Does Ketosis Cause Body Odor? [+My Experience]

  • Author: Kara
  • Date: November 10, 2022
  • Time to Read: 10 min.

Does ketosis cause body odor? Yes, and no. Nobody wants to be that person in the office that people are keeping a wide birth of. So if you have body odor, or the thought of getting it is putting you off starting the keto diet, we’ve got everything you need to know. Plus, I will take you through my (embarrassing) experience with keto BO!

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In this article, we will take you through everything you need to know about ketosis and BO.

We will take you through why you may experience BO issues when you start keto, what causes it, how long it’s likely to last, what you can do about it, and finally how to avoid it.

I will also take you through my personal (embarrassing) experience of BO on keto, and what I did about it.

Keto Body Odor

Where Does The BO Come From?

Your brain loves being in ketosis, and ketones are a great fuel source for it. Fat for energy is its preferred mode for optimal performance. When ketones become the brain’s main fuel source, we often feel more energized, and our concentration levels increase, making us more productive and clear-headed, it’s not all about the weight loss.

As we know, cutting out carbs, or severely reducing your carb intake, makes the body consume stored fats, which is where the weight loss occurs.

When we are on keto, or for some, a low-carb diet, our livers start to convert fats into acetate, which then turns to acetone. This process produces smells that have a distinct and pungent aroma that is not very pleasant.

It is not especially strong smelling in all people that are in ketosis, so it isn’t something to panic about.

Not all people are able to smell acetoacetate so you will not be clearing out any rooms when you enter them during ketosis.

What Are the Types of Body Odor While in Ketosis?

As we all know, keto is one of the most effective ways to lose weight fast. In fact, many people use it to get rid of stubborn belly fat while doing little exercise (myself included initially).

Unfortunately, many people have heard that body odor is one of the unfortunate side effects of this way of eating, and it can discourage them from trying it out for themselves. Bad breath is another side effect.

Does Ketosis Cause Body Odor

I get it, nobody wants to be the person that others keep a wide birth from!

Normal body odors are caused by bacteria, fungi, and sweat.

A standard level of personal hygiene is more than enough to keep these odor causes at bay.

With habitual showering or bathing, and deodorants, most body odors are eliminated, leaving you smelling clean and fresh.

How Is Ketosis Body Odor Different From Regular BO?

As we have discussed, when you’re in ketosis you’ll be producing more ketones and a few byproducts like acetone in your body, these can be secreted through urine, breath, and sweat.

This does not automatically make you smell, but increased levels might slightly elevate your body odors.

There are many factors that will determine your level of body odor.

The main one is body chemistry.

Skin pH neutrality allows the growth of bacteria on the skin, which can potentially lead to body odors.

When you apply something like a skin toner with an acidic pH before applying your deodorant, your skin’s pH level will be too low to support the expansion and growth of bacteria that cause bad odors.

This doesn’t directly come from keto and is part of a wider range of conditions that range from individual body chemistry to environmental factors.

So, whereas regular BO is from unhygienic habits, keto BO is to do with the change in chemicals in your body

What Causes Body Odor When You Are in Ketosis?

When you are in ketosis, your body produces ketones, which are a byproduct of burning fat. Within these ketones is a chemical called acetone. As you get deeper into ketosis, your ketone levels increase. In turn, this increases the amount of acetone being produced. It is this acetone that you can smell when you are entering ketosis.

We can think of the process of ketosis, as helping your body to release more acetone than usual.

If acetone sounds familiar, it is because it is an organic compound that is often found in nail polish remover. We can therefore say this smell is caused by the breakdown of fatty acids.

If you have ever used acetone for your nails, or DIY, you will know that it doesn’t smell the best.

So, what causes body odor when you are in ketosis?

Well, the main cause is that you are releasing more of these acetone compounds than usual, and your body is not used to this. 

The acetone will then interact with the normal bacteria found on your body. This reaction between the acetone and the microbiomes releases the smell that we perceive to be body odor.

The combination of these factors can give you the impression that your body odor is worse than usual, but this is probably not the case.

Keto Body Odor: How Does It Smell?

Keto body odor is most commonly described as smelling metallic, or of rotten fruit (slightly sweet fruity smell). The funniest description I have seen was on a Reddit thread where the author said that their body odor “kind of smells like fat is soaking into my sweat“.

There is an irony in this, as that is kind of what it is.

For me, it is an unusual odor, but it can be quite a pungent smell.

Understanding Why I Smell While on Keto Diet

With any new diet, or way of eating, there is a period of experimentation and learning, which will make your weight loss journey unique to anyone else’s.

You will find what works for you, and what doesn’t. If you find that you are noticing that you smell differently from what you normally would, then this might not necessarily be a bad thing.

Different isn’t always bad, so if you notice that you are uncomfortable with how you smell, then you should speak with someone close like a trusted friend or spouse, and ask them if you are as bad smelling as you think.

Should I be Worried If I Don’t Smell on Keto?

No! You should not be worried if you don’t smell on keto. Entering ketosis will be a different experience for everybody. Some people will get body odor when going through this transition. Other people will not have this reaction at all.

Read on to find out my experience of transitioning into keto, and when I did and didn’t experience body odor.

How to Prevent the Odor On A Keto Diet?

The easiest way to ensure that you don’t accumulate the odor causing compounds in your body (i.e wash well), and stay hydrated.

