Did you know one of the worst side effects of going low carb is bad breath?

Even if you’re crazy about your dental hygiene, start a ketogenic diet and you may find yourself struggling (and losing!) the fight against keto breath.

Why do you suddenly have dragon breath when your body’s looking on point and you’re feeling amazing otherwise?

Will keto breath go away on its own or will you have to jump keto ship just to speak to your friends and family members in close quarters again?

To help you love everything about being on a keto diet, today we’re solving this embarrassing problem the easy way by dishing:

So let’s start by learning what your crew’s too nice to say to your face.

What Is Keto Breath?

Is keto breath the same as old high school math teacher bad breath?

Bad breath, also known as halitosis, is typically characterized by unpleasant smells coming from your mouth region. It’s a common symptom of ketosis, and usually the causes of bad breath include[*]:

  • Poor dental hygiene
  • Dental problems like gingivitis
  • Certain foods (like onions, coffee and garlic)
  • Tobacco products
  • Specific health conditions
  • Dry mouth
  • Oral infections
  • Medications
  • An overgrowth of bad gut bacteria

Though it’s not fun, you’ll want to visit your dentist and doctor to rule out a few of these issues if you’re experiencing less than fresh breath.

Unlike the general war of smells from leftover food particles and bacteria in your mouth that is halitosis, keto breath is very specific.

It’s been described as a pungent, acidic and fruity smell.

Though some say it’s more of a metallic taste in your mouth.

And others claim your breath (and urine) smell more like nail polish remover or even varnish.

One Redditor was even accused of day drinking since their keto breath smelled like strong vodka[*]!

All kidding aside, the silver lining to keto breath is that it means you’re actually in ketosis.

There are three main reasons why your breath may be a little funky on a ketogenic diet:

  • Acetone is produced as a ketone and extra ketones need to leave your body.
  • Ammonia generated via protein digestion also needs to bounce.
  • Dehydration causing dry mouth compounds halitosis and keto breath.

Let’s talk about how each of these is to blame for ketosis breath now.

Acetone Produced Via Ketosis Causes Keto Breath

To comprende this explanation for keto breath, you have to fully understand how keto works first.

When you switch from the Standard American Diet (SAD) of eating close to 300g of daily carbs to a ketogenic diet of less than 25g of daily net carbs, your body will stop using glucose for energy and start to use fat.

Being in ketosis is when your body kicks into fat burning mode, using fat for fuel instead of sugar.

In order for your body to use this type of fuel, your liver produces ketones, which is where the word “ketosis” comes from.

Your body produces three main types of ketone bodies:

Your body makes a small supply of ketones even if you’re not in keto. But once you switch, your liver goes into overdrive ketone production.

The result?

Sometimes you body has too many ketones.

Ketones are harmless and when you have an excess, your body just lets them pass through via your urine or your breath.

As ketones circulate in your blood, they interact with the air in your lungs before being released from your mouth.

Since acetone is an ingredient in nail polish remover, that could explain the strange, sweet smell of your breath and pee.

Studies show besides testing for acetoacetate in urine, acetone on your breath is a proven sign of being in ketosis[*].

While switching to keto will cause this acetone release, not getting your macros right may trigger the next possible reason for your keto breath too.

Eating Too Much Protein Can Also Cause Keto Breath

A standard ketogenic diet (SKD) relies on a breakdown of daily calories from macronutrients like so:

  • 70–80% of your calories come from fat
  • 20–25% from protein
  • 5–10% from carbs

In an effort to cut carbs, many new ketoers eat too much protein instead of eating more fat.

Or they don’t calculate their macros correctly and eat much more protein than they should — especially women who need a lot less protein than men.

Chock up too much protein than your body can use, however, and you’ll come face-to-face with your smelly keto breath.  

See, your body naturally produces ammonia when it breaks down proteins[*]. But just like acetone, that extra ammonia gets released through your urine and your breath.

If you’ve ever smelled ammonia before, you know it’s super strong and chemical-like, similar to many cleaning products. Ammonia is so powerful it’s not even recommended to inhale — yikes!

So it’s no wonder you have very strong breath and urine when your protein levels are too high.

You’ll want to stick to the low end of the protein scale if you’re not building muscle or exerting yourself with high physical activity every day.

Now let’s round everything out with the last possible culprit for your keto breath.

Dehydration Can Cause Dry Mouth and Compound Keto Breath

A low carb diet can cause dehydration, which is when you take in less water and fluids than your body uses or expels.

When you’re chowing down on carbs, your body holds the excess glucose you don’t use as glycogen stores in your liver and muscles.

