Partially Hydrolyzed Guar Gum

PHGG · Sunfiber

Snapshot

Indications	Contraindications
Irritable bowel syndrome bloating¹ Pediatric constipation² Loose stool form³ Reduced laxative use⁴ Enteral feeding tolerance⁵ Pediatric abdominal pain⁶ Ileostomy output⁷ Glycemic markers⁸	Milk allergy⁹ Soy allergy⁹ Egg allergy⁹

Partially hydrolyzed guar gum (PHGG), also sold as Sunfiber, is a water-soluble, non-gelling fiber made by enzymatic breakdown of guar gum, acting as a prebiotic that raises colonic bifidobacteria and short-chain fatty acids^{3, 10}. It is taken to regulate bowel function: bloating in irritable bowel syndrome (IBS), stool form in loose-stool tendency, and constipation in children. Further uses include tolerance of fiber-containing enteral formulas after gastrointestinal surgery and, in small studies, glycemic markers, cold-like symptoms, and skin hydration.

Evidence is most consistent for IBS bloating, while constipation results are mixed. In older long-term care residents, a placebo-controlled trial found no change in stool frequency or form but less laxative use. In hospitalized patients, a 2021 retrospective cohort study found fewer influenza cases among those taking PHGG; no randomized trial has tested this¹¹. Products list PHGG as powders or capsules, alone or within fiber blends, protein powders, and enteral formulas; see Form comparison.

Combination products carry the main label cautions, since some contain milk, soy, or egg allergens⁹. Per product labeling, people taking prescription medications are directed to consult a physician or pharmacist before use⁹.

Last updated October 16, 2026. Read how we make monographs.

In the full monograph

42 sources, 29 studies

When to useThe situations practitioners use it for, each with the reason and the study behind it.
SafetyWho should avoid it, who needs extra care, and the side effects reported in studies.
InteractionsThe medicines and supplements it interacts with, the effect of each, and what labeling says to watch.
Protocol notesThe doses used in studies, how and when they were taken, and how the forms on the market compare.
How it worksWhat it is and how it works in the body, in plain terms.
Published studiesThe studies behind each use, popular claims checked against them, and trials still under way.
Word of mouthWhat patients and practitioners report online, kept separate from the clinical evidence.
Clinical perspectiveA closing read of where the evidence is solid, where it is thin, and what has not been studied.

Snapshot

In the full monograph

Sources