Botanical

Yacon

Also called Smallanthus sonchifolius, yacon syrup, yacon root, yacon flour, Peruvian ground apple

By Kymata Labs EditorialMedical review pendingLast reviewed October 13, 2026 · What changed

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Summary

Yacon is an Andean root high in prebiotic fructooligosaccharides (FOS). A 2025 meta-analysis of 7 trials (239 people) found no overall effect on fasting glucose, insulin or cholesterol. Small trials show faster gut transit, a lower blood-sugar rise after breakfast and modest extra weight loss alongside dieting. Higher syrup doses can cause digestive upset.

Top graded outcomes:C evidence grade Fasting glucose, insulin and cholesterolD evidence grade Colonic transit timeD evidence grade Weight, waist and body fat during an energy-restricted diet

Key facts

What it is
Root of Smallanthus sonchifolius, a crop rich in fructooligosaccharides (FOS), sold as syrup or dried flour[3][4]
Meta-analysis
7 RCTs, 239 participants: no significant effect on fasting glucose, insulin, HOMA-IR or lipids overall[1]
Gut transit
20 g/day yacon syrup (6.4 g FOS) cut whole-gut transit time from 59.7 to 38.4 hours in 16 healthy adults[3]
Post-meal glucose
40 g yacon syrup with breakfast lowered glucose at 30 minutes and insulin at 15–45 minutes versus placebo in 40 women[5]
Tolerance
In obese women, 0.14 g FOS per kg per day was the dose without undesirable digestive effects[7]
Evidence base
5 graded human outcomes on this page
Last reviewed
October 13, 2026

How it works

ProposedYacon FOS are not digested in the small intestine and are fermented by colon bacteria, acting as a prebiotic fibre. This lowers stool pH, speeds transit and adds bulk. FOS also replace digestible sugars, which may blunt post-meal glucose and insulin; phenolic compounds may contribute.[2][3][5]

What the human research says

Human trials only, one row per outcome. The form column shows what each trial actually tested. Grades follow our evidence-grading policy.

At a glance: strongest evidence per outcome

Evidence at a glance: strongest human evidence per outcome
OutcomeGradeEffectStrongest evidenceRows
Blood sugarGrade CNo effectMeta-analysis of 7 trials · n = 239 · 2025Form tested: Yacon syrup, flour or root products3 rows
WeightGrade DImprovedRCT · n = 26 · 2019Form tested: Yacon flour in a breakfast drink1 row
DigestionGrade DImprovedCrossover RCT · n = 16 · 2008Form tested: Yacon syrup1 row

Every graded row

Outcome
Grade
Form tested
Sort

Showing 5 of 5 outcomes. Human trials only.

OutcomeEffectGradeBest evidencePMID
Fasting glucose, insulin and cholesterolNo effectGrade C

Meta-analysis · n = 239 · 2025

Adults in 7 randomised trials

Form: Yacon syrup, flour or root products · Dose: Varied · Duration: Varied

No significant effect on fasting glucose, insulin, HOMA-IR, total, LDL or HDL cholesterol, or triglycerides; subgroups using it for more than 8 weeks showed lower fasting glucose and LDL.

41152200 (opens PubMed)Source [1]
Serum glucose, lipids and bowel transit in older adultsMixedGrade D

RCT · n = 72 · 2014

Older adults, mean age 67 (Brazil)

Form: Freeze-dried powdered yacon · Dose: 7.4 g FOS per day · Duration: 9 weeks

Serum glucose fell (p = 0.013) but lipids did not change; no bloating, flatulence or discomfort.

24398786 (opens PubMed)Source [6]
Blood glucose and insulin after breakfastImprovedGrade D

Crossover RCT · n = 40 · 2019

Women of normal weight or grade I obesity (Brazil)

Form: Yacon syrup · Dose: 40 g with breakfast (14 g FOS) · Duration: Single meals

Glucose was lower at 30 minutes and insulin at 15, 30 and 45 minutes versus placebo; triglycerides did not differ.

31732062 (opens PubMed)Source [5]
Weight, waist and body fat during an energy-restricted dietImprovedGrade D

RCT · n = 26 · 2019

Adults with excess weight (mean BMI 30.4)

Form: Yacon flour in a breakfast drink · Dose: 25 g/day (about 0.1 g FOS per kg) · Duration: 6 weeks

Added to a −500 kcal/day diet, yacon flour led to greater reductions in weight, waist, sagittal abdominal diameter and body fat than diet alone, with better bowel function and no digestive side effects.

30661690 (opens PubMed)Source [4]
Colonic transit timeImprovedGrade D

Crossover RCT · n = 16 · 2008

Healthy adults (8 men, 8 women)

Form: Yacon syrup · Dose: 20 g/day (6.4 g FOS) · Duration: 2 weeks per period

Transit time fell from 59.7 to 38.4 hours (p < 0.001); stool frequency and softness rose slightly but not significantly; bloating was not more common than placebo.