Any time you run low on glucose for energy, your body turns to these reserves.

But for every gram of stored glycogen you have in your body, you’ll also find three or four grams of water attached.

This is why you lose so much water weight in the beginning of keto; your body goes through these glycogen stores and that releases all that water from your system.

While you’re not losing fat, per se, you will feel slimmer, less bloated and fit in your clothes better as a result of your body flushing out this extra water.

Here’s the bad news: once all these glycogen stores are purged, your body doesn’t have a way of holding on to water when you’re in keto.

Ketoers are extra prone to dehydration — especially when they’re first starting out — because they’re not used to constantly rehydrating and giving their bodies the water it desperately needs.

What happens when you don’t have enough water?

You become dehydrated, which can lead to[*]:

Though all these are serious, that last one is important when you’re dealing with bad breath.

A dry mouth produces less saliva, which is responsible for getting rid of odor-causing bacteria hanging out in your mouth.

If you don’t have enough saliva to eliminate the bad bacteria, they multiply. Similarly, when you don’t give your body water to flush away excess ketones, they build up and stick around in your mouth.

Now you see how the situation compounds into chaos for your breath.

So can you prevent keto breath?

Or is it a side effect of ketosis and low-carb dieting you’ll have to live with forever?

How To Fix Your Keto Breath

Keto breath

You’re making amazing strides for your health by being on a keto diet. So you shouldn’t let a small issue like bad breath derail your achievements.

Try one or all six of these ways to tame the beast that is your keto breath and thank us later:

#1. Boost Your Oral Hygiene Game

Like we said earlier, poor oral hygiene isn’t the same as keto breath, but a dirty mouth doesn’t help the situation and makes everything way worse.

Besides brushing your teeth twice a day — and maybe after every meal if you can’t stand your keto breath — consider adding these additional dental health practices to your routine:

  • Flossing is a pain, but will get rid of small food particles between your teeth which will normally rot there and cause bad breath.
  • Tongue cleaning with a tongue scraper is almost twice as effective at removing bacteria as regular brushing because your tongue is like flypaper for germs[*].
  • Oral rinses designed for dry mouth may contain antibacterial agents and help lubricate your mouth to prevent bad breath and dry mouth all in one.
  • Oil pulling with coconut oil, which is naturally antibacterial, will attract leftover food particles and bacteria hiding in your mouth. When you spit, you eliminate all this nastiness and deep clean your teeth, tongue and gums.

#2. Recalculate Your Macros

Did you know you should recalculate your macros every time you lose a decent chunk of weight or decrease/increase your regular physical activity levels?

It’s true; your body quickly adapts so you’ll need to be one step ahead if you want to lose weight.

As we’ve learned, having too much protein in your diet can lead to keto breath by way of excess ammonia.

But so can having too few carbs.

That’s why you’ll need to take a scientific approach and experiment to see which one is at the root of your keto breath.

So try this 3-step process to see if your keto breath improves while staying in ketosis:

  • Recalculate your macros using the PK Keto Macro Calculator to make sure you’re actually in optimal ranges for ketosis and weight loss for your body.


  • Select the Standard Ketogenic Calculator for a classic ketogenic diet of 75% fat, 20% protein, 5% carbohydrate (recommended)
  • Select Specialized Macronutrient Calculator to input specific amounts of fat, protein, and carbohydrate

Choose Calculator Type*

Unit of Measurement*

Your Details*





Activity Level

Choose what describes you best

Calorie Intake Goal


  • Input "0" to maintain your bodyweight
  • Input a surplus percentage for weight gain
  • Input a deficit percentage for weight loss


  • 5-10% is a small deficit
  • 10-20% is a moderate deficit
  • 20-30% is a large deficit
0% Changed

Advanced Fields

Input Your Body Fat %

Input Your Protein Ratio

Guide to picking your protein ratio

  • To maintain muscle, leave protein ratio between 0.60 to 0.80 grams per lb of lean body mass (1.3 to 1.7 grams per kg LBM)
  • To gain muscle, the protein ratio should be between 0.8 to 1.2 grams per lb of lean body mass (1.7 to 2.3 grams per kg LBM)

Input Your Total Carb Intake

Input the grams of carbs you want to consume on a daily basis

  • Start at the low end of you protein intake and turn to healthy fats like avocados and macadamia nuts before adding more protein to your diet. This simple switch from a high protein diet to more fat should cut the amount of excess ammonia, which should lead to fresher breath.
  • Increase your carb intake slightly and slowly. If you’re currently at 20g of net carbs per day, try bumping up to 25g to see if you notice any changes. This should reduce the amount of excess ketones you have floating around so less of them are forced out via your bad breath.

