Allulose vs Erythritol Side Effects: A Detailed Comparison
Both allulose and erythritol are popular low-calorie sweeteners positioned as healthier alternatives to sugar. But when it comes to side effects — particularly digestive side effects — they are not created equal. Understanding the differences can help you choose the sweetener that works best for your body.
How Each Sweetener Is Processed by Your Body
Allulose
Allulose is a rare sugar (monosaccharide) that is absorbed in the small intestine and excreted largely unchanged through the kidneys. It does not undergo significant fermentation in the colon. This is critical because colonic fermentation is the primary cause of GI side effects from sweeteners.
Erythritol
Erythritol is a sugar alcohol (polyol) that is also absorbed in the small intestine — about 90% of it. The absorbed portion is excreted through urine. However, the 10% that is not absorbed reaches the colon, where it can be fermented by gut bacteria, producing gas and drawing water into the intestines.
Digestive Side Effects Compared
Allulose Side Effects
At moderate doses (up to about 0.4g per kg of body weight per serving, or roughly 27g for a 150-pound person), allulose is very well tolerated. Clinical studies show minimal GI effects at these doses. At higher doses, some people may experience:
- Mild bloating
- Loose stools
- Mild nausea (rare)
These effects are typically mild and transient. Importantly, allulose is classified as FODMAP friendly — it does not cause the osmotic or fermentation effects that many other sweeteners do.
Erythritol Side Effects
Erythritol is generally well tolerated compared to other sugar alcohols (xylitol, maltitol, sorbitol are worse). However, common side effects include:
- Bloating and gas
- Stomach rumbling (borborygmi)
- Nausea at moderate to high doses
- Diarrhea or loose stools, especially at doses above 50g
- A cooling or "minty" sensation in the mouth
A 2023 study published in Nature Medicine also raised concerns about erythritol and cardiovascular risk, finding that high blood levels of erythritol were associated with increased risk of heart attack and stroke. While this study has limitations and does not prove causation, it generated significant discussion in the medical community.
GI Tolerance: Head-to-Head
Clinical studies directly comparing GI tolerance have consistently found allulose to be better tolerated:
- A study in the Journal of Food Science found that allulose caused significantly fewer digestive symptoms than equivalent doses of erythritol
- The threshold for GI discomfort is higher with allulose — most people can consume 30–50g per day without issues, while erythritol symptoms often begin at 30–40g per day
- Allulose does not cause the osmotic laxative effect that sugar alcohols are known for
Non-Digestive Side Effects
Allulose
- No known cardiovascular concerns
- No impact on blood sugar or insulin
- May actually provide metabolic benefits (GLP-1 activation, fat reduction)
- FDA GRAS status with a strong safety profile
Erythritol
- Potential cardiovascular concerns (2023 Nature Medicine study)
- No impact on blood sugar (glycemic index of 0)
- No known metabolic benefits
- FDA GRAS status
Who Should Choose Allulose Over Erythritol?
Allulose is the better choice for:
- People with IBS or sensitive digestion: Allulose's FODMAP-friendly status makes it significantly easier on sensitive GI systems
- People who consume larger amounts of sweetener daily: The higher GI tolerance threshold means fewer issues at real-world usage levels
- People concerned about cardiovascular health: The erythritol-cardiovascular link, while not conclusive, is worth considering
- People who dislike the cooling sensation: Erythritol has a notable cooling effect that some people find unpleasant
- Bakers and cooks: Allulose caramelizes and browns; erythritol does not
When Erythritol Might Be Preferred
Erythritol still has some advantages. It has slightly fewer calories (0.2 cal/g vs 0.4 cal/g for allulose), is typically less expensive, and matches sugar's sweetness more closely (70% for erythritol vs 70% for allulose — roughly equivalent). For people who tolerate it well and use it in moderate amounts, erythritol remains a reasonable choice.
Frequently Asked Questions
Can allulose cause diarrhea like erythritol?
At very high doses, allulose can cause loose stools. However, the threshold is significantly higher than erythritol, and the effect is generally milder. At normal usage levels (a few tablespoons per day), most people experience no GI issues with allulose.
Is allulose safer than erythritol?
Both have FDA GRAS status. However, allulose has a cleaner safety profile with no cardiovascular concerns and better GI tolerance. The 2023 erythritol-cardiovascular study added a question mark to erythritol's long-term safety that does not exist for allulose.
Can I mix allulose and erythritol?
Yes. Some products blend the two sweeteners. This can work well in small amounts, but be mindful of the combined GI impact if you are consuming larger quantities.
Which sweetener is better for diabetics?
Both have a glycemic index of zero and do not raise blood sugar. However, allulose has the added benefit of potentially improving glucose metabolism through GLP-1 activation, making it the more research-supported choice for people managing blood sugar.
The Bottom Line
When comparing allulose vs erythritol side effects, allulose wins on digestive tolerance, cardiovascular safety profile, and metabolic benefits. Erythritol is a reasonable sweetener, but for people who prioritize minimizing side effects, allulose is the superior choice. For more details, visit our allulose comparison page.