fbpx Skip nav to main content.
Home > Dr. Megan’s Blog > Prednisone Half-Life: When Will it Be Out of My System?

Prednisone Half-Life: When Will it Be Out of My System?

Prednisone Half-Life: When Will it Be Out of My System?

What is Prednisone’s Half-Life?

What in the world is a “half-life,” and why does it matter when you’re taking prednisone? In this article, you will learn exactly what a half-life is, why it matters, and about the lingering effects of prednisone, even after the half-life.

Watch now!

Prednisone Half-life

Prednisone’s half-life is between 2-3 hours.

What is a Half-Life?

Like most people, you’ve probably never heard of a half-life before. Simply put, a half-life is how long it takes for half of the effects of something to be gone. For example: if an atomic bomb goes off, how long will it take for half of the radiation to disappear? The radiation is an effect of the atomic bomb, and scientific calculations are done to figure out how long it takes for half of the radiation to disappear. 

Be this as it may, while it is important, I am sure that what you really want to know is, when am I going to feel better? This is a valid question.

Prdnisone Half life

The Half-Life Calculation

There is a certain calculation that is used when trying to figure the half-life of prednisone. When you’re calculating, it’s only about 5.5 half-lives that you need to count until you can say it’s pretty much close to zero of the molecule left in your body. If we multiply 3 (the upper limit of the average half life of prednisone) by 5.5, we get 16.5. If we want even closer to 100% of the molecule gone, we can go to the full 6 half-lives, and that is 18 hours.

Therefore, after roughly eighteen hours, your body is free of the prednisone. 

When will Prednisone be out of my system? 18-24 hours after you last took it.

One may ask, “what difference does this make?” I mean after all, you’ve taken prednisone, and eighteen hours later, it’s out of your system, right? Well, somewhat. There are many factors that have an effect on this. If you’re taking prednisone at 8:00 AM versus 8:00 PM, that changes how much it is active in your system during different times of the day.

For example, if you are taking prednisone, but you experience insomnia as a side effect, you would want to be taking it as early as possible. I would suggest around 5:00 or 6:00 in the morning, so that it could wear off completely by the time you need to fall asleep at night. That can help you get a more restful night’s sleep.

When and How Should You Take Prednisone?

This question may vary slightly from person to person. Your doctor will evaluate you and your situation and see what path is the best for you. 

Some doctors will prescribe prednisone to be taken every other day. So, you’ll take 5 milligrams on Monday. Skip Tuesday, take 5 milligrams on Wednesday. This could be happening because of the half-life. This will also help combat some of the side effects.

It’s giving your body a day off to hopefully help your adrenal glands recover. While there isn’t much research backing this strategy, it is a strategy used to help you cope better and help you recover from the prednisone side effects more effectively. 

Prednisone Side Effects Like a Tornado

It is no surprise that experiencing prednisone side effects is like a whirlwind. In fact, these side effects are comparable to a tornado. How so? For example, let’s pretend that prednisone is an actual tornado and the illness you are taking it for is a building.

Now, the tornado comes through and destroys the building (your illness). It’s great. You didn’t want that anyway, right? However, it causes a multitude of collateral damage (the side effects). 

The landscaping, other buildings, and actual people are always affected by a tornado–even if it destroys a building that isn’t wanted or useful. A tornado might be a great way to get rid of a building. 

The landscaping can be comparable to other issues that occur within your body due to the side effects, and your body can be compared to the building, which is the physical results that are visible to people due to the prednisone side effects (moon face and weight gain). 

Therefore, even when prednisone is out of your system, the collateral damage is still there. Just like in a real-life tornado, it is going to take time to repair and rebuild. Prednisone side effects do not instantly go away.

prednisone side effects

However, there are exceptions. For example, if you experience an increased appetite, your appetite may return to normal after you stop taking it. 

Can I Still Have Side Effects if Prednisone is Out of My System?

This is a very common question. A Prednisone Warrior wrote me asking:

It’s been a year since I got off Prednisone… However, it dramatically affected my brain, which has not much gone away, unfortunately.

So, I wonder if there are some permanent side effects of that horrendous medicine. I’ve never gotten back to where my head was before I started it.

I’ll NEVER take it again!

I replied to her, informing her that there are some permanent side effects of prednisone. Check out this link to learn more. 

Usually, the brain eventually heals from the effects of prednisone. Unfortunately, the time it takes is unpredictable. Read here to learn more.

This patient was relieved to find out it was the prednisone having this effect on her brain. She responded to me stating:

My lovely and caring PCP told me that since it was “no longer in my body” I wasn’t having side effects, but I felt I was!!

I have been concerned about what was going on in my head, and when I asked, you responded that it was a “tricky question,” but I know I’m still experiencing stuff I knew I didn’t before Prednisone.

Thank you so very much Dr. Megan!!!

When Does Prednisone Anxiety Go Away?

As we saw with the Prednisone Warrior above, psychiatric side effects–anxiety, and mood changes–might not go away quickly. Why is this? 

The reason this is is because while the actual drug is out of your body, the effects are still there. Remember the tornado analogy from earlier? It is something like that. Prednisone changes things in your body, from your brain functioning, to your adrenal glands, to all over– these side effects can be very long-term.

For some people, it can take up to a year to really recover back to their formal adrenal-sufficient self. So, if you have stopped taking prednisone and are still noticing these side effects, be patient with yourself. 

Talk to your Doctor

talk to your doctor-prednisone


If you are feeling terrible after taking prednisone, you need to talk to your doctor. You need to say, “Hey, I don’t feel so good. You took me off the prednisone, but I still need some help. Can you help me?”

Talking to your doctor about it is imperative because you shouldn’t feel awful after taking prednisone. You should be able to have the dose taken down slowly enough, so that you can recover properly. If you have any other real burning questions behind prednisone half-life, let me know below. I would love to know what those are, so I can answer them in either comments or in a future video.

In addition to this, if you need help recovering from prednisone, I have a Prednisone Checklist, and I will link that below for you. It has ways to cope with prednisone while you’re taking it and to help you recover after you’ve stopped taking it. 

Don’t forget your checklist by signing up below!

Free Prednisone Checklist

  • This field is for validation purposes and should be left unchanged.

Check out these other articles about taking prednisone below: 

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