If your keto breath goes away but you notice you’re not losing as much weight, you can either cut back the carbs or increase your physical activity to burn off more of what you eat.

If that fails to work, make sure to cross off these 10 reasons why you’re not losing weight in keto.

#3. Drink More Lemon Water

You know the old adage about drinking half your weight in ounces of water each day?

While that’s never been scientifically proven, you do need to drink more water when you’re in ketosis because your body will not have those glycogen stores to hold onto water like it used to[*].

Besides combating dehydration, water also has another benefit: washing away the ketones on your breath and diluting the smell of those you pee out.

Water will also keep you from experiencing dry mouth, which we know amplifies keto breath.

If using the “eight glasses of water a day” rule helps you remember to drink and track your water intake, by all means keep using it.

Just don’t drink too much water without replenishing your electrolytes or you’ll risk flushing all those away — and that’s a big problem.

Lemon water will not only freshen your breath, lemons have antibacterial properties to help kill off lingering odor-causing germs in your mouth too[*].

If you’re feeling fancy, go ahead and add stevia to your lemon water for a carb-less faux lemonade.

#4. Skip Your Standard Mints and Gums

You may have never thought to check the label on the gum you keep in your purse or look up the nutrition facts for the mints you stash at your desk, but you’ll need to when you’re in ketosis.

These are full of sugars and hidden carbs and will kick you out of keto faster than you can get back in.

#5. Be Careful with Sugar-Free Alternatives

You may be ditching your usual gum or mints, but that doesn’t mean sugar free alternatives are the better option.

These are usually packed with sugar alcohols and artificial sweeteners, which are not zero-carb and can both raise your blood sugar and spike your insulin levels[*].

Stay away from anything containing:

  • Sorbitol
  • Maltitol
  • Xylitol
  • Isomalt
  • Aspartame
  • Sucralose
  • Saccharin
  • Mannitol
  • Lactitol
  • Polydextrose
  • Hydrogenated starch hydrolysates

Ingesting these sugar alcohols and sugar alternatives has been associated with increased sugar cravings, migraines and extreme gastrointestinal discomfort, such as[*]:

  • Bloating
  • Cramping
  • Flatulence
  • Diarrhea

There’s a better way to freshen your breath naturally sans painful side effects…

#6. Try All Natural Breath Fresheners

Before the age of commercially-made mints and gums, the mint plant was the It breath freshener of medieval Europe. People chewed whole leaves to sweeten their breath and mixed the mashed leaves with vinegar to rinse their mouths[*].

These holistic foragers also invited other fragrant herbs and spices to the fresh breath party, including:

  • Parsley
  • Cinnamon
  • Clove
  • Marjoram
  • Cardamom
  • Rosemary
  • Sage
  • Fennel seeds

You can find all-natural extracts of these plants to spray in your mouth at health food stores, but you can also chew on them yourself or add these herbs to your fave keto recipes.

Feeling extra productive?

Why not create your own homemade mouthwash or breath spray?

Using high quality, food-grade essential oils containing any of those herbs, follow this natural breath freshener recipe:

  1. Grab a spray bottle or mason jar and clean it well.
  2. Add three drops of an essential oil of your choice (either one flavor or a combo of flavors) to your container.
  3. Fill the rest of your vessel with ¼ cup vinegar and ½ cup distilled water.
  4. Shake to combine.
  5. Spray in your mouth or take a swig, swish it around and spit out to get rid of bad breath bacteria.

Follow all six of these tips and your keto breath will disappear faster than your tax refund. But you should also take comfort in knowing…  

Keto Breath Doesn’t Last Forever

While some lucky ketoers never experience the humiliation that is keto breath on a first date, others struggle with it the very first week.

The good news is keto breath eventually rides off into the sunset and out of your life.

By combining a few of these techniques and sticking to your ketogenic diet for a few months, your body will naturally adapt to your low-carb way of eating.

Your body will stop producing so many extra ketones and find a healthy balance around the end of your first fully fat-adapted month. With fewer excess ketones squirming their way out, you’ll have better breath.

Now there’s no reason for abandoning your ketogenic diet — especially if you’ve noticed awesome results thus far (sans bad breath, of course).

Another upside to keto breath is the fact that you must be doing keto right in order to be saddled with this problem, so kudos and pat yourself on the back for that!

While keto breath isn’t sexy, it does mean you’re well on your way to reaching your weight loss and body goals — and that’s definitely worth celebrating.


Make Keto Easier

Lose weight and obtain optimal overall health — in an easy and natural way.


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