Alpha-cyclodextrin
Also called α-cyclodextrin, alpha-CD, αCD, cyclohexaamylose, alpha-dextrin, fat-binding fiber.
Best grade D across 6 graded outcomes Other Last checked
The short answer
From 11 sourcesAlpha-cyclodextrin is a soluble corn-derived fiber sold as a fat binder. The fat-binding idea failed in a Mayo Clinic crossover, and a 401-person, 6-month trial found no cholesterol benefit. The best support is a modest effect on blood sugar after a starchy meal, which is the basis of an EU claim.
Every graded outcome on this page
6 rows · line = participants- DGrade DCardiometabolic indices with oral cyclodextrinsCardiometabolicn 742
- DGrade D10 km cycling time trial and post-exercise fatigueExercisen 81
- DGrade DBlood lipids and glucose markers in healthy adultsLipids and glucosen 75
- DGrade DGlycaemic and appetite responses to breadBlood sugar after mealsn 10
- DGrade DStool fat losses (the fat-binding mechanism)Fat bindingn 8
- ∅No effectTotal cholesterol and weight-loss supportCholesteroln 401
- 3 more graded outcomes, in the evidence chapter
Key facts
- Fat binding
- 2 g with each meal for 3 days did not raise stool fat vs placebo in 8 healthy adults (Mayo Clinic crossover)3
- Cholesterol
- In 401 adults with prediabetes and overweight, 6 months of alpha-cyclodextrin changed total cholesterol by -1.5 mg/dL vs placebo (p = 0.51)1
- Side effects
- Constipation 16 vs 4 participants and cough 8 vs 1 vs placebo in the 401-person trial; about 8% vs 3% reported minor GI symptoms in a 75-person crossover12
- Blood sugar after meals
- An EU claim (added in 2013) covers food with at least 5 g per 50 g of starch in the meal; the 2026 meta-analysis found modest after-meal effects only789
- Endurance
- 1 g/day for 9 weeks cut 10 km cycling time by about 53 s in 81 men; the trial was funded by Asahi Quality & Innovations, five of its six authors work there, and four filed a patent on the use5
What it is
Alpha-cyclodextrin is a soluble fiber of six glucose units in a ring, sold as a fat binder and studied for after-meal blood sugar.
Forms, side by side
2 forms named in our sources. The rest show what our data holds, and say plainly where it holds nothing yet.
Alpha-cyclodextrin forms compared
2 forms| 2 forms | Powder, capsules and tablets (fat-binder products) | As a food ingredient (enriched breads, fiber) |
|---|---|---|
| Absorption in people | It is not digested in the small intestine and is fermented by gut microbes. Stool fat did not rise with 2 g per meal.53 | Not reported in the cited abstracts.6 |
| GI tolerance | No serious adverse events related to it in a 75-person crossover; constipation and cough were more common than placebo in the 401-person trial.12 | Not reported in the cited abstracts.6 |
| Studied for | Cholesterol (6 g/day), fat binding (2 g per meal) and endurance (1 g/day) | Blood sugar after starchy meals |
- Alpha-cyclodextrin powder, capsules and tablets (fat-binder products)
- Absorption in people
- It is not digested in the small intestine and is fermented by gut microbes. Stool fat did not rise with 2 g per meal.53
- GI tolerance
- No serious adverse events related to it in a 75-person crossover; constipation and cough were more common than placebo in the 401-person trial.12
- Studied for
- Cholesterol (6 g/day), fat binding (2 g per meal) and endurance (1 g/day)
- Alpha-cyclodextrin as a food ingredient (enriched breads, fiber)
What the human research says
Human trials only, one row per outcome. The form line shows what each trial actually tested. Grades follow our evidence-grading policy.
Trial map
6 graded outcomes, largest study first6 graded outcomes: 2 improved, 2 mixed, 2 no effect. The largest, a 2026 meta-analysis of 742 people on cardiometabolic indices with oral cyclodextrins, found mixed results. Outcomes that improved came from smaller studies: a median of 46 people, against 205 for no effect.
Bar: the ages a study enrolled (running to the edge when it states no upper or lower limit). Dot: only a mean age, counted as near your age within 5 years. Tick: the mean age inside a range.
