fbpx Skip nav to main content.
Home > Dr. Megan’s Blog > Water Weight Gain – How Prednisone Causes It

Water Weight Gain – How Prednisone Causes It

Water Weight Gain – How Prednisone Causes It

You know that scene from the movie, A League of Their Own, where the drunk coach stumbles into the bathroom and pees FOREVER? It seems like something only a drunk, enhanced by magical audio and video editing, could accomplish.

But when you’re on prednisone, suddenly anything is possible. Water weight gain happens in a mysterious and somewhat counter-intuitive way.

Watch now!

Water Retention

While taking prednisone, you can retain water like the best of ‘em. You can gain several pounds of water in a few days, then in one rushed trip to the bathroom lose what feels like a whole pound!

Urine Output

When I was on prednisone, days would go by when my urine output was normal. Then one day, even though my water intake had not changed, that day there was significantly more urine. Like the girls on the baseball team counting the time it took the coach, played by Tom Hanks, to finish peeing, it was taking so long I thought I should time myself!

Prednisone vs. Pregnant Zone

Fun Fact: The auto-generated captions of the videos I create often translate “prednisone” into “pregnant zone”! Almost too true!

Having been pregnant several times and experienced the water retention typical for a mother creating extra blood to support a growing baby, I noticed that prednisone water retention is different. Pregnant mamas can attest to water and swelling pooling on their ankles, and overall swelling everywhere in the body. In the last trimester, my wedding ring wouldn’t fit. Heck, even my nose was “pregnant” with swelling. The best part? As soon as the baby appears, the pregnancy water weight disappears.


Prednisone doesn’t play fair like that. It doesn’t distribute the extra water throughout the whole body. Prednisone dumps the water and redistributes fat in the least flattering manner:

  • rounding out the face into a “moon face”
  • ballooning the stomach so that even men look pregnant
  • piling on the shoulders so you resemble a buffalo
Buffalo crosses the road at Yellowstone National Park. Prednisone causes weight redistribution to look like a buffalo hump.


Why does prednisone cause water weight gain?

The molecule of prednisone resembles the hormones (such as cortisol) in your body that regulate your water and sodium (salt) balance.

Prednisone Chemical Structure

Prednisone also looks like the hormone aldosterone, which is the hormone in our bodies that regulates water. Aldosterone’s job is to make sure we have enough water and salt in the right balance. Aldosterone makes you pee or makes you thirsty. Prednisone interferes with the gentle balance of the Renin-Angiotensin-Aldosterone System leading to bloating, swelling, joint pain, and weight gain. New evidence shows that prednisone might bind to the mineralocorticoid receptor, which is normally only for aldosterone, more than the glucocorticoid receptor, which the body uses for cortisol. This means there may be more side effects from aldosterone-like effects than originally thought.

Prednisone mimics aldosterone causing water weight gain.
Aldosterone Chemical Structure

At low doses, prednisone doesn’t mess with the water and sodium much. The higher the dose, the more the molecule interferes with your body’s normal water balancing mechanism, mimicking aldosterone. That’s why the higher dose you take, the more likely your face will round out and you will gain water weight.

Your water balance normally works by:

  1. Telling you that you’re thirsty
  2. Making you crave salty food
  3. Telling your kidneys to get rid of a bunch of water through urine

…depending on which aspect of the water system is out of balance.

Since prednisone interferes with this system, you might crave food, such as salty food, more than you usually do. And then one day your water balance system might finally catch up and tell your kidneys to get rid of all this extra water, and you feel like Tom Hanks. But prednisone is powerful, so it takes over and your body forgets to keep it in balance like it normally would.


What Can I Do?

Prednisone is hijacking your water system, artificially making you crave salty food. It may seem impossible, but to naturally limit weight gain from prednisone, you need to:

  • limit salty foods
  • drink lots of water (instead of carbonated beverages)


Hidden Salt

Salty foods can be deceiving. Many salty foods don’t seem like they would be salty or high in sodium, but are disguising as otherwise healthful foods.

  • Canned foods, even vegetables.
  • Frozen entrees, even with “lean” or “health” on the label.
  • Jars of marinara sauce.
  • Preserved meats.

This is why it’s best to eat foods as close to the dirt as possible; the fresher the better.

The Water Will Go Away

Like giving birth, once you finally stop taking prednisone, the water weight will go away. But not as quickly as with delivering a baby. The hormones that prednisone hijacks take a while to adjust to working on their own again. This is another reason to never stop taking prednisone “cold turkey,” because prednisone must be carefully tapered slowly, allowing the body to restart its own systems.

What unexpected side effect of prednisone have you experienced?

Get Nutranize® Zone™  to feel like yourself again while on Prednisone!

Dr. Megan Milne, PharmD, BCACP

Dr. Megan Milne, PharmD, BCACP, is an award-winning clinical pharmacist board certified in the types of conditions people take prednisone for. Dr. Megan had to take prednisone herself for an autoimmune condition so understands what it feels like to suffer prednisone side effects and made it her mission to counteract them as the Prednisone Pharmacist.

Related Posts