Is Stevia Bad for You? The Science and Side Effects

Stevia is a ubiquitous sweetener, but how much should we really be consuming? Find out why we avoid it in our products.

— On Apr 07, 2025

Is Stevia Bad for You? The Science and Side Effects

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Stevia—it’s everywhere. From low-sugar beverages and condiments to baked goods and dairy products, this no-calorie sweetener is living its heyday. As a registered dietitian, I’m often asked if stevia sweeteners are good since they’re plant-based. And while I’d love to give a tight yes or no response, the answer is not that simple.

While using a non-nutritive sugar substitute like stevia may be an alternative to table sugar, much more research is needed to understand its overall impact on our health. And though high-purity stevia leaf extract is considered safe, there are some interesting scientific findings you may want to understand before adding stevia to your diet.

What Is Stevia Leaf?

Stevia rebaudiana (Bertoni) is a shrub native to South America, and its leaves have been used for medicinal purposes for hundreds of years. Since it's derived from a plant, stevia is considered a natural sweetener.

However, the stevia sweeteners most commonly used are not whole-leaf stevia or even a crude extract but rather a highly purified component of the stevia leaf called steviol glycosides. This compound is produced in all different manners, from fermentation to bioconversion, which results in slightly different tasting extracts, including rebaudioside A (Reb A for short), Reb D, and Reb M.

What is the stevia you buy in stores?

These rebaudiosides make up the stevia products that can be purchased in stores. Brands often combine stevia with other low-calorie sweeteners or no-calorie sweeteners to produce specific flavors. For example:

Truvia blends Reb A and erythritol.
Stevia in the Raw and Pure Via combine Reb A and dextrose.
SweatLeaf blends Reb A with inulin and silica.

Interestingly, these high-purity extracts are 250-300 times sweeter than table sugar, which is another reason they are combined with other sweeteners and fillers when sold in bulk. Dextrose, maltodextrin, and inulin help provide volume and cut through the intense sweetness, allowing for a better 1:1 sugar swap when cooking or baking.

What type of sweetener is used in greens powders?

Each greens powder formula is unique, but stevia is a popular sweetener choice for many brands. Alternatively, Live it Up Super Greens is naturally sweetened with monk fruit extract.

Brand
Sweetener used	Stevia leaf (unspecified)	Stevia extract (Reb A)	Stevia extract (unspecified)	Monk fruit extract

When used in greens powders, stevia sweeteners are usually the highly purified stevia leaf extract Reb A without other combined sweeteners. But as you’ll see in the next section, this may not be the case for all greens supplements.

Stevia Dosage and Safety Evaluations

In 2008, highly purified steviol glycosides, specifically Reb A purified from the Bertoni stevia plant, was determined to be GRAS (Generally Recognized as Safe) by the U.S. Food and Drug Administration (FDA). This form of stevia is also approved by the EFSA (European Food Safety Authority) and the JECFA (Joint FAO/WHO Expert Committee on Food Additives).

How much is safe?

It has been determined that 0-4mg steviol glycosides per kg body weight is well within safe levels. This amounts to about 12mg per kg of Reb A and 10mg per kg of stevioside. This ADI (acceptable daily intake level) is 100 times less than the level at which harm may be observed in clinical trials.

Which types of stevia should be avoided?

There is not enough toxicology information on whole stevia leaf and crude stevia leaf extracts to determine safe levels, and so these are not considered GRAS and therefore are not FDA approved for use in food. But this is where the water gets murky. The FDA does not regulate dietary supplements, so supplement companies could be adding whole stevia leaf or crude stevia extracts without oversight.

For example, Bloom Greens is sweetened with “Stevia leaf extract (Reb A), clearly indicating that the approved form is being used.

AG1, on the other hand, uses “Stevia (Stevia rebaudiana) leaf powder,” which indicates it is the whole leaf. Upon digging a little further, AG1’s FAQ mentions that they use a “pure extract from the stevia leaf,” which I’m hoping means they are using the GRAS version, though they’ve made it difficult to decipher.

Because dietary supplement regulation is so lax, not many consumers may know what to look for to ensure their greens powder contains ingredients that have been proven safe.

Potential Health Benefits of Stevia

Several studies have come out looking at the effects of stevia on health. While much more research is needed for this fairly new, natural sugar substitute, here are just a few potential health benefits stevia may provide.

1. Calorie Reduction

The most alluring property of stevia is its non-caloric status. For most people, stevia represents a way to help reduce table sugar in their diet while keeping the sweet flavor people love.

