Sugar Free Electrolytes: Stevia, Monk Fruit and What They Do

Jasmine Meagher, founder of Ritua
Jasmine Meagher, BSc Food Science and Nutrition
Founder, Ritua · 9 min read

If you have looked at a sugar free electrolyte drink and paused at the word "sweeteners", that is a reasonable place to pause. Stevia and monk fruit get marketed as though being plant derived settles the question, and attacked as though being an additive settles it the other way. Neither framing helps.

So here is the honest version: what these sweeteners are, how Australian regulators assessed them, what the trials show on blood glucose, where the microbiome research sits, what the 2023 World Health Organization guideline actually said, and whether you can taste them. Some of this is settled. Some is not, and I will say which.

What steviol glycosides and mogrosides actually are

Stevia on an ingredient list is shorthand for steviol glycosides, compounds purified from the leaves of Stevia rebaudiana Bertoni, a South American member of the daisy family. Structurally they are a steviol backbone with sugar units attached, and the two named most often are stevioside and rebaudioside A. Food Standards Australia New Zealand puts them at roughly 150 to 300 times sweeter than sugar, which is why a serve is measured in milligrams.

Monk fruit is the fruit of Siraitia grosvenorii, a vine native to southern China, known there as luo han guo. Its sweetness comes from cucurbitane triterpene glycosides called mogrosides. In the FSANZ assessment, mogroside V is the predominant sweet compound at roughly 30 to 40 per cent of commercial extracts, and the extract is 250 to 400 times sweeter than sucrose.

Both are worth calling what they are: purified plant extracts used as food additives. "Natural" is a marketing word, not a safety category. What matters is the assessment.

How they are approved and regulated in Australia

Sweeteners are not sold here on a manufacturer's say so. They are permitted additives under the Australia New Zealand Food Standards Code, and the permissions sit in Schedule 15, which lists, food class by food class, which substances may be used and at what maximum level. Steviol glycosides carry the additive number 960 and are permitted in food class 13.4, formulated supplementary sports foods, at up to 175 mg per kilogram.

Alongside each permission sits an acceptable daily intake, the amount a person could consume daily across a lifetime without appreciable risk. In 2023 FSANZ and New Zealand's Ministry for Primary Industries measured steviol glycoside levels in commercially available foods and ran a fresh dietary exposure assessment. No public health and safety issues were identified.

The acceptable daily intake for steviol glycosides is 0 to 4 mg per kilogram of body weight per day, expressed as steviol equivalents. In the 2023 review, estimated dietary exposures across Australia and New Zealand were well below the ADI in every population group assessed, with mean exposures of 3 to 20 per cent of the ADI.

Monk fruit took a different route. FSANZ approved it through Application A1129, and the legislative variation adding "monk fruit extract (luo han guo extract)" to the Code was registered in January 2019. FSANZ concluded an ADI "not specified" was appropriate, the classification used when no hazard is identified at any realistic intake: no genotoxicity, and no adverse effects in repeat dose studies at the highest doses tested, which ran to several grams per kilogram of body weight per day in rats.

One detail from the FSANZ assessment matters later: steviol glycosides are not absorbed intact. They are "deglycosylated by microflora in the colon", after which the steviol core is absorbed, conjugated in the liver and excreted mainly in urine. Gut bacteria act on them first, which is why the microbiome question keeps coming up.

Blood glucose and insulin: what the trials found

One trial tested these two sweeteners head to head. Tey and colleagues, in the International Journal of Obesity in 2017, gave participants a mid morning drink sweetened with aspartame, monk fruit, stevia or 65 grams of sucrose, then an unrestricted lunch an hour later. Across the three hours measured there were no differences in total area under the curve for glucose or insulin between the four beverages. Two caveats: participants ate more at that lunch after the sweetened drinks, closing the energy gap, and the sample was 30 healthy men. One piece of evidence, not the answer.

The broader picture is sturdier. A 2023 network meta-analysis in Nutrients pooled 36 acute trials in 472 mostly healthy participants. Where the sweetened drinks were consumed on their own, they had no effect on postprandial glucose, insulin or the gut hormones measured, behaving essentially like water, while the sugar sweetened comparators raised glucose, insulin, GLP-1 and GIP. Worth knowing: the authors rated their own confidence as low to moderate, and the review was funded by an industry linked body, the Institute for the Advancement of Food and Nutrition Sciences.

