Tranexamic Acid 5%.

"The Naturium Tranexamic Acid 5% is honestly the best out there. It's super smooth on the skin and because of the quality formulation you won't get too much prickling or irritation, which I think is really important if you're going to pair it alongside another potent active. You're going to want to look for something in a 5% concentration to really get maximum results, and this is the one in the yellow pump that you want because this is the right 5% strength to give you the very best results. I personally use it morning and evening because for me I think that gives the very best results. If you're new to tranexamic acid, I would start gently and gradually work your way up. Use it just once a day for the first month to allow your skin to become accustomed to the active, and then when your skin can tolerate it, you can move to twice daily which is where you're going to see those next level results."