No single sweetener is universally “the healthiest,” but the strongest candidates share a few traits: they don’t spike blood sugar, they don’t disrupt gut bacteria, and they come with minimal long-term safety concerns. Based on current evidence, stevia, monk fruit, and allulose consistently rise to the top of that list, each for slightly different reasons. The best choice depends on what matters most to you, whether that’s blood sugar control, gut health, taste, or how you plan to use it in cooking.
Stevia and Monk Fruit: The Strongest Overall Options
Stevia and monk fruit are both zero-calorie, plant-derived sweeteners that have no meaningful effect on blood sugar. Stevia comes from the leaves of the Stevia rebaudiana plant, while monk fruit gets its sweetness from compounds called mogrosides found in a small melon grown in Southeast Asia. Both are hundreds of times sweeter than sugar, so you need very little.
Monk fruit extract has shown particular promise for metabolic health. In animal studies, it improved insulin sensitivity, reduced high blood sugar, and lowered cholesterol and triglyceride levels while raising beneficial HDL cholesterol. It also appears to slow the absorption of certain sugars in the intestine, blunting the blood sugar rise after a meal. These effects come from its active compounds activating a metabolic pathway in cells that helps regulate how the body processes fat and glucose.
Stevia’s track record on blood sugar is a bit more mixed. Some research links its active compounds to lower blood sugar and increased insulin production, but many other studies have found no significant effect either way. What is consistent across studies: stevia does not cause blood sugar spikes the way regular sugar does. For someone managing diabetes or prediabetes, that alone is a meaningful advantage.
Both sweeteners also perform well for gut health. A 2025 analysis published in Frontiers in Microbiology found that rebaudioside A (the primary sweet compound in stevia) promoted beneficial gut bacteria families that produce butyrate, a short-chain fatty acid important for maintaining the intestinal lining. Monk fruit has shown similar gut-friendly profiles in preliminary research, though it’s been studied less extensively than stevia in this area.
Allulose: A Rare Sugar With Very Few Calories
Allulose is a sugar that exists naturally in small amounts in figs, raisins, and maple syrup. It tastes and behaves like regular sugar in cooking, which makes it unusually versatile. It browns, dissolves, and creates texture in baked goods in ways that stevia and monk fruit simply can’t.
What makes allulose interesting metabolically is that your body barely uses it. The FDA recognizes a caloric value of just 0.4 calories per gram, compared to 4 calories per gram for table sugar. About 70% of consumed allulose passes through the body and is eliminated intact in urine and feces within 48 hours. It doesn’t raise blood sugar or trigger a significant insulin response, which is why the FDA allows manufacturers to exclude it from the “total sugars” and “added sugars” lines on nutrition labels.
The main downside is digestive tolerance. In amounts above roughly 30 to 50 grams in a single sitting, allulose can cause bloating, gas, or diarrhea. Starting with small amounts and increasing gradually helps most people find a comfortable threshold.
Xylitol: Good for Teeth, Risky for Pets
Xylitol is a sugar alcohol found naturally in birch bark and some fruits. It has about 40% fewer calories than sugar (2.4 calories per gram) and a well-documented benefit that other sweeteners can’t claim: it actively reduces the risk of cavities. Bacteria in the mouth can’t ferment xylitol the way they ferment sugar, so it starves the organisms that cause tooth decay. This is why it’s a common ingredient in sugar-free gum and toothpaste.
For gut health, xylitol performs reasonably well. Research shows it promotes beneficial bacterial families like Lachnospiraceae and Ruminococcaceae, both of which produce butyrate and support a healthy intestinal environment. Its blood sugar impact is modest, raising glucose less than sugar but more than stevia or monk fruit.
One critical safety note: xylitol is extremely toxic to dogs. Doses as low as 100 mg per kilogram of body weight can trigger a dangerous drop in blood sugar, and doses above 500 mg per kilogram can cause liver failure. For a 20-pound dog, that’s less than a gram to reach the danger zone. If you have dogs at home, store xylitol products with the same caution you’d give chocolate or medications.
