Using stevia can reduce calories in foods and drinks, but it may also have some adverse effects. Possible side effects include nausea, bloating, low blood pressure, and hormone disruption.

Stevia is a non-nutritive or zero-calorie sweetener made of steviol glycosides. These are compounds extracted and refined from the leaves of the Stevia rebaudiana plant.

Many people choose to replace sugar with stevia to reduce their calorie consumption. In this article, we look at the possible risks and side effects associated with this natural sweetener.

Stevia leaves are about 200-300 times sweeter than traditional white sugar and people have used them for centuries as a sweetener and herbal supplement.

However, the United States Food and Drug Administration (FDA) only consider high-purity steviol glycosides to be safe for human consumption currently.

Because the FDA have not approved crude stevia extracts and stevia leaves as a food additive, companies are not allowed to import them into the United States for use as sweeteners.

According to the Joint FAO/WHO Expert Committee on Food Additives, the acceptable daily intake for steviol equivalents is 4 milligrams (mg) per kilogram of body weight. That equates to about 12 mg of high-purity stevia extracts per kilogram of body weight per day.

When used as a sweetener or to flavor foods, experts do not consider highly purified stevia to cause adverse side effects.

While several studies have identified potential side effects of stevia over the last few decades, most were done using laboratory animals, and many have since been disproved.

Potential side effects linked to stevia consumption include:

Kidney damage

Stevia is considered a diuretic, meaning that it increases the speed at which the body expels water and electrolytes from the body in urine. Because the kidney is responsible for filtering and creating urine, researchers initially thought that long-term consumption of stevia could damage the organ.

More recent studies, however, have concluded that stevia may help prevent kidney damage. A 2018 clinical trial of participants with chronic kidney disease found that stevia supplements reduced creatinine, uric acid, blood sugar, and microalbumin.

Gastrointestinal symptoms

Some stevia products contain added sugar alcohols that may cause unpleasant symptoms iwhen consumed in large amounts.

Symptoms of hypersensitivity to sugar alcohols can include:

Currently, human studies are lacking, but in vitro and animal studies suggest stevia may improve bacterial diversity and reduce inflammation in the colon. Stevia use has been shown to help limit and reduce diarrhea.

Low blood pressure

Stevia is known to act as a vasodilator, causing the blood vessels to widen and lowering overall blood pressure. Currently, researchers have only explored the potentially positive aspects of this use.

There is no evidence that stevia lowers blood pressure to dangerous levels. People with chronic low blood pressure and those who take blood pressure-lowering medications should speak to a doctor before adding stevia to their diet.

Endocrine disruption

Steviol glycosides have a molecular structure similar to steroids, so it is thought that they may interfere with hormone production. A 2016 study found that human sperm cells exposed to steviol experienced an increase in progesterone production.

Further research in humans is needed to draw any solid conclusions. At this point, we don’t have enough evidence to suggest that stevia could act as an endocrine disruptor in humans.

Some people are at an increased risk of developing side effects from regular stevia use. This is because stevia can lower blood sugars and blood pressure, and act as a diuretic.

Stevia can also interact with certain medications, so it is important to discuss stevia with a doctor before consuming or purchasing the product.

There are many different types of steviol glycoside found in stevia, classified into five major groups.

Although most of the existing research concerns the two major compounds in stevia — stevioside and rebaudioside A (reb A) — a 2016 study using human fecal samples concluded that all forms of the compound are probably safe for general use.

However, research supporting the safe use of less refined stevia compounds is still lacking. As a result, the FDA does not recognize stevia leaves and crude extracts as safe for consumption.

Increasingly, stevia supplements and extracts in some countries are being found to contain counterfeit ingredients, primarily artificial sweeteners that are linked to known health risks. At this writing, there have been no reports of stevia products in the United States or the UK having been adulterated.

When consumed at low doses, purified stevia is generally not considered to pose health risks for pregnant people.

Older studies using hamster embryos have established that stevia did not affect pregnancy or fertility outcomes and was non-toxic to fetal tissues.

However, some of the common counterfeit ingredients found in stevia mixtures and formulas from other countries are not recommended during pregnancy. The most notable of these ingredients is saccharin.

Researchers still do not understand the full range of risks associated with stevia. A 2017 review exploring health-outcomes and complications linked to zero-calorie sweeteners concluded that not enough studies had been done to make a judgment about stevia’s overall safety.

The World Health Organization has set the Acceptable Daily Intake (ADI) for steviol at 4 milligrams (mg) per kilogram of body weight, or 12 mg of stevia extract per kg of body weight.