Why does this happen? Undamaged hair is protected by a natural layer of oil that binds to its surface and keeps your strands from absorbing stinky smells. Over time, however, thanks to heat styling, coloring, keratin treatments and plain-old aging, the hair loses some of that protective layer of oil and become more porous, leaving it vulnerable to odor penetration. And the kind of smells most likely to stick around? Alas, the greasy paella-esque ones are typically the most potent because they are oily, and oil, once it gets inside the fibers of your hair, tends to stick there, making it hard to remove, even with shampoo.
So what can you do? For starters, fake it. Outside smells are able to penetrate your strands because your hair is lacking the protective oil that once wrapped around its outer layer. So, find a substitute. A finishing serum or styling oil applied to dry hair can create a similar shield, keeping the stink (and other environmental aggressors) at bay. Presumably, being conscientious about hair hydration will also help, as strands stuffed with moisture are less porous. Prose offers a plethora of hydrating ingredients and nourishing oils to accomplish all of this; you can read more about them here.
Finally, for those smells that still sneak inside your strands, arm yourself with an antidote. Prose hair care formulas can contain an odorless molecule derived from lemongrass essential oil for exactly this purpose. After you wash and condition with your Prose regimen, this molecule stays put inside your strands, standing guard. If any smells do manage to invade, it instantly seeks them out and neutralizes their odor.
To create your own customized, odor-preventing hair care regimen, get started here.