Longer term, a 2019 systematic review in Nutrients pooled nine randomised trials of steviol glycosides in 462 participants and found no significant effect on HbA1c and no reduction in body weight or BMI against placebo. Stevia is not a blood sugar intervention. The accurate claim is duller: it sweetens without the glucose load sugar brings.

The gut microbiome question, honestly

This is where I would not tell you the evidence is settled, because it is not. The study that changed the conversation appeared in Cell in 2022: a randomised trial in 120 healthy adults taking sachets of saccharin, sucralose, aspartame or stevia for two weeks, below the acceptable daily intake. As groups, each sweetener distinctly altered the stool and oral microbiome and the plasma metabolome. But only saccharin and sucralose significantly impaired glycaemic responses. Stevia and aspartame did not. Effects were also strikingly person specific, and germ free mice given the participants' microbiomes reproduced their donors' responses.

The most specific test of stevia came two years later. Kwok and colleagues, in the Journal of Nutrition in 2024, ran a randomised, double blinded trial in 59 healthy adults, 36 of them women, drinking either 25 per cent of the ADI of stevia or 30 grams of sucrose daily for four weeks. At week four there were no significant differences between groups in the gut microbiome at phylum, family, genus or species level, and none in faecal short chain fatty acids or fasting cardiometabolic measures.

That is reassuring, and it is still one trial, four weeks, 59 healthy people. Nobody has run a multi year trial in a general population, and for monk fruit the microbiome literature is thinner again. The fair summary: the alarming findings here have mostly attached to saccharin and sucralose, and "we do not yet know the long term picture" remains true for the whole class.

The 2023 WHO guideline and what it was about

In May 2023 the World Health Organization released a guideline on non sugar sweeteners and the headlines were blunt. The recommendation reads: "WHO suggests that non-sugar sweeteners not be used as a means of achieving weight control or reducing the risk of noncommunicable diseases." It covers the class, stevia included, and applies to everyone except people with pre-existing diabetes.

Three things get lost in the summaries. It is a conditional recommendation on evidence WHO itself graded low certainty, and WHO flagged that what it saw might be confounded by the baseline characteristics of people who choose sweeteners. The question was about weight control and chronic disease risk, not acute safety. And WHO said so directly: the executive summary states the guidance "is based on evidence of health effects of NSS use at levels already considered safe (i.e. within the ADI), and is not intended to provide updated or alternative guidance on safe or maximal levels of intake."

WHO did not revise anyone's ADI and did not declare sweeteners unsafe. It concluded that swapping sugar for sweeteners is not a reliable weight loss strategy, a claim about behaviour and long term outcomes rather than toxicology. If you want electrolytes without a sugar hit, rather than expecting a drink to make you lose weight, the guideline is not addressed to your decision.

Taste and tolerance, the practical part

The most common real world objection to stevia is not safety. It is that people can taste it and some do not like it. That is not imagined. Researchers screening all 25 human bitter taste receptors against steviol glycosides reported in the Journal of Agricultural and Food Chemistry that two, hTAS2R4 and hTAS2R14, mediate the bitter off taste, and that individual glycosides differ in their sweet to bitter balance. So the specific extract matters, and so does your own receptor genetics. Two people can drink the same sachet and honestly report different experiences.

Blending is the usual answer. Monk fruit carries a rounder sweetness with less of the lingering edge, so pairing the two lets a formulator use less of each. Tolerance is separate. Both are used at milligram levels, so they are not a meaningful source of fermentable carbohydrate the way sugar alcohols such as sorbitol or maltitol can be. If a sugar free drink upsets your stomach, the sweetener is worth suspecting, but so is everything else in the sachet.

