Sweetness should make an electrolyte drink more enjoyable, not leave behind a bitter, metallic, or artificial-tasting aftertaste. That is why Fiber-O-Lytes uses rebaudioside M, better known as Reb M.
Reb M is a high-intensity sweetener related to the stevia plant. However, it offers a cleaner, more sugar-like taste than Reb A, the form traditionally used in many stevia products. It also provides sweetness without adding sugar, making it a useful alternative to both sugar and artificial sweeteners.
Content outline
- What is Reb M?
- Is Reb M the same as traditional stevia?
- Why does Reb M taste better than Reb A?
- How is Reb M different from artificial sweeteners?
- Is Reb M safe?
- Why do we use Reb M in Fiber-O-Lytes?
- Summary
What is Reb M?
Reb M is a steviol glycoside, one of several that are found to occur naturally in the leaves of the Stevia rebaudiana plant that is native to South America [1]. The stevia leaves contain a number of glycosides; these include:
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Stevioside
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Rebaudioside A, or Reb A
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Rebaudioside D, or Reb D
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Rebaudioside M, or Reb M [2]
Each contains a very slight difference in its chemical structure that offers a variation in taste. Reb A is the most abundant of the glycosides found in the leaf, and manufacturers tend to use it in their products. Whereas Reb M has a smoother quality and taste.
Is Reb M the same as traditional stevia?
Both Reb M and Reb A belong to the stevia family and are glycosides. However, they differ in molecular structure, so although both taste sweet, their structures affect how our taste receptors perceive them. In traditional stevia products, Reb A has been largely used, and it does deliver sweetness, but people have noticed the flavour can have a:
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Bitter edge
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Licorice-like flavor
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Metallic note
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Sweetness that lingers for too long
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Delay before the sweetness becomes noticeable
These characteristics have led to Reb A receiving mixed reviews surrounding its reputation. Using Reb M has solved this problem as it delivers the sweetness without the potential flavour kickback.
Reb M belongs to the stevia family, but it is not identical to the traditional Reb A extracts used in many stevia-sweetened products. Both are steviol glycosides, but differences in their molecular structures affect how your taste receptors experience them.
Traditional stevia products often contain a high proportion of Reb A. Although Reb A delivers plenty of sweetness, some people notice:
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A bitter edge
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A licorice-like flavor
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A metallic note
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Sweetness that lingers for too long
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A delay before the sweetness becomes noticeable [3]
These characteristics have sometimes given stevia a mixed reputation. Reb M helps solve the taste problem rather than simply adding more sweetener to cover it.
Why does one type of stevia taste different from another?
Steviol glycosides share the same central structure but carry different arrangements of glucose molecules. These subtle differences influence how strongly and for how long each compound activates the sweet and bitter taste receptors in your mouth.
In simple terms, Reb M is shaped differently from Reb A. That shape produces a sweetness profile that more closely resembles sugar, with fewer distracting flavors.
Why does Reb M taste better than Reb A?
Research suggests that Reb M generally provides faster, cleaner sweetness with less bitterness than Reb A.
In a study involving 126 consumers, Reb M and Reb D did not differ significantly from sugar in their perceived sweetness and bitterness while in the mouth. Reb A, by comparison, was rated as significantly more bitter. Participants were also more likely to describe Reb A as bitter, artificial, and chemical-tasting [4].
Earlier sensory research found that Reb M had a faster onset of sweetness and produced less bitterness, sourness, and astringency than Reb A. It also caused less lingering bitterness after swallowing [5].
This more balanced flavor profile makes Reb M especially useful in drinks. A cleaner sweetness allows the fruit flavors to come through without being overshadowed by a strong stevia aftertaste.
How is Reb M different from artificial sweeteners?
Artificial sweeteners are chemically synthesized sweetening ingredients. Common examples include aspartame, sucralose, saccharin, and acesulfame potassium. Reb M differs because its structure is based on a steviol glycoside found naturally in the stevia leaf. Modern production methods may extract it from specially cultivated plants or use fermentation or enzymes to produce the same sweetening molecule more efficiently.
Reb M also has a different flavor profile from artificial sweeteners. Depending on the ingredient and formulation, some artificial sweeteners can produce metallic, bitter, or lingering notes. Reb M was selected for Fiber-O-Lytes because it creates a clean sweetness that complements our chosen fruit flavors.
Is Reb M safe?
Yes, high-purity glycosides, such as Reb M, are generally considered safe by most food safety authorities around the world. Reb M is made via different approved production methods, and the FDA has no questions regarding its safety when it is produced using these approved production methods.
The acceptable daily intake established for steviol glycosides is 4 milligrams per kilogram of body weight [6], expressed as steviol equivalents. This limit includes a substantial safety margin and applies to regular intake over a lifetime, not just a single serving.
Why do we use Reb M in Fiber-O-Lytes?
Fiber-O-Lytes brings together soluble fiber and electrolytes in one convenient drink. Using Reb M allows the drink to taste sweet without using actual sugar. We use Reb M rather than Reb A so there is no undesirable aftertaste.
Designing Fiber-O-Lytes the way we have means it's:
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Clean-tasting: Less of the bitterness associated with traditional Reb A
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Sugar-free: Adds sweetness without adding sugar
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Fruit-friendly: Allows the main flavors to remain fresh and noticeable
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Convenient: A small quantity delivers the sweetness needed
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No artificial sweeteners: Suitable for people who prefer to avoid them
Each serving of Fiber-O-Lytes provides you with 6 grams of soluble fiber alongside electrolytes. This drink offers an easy way to consume them daily without having to prepare the individual products separately.
Summary
Choosing a sweetener is not simply a matter of replacing one source of sweetness with another. Taste develops through the interaction of the sweetener, flavorings, acidity, minerals, and every other ingredient in the formula.
Reb M gives Fiber-O-Lytes a smooth, approachable sweetness without the added sugar, bitterness, or pronounced aftertaste found in some alternatives. It helps the fruit flavors taste like the main event, exactly as they should.
Ready to taste the difference? Explore Fiber-O-Lytes in watermelon, strawberry and citrus flavors and find your new favorite way to combine soluble fiber with electrolytes. Alternatively, it is available in an unflavored version, too.
Written by: Leanne Edermaniger, M.Sc. Leanne is a professional science writer who specializes in writing about human health and wellbeing. Her work focuses on translating complex medical science into evidence-based, practical health guidance.
