Next-Generation Natural Sweeteners Reb-M & Reb-D Zero Calories, No Weight Gain
As awareness of healthy eating continues to rise, zero-calorie natural sweeteners have become a major focus of consumer attention. In June 2025, a study published in the international journal Food Chemistry: X systematically investigated the comprehensive metabolic effects of the emerging steviol glycosides Reb-D and Reb-M.
The study demonstrated that these two novel sweeteners showed no adverse effects across multiple key metabolic dimensions—including body weight, liver, adipose tissue, skeletal muscle, and gut health—highlighting their strong potential as safe sugar alternatives.
PART 01
What Are Steviol Glycosides Reb-M and Reb-D?
Steviol glycosides (commonly known as stevia sweeteners) are glycosides extracted from Stevia rebaudiana and are currently the most widely used natural zero-calorie sugar substitutes in the food and beverage industry.
Among the various steviol glycosides, Rebaudioside A (Reb-A) once became the star of the sweetener market due to its high sweetness and relatively low bitterness. However, with advances in technology, two new rising stars in the steviol glycoside family—Reb-M and Reb-D—have gained increasing attention.
Although their content in dried stevia leaves is relatively low (Reb-M at approximately 0.1% and Reb-D at approximately 0.2%, far lower than Reb-A’s 2.3–3.8%), they offer a more natural flavor profile and a more balanced sweetness. As a result, Reb-M and Reb-D are gradually becoming the preferred choice for the next generation of sugar substitutes.
PART 02
Verified Safety Across Five Key Dimensions — Enjoy Sweetness with Confidence
(1) Body Weight: Sweet Without Weight Gain
In the study, mice were given drinking water containing 0.02% Reb-D or Reb-M for 16 consecutive weeks. The results showed:
Reb-D and Reb-M do not induce or exacerbate obesity.
This finding is undoubtedly good news for consumers who wish to enjoy sweetness without worrying about weight gain.
(2) Liver Safety: Protecting a Vital Metabolic Organ
As a central metabolic organ, liver health is critical to overall well-being.
The study indicated that long-term intake of fructose/sucrose mixtures increased the protein levels of key hepatic lipogenesis enzymes (ACC and FAS), showing a tendency to promote fat synthesis in the liver.
Reb-D and Reb-M do not promote hepatic steatosis.
In contrast, Reb-D and Reb-M did not exhibit such effects. Their outcomes were comparable to those of the standard high-fat diet group, with consistent results observed in both male and female mice. These findings provide strong evidence supporting the liver safety of Reb-D and Reb-M.
(3) Fat-Burning Engine: Brown Adipose Tissue Activation
The study also explored the effects of sweeteners on the thermogenic function of brown adipose tissue (BAT), often referred to as the body’s “fat-burning engine.” BAT thermogenesis plays a crucial role in maintaining energy balance.
Reb-D and Reb-M do not impair brown adipose tissue function.
Under normal dietary conditions, Reb-D, Reb-M, and fructose/sucrose mixtures did not significantly alter the expression of the key thermogenic protein UCP1 in BAT. However, under high-fat diet conditions, supplementation with Reb-D or Reb-M slightly increased UCP1 protein expression.
This suggests that Reb-D and Reb-M not only do not compromise BAT thermogenic function, but may also exert positive regulatory effects under high-fat dietary conditions.
(4) Skeletal Muscle Metabolism: Stable Energy Utilization
Skeletal muscle is a major energy-consuming tissue, and its metabolic status directly influences overall health.
Intake of Reb-D and Reb-M does not interfere with skeletal muscle metabolism.
Compared with controls, fructose/sucrose intake increased the expression of mitochondrial oxidative phosphorylation (OXPHOS) proteins and the muscle differentiation marker MyoD. While the non-caloric sweeteners Reb-D and Reb-M also enhanced certain mitochondrial proteins, they did not affect muscle differentiation markers.
Notably, Reb-D showed a tendency to enhance insulin signaling activity (p-AKT/AKT), indicating potential additional health benefits. Overall, the findings confirm that Reb-D and Reb-M do not cause adverse effects on skeletal muscle metabolism.
(5) Gut Microbiota: Promoting a Healthier Microbial Ecosystem
Often referred to as the body’s “second genome,” the gut microbiota plays a critical role in overall metabolic health.
Reb-D and Reb-M exert beneficial effects on gut microbiota composition.
The study found that fructose/sucrose mixtures reduced microbial diversity and promoted the overgrowth of potentially harmful bacteria (such as Robinsoniella). In contrast, Reb-D and Reb-M promoted the growth of beneficial bacteria, including Akkermansia, and enriched bacterial genera associated with short-chain fatty acid production and improved metabolic health (such as Faecalibacterium in the Reb-M group).