So for someone looking to reduce calories, swapping this no-calorie sweetener for table sugar may help with their weight management goals. One small randomized controlled trial in healthy adults indicated that drinking a stevia beverage consumption prior to lunch reduces appetite and could potentially impact total energy intake and body weight.

2. Sugar Substitute

The great news is that research shows stevia does not affect the body in the same ways that table sugar does. If someone wants to impact their overall health without added sugar, using a natural sugar substitute such as stevia could be a tool in their nutritional toolkit to help get the job done.

3. Dental Health

Whether from food or beverages, simple sugars increase our risk for cavities. Both the type and the amount can impact the health of our teeth. The more often we consume sugar-laden foods and drinks, the higher incidence of dental caries we may have. Since stevia sweeteners do not contain sugar or calories, they do not contribute to your risk of cavities.

4. Antioxidant Power

Both stevia leaves as well as the highly purified steviol glycosides contain antioxidants. Antioxidants help the body handle oxidative stress, which is the precursor to internal inflammation. Since steviol glycosides are more processed, they contain fewer antioxidants than the whole leaf, though studies indicate that even Reb A contains more antioxidants than table sugar.

Stevia Side Effects

Just as potential benefits have been found, side effects have also been discovered in the last few years of research. It’s always important to weigh the pros and cons of a food additive to ensure that it’s right for your potential goals.

1. Digestive Issues

Since Reb A is often combined with other sweeteners, it may increase the likelihood of digestive distress, such as gas, bloating, or diarrhea. This is particularly true when combined with sugar alcohols such as erythritol. Sugar alcohols naturally pull fluid into the colon, causing an increased risk for diarrhea and other gut discomfort.

2. Impact on Gut Microbiota

Research is not yet conclusive as to whether stevia sweeteners are benign when it comes to the health of our gut health. Some studies indicate that consuming stevia may inhibit the growth of our beneficial bacteria and may hamper communication within our microbial community. Both could lead to dysbiosis, an imbalance between good and bad gut microbiota.

At the same time, some research has shown no effect or even a positive effect on human microflora. Ultimately, stevia's effect on your gut health depends on how much and how often you consume stevia.

3. May Not Help Maintain Healthy Weight

While non-caloric sweeteners have been touted as a replacement for sugar-laden calories, research does not yet dependably show that swapping out sugar for these types of sweeteners is helpful for weight management and helping to reduce energy intake.

First, because stevia is such an intense sweetener, up to 300 times sweeter than table sugar, some research shows that it might cause cravings later in the day. Additionally, the promise of weight management and other benefits are inconsistent in the current research, with many finding no correlation and some even detecting weight gain.

4. Headaches and Dizziness

While more information is needed about the origin of this side effect, some people have linked headaches and dizziness to consuming stevia.

Headaches may be caused by several different triggers, one being non-caloric, high intensity sweeteners. Triggers are quite individual, so if you’re experiencing headaches or dizziness, try cutting out the potential culprit from your diet to see if that helps. It’s also important to chat with your healthcare provider about any symptoms that persist.

Stevia Taste

Taste is very individual, but for some, the flavor and aftertaste of stevia sweeteners are not super desirable. You may have tried something in the past, thought it tasted a bit off, and didn’t realize this was stevia's flavor coming through. This is not to say everyone dislikes it, and many people don’t mind the taste!

Stevia’s flavor is often described as

Overpoweringly sweet
A bit bitter
Zingy
Artificial tasting
Having a “weird” aftertaste.

When it comes to greens powders, several brands use stevia as their primary sweetener, and it’s not for everyone’s taste buds.

For example, Bloom Greens uses the highly purified stevia extract (Reb A) and while many people enjoy the flavors, others have said it is “overly sweet,” “has a very strong stevia taste and it lingers on the tongue,” and “it tastes like it has a lot of artificial sweetener.”

Another greens supplement that uses stevia is AG1. Reviews are generally good, though some customers indicate that the product is too sweet, “Even though there is no added sugar, the taste is really sweet and did not suit me,” and “I have a sweet tooth and this is too sweet for me.”

Dietitian Tip: If your stevia-sweetened supplements are too sweet for your liking, try toning them down in a smoothie with greek yogurt and tart fruits. Alternatively, opt for a stevia-free powder like Super Greens, which tastes fresh and only lightly sweet.

Final Verdict: Is Stevia Safe?

Yes, the highly purified steviol glycosides extracted from the stevia rebaudiana plant, such as Reb A, are generally considered safe for everyday consumption in moderate amounts.

