I stumbled upon many different posts recently about xylitol. These posts always contain the same questions/comments:

  • Is it safe?
  • Xylitol gives me diarrhea!
  • Is it Bulletproof?
  • Will it spike my blood sugar?
  • Will it harm the bacteria in my digestive tract?
  • What should I use as the source of my xylitol?
  • Is it genetically modified?

In this blog article, I will answer all of these questions and more to help you decide if its occasional use is right for you!

So What is Xylitol?

Xylitol is a five-carbon sugar alcohol also known as a polyol. Your body produces the polyol on a daily basis (about five to ten grams) from the carbohydrate metabolism of the food you eat.1 Your body also produces the enzymes xylose reductase and xylitol dehydrogenase to metabolize it properly. Dogs cannot metabolize the polyol properly and small amounts of it can be lethal. Keep it away from your pets!2

Xylitol is considered to be as sweet as table sugar and has fewer calories. Xylitol is either sourced from corn or birch trees.3 I prefer that it is sourced from birch trees because there is no chance of it to be produced from GM (genetically modified) corn. GM free made from corn does exist, but because of possible cross contamination, I would avoid it.

Recommended brand of xylitol:

Positive Aspects of Xylitol’s Use

Optimal oral health

I recommend the use of xylitol containing toothpastes and mouthwashes for optimal oral health. Chewing xylitol containing gum on occasion can also be good for dental health. Europe has been using xylitol to prevent dental caries instead of fluoride with great results for years! Some bacteria are not able to metabolize it properly. Xylitol inhibits the opportunistic growth of Streptococcus mutans (one of the main causes of tooth decay) in the oral cavity. Xylitol inhibits the bacteria’s metabolism and limits its polysaccharide production (important for the formation of biofilm) therefore rendering it defenseless against your immune system. Plaque that is visible on teeth is a formation of biofilm. If you suffer from SIBO, I recommend that you use xylitol toothpaste or mouthwash only, rinse your mouth out thoroughly after every use, and try not to swallow any as much as possible.4 5 6 7

Reducing ear infections

Studies have shown that increased intake reduces the chance of getting middle ear and sinus infections. Chewing gum with the polyol has been shown to reduce S. pneumoniae and H. influenzae populations, which are known for causing upper respiratory infections and ear infections.8

Fighting diabetes

Xylitol is as sweet as table sugar and has about 50% less calories. Xylitol also appears not to spike blood sugar, which makes it perfect for diabetics.9

Possible bone remineralization

Studies of supplemental xylitol in animals have shown both increased tooth enamel remineralization and increased bone density. Because of this, xylitol might be useful in combating osteoporosis.10

Negative Aspects of Xylitol’s Use


The intake of large amounts of the sugar alcohol causes diarrhea. A huge intake of the polyol might overwhelm the body’s ability to break it down, causing irritation to the intestinal tract. This irritation is what causes the diarrhea. I recommend that children intake no more than fifty grams of xylitol a day and most adults should take in no more than 100 grams to prevent diarrhea. If you want to get technical, the scientific recommendation is 0.37 g of xylitol per kg of weight for males and 0.42 g of xylitol per kg of weight for females.11

Studies have shown that the body will adapt over time and diarrhea will either lessen or cease if you choose to take larger amounts for a longer time.12

Contribution to SIBO

Even though there are bacteria that are inhibited by xylitol, some bacteria are able to break it down and feast upon its fermentable goodness. This bacterial feast occurs in your intestines. Most polyols ferment in the gut and cause issues in people that are suffering from SIBO (small intestinal bacterial overgrowth). The link between intake and SIBO explains why in some people, excessive intake creates gas, intestinal distension, and intestinal cramps.

Because of this fermentation, xylitol intake will not harm the bacterial flora in your intestines. It will on the other hand enhance it, even to the point where you might develop SIBO!

It is also possible that the intake of large amounts of xylitol over time can contribute to one developing SIBO if the conditions in their intestines are ripe. I suggest that if you are suffering from SIBO or if you have any of the listed side effects above when you ingest it, to stay away from all sugar alcohols until your condition improves.13

To answer the final question, yes, it is considered Bulletproof!14