This means drinking water consistently throughout the day, every day – with no exceptions.

This will help you to flush out the toxins that are accumulating in your system, this will reduce their build up and emanation from within your body.

It is important to remember that these chemicals are natural, and that they are produced in everyone’s bodies, but because of the way that keto works, you will have an increased amount of these compounds.

This doesn’t mean that there is anything wrong with you, it just means that your body is working like it is supposed to under those conditions.

Keto Body Odor Top Tip

Another top tip that I found is to wipe your armpits with tea tree oil before adding on your deodorant. Yes, you smell a bit like tea tree!

Tea tree oil is a natural antiseptic

I don’t know whether it was psychological or not, but it seemed to help me.

What’s even better is that I carried a small bottle of this around in my bag with some wipes, and would nip off to the loo and wipe down my arm pits if I felt like they were getting a bit too smelly!

Gradually Enter Ketosis

Another top tip people offer is to gradually decrease your carbohydrate intake over a longer period of time, so you enter ketosis more gradually.

This is supposed to give you time to adapt to the increased acetone and the excretion of such. It is hard to know whether this works or not, or whether the people who have embarked on keto this way, would have never had body odor in the first place.

Embrace It

This may seem like a really strange thing to say – none of us want to have body odor. But if I’ve learned anything on this keto journey, is that it will change your life forever, in so many ways, and all for the better. 

Embrace the few days, to a couple of weeks that you may experience this, and wear it with pride. 

All that it means that that your body is detoxifying, and that you’re about to embark on an amazing journey in life.

It will soon pass.

When Am I Likely To Notice Keto BO?

Keto body odor will normally kick in 3 days after entering, and maintaining ketosis. There is nothing to be concerned about if you do not get body odor. It does not mean that you are not entering ketosis, or that you’re not doing keto right. Everybody will react in a different way to entering ketosis and becoming fat adapted.

How Long Will The BO Last?

For me, keto body odor lasted 3-5 days maximum. The absolute worst I have heard is somebody struggling with this for up to two weeks. If you read around the internet, the longest I have seen anybody say they have struggled for is 3 weeks

Will The BO Last All Of The Time I’m On Keto?

No, keto body odor is short-lived, from a few days to a few weeks maximum. If you remain on keto, this will soon go away, and you won’t have to worry about it again. The only time you will have to worry about this, is if you cheat on keto, and kick yourself out of ketosis. 

Will I Get BO On Keto every time I come Out Of Ketosis?

No, you will not necessarily get keto BO every time you fall out of ketosis, and get your body back into ketosis. There will be a number of factors that should be considered, such as how long you have been out of ketosis. The longer, the more that the body will not be used to the levels of acetone from ketones.

My Keto BO Experience

Ok, I did say I would share my experience of body odor on ketosis. So here we go.

When I first started eating a keto diet, I had none of the common side effects.

The main things for me were that I felt very thirsty, and had a few nights of restless sleep.

The first was easy to deal with, and the second, soon passed. It was as though I was acting out my dreams and would wake up shattered.

Ha! I thought. I’m superhuman, I didn’t get any of the side effects that people were talking about all over the internet.

I felt smug, I transitioned onto keto with no issues at all and soon started feeling all of the benefits of keto.

After being on keto for over a year, life got busy. I was thrown several curve balls. Rather than sticking to keto, as I knew it was what worked for me. I started eating carbs again. I was working away a lot, and they were easy to get hold of.

Anyway, after a few months of eating carbs again, I was feeling rubbish. Not sleeping well, no energy, putting on excessive weight.

I felt terrible.

So, I knew exactly what I needed to do to stop feeling like this. I needed to become a keto eater again.

I cleared my cupboards out of all of the carb-laden food, and started again.

Having had no symptoms the first time, I didn’t expect to have any symptoms the second time – why would you do the same thing and expect a different result?

Oh, how wrong I was!

This time around, I ended up with keto breath, keto body odor, and mild headaches. Ironically, no sleepless nights though.

On day three of being strict keto, I thought I whiffed a bit of BO. I didn’t really think anything of it and assumed I’d just been rushing around too much.

The next day at work, I was in a big meeting. I’d not even considered having BO. I reached across the table to get the water jug, stretching my arm in front of one of my colleagues.

My colleague noticeably flinched and moved back…as if that wasn’t bad enough, they’d moved back so quickly that they had tipped their chair back, falling off it.

Well, that just drew attention to the whole situation.

Our boss asked what had happened, I looked at my colleague pleadingly not to announce that the smell of my armpits had tipped them over the edge.

My colleague made eye contact with me, saw the pleading in my eyes, and made an excuse about the chair catching on the flooring.

I have never been so grateful in my life.

To this day, we have never discussed that incident, nor will we!

There you have it, my embarrassing keto body odor experience – have you had anything similar? Share it with the community in the comments below.

We can all comisserate together.

Keto Body Odor: Closing Off

In conclusion, ketosis causes a number of unpleasant side effects, including body odor. However, these symptoms usually disappear after a couple of days, to a couple of weeks. In fact, many people report that their body odor actually improves the longer they’re on the diet. This is because the ketones themselves help cleanse the system, which means fewer bacteria and fewer toxins floating around.

As such, it’s possible that your body odor will improve over time. There is no guaranteed way to prevent yourself from getting keto body odor, but if you have any top tips, please let us know below.

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