4Blood lipids and glucose markers in healthy adults: mixed, 18–75
2Total cholesterol and weight-loss support: no effect, 18+
310 km cycling time trial and post-exercise fatigue: improved, 20–49
6Stool fat losses (the fat-binding mechanism): no effect, 23–54
1Cardiometabolic indices with oral cyclodextrins: mixed, ages not stated
5Glycaemic and appetite responses to bread: improved, ages not stated
1Cardiometabolic indices with oral cyclodextrins
Mixed · Grade D · Meta-analysis, 742 people, 2026
Adults in 13 RCTs of oral cyclodextrins, from acute postprandial studies to 6 months
Dose, result and source| Outcome | Found | People | Study | Who was studied |
|---|---|---|---|---|
| Cardiometabolic indices with oral cyclodextrins | Mixed | 742 | Grade D · Meta-analysis, 2026 | Adults in 13 RCTs of oral cyclodextrins, from acute postprandial studies to 6 months |
| Total cholesterol and weight-loss support | No effect | 401 | No-effect grade · RCT, 2020 | Adults with prediabetes and BMI 25 or higher (mean BMI 34.6); 200 on alpha-cyclodextrin vs 201 on placebo |
| 10 km cycling time trial and post-exercise fatigue | Improved | 81 | Grade D · RCT, 2025 | Healthy non-athlete men aged 20 to 49 who exercise regularly (42 placebo, 39 alpha-cyclodextrin) |
| Blood lipids and glucose markers in healthy adults | Mixed | 75 | Grade D · Crossover RCT, 2016 | Healthy adults aged 18 to 75; 75 of 103 screened completed |
| Glycaemic and appetite responses to bread | Improved | 10 | Grade D · Crossover RCT, 2022 | Ten healthy normoglycaemic adults |
| Stool fat losses (the fat-binding mechanism) | No effect | 8 | Grade D · Crossover RCT, 2018 | Eight healthy volunteers (5 premenopausal women, 3 men, ages 23 to 54, BMI 18 to 27) |
Every graded row
6 rowsShowing 6 of 6 outcomes. Human trials only.
DGrade DCardiometabolic indices with oral cyclodextrinsCardiometabolicNo consistent long-term benefit; modest after-meal effectMeta-analysis · 13 studies
n 742 · 2026
Mixed Pooled long-term effects were not significant for triglycerides (WMD 0.03 mmol/L; p = 0.68), blood glucose (-0.05 mmol/L; p = 0.25) or HbA1c (-0.06%; p = 0.59). The 24-week subgroup showed higher triglycerides (+0.29 mmol/L; p = 0.03). Some products may modestly improve postprandial glucose responses.
- Design
- Meta-analysis, 13 studies, n = 742, 2026
- Population
- Adults in 13 RCTs of oral cyclodextrins, from acute postprandial studies to 6 months
- Form
- Oral cyclodextrins (alpha-cyclodextrin among them)
- Dose
- Varied by trial
- Duration
- Hours to 6 months
- Source
- Reference 7 · PubMed 42318184 (opens PubMed)
DGrade D10 km cycling time trial and post-exercise fatigueExerciseFaster time trial and less fatigue in one trialRCT
n 81 · 2025
Improved 10 km time trial averaged 1,073.2 s vs 1,126.4 s on placebo (p = 0.016). Post-exercise fatigue scores were lower (p = 0.043) and exercise heart rate rose less (144.2 vs 152.3 bpm; p = 0.016).
- Design
- RCT, n = 81, 2025
- Population
- Healthy non-athlete men aged 20 to 49 who exercise regularly (42 placebo, 39 alpha-cyclodextrin)
- Form
- Alpha-cyclodextrin
- Dose
- 1 g/day
- Duration
- 9 weeks
- Source
- Reference 5 · PubMed 39764495 (opens PubMed)
DGrade DBlood lipids and glucose markers in healthy adultsLipids and glucoseSmall changes in secondary markersCrossover RCT
n 75 · 2016
Mixed Small-LDL particle number fell 10% (p < 0.045), fasting glucose 1.6% (p < 0.05) and an insulin resistance index 11% (p < 0.04) vs placebo. Minor GI symptoms occurred in about 8% on alpha-cyclodextrin vs 3% on placebo (p = 0.2). No serious adverse events were attributed to it.
- Design
- Crossover RCT, n = 75, 2016
- Population
- Healthy adults aged 18 to 75; 75 of 103 screened completed
- Form
- Alpha-cyclodextrin
- Dose
- 6 g/day
- Duration
- 12 to 14 weeks per arm, 7-day washout
- Source
- Reference 2 · PubMed 27405337 (opens PubMed)
DGrade DGlycaemic and appetite responses to breadBlood sugar after mealsLower glycaemic index of enriched breadCrossover RCT
n 10 · 2022
Improved Alpha-cyclodextrin bread had a glycaemic index of 49.7, classed as low, and gave a lower desire for the next meal than white bread. Glucose, insulin and GLP-1 responses were reduced similarly with the two enriched breads.
