Does Salt Water Dehydrate You? (2024)

You likely learned at a young age that human beings cannot drink salt water. Whenever you go for a swim in the ocean inevitably some bitter-tasting salt water will get into your mouth, and you’ll understand the aesthetic difference between refreshing, pure drinking water and salt water, which carries a strong briny taste.

For scientists, the reason for this is simple: salt water dehydrates you. But the body also needs sodium, an integral component of salt, in order to retain water. What causes this seeming contradiction? And why is salt water unsafe to drink?

What Happens When You Drink Salt Water

Salt water contains a much higher concentration of salt than your body requires to survive, and in fact a higher concentration than it can handle. When your body detects excess salt in your bloodstream your kidneys kick into overdrive to filter and remove the salt through the passage of urine. However, the kidneys require a good deal of water in order to process a small amount of water.

When you drink salt water you are ingesting a high concentration of salt, and not enough water to safely filter it out of your body. So, while you are drinking water, during your body’s natural processes you lose more water than you ingest, leaving behind a toxic level of salt in your system.

As your kidneys continue to create excess urine to dilute the salt you will become severely dehydrated. This process will kill you if you continue to only drink salt water.