There are several factors that can affect the intensity of the self-tanner color on your skin and you need to start your quest for an ultra dark fake tan by taking your natural skin tone into account. Very fair skin will have a more difficult time achieving, and mainly maintaining, a very dark result without it getting patchy. The main thing that will determine how tan you get is DHA, the active bronzing ingredient all self tanners (learn more in this video). If you're ready to dive in further, here are some variables that will help you get the darkest result from your self tanner.

1. Exfoliate your skin before applying self-tanner: Removing dead skin cells from your skin's surface will help the self-tanner to adhere deeper and absorb more evenly. It will also make your tan last longer. Use a clear body gel and an exfoliating mitt with a grit specifically designed for self tanning to make sure you're not harming your skin barrier, but getting down to fresh skin cells. (Pre-Tan Exfoliating Glove, $15)

2. Products with a high concentration of DHA will give the darkest tan: you'll have to look beyond the drugstore or Sephora for this one. Look for professional-grade self tanners that list their DHA concentration. This is the active ingredient that adheres to the skin and produces the tanning effect. DHA is actually a clear so you can't rely on the color of the product in the bottle to guide you. There are self tanners that are made for beauty professionals and tanning salons, like GlowPro Tanning Mousse, that will list the DHA percentage for you. Anything 10% DHA or higher is considered "dark." 14-15% DHA is the maximum amount your skin can absorb at once. GlowPro Tan's is a Professional Tanning line that discloses the DHA of every tanning product they make.

3. Apply multiple layers: If you want an even deeper color, you can apply multiple layers of self-tanner. Allow each layer to dry completely before applying the next layer. If you're using a self tanner with a heavy instant bronzer (meaning it looks really, really dark when you pump it out), rinse off between washes. The instant bronzer will clog the skin cells and prevent them from absorbing more DHA.

4. Choose a self-tanner with a dark guide color: most self-tanners have a guide color that shows where you have applied the product and helps you to achieve an even coverage. Some brands really load up the instant bronzer as a marketing tactic to make consumers think the product color will be similar to their end result. While DHA is the only thing that will give your skin lasting color, heavy instant bronzers can leave residue behind even after you shower and give you a color boost. *Warning* this residue will also transfer onto clothes and sheets so choose this option at your own risk. 

5. Use a tan extending lotion: self tanner adheres to your outermost skin cells, which are constantly turning over (shedding). Using a Tan Extending Lotion ($25) will tan the fresh cells that are appearing to keep your tan darker and lasting longer.

It's important to remember that self-tanner does not provide any protection against the sun's harmful UV rays, so it's still important to use sunscreen and other sun protection measures when you are outside.