Erythritol: A Question Mark on Heart Health
Erythritol is another sugar alcohol, with nearly zero calories and a clean, mild sweetness. It doesn’t raise blood sugar and causes less digestive upset than xylitol or other sugar alcohols. For years, it was considered one of the safest options available.
That reputation took a hit in 2023, and the concern hasn’t gone away. A study published in JACC: Advances tracked older adults over a median follow-up of about 8.4 years and found that higher circulating levels of erythritol were significantly associated with heart failure hospitalization, cardiovascular death, and total mortality, even after adjusting for traditional risk factors like high blood pressure and cholesterol. A related compound, erythronate, was additionally linked to coronary heart disease and stroke.
Researchers are still working out whether erythritol directly contributes to these outcomes or whether elevated blood levels simply reflect existing metabolic problems. People with obesity or diabetes tend to produce more erythritol internally as a byproduct of glucose metabolism, which complicates the picture. Until this is clarified, erythritol isn’t as easy to recommend as it once was, particularly for people already at higher cardiovascular risk.
Artificial Sweeteners and Gut Health
Sucralose and saccharin remain popular because they’re inexpensive, widely available, and calorie-free. But accumulating evidence suggests they take a toll on the gut microbiome that natural alternatives don’t. A 2025 analysis comparing multiple sweeteners found that sucralose caused the largest reduction in microbial diversity of any sweetener tested. It enriched potentially harmful bacterial families like Enterobacteriaceae while suppressing other communities to less than 10% of their normal levels. Saccharin also decreased diversity, though to a lesser degree.
By contrast, stevia extract and xylitol were far less disruptive, actually promoting the beneficial bacteria involved in producing short-chain fatty acids. This gut health distinction is one of the clearest dividing lines between synthetic and natural sweetener options.
Yacon Syrup: A Prebiotic Sweetener
Yacon syrup is less well-known but worth mentioning for people interested in gut health specifically. Made from the root of a South American plant, it’s rich in fructooligosaccharides, a type of fiber that feeds beneficial gut bacteria. It functions as both a sweetener and a prebiotic.
A meta-analysis of clinical trials found that yacon root significantly reduced BMI and tended to lower body weight, waist circumference, and triglyceride levels. Its fructooligosaccharides slow gastric emptying, suppress hunger, and reduce the intestine’s absorption of sugar and fat. Study participants typically consumed between 6.4 and 14 grams of fructooligosaccharides per day to see benefits. The taste is mildly sweet, similar to molasses, and it works best as a drizzle or in dressings rather than as a 1:1 sugar replacement in baking.
What the WHO Says About Sugar Substitutes
It’s worth noting that the World Health Organization released a guideline advising against using non-sugar sweeteners for weight control. Their position isn’t that these sweeteners are dangerous, but that the evidence doesn’t support them as an effective long-term strategy for reducing body fat or preventing metabolic disease. The concern is that sweeteners may maintain a preference for sweet tastes, making it harder to reduce overall sugar consumption over time.
This doesn’t mean sweeteners are useless. If you’re replacing a daily soda habit with a stevia-sweetened drink, you’re still cutting hundreds of calories and avoiding blood sugar spikes. The WHO’s point is that sweeteners work best as a bridge toward eating less sweet food overall, not as a permanent substitute that lets everything else stay the same.
Choosing the Right One for You
If blood sugar control is your priority, monk fruit and stevia are the strongest picks, with allulose close behind. If you bake frequently and want something that behaves like sugar, allulose is the most practical option. For dental health, xylitol has unique advantages no other sweetener matches. If gut health is your main concern, stevia extract and xylitol both promote beneficial bacteria, while yacon syrup adds a prebiotic dimension.
Most people do well with a mix. Using stevia in coffee, allulose in baking, and xylitol in gum gives you the benefits of each without overloading on any single one. The sweeteners with the most caution flags right now are erythritol (due to unresolved cardiovascular questions) and sucralose (due to its measurable impact on gut bacteria). Neither needs to be treated as poison, but if you’re choosing between options, the alternatives above have cleaner safety profiles.