What are the side effects of using stevia in coffee?

January 5, 2026 •

4 min read

Stevia is a non-nutritive, zero-calorie sweetener derived from the Stevia rebaudiana plant and is a popular sugar alternative. However, despite its natural origin, adding stevia to your daily coffee may produce a variety of side effects, ranging from digestive discomfort to an undesirable aftertaste.

Quick Summary

Using stevia in coffee can lead to side effects like digestive upset, a bitter aftertaste, and potential interactions with certain medications. Product purity and individual sensitivity are key factors.

Key Points

Digestive Distress: Stevia blends containing sugar alcohols like erythritol can cause bloating, gas, and nausea in sensitive individuals, though pure stevia extract is less likely to.
Bitter Aftertaste: A metallic, licorice-like aftertaste is a common side effect of stevia, which can alter the flavor of your coffee.
Blood Pressure and Sugar Effects: Stevia can lower blood pressure and blood sugar. Diabetics and those on blood pressure medication should use it cautiously and monitor their levels.
Allergy Risk: While rare, individuals allergic to ragweed and related plants may experience cross-reactive allergic reactions to stevia, especially in less-purified forms.
Check Your Product: The safety and side effects depend heavily on the type of stevia product. Highly purified extracts (Reb-A) are generally safe, while crude extracts are not approved, and blends contain other additives.
Moderation is Key: Consuming stevia in moderation is recommended, as excessive intake may lead to unintended effects, including potential microbiome disruption.

Common Side Effects of Using Stevia in Coffee

While generally recognized as safe (GRAS) by the U.S. Food and Drug Administration (FDA) in its highly purified form, stevia isn't without potential drawbacks, especially when used in coffee. A key distinction lies between pure stevia extract and blended products, which often contain other ingredients that can cause adverse reactions.

Digestive Issues

One of the most frequently reported side effects is gastrointestinal distress, which is typically caused by sugar alcohols added to many stevia blend products to improve flavor and texture.

Bloating and Gas: Sugar alcohols like erythritol are not fully absorbed by the body. They ferment in the large intestine, causing gas and bloating for some sensitive individuals.
Nausea and Diarrhea: Consuming these sugar alcohols in large quantities can also have a laxative effect, leading to nausea, diarrhea, and abdominal cramping.
Gut Microbiome Disruption: Some animal studies and human in vitro research have suggested that non-nutritive sweeteners, including stevia, could potentially alter the balance of beneficial gut bacteria. While more human research is needed, this could potentially lead to further digestive problems.

Unpleasant Aftertaste

For many coffee drinkers, the most immediate issue with stevia is its distinctive flavor profile. Stevia has a mild, licorice-like taste that some find bitter or metallic, which can clash with and alter the flavor of their coffee. The intensity of this aftertaste can depend on the brand, the amount used, and the individual's palate. In contrast, pure stevia leaf, which is not FDA-approved for commercial use, is much more potent and unrefined, often intensifying these off-flavors.

Effects on Blood Sugar and Blood Pressure

While often promoted for its benefits for diabetics, stevia can have important effects on blood sugar and blood pressure levels that require careful consideration.

Blood Sugar Regulation: Pure stevia does not raise blood sugar and has a glycemic index of zero, making it suitable for many with diabetes. However, many stevia blends contain additives like dextrose or maltodextrin that can impact blood glucose levels. People with diabetes must carefully read labels to avoid these sugar-based fillers. Additionally, stevia can lower blood sugar, which could be an issue for those on blood sugar-lowering medications.
Blood Pressure Levels: Stevia has been shown to have a blood pressure-lowering effect. While this can be beneficial for individuals with hypertension, those who already have low blood pressure or are on antihypertensive medication should monitor their intake carefully to avoid a dangerous drop in blood pressure.

Allergic Reactions

Although rare, some individuals may experience an allergic reaction to stevia. The stevia plant belongs to the Asteraceae family, which also includes ragweed, daisies, and chrysanthemums.

