Whether you spend countless hours in the bathroom or splurge at the blow-dry bar, most of us have a difficult time keeping a blow-out fresh for more than a day, myself included. No matter the technique, it seems only my trusty dry shampoo can revive locks downtrodden by moisture, product overload, wash-free day.

I've known and liked a lot of hair primers, but for some reason they felt like the extra step I didn't need. I never really thought about the science of a blow-out breakdown until Living Proof's Prime Style Extender got me thinking.

The premise is relatively simple. When hair is heated and dried, temporary hydrogen bonds lock and retain their shape. When moisture levels shift from the weather or the thermostat, however, these bonds weaken, causing your hair to fall flat, frizz up, and lose its luster. Living Proof's silicone- and oil-free formula (patented with the molecule OFPMA, which protects these bonds from breaking) acts like a face primer to your makeup; in this case it's a foundation to mousse, hairspray, and whatever other styling product used.

Directions say to slather a generous amount over roots and tips on damp hair before blow-drying. As anyone with an oily scalp can attest, I was initially worried about putting product that close to my roots, but went in with a quarter-sized dollop. After combing through and blow-drying, hair felt fuller and fluffier, but not in a puffy way. Curiously enough, my hair texture also felt different; a bit mattified with less slip, similar to what a face primer would do for your skin. Over the next two days, touch-ups were minimal, even in the cloudy and damp San Francisco fog. The product works best when heat-activated-the effects aren't as dramatic after air drying.

Adding a primer to your hair routine may feel like yet another step, but the science makes sense and the results are visible. If moisture is the bane of your blow-out's life cycle, then this weightless extender might save you an extra wash.

Photo Credit: Living Proof Prime Style Extender