Sugar substitutes – stevia explained

There were high hopes for stevia when it was approved for sale in 2012, but has it lived up to expectations? We take a closer look at the nutritional claims of stevia, find out where it can be found and ask whether it's a worthy alternative to sugar.

A sachet of stevia extract next to a cup of tea

Commonly known as sweet leaf or sugar leaf, stevia rebaudiana is a widely grown plant that belongs to the sunflower family and is native to Central and South America. Studies have shown it to be a safe, naturally derived, calorie-free sugar substitute, and it's used to sweeten a number of foods and beverages. The compound responsible for the plant’s sweetness is a glycoside found in the plant's leaves. Steviol glycosides are said to be up to 300 times sweeter than sugar.

How it's used

Fresh leaves from the stevia plant can be used in hot or cold drinks, or on their own as a herbal tea. The leaves are dried to form a powder, which can be used in baking – one teaspoon of stevia powder is about the same sweetness as one cup of sugar. It is important to note, however, that stevia does not caramelise. Stevia-based sweeteners can be found in products including yogurts, chocolates and fizzy drinks.

Nutritional information

With no calories, sugar or carbohydrates, stevia’s GI score is 0. Stevia was only approved for sale in the EU in 2012, and it was hoped it would prove useful for diabetics looking for a naturally derived, low-calorie sweetener. 

Health claims

In tests, pure stevia extract has been found to have no effect on blood glucose levels (and may even improve the ability of the body to metabolise glucose). Studies attempting to illustrate stevia's ability to improve insulin sensitivity and benefit diabetes are showing some promise, but it is too early to draw any firm conclusions.

However, because pure stevia extract has a bitter aftertaste, many stevia-based sweeteners are blended with other sugars and artificial sweeteners to improve taste. By blending them with other sweetening ingredients such as dextrose, maltodextrin and sucrose, some stevia products are then capable of raising blood glucose levels. It is therefore important to read the labels on products that claim to be stevia.

Other research suggests stevia may be useful in the treatment of hypertension and management of type 2 diabetes and it is recognised for its anti-inflammatory properties. When not blended with other sweeteners, stevia contains no calories, so it can be beneficial for weight loss and for those looking for an alternative to sugar.

Fresh stevia leaves next to a bowl of sweetener

Is it better for you than sugar?

Unfortunately, many commercial stevia products are highly purified stevia extracts and are not always as healthy as some of their 'natural' labels would lead you to believe. Like with other sugar alternatives, it is the extraction and processing methods that change the properties of the whole leaf into something quite different.

In the sense that pure stevia doesn’t add calories, affect blood sugar or insulin levels, or contribute to tooth decay, it is a better choice than sugar. However, highly refined extracts perpetuate the desire for sweet-tasting foods and drinks and therefore over-consumption is not recommended. As the long-term effects of sweeteners are still unknown, there is a clear need for further experimentation with respect to the metabolic processes involved. 

This article was last reviewed on 5 July 2019 by Kerry Torrens.

A qualified nutritionist (MBANT), Kerry Torrens is a contributing author to a number of nutritional and cookery publications including BBC Good Food magazine. Kerry is a member of the The Royal Society of Medicine, Complementary and Natural Healthcare Council (CNHC), British Association for Applied Nutrition and Nutritional Therapy (BANT).

Jo Lewin is a registered nutritionist (RNutr) with the Association for Nutrition with a specialism in public health. Follow her on Twitter @nutri_jo.

Whether you're looking for sweet substitutes, sugar-free baking guides or simply want to find out more about your recommended daily amounts, find all the answers in our sugar hub:
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Have you tried stevia? Do you find it a useful alternative to sugar? We'd love to hear your thoughts...

Comments, questions and tips

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Tammy Berry's picture
Tammy Berry
21st Jun, 2018
My grandmother was told by her oncologist that the cancer spreading through her mouth, lung, and brain was originally caused by the stevia she grew, free of pesticides, in her kitchen. (Yes, smoking is the leading cause of mouth and lung cancers. However, she never smoked a day in her life and never spent any appreciable time with others who did, so even secondhand smoke inhalation was not a consideration in her case.)
18th Jun, 2018
Pure stevia tastes terrible, if its in something and tastes good you have been conned, if you buy the sugar substitute and it tastes good, you were conned, read the label next time. If stevia could be made palatable it would have been in use b4 they invented the wheel.
20th Jan, 2016
I have at times used stevia. I find it needs to be used moderately because of the bitter aftertaste and also because I needed to cut down on the sweet taste in order to not crave more sweetness. It is amazing how quickly one can change ones expectation of sweetness.
14th Jun, 2014
I have tried different stevia sweeteners, but alas so far they've all got something else added, very misleading when you're trying to quit sugar. I've been on the internet and so many suppliers are out of stock or are not pure stevia. I wanted stevia granules or drops, they have them only in the U.S.A. but it's pretty expensive when you add postage, don't know who to try, any ideas anyone.
20th Jan, 2016
I buy stevia drops in our local health food store. I think most good H F stores carry them.
22nd Sep, 2014
Hi Geraldine - I buy Stevia on Ebay from Lovingsugarfree. They sell drops, concentrated powder and stevia mixes as well as Xylitol products. Hope this helps.
a little sermon
7th Sep, 2018
I thought Stevia would the answer, but it makes my skin itch. I've read a lot about Stevia but only once heard this effect. Has anyone else found this? Is it well known and listed as an official side effect? I certainly hope Stevia doesn't become so popular that manufacturers start using it in nearly all 'healthy' or 'diet' foods. I'd be stymied!
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