The Truth About Water Pills and Weight Loss

They’ll dry you out without reducing body fat.

a woman stands with arms outstretched in front of a massive waterfall

Updated on May 26, 2023.

People looking for quick weight loss sometimes turn to diuretics, or water pills. They may buy them at a drugstore, order them online, or in some cases even take someone else’s prescription.

Diuretics are a type of medication that forces the body to get rid of fluids in a way it wouldn’t otherwise do on its own, explains bariatric surgeon Matthew Brengman, MD, of Advanced Surgical Partners of Virginia. (Some plants have diuretic properties as well.)

People may be tempted to use diuretics to shed water weight and thereby lose a few pounds fast. But is using a diuretic to lose weight a good idea?

Here are some of the top myths about water pills and the facts you need to know to use them safely and responsibly.

Myth: Taking water pills for weight loss is safe

Fact: Whether you got them by prescription or over the counter (OTC), water pills are not necessarily safe. Taking them without the supervision of a healthcare provider (HCP) can dangerously alter your body chemistry.

“The first thing is that you shouldn’t be taking someone else’s water pills, and they aren’t safe to take without the care of the doctor,” says Dr. Brengman. “Secondly, when you take a water pill and it causes you to urinate out the fluid in your body, it’s not just water. The fluid also contains important electrolytes, like sodium and potassium. So, unless you’re being monitored for those electrolytes and having replacement if necessary, it’s very easy to get your body chemistry out of whack. Electrolyte imbalance can cause a whole set of complications that can be life-threatening. You have to be very careful when you start messing around with your body’s mechanisms of retaining water.”

Myth: Over-the-counter water pills are the same as what you’d get from your HCP

Fact: Diuretics from the drugstore shelf are different than the medications that an HCP would prescribe. Prescription water pills are much more potent than their OTC counterparts and should only be used for the conditions they’re meant to treat. 

“Water pills come in different varieties,” Brengman explains. “Some are prescription medications given by a physician for a specific illness or disorder—most commonly, high blood pressure and congestive heart failure. Obesity is not one of the conditions that we generally treat with water pills. Over-the-counter water pills are mostly caffeine or herbal remedies. Caffeine by itself is a very weak diuretic, and herbal remedies are unregulated and can have dangerous interactions with other medications.”

Myth: Water pills are a good option for permanent weight loss

Fact: Taking a water pill may temporarily move the needle on the scale, but the change won’t last.

“Losing water weight is not the same thing as losing weight,” says Brengman. “Just because we lower the number on the scale by three or four pounds, that doesn’t mean we’ll see the health benefits of losing weight, because we haven’t altered the amount of fat in the body. It’s not true weight loss, and its effects are temporary.”

Myth: Water pills won’t interfere with other medications

Fact: Water pills definitely can alter the way other medications work in your body, which can cause harmful and dangerous side effects.

“Water pills can interact with other medications, especially heart medicines,” Brengman explains. “Heart medications affect our blood chemistry, and when you alter the blood chemistry by taking a water pill, you can alter the effects of these medications. Other medicines are also eliminated from your body by urinating them out. If you are causing the body to urinate more, the level of the medicine in the blood can get low. That can affect the underlying disease that’s being treated.”

The bottom line?

Don’t take water pills for weight loss.

“While it’s tempting to take that pill to fit into the dress that’s one size smaller, or the pants that are one size smaller, it’s probably not worth the risk of the side effects that can occur,” says Brengman.

Instead, for healthy weight loss that lasts, talk to your HCP about starting a program that focuses on eating well and exercising. According to the Centers for Disease Control and Prevention (CDC), to lose one or two pounds a week, you’d need to cut out 500-1,000 calories per day from your diet. And to maintain that healthy weight, they recommend being physically active most days of the week for about 60 to 90 minutes.  

True weight loss means committing to a healthy lifestyle, not popping a (sometimes dangerous) quick fix.

Article sources open article sources

Mayo Clinic. Diuretics. August 13, 2021.
Cleveland Clinic. Diuretics. October 1, 2021.

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