Should you Drink your own Urine in a Survival Situation?

Courtesy of flickr user Yaniv Ben-Arie

The short answer is no. The longer answer, is also no.

I was recently watching an episode of Man, Woman, Wild, my first and last. I'd never seen the show and decided to give it a try. I was severely disappointed.

The two were stranded in the middle of the desert in Mexico and the husband, who is supposedly a former US Army Special Forces Survival "Expert" suggested that the two drink their own urine. Netflix lists this episode as the first episode of the first season, but it was actually aired as the fifth episode, in case you wish to watch it.

I was shocked that a man supposedly trained by the US army would suggest such a thing. The Army's own Field Manual (FM 21-76 p. 176) clearly states not to drink urine. In this article I'll explain exactly why that is.


Many people tell harrowing stories of survival listing urine as their only source of water and one of the reasons why they survived. But most competent survival experts will tell you that these individuals survived in spite of their drinking urine, rather than because of it. To explain why this is we need to look at what exactly urine is.

Urine is composed of about 95% (depending on your body's level of hydration) water. If it's mostly water, doesn't that mean it's a perfect source of hydration? Not really, as looking at the other components of urine will tell you. The rest of your urine is typically composed of, in order of decreasing concentration, urea 9.3 g/L, chloride 1.87 g/L, sodium 1.17 g/L, potassium 0.750 g/L, creatinine 0.670 g/L. Urea is a chemical that is irritating to the skin and intestinal tract in moderate to large doses, but relatively harmless in small doses. Sodium, potassium, and chloride are your electrolytes. Creatinine is a mildly toxic compound and is a waste byproduct of normal liver function.

Ignoring the creatinine and urea (which aren't in large enough concentrations to make someone seriously ill) the electrolytes in the urine will server to dehydrate you, rather than hydrate you.

But wait, aren't electrolytes good?

Yes, but only if you are properly hydrated. Electrolytes, simply stated, facilitate communication between brain and nerve cells, among other functions. When your electrolyte levels drop, you become lethargic, slow-headed and in very severe situations can have motor function disabilities. However there are several mechanisms wherein too many electrolytes can be detrimental.

The main one I'll explain pertains to the blood's tonicity. Using sodium chloride (salt) as an example, the blood's natural salinity is at .009% sodium chloride. The body is always attempting to keep your blood at this level. Too little salt can be damaging, as noted above. Too much salt, however, can be equally as damaging to your cellular functions. So if the blood has too much salt (or other electrolytes) it will attempt to remove it. Urine is one of the ways, but the most immediate method is through your sweat.

In other words, if you have too much salt (and other electrolytes) your body will cause you to sweat and pee more frequently and at greater volumes.

Okay, but if you're in a survival situation, you're already sweating a lot, so aren't you at a lower level of electrolytes anyway? Most likely yes, especially in a high heat situation. But when you ingest electrolytes that takes much needed water away from your cells (and other parts of your body) in order to maintain the proper tonicity of the blood as mentioned earlier. Its the reason why you retain water when you ingest too much salt, the body forces water into your blood (and other areas) in order to maintain it's tonicity. Where does it get the water from? Essentially, from your cells.

If you've ever done this experiment in high school you should recall that adding salt water into a microscope slide with living cells will cause them to shrivel up. That's what's happening to your cells when you ingest too much salt.

The only time you should ingest electrolytes is when you're already getting enough hydration. The minimum necessary amount of water you need in a survival situation to function adequately is roughly 2 gallons per day (and a LOT more in a desert). That doesn't mean half a gallon of Gatorade and 1.5 gallons of water. If you're loosing electrolytes, you need to drink those two gallons of water and then add in your Gatorade, not substitute water for Gatorade.

The long and short of all of this is that drinking urine will, in the end run, dehydrate you, not rehydrate you, in spite of it being 95% water.

So what can you do if urine is your only source of hydration? You need to purify that urine until it's roughly 98% or 99% water. (You won't be able to get it to 100% without some serious chemical equipment.) If you have a cup, a plastic sheet and some pebbles you can make a solar still. You can use a filtration system (although it's hard on the filters). With a pot, a lid, and a simple rubber tube you can desalinate it. All three methods I'll write about in another article. The simple message is that you can use urine as an emergency hydration source... if you purify it first.

Oh and by the way, later on in that episode of Man, Woman, Wild, female present, Ruth England, became so dehydrated that they had to call in the production crew's medic to help her. The drama starts at about 26 minutes into the program. The medic arrives, gives Mrs. England some water, and sits there watching her deteriorate to the point of vomiting, on the verge of a possibly fatal hyperthermic event (heat stroke). I'm only an EMT, but had I been there I would have ordered a medivac for Mrs. England, instead of waiting it out over an hour in the hot desert sun. There's so much bad about this episode I'll be writing a few posts about it...