I'm on I think my 4th bottle of this. My skin is quite sensitive to Vitamin...

I'm on I think my 4th bottle of this. My skin is quite sensitive to Vitamin C, but this product causes absolutely no irritation. After a few weeks of use I noticed a healthy glow and texture to my skin. I do agree with the claims that this product strengthens the skin. I will note that I mix it with a pump of some kind of hyaluronic acid serum just to thin out the product, as it is dark in color which can show up if the product isn't diluted a bit.