Allulose Side Effects: Doses, Tolerance & Human Studies
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By Brandon Kuipers, founder of Ozzi · Reviewed September 10, 2026
Allulose has generally reassuring human tolerance findings at the amounts and durations studied, with digestive symptoms becoming more relevant as exposure increases. The studies do not establish a universal symptom-free cutoff. Our drink contains 8 g allulose per stick, and we distinguish that serving from the larger or divided doses used in tolerance experiments.
Can allulose cause bloating or diarrhea?
Yes, human studies have recorded bloating, abdominal discomfort, nausea and loose stools, particularly as amounts increase. That does not mean an 8 g serving commonly causes these effects. It means dose, dosing pattern and individual tolerance need to be considered together. The research below does not provide a reliable symptom rate for an 8 g Ozzi serving.
What do the human tolerance studies show?
| Study | Amount and duration | Main finding and limit |
|---|---|---|
| Hayashi et al., 2010 | 5 g three times daily for 12 weeks; 17 participants in the repeated-intake experiment | No abnormal clinical effects attributed to this intake were reported. Small sample; this was not Ozzi. Hayashi N et al., 2010 |
| Han et al., 2018 | 29 young adults; escalating single amounts of 0.1–0.5 g/kg and a separate daily escalation | More digestive symptoms at higher exposures. The authors proposed study-specific limits, not a guarantee of no symptoms below them. Han Y et al., 2018 |
| Bloomer et al., 2024 | 40 adults; placebo or 1–3 packets of a different hydration product daily for four weeks | Generally well tolerated, with mild bloating/cramping signals. The proprietary blend does not disclose a clean allulose-only amount. Bloomer RJ et al., 2024 |
| Qi et al., 2026 | 50 adults randomized, 49 completed; 12 g twice daily or 18 g twice daily for 30 days | Symptoms were generally mild and transient, often early in use. No zero-allulose control; these are not 8 g serving data. Qi L et al., 2026 |
Is 25 g a proven threshold for discomfort?
No. The often-cited 2018 study scaled intake to body weight. At the study's average body weight, 0.4 g/kg was approximately 25 g. A proposed limit aimed at avoiding severe symptoms is different from proving that milder symptoms never occur below it. Han Y et al., 2018.
The newer 30-day study used separate 12 g or 18 g servings twice daily and reported digestive symptoms in 48% overall, generally mild and transient. Without a zero-allulose control, it cannot establish how many symptoms were caused by allulose, and it cannot estimate the rate at 8 g. It does show why “discomfort only starts at 25 g” is too absolute. Qi L et al., 2026.
How does this relate to one Ozzi stick?
One stick contains 8 g allulose, below each individual serving in the 2026 divided-dose tolerance study. Our amount was selected with glucose research in mind, including a study testing 7.5 and 10 g alongside sucrose. That provides dose context, not a clinical safety or appetite trial of our complete formula. Franchi F et al., 2021.
Do not convert an allulose-only experiment into a maximum number of Ozzi sticks. Each stick supplies several ingredients, and the current product label governs use. Mix a stick in 16–20 oz cold water and follow its daily-use directions. If a serving disagrees with you, do not increase the amount to push through symptoms.
Are there human allulose and GLP-1 studies?
Yes. Human studies have measured GLP-1 after allulose, including an 18-person experiment using 25 g delivered into the stomach and a smaller 2026 meal experiment using 10 g. They should not be described as “no human evidence,” nor as proof that every serving produces fewer cravings. Teysseire F et al., 2022; Noh J et al., 2026.
GLP-1 measurement requires careful sample handling and a clear distinction between active and total hormone. Those methods affect interpretation; they are not a reason to assume an unmeasured benefit. Wewer Albrechtsen NJ et al., 2015.
Does allulose work through sweet receptors in the stomach?
The mechanism should not be reduced to that claim. In the 25 g human experiment, blocking the sweet-taste receptor with lactisole did not prevent the gut-hormone responses. There is broader research on intestinal and gut–nerve signaling, which our allulose library separates by evidence type. Teysseire F et al., 2022.
Do our capsules contain allulose?
No. Our capsules are a different format with konjac glucomannan, L-lysine butyrate, African mango, ursolic acid and chromium. Their label lists chicory root inulin under Other Ingredients. Choosing capsules removes allulose from that serving; it is not a promise that another formula cannot cause digestive symptoms. Compare both labels.
What does this tell us about long-term use?
The experiments described here range from acute exposure to 12 weeks. They do not establish years-long tolerance in every population. Keep duration, study size and participant health in view when reading reassuring short-term findings. Significant or persistent symptoms deserve medical advice rather than an assumption that they are normal adaptation.
Read the individual studies
Allulose · 2024 · Human tolerance study
40 adults; four randomized groups; placebo or one, two or three hydration-product packets daily for four weeks.
The beverage was generally well tolerated over four weeks, with some mild gastrointestinal signals. Its packets contained an allulose/amino-acid/electrolyte blend, so this does not validate three Ozzi sticks daily.
Allulose · 2010 · Human trial
26-person acute randomized crossover, 5 g with a meal; separate 17-person 12-week trial, 5 g three times daily.
The repeated-intake experiment offers reassuring small-study context at 15 g per day. It does not establish a universal tolerance threshold or long-term outcomes beyond the study.
Common questions
How much allulose is in Ozzi?
Our drink sticks contain 8 g allulose each. Our capsules contain no allulose. Follow the current label for the format you use.
Does allulose cause diarrhea below 25 g?
The evidence does not establish 25 g as a universal threshold. Symptoms depend on the person and dosing pattern, and the available studies do not estimate the symptom rate for an 8 g Ozzi serving.
Does the hydration-beverage study prove three Ozzi sticks are safe?
No. It tested another product with a proprietary blend and different ingredients. Its packet counts cannot be converted into an Ozzi daily-use limit.
Where can I find more allulose research?
Our public Research library includes human glucose, gut-hormone and tolerance studies, along with clearly labeled animal and laboratory research.
Explore our drink sticks · Explore our capsules · Ingredients and labels · Full research library
