Does urine have health benefits?

Question

Some people claim urine cures everything from colds to cancer.

I read these claims here

• Advocates claim it has antibacterial, antifungal, antiviral and anticancer properties. [...]
• Research in the 1990s claimed that drinking urine could cure jet lag. [...]
• It is highly sterile. The Aztecs used it to prevent wounds becoming infected.

My question is: Does urine have genuine health benefits?

Answer 1

With respect to the claim that urotherapy can cure cancer, the American Cancer Society has this to say:

No well-controlled studies published in available scientific literature support the claims that urotherapy can control or reverse the spread of cancer.

It goes on:

What is the evidence?

There are some individual reports of urotherapy's ability to stop cancer growth. However, available scientific evidence does not support claims that urine or urea given in any form is helpful for cancer patients. Two small studies done during the 1980s found urea did not cause tumors to shrink in patients with cancer in the liver.

Are there any possible problems or complications?

Individuals have reported that drinking or injecting urine or applying it directly to the skin is safe and not linked to any harmful side effects, but the safety of these practices has not been established by scientific studies. There have been reports of nausea, vomiting, upset stomach, and diarrhea after drinking one's own urine, especially during the first few days. Some medications are excreted into the urine, and by drinking their own urine, patients can accumulate toxic levels of these drugs.

Relying on this type of treatment alone, and avoiding or delaying conventional medical care for cancer, may have serious health consequences.

So, no. There is no evidence that drinking your own urine will cure cancer. It can potentially cause more harm than good.

Answer 2

Hypothesis: Drinking urine may prolong survival time after water deprivation.

SITUATION: You get trapped somewhere without food and water and you hope to be rescued by someone in few days. You drink your own urine in hope to postpone death from dehydration.

THINGS TO CONSIDER:

1. There were many reports how people survived without water from 7 to 10 days and they didn't mention any urine drinking.
2. A healthy, sedentary young adult in a moderate climate loses at least about 1 liter of water per day — obligatory water loss by urination, breathing and invisible perspiration, but no sweating; you lose about 500 mL of water with the urine.
3. You die when you lose 10-15% of your initial body weight due to water loss; for a 70 kg person, this is 7-10.5 kg body mass (7-10.5 liters of water). So, the question is can you replace some of this water by drinking urine. Yes, you can, but more water (urine) you drink, the more urine you will excrete, so the expected water replacement doesn't actually work.
4. On the first day without water, when you are still relatively well hydrated you excrete about 500 mL urine, but by consuming this you also consume some urea and sodium — these will eventually need to be excreted again and some water will be needed for that, so the net benefit of drinking 500 mL of urine will be....less than 500 mL...
5. With progression of dehydration, you will excrete smaller amounts of urine, which will be highly concentrated. If you drink this concentrated urine, you will obligatory excrete (urinate) more water (to excrete ingested urea and sodium) than you drank it — so in this stage, by drinking urine you are actually dehydrating yourself.
6. The water from the urine you drank in the first few days will be excreted in those first days and you will be pretty much out of urine probably after the day 5. This means you can not prolong your survival time with drinking urine (assuming you can survive without any water (or urine) for 7-10 days anyway).

The above consideration is based on the theoretical knowledge about how water is lost from the body and it lacks any measurements and accurate calculations, but roughly this is how I believe this works.

In another situation, like in a hot desert, your survival time without water may be as low as a day or two. In this situation, drinking urine might prolong your survival for...only an hour or so, because you will quickly sweat out that water from the urine you have drunk.

About OTHER CLAIMS in the original question:

• "Urine is highly sterile...so it can be used to disinfect wounds". Urine is not highly sterile but usually contains a certain amount of bacteria from the urinary tract. Besides that, they are not sterile but sterilizing fluids that kill bacteria; even sterile water does not kill bacteria (apart from those that drown in it).
• "Urine...cures jet lag". Maybe it does, maybe it does not, but I did not find any reliable source which would prove that this is the best method.
• "Urine can be used to treat bacterial and fungal infections." Urine actually allows bacteria to grow and multiplicate. For example, urine sample intended for urine culture (checking for bacteria in urine) has to be refrigerated or some preservative used before transported to the lab, otherwise the bacteria in urine will multiplicate, which will lead to erroneous result.