All are affiliate links . Remember, you don't add vitamin C if you're trying a new retinol or a new niacinamide. You truly need less with skincare! But, if I had to choose, here are some I like :)
3 patents, encapsulated and you don't have to worry about pH with no water in this formula. Apply to damp skin (not wet!). Note: it's 20%, that means it's STRONG. Don't start using daily at first.