- Design
- Crossover RCT, n = 10, 2022
- Population
- Ten healthy normoglycaemic adults
- Form
- Wheat bread enriched with alpha-cyclodextrin (or with a hydroxytyrosol complex)
- Dose
- Dose not stated in the abstract (bread portions giving 50 g available carbohydrate)
- Duration
- Single meals, 180-minute follow-up
- Source
- Reference 6 · PubMed 35668121 (opens PubMed)
DGrade DStool fat losses (the fat-binding mechanism)Fat bindingNo extra dietary fat lost in stoolCrossover RCT
n 8 · 2018
No effect About 20% of the 14C tripalmitin tracer was recovered in fecal lipids, with no difference between alpha-cyclodextrin and placebo. Total fecal fat and tracer appearance in plasma triglycerides also did not differ.
- Design
- Crossover RCT, n = 8, 2018
- Population
- Eight healthy volunteers (5 premenopausal women, 3 men, ages 23 to 54, BMI 18 to 27)
- Form
- Alpha-cyclodextrin
- Dose
- 2 g with each meal for 3 days (breakfast plus 2 g per meal for 2 more days)
- Duration
- 3 days, at least 2-week washout
- Source
- Reference 3 · PubMed 30107536 (opens PubMed)
∅No effectTotal cholesterol and weight-loss supportCholesterolNo cholesterol benefitRCT
n 401 · 2020
No effect No difference in total cholesterol after 6 months (-1.5 mg/dL; 95% CI -6.6 to 3.5; p = 0.51). Alpha-cyclodextrin was associated with constipation (16 vs 4; p = 0.006) and cough (8 vs 1; p = 0.02). All participants also received dietetic advice for weight loss.
- Design
- RCT, n = 401, 2020
- Population
- Adults with prediabetes and BMI 25 or higher (mean BMI 34.6); 200 on alpha-cyclodextrin vs 201 on placebo
- Form
- Alpha-cyclodextrin (2 x 2 design with hydrolyzed ginseng)
- Dose
- 6 g/day (two 1,000 mg tablets after each of three meals, per the full text)
- Duration
- 6 months
- Source
- Reference 1 · PubMed 33201232 (opens PubMed)
What the numbers add up to
Each point is worked out from the data and the sources numbered on this page, with the arithmetic shown under it. It adds no new data and is not medical advice.
The fat-binding story did not hold up in the best tests
The after-meal glucose effect is the best-supported use
The most positive results come from people tied to the product
Studied doses
Doses used in research, shown against the official limits. They describe the studies, not a recommendation for you.
Studied doses in research, not advice. These are amounts used in research, not personal advice. Your clinician or pharmacist can say what fits you.
Doses studied in human trials
Interactions and safety
Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.
Interactions
0 agentsNone found in our sources.
Check with what you take
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Starting from one medicine? The interaction checker rates how serious each pair is, on a curated list of 19 entries for 11 medicines. This cabinet has no severity rating: it lists every interaction row our supplement pages cite.
Who should be careful
4 groups- Constipation-prone people
- Constipation was more common with alpha-cyclodextrin than placebo in a 401-person, 6-month trial (16 vs 4 participants).1
- People expecting fat or cholesterol effects
- Stool fat did not rise and total cholesterol did not change in the larger and better-controlled trials cited.13
- People on glucose-lowering drugs
- The after-meal glucose effect is modest, but anyone on diabetes medicine who adds a fiber that changes post-meal glucose should tell their prescriber. No drug interaction studies were found in the sources reviewed.78
- Pregnancy, breastfeeding and children
- No alpha-cyclodextrin supplement studies in these groups were found in the sources reviewed, so safety of concentrated products is unknown.10
How to read the label
What to check on the Supplement Facts panel.
How to read the label
3 checksCheck grams of alpha-cyclodextrin
Know the claim limits
Frequently asked questions
Short answers to common questions; the numbers link to the sources below.
Common questions
6 answersWhat is alpha-cyclodextrin?
Does alpha-cyclodextrin bind fat?
Not measurably in the best human test: 2 g with each meal for 3 days did not increase stool fat in 8 healthy adults.3
Does it lower cholesterol?
Does it help blood sugar?