Cross-Reactivity: For those with a sensitivity to ragweed and related plants, there is a small risk of cross-reactive allergic reactions. Symptoms may include itching or tingling in the mouth or, in rare cases, more severe respiratory issues.
Product Purity: The risk is higher with less-refined stevia products and lower with highly purified steviol glycosides, which have had most of the allergenic proteins removed.

Reproductive Health Concerns

Initial concerns about stevia affecting fertility were based on outdated animal studies that used extremely high doses of crude extracts. Later studies and regulatory body assessments have shown no evidence of reproductive toxicity in humans at normal consumption levels. The myth that stevia acts as a contraceptive is widely debunked by modern research, which often shows stevia to be safe for reproductive health in moderate amounts.

Comparison: Pure Stevia Extract vs. Stevia Blends

To make an informed decision, it is important to understand the difference between pure stevia extract and blended products commonly found in stores.


Feature	Pure Stevia Extract (Reb-A)	Stevia Blends (e.g., Truvia)
Ingredients	High-purity steviol glycosides (>95%).	Steviol glycosides combined with additives like erythritol, dextrose, or maltodextrin.
Potential Side Effects	Mild aftertaste for some. Minimal digestive issues from the stevia itself.	Digestive issues (bloating, gas, diarrhea) due to sugar alcohols. Possible blood sugar impact from fillers like dextrose.
Taste Profile	Very sweet but may have a bitter or metallic aftertaste.	Often formulated to have a taste and texture closer to sugar, with fewer off-flavors, but still detectable by some.
FDA Status	Generally Recognized as Safe (GRAS) for commercial use.	Safe for consumption, though any additives must also be approved.

Is Using Stevia in Your Coffee Right for You?

For most people, adding highly purified stevia extract to coffee in moderation is a safe way to sweeten their beverage without adding calories or spiking blood sugar. However, individuals with certain pre-existing conditions or sensitivities should exercise caution.

Individuals with Digestive Issues: If you experience frequent bloating or gas, you may be sensitive to the sugar alcohols found in many stevia blends. Opt for pure stevia extract or another sweetener.
Diabetics and Individuals with Low Blood Pressure: Monitor blood sugar and blood pressure levels closely, especially when starting stevia. Always choose pure stevia products and consult your doctor to avoid interactions with medication.
Taste Sensitivity: If you dislike the aftertaste, try different brands or experiment with liquid stevia drops, which can sometimes have a cleaner flavor profile.

Conclusion

Using stevia in coffee can be a smart, zero-calorie alternative to sugar, but it is important to be aware of the potential side effects. Digestive issues are common, largely due to sugar alcohol additives in blended products, while pure stevia can leave an aftertaste. Interactions with medications for diabetes and high blood pressure also warrant a discussion with a healthcare provider. By understanding the differences between stevia products and listening to your body, you can decide if it is the right sweetener for you. You can learn more about stevia's effects on the body from resources like Healthline.

Frequently Asked Questions

The bloating you feel is likely caused by sugar alcohols, such as erythritol, which are often added to stevia blends to improve flavor and texture. These additives can ferment in the gut, causing gas and digestive discomfort.

Yes, some research suggests that stevia can lower blood pressure. If you already have low blood pressure or are taking medication for it, you should consult a doctor before adding stevia to your daily routine.

Yes, pure stevia extract (steviol glycosides) is less likely to cause digestive side effects. The primary issues linked to stevia are often caused by the sugar alcohols and fillers found in blended products.

No, pure stevia extract does not raise blood sugar. However, some blended products contain dextrose or maltodextrin, which can increase blood glucose levels. Always check the ingredients list.

While rare, an allergy to stevia is possible, especially for those sensitive to plants in the Asteraceae family, such as ragweed. Symptoms may include a tingling mouth or skin rash.

No, the link between stevia and infertility is a myth based on flawed, outdated animal studies that used extremely high doses of crude extracts. Modern regulatory bodies consider highly purified stevia safe for reproductive health.

Stevia can have a distinct aftertaste that some describe as bitter, metallic, or licorice-like, which can be amplified in coffee. This off-flavor is a common reason why people dislike it.