Additionally, Reb-D was associated with specific probiotics such as Bifidobacterium. These results suggest that Reb-D and Reb-M help shape a healthier and more balanced gut microbiota.
The study demonstrated that these two novel sweeteners showed no adverse effects across multiple key metabolic dimensions—including body weight, liver, adipose tissue, skeletal muscle, and gut health—highlighting their strong potential as safe sugar alternatives.
PART 01
What Are Steviol Glycosides Reb-M and Reb-D?
Steviol glycosides (commonly known as stevia sweeteners) are glycosides extracted from Stevia rebaudiana and are currently the most widely used natural zero-calorie sugar substitutes in the food and beverage industry.
Among the various steviol glycosides, Rebaudioside A (Reb-A) once became the star of the sweetener market due to its high sweetness and relatively low bitterness. However, with advances in technology, two new rising stars in the steviol glycoside family—Reb-M and Reb-D—have gained increasing attention.
Although their content in dried stevia leaves is relatively low (Reb-M at approximately 0.1% and Reb-D at approximately 0.2%, far lower than Reb-A’s 2.3–3.8%), they offer a more natural flavor profile and a more balanced sweetness. As a result, Reb-M and Reb-D are gradually becoming the preferred choice for the next generation of sugar substitutes.
PART 02
Verified Safety Across Five Key Dimensions — Enjoy Sweetness with Confidence
(1) Body Weight: Sweet Without Weight Gain
In the study, mice were given drinking water containing 0.02% Reb-D or Reb-M for 16 consecutive weeks. The results showed:
- Under both normal and high-fat diets, there were no significant differences in body weight gain, energy intake, fat accumulation, or other obesity-related indicators compared with the control group.
- The Reb-D group even exhibited improved blood glucose and lipid profiles, suggesting potential metabolic regulatory benefits.
Reb-D and Reb-M do not induce or exacerbate obesity.
This finding is undoubtedly good news for consumers who wish to enjoy sweetness without worrying about weight gain.
As a central metabolic organ, liver health is critical to overall well-being.
The study indicated that long-term intake of fructose/sucrose mixtures increased the protein levels of key hepatic lipogenesis enzymes (ACC and FAS), showing a tendency to promote fat synthesis in the liver.
Reb-D and Reb-M do not promote hepatic steatosis.
In contrast, Reb-D and Reb-M did not exhibit such effects. Their outcomes were comparable to those of the standard high-fat diet group, with consistent results observed in both male and female mice. These findings provide strong evidence supporting the liver safety of Reb-D and Reb-M.
The study also explored the effects of sweeteners on the thermogenic function of brown adipose tissue (BAT), often referred to as the body’s “fat-burning engine.” BAT thermogenesis plays a crucial role in maintaining energy balance.
Reb-D and Reb-M do not impair brown adipose tissue function.
Under normal dietary conditions, Reb-D, Reb-M, and fructose/sucrose mixtures did not significantly alter the expression of the key thermogenic protein UCP1 in BAT. However, under high-fat diet conditions, supplementation with Reb-D or Reb-M slightly increased UCP1 protein expression.
This suggests that Reb-D and Reb-M not only do not compromise BAT thermogenic function, but may also exert positive regulatory effects under high-fat dietary conditions.
Skeletal muscle is a major energy-consuming tissue, and its metabolic status directly influences overall health.
Intake of Reb-D and Reb-M does not interfere with skeletal muscle metabolism.
Compared with controls, fructose/sucrose intake increased the expression of mitochondrial oxidative phosphorylation (OXPHOS) proteins and the muscle differentiation marker MyoD. While the non-caloric sweeteners Reb-D and Reb-M also enhanced certain mitochondrial proteins, they did not affect muscle differentiation markers.
Notably, Reb-D showed a tendency to enhance insulin signaling activity (p-AKT/AKT), indicating potential additional health benefits. Overall, the findings confirm that Reb-D and Reb-M do not cause adverse effects on skeletal muscle metabolism.
Often referred to as the body’s “second genome,” the gut microbiota plays a critical role in overall metabolic health.
Reb-D and Reb-M exert beneficial effects on gut microbiota composition.
The study found that fructose/sucrose mixtures reduced microbial diversity and promoted the overgrowth of potentially harmful bacteria (such as Robinsoniella). In contrast, Reb-D and Reb-M promoted the growth of beneficial bacteria, including Akkermansia, and enriched bacterial genera associated with short-chain fatty acid production and improved metabolic health (such as Faecalibacterium in the Reb-M group).
Additionally, Reb-D was associated with specific probiotics such as Bifidobacterium. These results suggest that Reb-D and Reb-M help shape a healthier and more balanced gut microbiota.