18781073 (opens PubMed)Source [3]

Forms

FormElemental %Absorption (human data)GI toleranceStudied for
Yacon syrupVaries[3][2]Not applicable (whole compound or extract; no elemental fraction)FOS are largely undigested in the small intestine and fermented in the colon.[3][2]Well tolerated at 20 g/day; in obese women 0.14 g FOS/kg/day was identified as the intake without undesirable digestive effects (0.29 g/kg/day was also tested).[3][7]Transit, post-meal glucose and weight trials
Yacon flour or freeze-dried powderVaries[4][6]Not applicable (whole compound or extract; no elemental fraction)Fermented in the colon like other FOS sources.[4][6]No digestive side effects at 25 g/day flour or 7.4 g FOS/day powder.[4][6]Weight and older-adult trials

Studied doses

Doses studied in human trials ranged from 6.4 g FOS/day (20 g syrup, 2 weeks) and 7.4 g FOS/day (powder, 9 weeks) to 14 g FOS in a single 40 g serving of syrup, with weight-based doses of 0.1–0.29 g FOS/kg/day for up to 120 days.[3][6][5][4][7]

These are amounts used in research, not personal advice. Your clinician or pharmacist can say what fits you.

Interactions

Published interactions only: each row cites a source. No row means none was found in our sources, not that a combination is safe.

Medicines

  • Diabetes medicinesRCTe.g. Insulin, sulfonylureas, metforminYacon syrup lowered post-breakfast glucose and insulin versus placebo, and a 9-week trial in older adults lowered serum glucose; effects could add to glucose-lowering drugs. No combination studies exist.[5][6]

Who should be careful

Sensitive digestion or IBS
Yacon is a concentrated FOS source; in one trial only the lower of two syrup doses was free of undesirable digestive effects.[7][3]
Daisy-family (Asteraceae) allergy
Yacon belongs to the Asteraceae family; no yacon-specific allergy data were found, but people with known daisy-family allergies may want to be cautious (inferred from plant family).[2]
People with diabetes on medication
Post-meal glucose and insulin fell after yacon syrup; glucose monitoring may need adjusting.[5]
Pregnancy, breastfeeding and children
No trials of yacon supplements in these groups were found.[1]

Talk to your pharmacist or clinician before starting a supplement, especially if you take prescription medicines.

How to read the label

  1. FOS content variesTrials dosed by FOS (6.4–14 g); 20 g of one syrup supplied 6.4 g FOS and 40 g of another supplied 14 g.[3][5]
  2. Syrup vs flourWeight trials used both syrup and flour; results may differ by product and FOS content.[4][7]

Cost per studied dose, without the sales pitch

Compare any product you already have by the amount it delivers, not by capsule count or front-of-pack weight.

Cost per studied dose

Enter the price, servings and the amount per serving from your label.

Formula: price ÷ (servings × amount per serving) × reference amount. Use the amount printed on the Supplement Facts panel, not the front-of-pack compound weight. Reference amounts are what trials studied or official limits, not advice for you. We don't rank or link products on this page.

Frequently asked questions

What is yacon syrup?

A sweet syrup from the yacon root that is high in fructooligosaccharides, a prebiotic fibre.[3][7]

Does yacon syrup help weight loss?

Small trials report modest extra weight loss, alongside dieting in one, and a 2025 pooled analysis of 12 studies found lower BMI, but study quality was limited.[4][7][2]

Does yacon lower blood sugar?

It blunted the glucose rise after breakfast, but a meta-analysis of 7 trials found no overall effect on fasting glucose or insulin.[5][1]

Does yacon help constipation?

It sped gut transit by about 21 hours in healthy volunteers; trials in constipated patients are still needed.[3]

What are the side effects?

Digestive upset at higher doses; trials at moderate doses reported no excess bloating.[7][3][6]

Sources

  1. [1]The Effect of Yacon Consumption on Glycemic Control and Lipid Profiles: A Systematic Review and Meta-Analysis of Randomised Controlled Trials.. Endocrinol Diabetes Metab, 2025. meta-analysis PMID 41152200
  2. [2]Yacon root is a functional food beneficial for human health: a meta-analysis of clinical trials.. Front Nutr, 2025. meta-analysis PMID 41459090
  3. [3]Effect of yacon (Smallanthus sonchifolius) on colonic transit time in healthy volunteers.. Digestion, 2008. crossover-RCT PMID 18781073
  4. [4]Consumption of yacon flour improves body composition and intestinal function in overweight adults: A randomized, double-blind, placebo-controlled clinical trial.. Clin Nutr ESPEN, 2019. RCT PMID 30661690
  5. [5]Yacon syrup reduces postprandial glycemic response to breakfast: A randomized, crossover, double-blind clinical trial.. Food Res Int, 2019. crossover-RCT PMID 31732062
  6. [6]Freeze-dried powdered yacon: effects of FOS on serum glucose, lipids and intestinal transit in the elderly.. Eur J Nutr, 2014. RCT PMID 24398786
  7. [7]Yacon syrup: beneficial effects on obesity and insulin resistance in humans.. Clin Nutr, 2009. RCT PMID 19254816

What changed

  1. October 13, 2026 · all · reviewIndependent adversarial review: added a daisy-family (Asteraceae) caution, flagged as inferred from plant family because no yacon allergy reports were found.Writer: Kymata Labs Editorial · No credentialed reviewer yet
  2. October 13, 2026 · all · reviewSecond-pass self-review: every PMID re-checked against NCBI esummary (title, year, no retraction or expression-of-concern flag), every dose, n and duration re-read against the PubMed abstract or PMC full text, grades held conservative, and interactions limited to what a cited source supports.Writer: Kymata Labs Editorial · No credentialed reviewer yet
  3. October 13, 2026 · all · new pageFirst draft. Source titles and years taken from NCBI E-utilities esummary; abstracts read for every evidence row.Writer: Kymata Labs Editorial · No credentialed reviewer yet

How we write, grade and correct these pages: editorial and evidence policy.

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