What are the side effects?
In the 401-person trial, constipation (16 vs 4) and cough (8 vs 1) were more common with alpha-cyclodextrin than placebo. Counting the rash seen with the ginseng arm too, 37 of 401 participants (9.2%) had one of these events.1
Is it legal in the US?
FDA issued a 'no questions' letter on GRAS notice 155 in 2004 for use in selected foods.10
Sources
11 sources: trial abstracts, NIH fact sheets and reference databases. Numbers in the text link here.
Sources cited on this page
11 sources- 1Effects of α-Cyclodextrin on Cholesterol Control and Hydrolyzed Ginseng Extract on Glycemic Control in People With Prediabetes: A Randomized Clinical Trial.RCT JAMA Netw Open, 2020 · PMID 33201232
- 2Randomized double blind clinical trial on the effect of oral α-cyclodextrin on serum lipids.Crossover RCT Lipids Health Dis, 2016 · PMID 27405337
- 3The Soluble Fiber α-Cyclodextrin Does Not Increase the Fecal Losses of Dietary Fat in Adults-A Double-Blind, Randomized, Placebo-Controlled, Crossover Trial.Crossover RCT J Nutr, 2018 · PMID 30107536
- 4The effect of α-cyclodextrin on postprandial lipid and glycemic responses to a fat-containing meal.Crossover RCT Metabolism, 2013 · PMID 23806736
- 5α-Cyclodextrin supplementation improves endurance exercise performance and reduces post-exercise fatigue in human males: a randomized, double-blind, placebo-controlled, parallel-group study.RCT Biosci Microbiota Food Health, 2025 · PMID 39764495
- 6Positive postprandial glycaemic and appetite-related effects of wheat breads enriched with either α-cyclodextrin or hydroxytyrosol/α-cyclodextrin inclusion complex.Crossover RCT Eur J Nutr, 2022 · PMID 35668121
- 7Effect of cyclodextrins on cardiometabolic indices: a systematic review and meta-analysis of randomized controlled trials.Meta-analysis J Diabetes Metab Disord, 2026 · PMID 42318184
- 8Scientific Opinion on the substantiation of health claims related to alpha cyclodextrin and reduction of post prandial glycaemic responses (ID 2926, further assessment) pursuant to Article 13(1) of Regulation (EC) No 1924/2006Guideline EFSA Journal, 2012 · doi.org
- 9Commission Regulation (EU) No 432/2012, annex as amended by Commission Regulation (EU) No 536/2013 (entry for alpha-cyclodextrin: at least 5 g per 50 g of starch in a quantified portion as part of the meal)Guideline European Commission, 2013 · legislation.gov.uk
- 10GRAS Notice GRN No. 155: alpha-Cyclodextrin (FDA has no questions, December 22, 2004)Database U.S. Food and Drug Administration, 2004 · hfpappexternal.fda.gov
- 11GRAS Notice GRN No. 678: Alpha-cyclodextrin (at the notifier's request, FDA ceased to evaluate the notice, April 14, 2017)Database U.S. Food and Drug Administration, 2017 · hfpappexternal.fda.gov
What changed
Every dated change to this page: what changed, who made it and why.
Change log
2 entries| Date | Change | Who and why |
|---|---|---|
| evidence | Adversarial review: 6-month trial dose (6 g/day) and funding taken from the full text; 8-person stool-fat crossover regraded no-effect to D (too small to show no effect); conflict-of-interest wording matched to the published statements; meta-analysis study count set to 13; EU claim dated to Regulation 536/2013; GRN 678 statement given its own FDA record as a source; EFSA detail that could not be opened removed; side-effect FAQ no longer attributes the ginseng rash to alpha-cyclodextrin. | Writer: Kymata Health EditorialTrigger: adversarial review |
| all | Initial editorial evidence review. Every PMID checked against NCBI E-utilities esummary (title, year, journal) and each cited abstract read; figures taken from the abstracts. EU claim from the consolidated annex of Regulation 432/2012 (entry inserted by Regulation 536/2013) and the 2012 EFSA opinion; US status from the FDA GRAS notice inventory record (page updated 2026-10-15). Several trials had authors tied to the product makers, as noted in the evidence rows. | Writer: Kymata Health EditorialTrigger: new page |
Supplement & Nutrient Encyclopedia. Educational information only; it is not medical advice and does not replace a clinician. Dietary supplements are not intended to diagnose, treat, cure or prevent any disease. Statements about supplements have not been evaluated by the FDA.