Why an electrolyte drink does not need sugar

This is the question underneath the sweetener question. Traditional sports drinks contain sugar for a specific reason: fuel. The joint position stand from the Academy of Nutrition and Dietetics, Dietitians of Canada and the American College of Sports Medicine, in Medicine and Science in Sports and Exercise in 2016, sets out when that fuel is required. For brief exercise under 45 minutes, carbohydrate during the session is listed as "not needed". For sustained high intensity work of 45 to 75 minutes, small amounts. For endurance exercise of one to two and a half hours, 30 to 60 grams per hour.

Read that against how most people actually use an electrolyte drink. A hot day at work, a flight, a heavy gym session, a walk in a Queensland summer. None are two hour endurance events and none create a carbohydrate requirement. If you are riding for three hours or racing a marathon you need fuel, and a sugar free drink is not that product. For everything else, the sugar is doing a job nobody asked it to do.

The bottom line

Steviol glycosides and mogrosides are purified plant extracts, assessed and permitted as food additives here, with an ADI of 0 to 4 mg per kilogram of body weight per day for steviol glycosides and no specified ADI for monk fruit extract. Australian and New Zealand exposures sit well below that figure. In acute trials neither produces the glucose and insulin response sugar does, and in the best randomised trial of stevia and the gut microbiome, four weeks at a quarter of the ADI changed nothing measurable.

What I will not tell you is that the long term microbiome question is closed. It is not, and the research that exists points mainly at saccharin and sucralose. The 2023 WHO guideline is worth reading, and it is about whether sweeteners help with weight control, not whether they are safe at approved levels. WHO said that itself.

If you want electrolytes without the sugar, that is a coherent choice and the evidence supports it. It is the reasoning behind Ritua Hydrate, sweetened with stevia and monk fruit rather than sugar. Read your own label either way.

This article is general information, not medical advice, and is not a substitute for guidance from your doctor, particularly if you are managing an existing health condition or taking medication.

Jasmine Meagher, founder of Ritua

Jasmine Meagher

BSc Food Science and Nutrition · Founder, Ritua

Jasmine founded Ritua to bring evidence-based, TGA-compliant supplements to Australian women. She writes about the research behind every ingredient Ritua sells.

Common questions

Is stevia approved in Australia?

Yes. Steviol glycosides are a permitted food additive, number 960, under Schedule 15 of the Australia New Zealand Food Standards Code, with an acceptable daily intake of 0 to 4 mg per kilogram of body weight per day expressed as steviol equivalents. FSANZ reviewed dietary exposure again in 2023 and identified no public health and safety issues.

Does monk fruit have an acceptable daily intake?

FSANZ concluded that an ADI "not specified" was appropriate for monk fruit extract, the classification used when no hazard is identified at realistic intakes. It is not a loophole. It reflects a toxicology package that found no genotoxicity and no adverse effects at the highest doses tested in animals.

Do stevia or monk fruit raise blood sugar?

In the acute trials, no. A 2017 crossover study in 30 healthy men found no difference in three hour glucose or insulin area under the curve between drinks sweetened with monk fruit, stevia, aspartame or sucrose, and a 2023 network meta-analysis of 36 trials found non nutritive sweetened beverages behaved like water on postprandial glucose and insulin. Longer term, steviol glycosides have not been shown to lower HbA1c.

Did the WHO say sweeteners are unsafe?

No. The 2023 guideline is a conditional recommendation, based on low certainty evidence, against using non sugar sweeteners as a strategy for weight control or reducing noncommunicable disease risk. Its executive summary states that it is based on health effects at levels already considered safe and is not intended to revise safe or maximal intake levels.

Do sweeteners damage your gut microbiome?

It depends on the sweetener and the person, and the long term picture is not established. In the 2022 Cell trial, all four sweeteners tested shifted the microbiome as groups, but only saccharin and sucralose impaired glycaemic responses. A 2024 randomised trial gave 59 adults a stevia beverage daily for four weeks and found no significant microbiome or short chain fatty acid differences against sucrose.

Why can I taste stevia when other people cannot?

Because it activates bitter taste receptors as well as sweet ones. A 2012 study screening all 25 human bitter receptors identified hTAS2R4 and hTAS2R14 as the two that mediate the bitter off taste of steviol glycosides. Receptor sensitivity varies between people, and different steviol glycosides differ in their sweet to bitter balance, which is why some products taste cleaner than others.

Sources

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