Red lipstick has always been an institute in glamour and sex appeal. There is nothing more standout than a pout that is the perfect shade of red.

I've worn a lot of shades of red in my day, but there is one favorite that will always be around for me. I mourned the loss of my last tube of it last year and am ecstatic that it is available again: MAC Viva Glam I.

Now despite already being in love with MAC lipsticks, I have to say this original shade is top notch. There's definitely a reason I keep coming back to it. It's a sultry deep red with blueish undertones. What is great about this lipstick is that despite it being matte, it is a dynamic color: I've noticed it looks different based on the makeup you are wearing and in what light you are standing. Sometimes it looks more vibrant and bright red, other times the blue really stands out making it look more deep and burgundy.

Top photos are in bright light, bottom are in natural lighting.

If you don't already know about the Viva Glam line, there's more than just great shades behind it. For every lipstick purchased from this line, MAC donates the selling price of that tube of lipstick to the MAC AIDS Fund. What happens next is awesome: They use the proceeds to help those with AIDS and AIDS related groups, with a dedication of education on HIV/AIDS for the prevention of the disease.

So there's not just looking great: there is looking great and feeling great, too.

So tell me, what's the red you can't live without? Any other great beauty finds that make you feel great buying them?