With that said, to ensure your safety, always double check your supplements to ensure that the stevia being used is Reb A or another approved purified extract and not just the stevia leaves or an unrefined extract. Additionally, with the potential side effects, make sure you are weighing all your options to find the best choice for your personal goals.

Since stevia leaf extract has quite a distinct flavor, which I’m not a big fan of, I prefer monk fruit extract. Like stevia, this natural no-calorie sugar substitute, known as Siraitia grosvenorii and lo han guo, is derived from a plant used for centuries as an herbal remedy. Similarly, monk fruit’s highly purified extracts, mogrosides, are FDA approved. I also like that monk fruit is only about 150 times sweeter than table sugar and contains antioxidants.

The most alluring part about monk fruit is that there are currently no known side effects other than the rare potential for allergic reactions. More studies are needed, but this helps me feel better about adding it to my diet.

And great news: Live it Up Super Greens contains monk fruit sweetener and not stevia!

Frequently Asked Questions

Is stevia worse for you than sugar?

Depending on your individual goals, stevia can be a good substitute for table sugar. While excessive sugar intake has potential health risks such as body weight gain, dental problems, and contributions to other health conditions, consuming moderate amounts may be acceptable for daily consumption.

Similarly, excessive stevia intake may also lead to potential side effects, such as an impact on gut health and digestive upset. However, moderate amounts are usually considered safe for consumption.

Is it OK to have stevia every day?

Yes, as long as you are consuming products that contain highly-purified stevia extracts in moderate amounts, it can be safe to have stevia every day.

Be aware that there are potential side effects of stevia, including digestive upset, headache and dizziness, and changes to the microbiome. If you are concerned about these, or experience any specific symptoms that are concerning or that do not go away, be sure to discuss with your healthcare provider.

What are the best stevia alternatives?

Most health professionals recommend plant-based sweeteners over artificial sweeteners like aspartame (Equal), acesulfame potassium (Sweet One), saccharin (Sweet n Low), sucralose (Splenda), and other artificial sweeteners. These manufactured non-nutritive sweeteners may be linked with more potential health concerns.

Other sugar substitutes include sugar alcohols, xylitol, sorbitol, and erythritol, which are naturally sweet compounds found in fruit. Of these low-calorie sweeteners, erythritol is the most commonly used. While it is considered Generally Recognized as Safe by the FDA, studies link it to potentially larger safety concerns. Additionally, sugar alcohols may also cause diarrhea and gas.

Derived from the Siraitia grosvenorii fruit, monk fruit is a natural plant-based sweetener that is considered safe with few side effects. This is the sugar substitute I most recommend, and it’s used to sweeten a number of greens powders like Live it Up Super Greens and Jocko Greens.

Is stevia the same as aspartame?

No, while both stevia and aspartame are sugar substitutes, that's where the similarities end. Stevia is a plant-derived sweetener, while aspartame is a manufactured artificial sweetener; therefore, stevia is considered more natural than aspartame. In addition, stevia is heat-stable for cooking and baking while aspartame is not. While stevia has some potential side effects, aspartame has considerably more potential health concerns.

Why are people avoiding stevia?

Some people avoid this sugar substitute due to its unpleasant flavor and aftertaste. Others avoid it because of its potential to disrupt the gut microbiome. The highly-purified stevia extract is generally considered safe, but it’s not advised to purchase products that contain whole stevia leaves or crude unrefined stevia extracts as they have not yet been proven to be safe.

How is stevia used?

The food industry adds stevia extracts to flavored waters and diet sodas to help provide an alternative to beverages sweetened with artificial sweeteners. Many other foods may contain stevia extract, including yogurts, baked goods, cereals, and even some candies.

For home use, stevia rebaudiana extracts can be purchased in liquid drops or powdered form and are added to morning coffee or tea as a sugar substitute or even used in baking. Since stevia is so much sweeter than sugar, it's important to follow a specific sugar-to-stevia ratio to get the appropriate sweetness level when baking.

Some powdered products might use 1 teaspoon of stevia extract for 1 cup of sugar. In liquid form, 15 drops of stevia extract often equals 1 tablespoon of sugar. Be sure to check the brand packaging to determine how much stevia is needed as a sugar replacement.

References

About the author:

Rachel Gargano, MS, RD, CSSD, CBS

Rachel is a registered dietitian based in Contra Costa County, California, with over 15 years experience. She specializes in whole-body wellness and plant-based nutrition, helping people understand the dynamic interplay between food and health so they can live life to the fullest. When not helping others, she enjoys spending time with her kids, being physically active, and tending to her abundant household plants.

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