Everyone obviously knows what a tan looks like, but it can be helpful to know a bit of the science behind tanning. It allows us to understand why certain things work for extending a tan and why no tan will last forever. Clarisonic co-founder and skin care expert Dr. Robb Akridge explains that suntanned skin is when skin cells produce a dark pigment (melanin) to try and protect skin from the sun's harmful days. A sunburn kills off skin cells, which results in telltale peeling skin.

Skin will have natural flaking of the epidermal layers (the outermost ones) because of skin's cell turnover. As skin sheds, the tan will become less noticeable because the pigment will be dulled. Given that skin's cell turnover is about every four weeks, a natural tan will never last forever.

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If you're not in the habit of regular moisturizing, it's time to start. Not only does it keep skin smooth and supple, it also helps prolong the life of a tan. If your tan is faux, hydrated skin will help lock in color for longer and helps reduce streaking and fading, according to the tanning experts at Nkd Skn. They recommend using an oil-free moisturizer because oils tend to break down sunless tans faster.

Look for a moisturizer with dihydroxyacetone (DHA), a color additive typically sourced from plants that subtly increases tans. It's usually found in self-tanners and gradual tan moisturizers, like Jergens Natural Glow Daily Firming Moisturizer, $9.99. Be aware that some people might be allergic to DHA, so always do a patch test before applying products all over.

There are even specific tan boosters like the Clarins Radiance-Plus Golden Glow Booster, $32. It's dubbed "sunshine in a bottle" and promises to increase skin's natural glow when users mix three drops with their moisturizer. E.L.F. offers a similar product: Sunkissed Booster Drops, $10.

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Those with faux glows should always do a thorough exfoliation before applying self-tanner. Dr. Purvisha Patel, M.D. and founder of Visha Skincare, says that using a scrub, like Visha Skincare Sugar Shrink Body Scrub, $36, will ensure that the self-tanner is evenly distributed, providing longer wear and a more natural-looking glow. Those who have been using fake tan products without exfoliating can start now. It'll remove any patchiness and create a more even (read: natural) bronzed goddess effect. Those with natural tans can gently exfoliate to ensure their color doesn't become patchy and it fades evenly.

Speaking of sunless tans, self-tanner is a brilliant way to extend the life of all tans. Choose a lighter shade going into the fall for a more convincing effect. Nkd Skn says the goal is a sun-kissed, natural-looking bronze as opposed to a super dark color and suggests using a gradual tan product or an in-shower one like the Nkd Skn Pre-Shower Tan, $19.99, to build up the color over a few days and allow greater control of the finished result. St. Tropez In Shower Gradual Tan, $25, comes in two shades for a customized finish.

Olga Lorencin, celebrity esthetician and founder of Olga Lorencin Transformative Skin Care and Olga Lorencin Skin Care Clinic, offers this simple routine: exfoliate, self-tan with a sunless tanner, hydrate and repeat.

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Consider Makeup

Bronzer is a no commitment, no effort way to make skin look a few shades darker. As with self-tanner, resist the urge to go too dark lest you want skin to look orange or dirty. And remember, bronzer can be applied to the face and body. When you're showing skin, it's important to maintain an even tan, so use bronzer above and below the neck. Benefit Hoola Zero Tanlines Allover Body Bronzer, $30, and Lancome Star Bronzer Magic Bronzing Brush Automatic Powder Brush for Face and Body, $37, are both easy-to-apply, universally flattering products that can be used from head to toe.

Plan Your Outfit

One of the simplest tricks of them all doesn't involve any skin care products. Akridge suggests wearing lighter colors to make a tan look darker. "Colors like yellow and white will make an average tan look like you have been living in the Bahamas," he says. So say goodbye to the rich jewel tones of fall and rock white long after Labor Day.

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