Drink Water All Day Long & Still Feel Dehydrated? A Functional MD Explains Why

It's a scenario Dana Cohen, M.D., integrative medicine physician and co-author of Quench, knows all too well: You gulp down water all day long, religiously refilling your (reusable!) water bottle. And yet—you feel perennially parched, your lips chapped, and your mouth desert-dry. Your mind reels with iterations of What gives? 

Don't get us wrong; reverse osmosis water filters are great—they clean your tap of potentially harmful contaminants and byproducts, after all. (Cohen's partial to this version from AquaTru.) However, she says these filters weed out everything—including healthy minerals, electrolytes, and the like. 

"If you're drinking all that plain bulk tap water that has nothing in it, you're flushing out electrolytes, not replacing those electrolytes," she says. Without those electrolytes1 (read: sodium, potassium, magnesium, chloride, et al.), you may not feel aptly hydrated throughout the day, even after gulping down gallons. 

So if you do use a reverse osmosis water filter and you can never seem to quench your thirst? You might want to think about remineralizing your water. Of course, you can opt for OTC electrolyte replacements, but Cohen says a dash of Himalayan sea salt and a squeeze of lemon can also do the trick. "Not every single glass of water, but in a couple of those glasses do a pinch of [salt] with some lemon to replace some other minerals," she adds. 

That sprinkle of salt helps pull water into your cells through sodium transporters, as functional nutrition expert and certified sports nutritionist Jaclyn Sklaver, M.S., CNS, CDN, LDN, once told us. "They enable more water to be absorbed by the intestines than plain water alone."