to a maximum of 15%) because it cannot penetrate the skin very well. Furthermore, this substance is extremely unstable, meaning that the moment it is active, it already begins to oxidize. Therefore - sorry for the bad news - pure Vitamin C (such as L-Ascorbic Acid) is actually most effective if you have it in powder form, mix it with toner or serum, and then apply it to the skin. Available from Naya, Merme, and Nuori.
Otherwise: a pump dispenser is better than a pipette, and dark glass as packaging is a must. For those who prefer to combine it directly with hyaluronic acid, ferulic acid, azelaic acid, and other fine substances, we recommend the excellent serums from Wildcrafted Organics, Lilfox, or Josh Rosebrook. This also eliminates the need for mixing. And the best part: these serums no longer contain classic, water-soluble Vitamin C, but stable derivatives - for effectiveness down to the last drop!
Brand new in Fall 2022: a Vitamin C moisturizer from Pai Skincare. This uses an oil-soluble derivative, which also guarantees stability. Perfect for morning care because Vitamin C protects against free radicals (it is also often referred to as 'photoprotective'), helps against hyperpigmentation/age spots, combats impurities, and - tadaa - stimulates collagen synthesis.
The new forms of Vitamin C also allow for a milder approach to the rest of the formulation. L-Ascorbic Acid requires an acidic pH in its environment - meaning that everything added to the formulation usually irritates the skin. So, it could be that if you previously reacted poorly to Vitamin C, you weren't reacting to the Vitamin C itself, but rather to all the carrier substances in its environment. It's worth trying the new derivatives, I would say.
Oh, and the exception: everyone with acute rosacea, couperose, or neurodermatitis. It's better to ask for a sample first, just to be safe.