10% Vitamin C + E Ferulic Acid Serum.

"One of my personal favorites is Timeless. This is the Timeless 10% Vitamin C + E Ferulic Acid Serum. They do 10, they do a 20. As with the retinoids earlier, I would say start with the 10, work your way up to the 20. Maybe use two bottles of the 10, then buy the 20. That way, your skin can get used to it, minimize side effects and irritation. Vitamin C helps create more collagen, but it's also preventative. It prevents that collagen degradation. So it's a bit of a double whammy. Vitamin C to get your glow game on point, prevent any collagen degradation, and also boost collagen production is another absolute essential when it comes to anti-aging."

"This is a 10% L-ascorbic acid plus vitamin E and ferulic acid serum, which are the same three trifecta ingredients that you will find in Skinceuticals C E Ferulic, but this one is way, way more affordable and in my opinion, in my experience, it is every bit as good as that one and you save over $100 on this one. Vitamin C serum is an absolutely crucial ingredient in a very well-rounded anti-aging routine. Putting a vitamin C under your sunscreen in the morning is going to supercharge your SPF results because vitamin C is an antioxidant. That means it will scavenge those free radicals that the sun creates on our skin, and those free radicals are what attack our collagen and break our collagen apart. So if you put a vitamin C serum under your sunscreen in the morning, you're going to supercharge your results and you're going to keep the collagen in your skin for longer. You are going to prevent it from breaking down from UV damage. It's going to scavenge those free radicals away. This one you can often find for 40, even 50% off, so that makes this around $13."

"I'm particularly fond of the 10% vitamin C because I think it's pretty hard to find a 10% vitamin C. We know from studies that that is sufficient to be effective, and also the irritation is lower the lower the concentration you get. So I think this is a perfect vitamin C serum if you're looking for a new one or even if you want something to last with you over time and you have sensitive skin. 10% is great, my favorite product from them. It's a 10% vitamin C serum for like $15 with vitamin E and ferulic acid, the stabilizers and the penetration enhancers to make it more effective."

"I love this brand and I will still continue to use this brand. Ascorbic acid has a lower pH. It's more acidic. And so, this is going to create that cell turnover and it works a little bit quicker. With vitamin C derivatives, they have a higher pH around five or six. The same pH is what your skin is naturally, which is why it tends to be more gentle, but with derivatives, they can take a little bit longer to work as well. In my opinion, and from my experience, it really is just the acidity of the vitamin C that caused this instant reaction with my skin. So, right after I applied it, within a half an hour, my skin started to feel quite tight, almost like I didn't have enough moisture on my skin. So that led me to apply more moisturizer on my skin. And then again, within an hour or so, I felt very tight, especially around my mouth. And then I started to get this warming sensation with my skin."