Stevia Leaf: What the Research Really Says (2026 Guide)
Stevia has become one of Australia’s favourite sugar alternatives. It’s in soft drinks, yoghurts and protein powders, and plenty of people grow it in a pot on the windowsill. But is it actually good for you, or just “less bad” than sugar? This guide looks at the difference between the leaf and the white powder, what the research shows, and what’s still uncertain.
What is stevia?
Stevia comes from Stevia rebaudiana, a small shrub in the daisy family native to Paraguay and Brazil. The Guaraní people have used its leaves, which they called ka’a he’ê (“sweet herb”), to sweeten yerba mate and medicines for centuries.
The sweetness comes from compounds called steviol glycosides, mainly stevioside and rebaudioside A. They’re roughly 200–300 times sweeter than sugar, but the body doesn’t absorb them as sugar, so they provide almost no kilojoules.
Leaf versus extract: not the same thing
It’s worth knowing there are two very different products:
- Dried stevia leaf is the whole leaf, crushed or cut. It’s green, about 10–15 times sweeter than sugar, and has a grassy, slightly liquorice aftertaste. It’s mainly used in herbal teas.
- Stevia extract (the white powder or drops in supermarkets) is a highly purified steviol glycoside. In Australia and New Zealand it’s an approved food additive (number 960), assessed by Food Standards Australia New Zealand.
Most of the research has been done on purified extracts, not on the whole leaf. So it’s best not to assume every finding applies equally to a cup of stevia leaf tea.
Is it safe?
Purified steviol glycosides have been reviewed by food safety agencies, including FSANZ and the international JECFA expert committee, which set an acceptable daily intake of 4 mg per kilogram of body weight (as steviol). Normal use in food and drinks is well below that. A 2016 review explained how these compounds pass through the gut, where bacteria break them down to steviol, which is then processed by the liver and excreted (Magnuson et al., 2016).
Blood sugar: neutral, which is the point
Stevia is often marketed as “good for blood sugar”. A 2019 systematic review and meta-analysis of randomised trials found steviol glycosides had no significant effect on blood glucose, insulin, HbA1c, blood pressure or body weight compared with control (Bundgaard Anker et al., 2019). A 2024 meta-analysis reported small reductions in some glucose measures, but with mixed trial quality (Zare et al., 2024).
In other words, stevia doesn’t raise blood sugar the way sugar does, which is useful. But it isn’t a treatment that lowers it either. The benefit comes from what it replaces.
Blood pressure and heart health
Some early trials suggested stevioside might lower blood pressure. When the trials were pooled in a 2015 meta-analysis, the overall effect on blood pressure, cholesterol and other cardiovascular risk factors was not significant (Onakpoya and Heneghan, 2015). Put plainly: results are mixed, and the better evidence doesn’t show a clear effect.
What about gut health?
There’s growing interest in whether non-sugar sweeteners affect gut bacteria. A 2019 review of experimental studies and trials found the evidence was limited and mostly from animal studies (Ruiz-Ojeda et al., 2019). A 2024 randomised trial found that consuming stevia for 12 weeks did not change the composition of the gut microbiota in healthy adults (Singh et al., 2024). That’s reassuring, but it’s still an active area of research.
Using stevia leaf at home
A pinch of dried stevia leaf goes a long way. Add a small amount to a pot of herbal or black tea, or to iced tea and cold brew, and taste before adding more, as too much tastes bitter. Fresh leaves from a garden plant can be steeped the same way. Stevia leaf doesn’t caramelise or add bulk, so it isn’t a direct swap for sugar in baking.
Who should take care?
We’re not aware of a current TGA safety advisory relating to stevia. However:
- Ragweed or daisy-family allergies: stevia belongs to the same family, so allergic reactions are possible, though uncommon.
- Diabetes or blood pressure medicines: large amounts of whole-leaf products may have additive effects. Monitor and check with your GP.
- Sugar alcohols: many stevia blends also contain erythritol or other sugar alcohols, which can cause bloating or loose stools in some people. Check the label.
- Pregnancy and children: purified extracts used in food are considered acceptable within normal limits, but there’s less data on concentrated whole-leaf products.
The bottom line
Stevia is a useful way to cut added sugar, and purified extracts have been assessed as safe at normal intakes. But the research doesn’t show it actively lowers blood sugar or blood pressure on its own. Its value is as a swap. Whole leaf tastes different from the white powder and has been studied less, so enjoy it as a natural sweetener rather than a health treatment.
This article is general information only and is not medical advice. It is not about any specific product. Talk to your GP or pharmacist about your own health. Safety information is current as at 24 October 2026; always check the TGA website for the latest advice.
References
- Magnuson BA, et al. Biological fate of low-calorie sweeteners. Nutr Rev. 2016. https://pubmed.ncbi.nlm.nih.gov/27753624/
- Bundgaard Anker CC, et al. Effect of steviol glycosides on human health with emphasis on type 2 diabetic biomarkers: a systematic review and meta-analysis of randomized controlled trials. Nutrients. 2019. https://pubmed.ncbi.nlm.nih.gov/31438580/
- Zare M, et al. Effect of stevia on blood glucose and HbA1C: a meta-analysis. Diabetes Metab Syndr. 2024. https://pubmed.ncbi.nlm.nih.gov/39098209/
- Onakpoya IJ, Heneghan CJ. Effect of the natural sweetener, steviol glycoside, on cardiovascular risk factors: a systematic review and meta-analysis of randomised clinical trials. Eur J Prev Cardiol. 2015. https://pubmed.ncbi.nlm.nih.gov/25412840/
- Ruiz-Ojeda FJ, et al. Effects of sweeteners on the gut microbiota: a review of experimental studies and clinical trials. Adv Nutr. 2019. https://pubmed.ncbi.nlm.nih.gov/30721958/
- Singh G, et al. Consumption of the non-nutritive sweetener stevia for 12 weeks does not alter the composition of the human gut microbiota. Nutrients. 2024. https://pubmed.ncbi.nlm.nih.gov/38257188/
