Supplements · Sweeteners · Diets
allulose causes osmotic diarrhea
In plain terms: Can the sweetener allulose give you diarrhea?
Part of: 🧪 allulose
Probably yes — but only at large doses; the small amounts used to blunt blood sugar are well below that threshold.
📅 Last reviewed: 2026-07-15 ⓘ
Evidence ladder
How far up the ladder this claim has climbed. A high consensus on a low rung means "consistent so far," not "proven in people."
Top evidence so far: Human trials (RCT / n-of-1)
How the studies fall
What the evidence shows
Allulose causes dose-dependent osmotic diarrhea above ~0.4 g/kg single dose (~28 g for a 70 kg adult); effective glycemic doses (5-10 g) are comfortably below the threshold. Well-tolerated at food-relevant doses.
The evidence (12)
| Source | Grade | Stance | Quality | Finding |
|---|---|---|---|---|
| Ndjite GM, Jiang A, Ravel C, Grant M, Jiang X, Hall B 2024 · bioRxiv (Cold Spring Harbor Laboratory) | in-vitro | tested-null | moderate | bioRxiv preprint (duplicate of pmid:40595444): AlsE enzyme distribution limited to 15.8% of human gut metagenomic samples, suggesting minimal gut microbial capacity to ferment D-allulose. |
| Han Y, Kwon EY, Yu MK, Lee SJ, Kim HJ, Kim SB, Kim YH, Choi MS 2018 · Nutrients | RCT | tested-null | low | 121 Korean overweight adults tolerated 4g and 7g/dose d-allulose twice daily for 12wk without significant GI/diarrhea events at these moderate doses |
| Nishii N, Nomizo T, Takashima S, Matsubara T, Tokuda M, Kitagawa H 2016 · The Journal of veterinary medical science | animal | supports | low | Single acute oral doses of D-allulose in dogs: 1 g/kg tolerated; at 4 g/kg, 5/6 dogs showed transient diarrhea and 1 vomited. Blood glucose dipped slightly without an insulin rise. |
| Minabou Ndjite G, Jiang AK, Ravel CT, Grant MR, Jiang X, Hall B 2025 · Communications biology | in-vitro | tested-null | moderate | AlsE enzyme needed to metabolize D-allulose is present in only 15.8% of human gut metagenomes and in a limited (116/85,202) set of bacterial species, suggesting minimal microbial fermentation of allulose in the colon. |
| Risso D, DunnGalvin G, Saxena S, Doolan A, Spence L, Karnik K 2024 · Food Funct | RCT | supports | moderate | Risso 2024 RCT children 2.5/4.3g well-tolerated only 1 loose stool; confirms threshold |
| Iida T, Hayashi N, Yamada T, Yoshikawa Y, Miyazato S, Kishimoto Y, Okuma K, Tokuda M, Izumori K 2010 · Metabolism | observational | supports | moderate | Iida 2010 psicose ~70% renally excreted poorly fermented; osmotic-laxation basis at high dose |
| Braunstein CR, Noronha JC, Khan TA, Mejia SB, Wolever TM, Josse RG, Kendall CW, Sievenpiper JL 2020 · Clin Nutr | meta-analysis | mixed | high | MA of fructose epimers <=30g/meal; benefits at low doses, with osmotic/GI symptoms emerging at higher allulose intakes flagged for tolerance |
| Osborn L, DuPuis K, Liu S, Della Corte D, Della Corte KA 2026 · Am J Clin Nutr | meta-analysis | mixed | high | SR/MA of allulose and tagatose on glycemic, lipid, uric-acid and anthropometric outcomes. Gastrointestinal-symptom outcomes were an exclusion criterion in the PICOS table, and the abstract reports no pooled tolerability result, so the review did not measure osmotic diarrhea. |
| Chen HP, Kao Y, Lin MW, Lee CT, Wu HT, Kuo HY 2025 · Nutrients | observational | mixed | low | Narrative review of low-calorie sweeteners' metabolic/GI/cardiovascular effects broadly; notes LCS can affect gut microbiota and that effects are context- and agent-dependent, without allulose-specific dose-diarrhea data. |
| Fukunaga K, Yoshimura T, Imachi H, Kobayashi T, Saheki T, Sato S, Saheki N, Jiang W, Murao K 2023 · Nutrients | RCT | tested-null | low | Randomized single-blind crossover, n=20 hospitalised T2D, 2 days per diet: diabetic diet with 8.5 g D-allulose per meal (25.5 g/day) vs the same diet without. Safety endpoint 'number of diarrheal episodes': 'No diarrhea or increased frequency of defecation was observed, and there were no safety concerns.' Dose sits below the claim's scoped ~0.4 g/kg single-dose threshold, so this null is neutral to the claim as scoped; higher doses were not tested here. |
| Han Y, Choi BR, Kim SY, Kim SB, Kim YH, Kwon EY, Choi MS 2018 · Nutrients | observational | supports | moderate | GI-tolerance trial severe diarrhea at 0.5 g/kg single dose; tolerated <=0.4 g/kg max daily 0.9 |
| Hayashi N, Iida T, Yamada T, Okuma K, Takehara I, Yamamoto T, Yamada K, Tokuda M 2010 · Biosci Biotechnol Biochem | RCT | tested-null | moderate | Single 5g D-psicose with meal in 26 adults incl borderline diabetics suppressed glucose with no diarrhea/GI adverse events at low dose |
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Educational only, not medical advice. Grades and scores reflect published evidence weighted by study design and quality; see the methodology.