Is Stevia Safe? Surprising Studies Reveal Otherwise

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The Pure TheraPro Team

The Pure TheraPro Education Team is comprised of researchers from diverse backgrounds including nutrition, functional medicine, fitness, supplement formulation & food science. All articles have been reviewed for content, accuracy, and compliance by a holistic integrative nutritionist certified by an accredited institution.
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Is Stevia safe? Does it impact your gut microbiome? You might be surprised at the findings of a new study from Israel. The all-natural sweetener produced from plant leaves may actually disrupt the way your gut bacteria communicate, which might lead to health issues. This study was conducted by researchers at Ben-Gurion University. 

The team found that although stevia doesn’t kill bacteria, signaling is influenced, meaning that the bacteria can’t effectively communicate with one another, which may lead to dysbiosis. Higher concentrations led to an exacerbation of these issues, increasing the negative impact on the gut microbiome.

Stevia has become a popular sugar substitute in the last several years and is viewed as a healthy and safe no-calorie alternative to sugar. It’s believed that the global stevia market will be worth $1.2 billion by 2027.

This study, however, warrants the need for additional research on the impact of stevia on digestive health.

Previous studies on stevia have also made researchers question its safety. Stevia, for example, may cause weight gain by influencing the production of short-chain fatty acids. 

Because stevia does not produce glycogen, it may also impact thyroid health, being that glycogen is necessary for the liver to convert T4 to active T3. This might lead to hypothyroidism and the multitude of symptoms of low thyroid hormone—weight gain, fatigue, hair loss, joint pain, digestive issues and a slow metabolism.

Although previous studies on sweeteners have focused on artificial ones, such as aspartame that were linked to a variety of serious health issues, this new research is puzzling many since stevia is an all-natural sugar substitute. Stevia is derived from a plant native to South America, and its leaves have been used for centuries in teas and natural medicines. One theory is the amount of stevia used having an impact whereas a smaller amount may not alter bacteria’s intricate communication system.


Our microbiome is extremely complex and sophisticated, and what we truly know about its workings is limited. What we do know is that some gut bacteria species utilize our cellular communication as part of theirs, almost synching with it. Any disruption in our cellular communication affects these bacteria, and vice versa. Cells speak through chemicals, and so do bacteria.

The new research on stevia shows that the stevia molecule binds to these chemical receptor sites that impact bacterial communication, hence, interfering with it and creating a gut disruption.

Aside from gut dysbiosis, animal studies on stevia’s safety have also raised some questions when it comes to the reproductive system. Long-term use of large quantities of stevia are linked to sterility in animals, impacting both female and males. Several studies have noted that stevia is toxic at high doses, at least in rodent studies. This toxicity impacts the endocrine and reproductive system and leads to a decrease in fertility as well as affecting their fetuses. 

Another rodent study demonstrated that stevia may play a role in reducing male fertility by shrinking the seminal vesicle.

In our product line, when a sweetener is necessary (typically protein or other powders), we’ve chosen to replace stevia with monk fruit. Other supplement companies are catching on and following our lead, which is welcome in an industry filled with problematic ingredients.



Somewhat resembling a melon, monk fruit (also known as lo han guo) is a small, green-color gourd grown on a vine in Southeast Asia. It’s believed that the fruit was first utilized by Buddhist monks in the 13th century, hence the fruit’s name.

Monk fruit contains compounds that, when extracted, are natural sweeteners 300–400 times the sweetness of cane sugar but with no calories and no effect on blood sugar. Along with its sweetening capability, monk fruit has long been regarded as the “longevity fruit” thanks to its high antioxidant levels. These antioxidants - mogrosides (see 2009 study), are metabolized differently by the body than natural sugars. In the United States, sweeteners made from monk fruit are classified by the FDA as “generally recognized as safe,” (GRAS) and highly beneficial.

Ancient Chinese usage of this fruit included drinking tea made from the boiled fruit to cool the body from external and internal sources and ailments from fever to heat stroke or soothe a sore throat. This method worked because of monk fruit’s anti-inflammatory abilities. 2013 study concluded that mogrosides may help reduce oxidative stress.

The benefits and safety profile of monk fruit currently far outweigh other alternative sweeteners (i.e. agave, stevia, xylitol, aspartame, sucralose). 

You'll find monk fruit in our vegan protein powders and some of our other products:

The last thing your gut needs is further disruption to the microbiome, so steer clear of stevia. Our Leaky Gut Defense contains monk fruit proven to reduce inflammation, along with non GMO ingredients that help soothe the gut lining and address the root cause. 

Our Just Relax contains ingredients that help you to achieve a sense of relaxation and calm, both body and mind. Sweetened with monk fruit, this drink mix is available in citrus and cherry flavors. 



Backed by multiple clinical studies, the patented ingredients in our Brain MagX help with cognitive decline, memory issues, traumatic brain injury, learning impairment and more. This naturally flavored blueberry drink mix is sweetened with monk fruit.