Medical disclaimer: GutVerdict summarizes what people say about supplements on Reddit. It is not medical advice, and nothing here is meant to diagnose, treat, cure, or prevent any disease. These statements have not been evaluated by the Food and Drug Administration. Talk to your doctor or pharmacist before starting a supplement, especially if you are pregnant, take medicines, or have a medical condition. New, severe or worsening symptoms (such as blood in the stool, weight loss, fever, or night-time symptoms) need a doctor, not a supplement. Full disclaimer.

Fiber · side effects reported by users

Sunfiber (PHGG) Side Effects: What Reddit Users Report

About this entry (PHGG (Sunfiber)): Partially hydrolyzed guar gum, a low-viscosity soluble fiber sold under the Sunfiber name.

18 of 507 Reddit owner comments about Sunfiber (PHGG) (4%) describe an unwanted effect. The effects people mention most are gas or bloating. These are self-reports from Reddit IBS and gut communities (November 2025 to October 2026), not a measured side-effect rate, and many people report no problems at all.

PHGG (Sunfiber) overall: 3.9 · tolerability 4.7 (higher means fewer unwanted-effect reports).

What people describe

Effect mentioned	Owner comments
Gas or bloating	6

How we counted: among the 18 comments that describe an unwanted effect, a category counts when a sentence names the effect with wording like "gave me" or "made me". Questions and sentences about an effect going away are skipped. One comment can count in more than one row, and keyword counts can include some unrelated mentions, so read the quotes below for context.

Most common complaints

Side effects: 15 owner comments
Bloating & gas: 8 owner comments
Pain & cramping: 6 owner comments

Safety notes from NIH and published research

Fermentable fibers can cause gas at first; most studies start at a few grams a day.^[PubMed]

Stop and talk to a doctor if an effect is severe or does not settle. Ask a pharmacist about interactions with any medicine you take.

In their words

2/5 Bloating & gasSide effects
“PHGG made my bloating worse before I added 5-HTP.”

owner comment via r/IBS · 2026-04-14 · 6 upvotes

2/5 Bloating & gasSide effects
“Yeah, if I had my preference I'd get to two kiwi before starting the Sunfiber, just because that's what I started with.”

owner comment via r/IBS · 2026-09-21 · 1 upvotes

2/5 Bloating & gasPain & cramping
“Ya psyllium made things worse for me but I started taking it in an empty stomach so I might try again with a meal and see but I took PHGG for a while.”

owner comment via r/SIBO · 2026-01-09 · 2 upvotes

4/5 Bloating & gasSide effects
“I am trying artischoke right know, and the PHGG helped me really good for about 2 years, currently it's causing more gas”

owner comment via r/SIBO · 2026-02-06 · 2 upvotes

1/5 Side effects
“yes PHGG is advised a lot (although made things worse for me).”

owner comment via r/SIBO · 2026-05-04 · 2 upvotes

4/5 Bloating & gasGentle
“PHGG gave me gas that was hard to pass and very uncomfortable.”

owner comment via r/SIBO · 2026-06-19 · 2 upvotes

2/5 Side effects
“But PHGG made me feel nauseous and psyllium husk basically impacted me.”

owner comment via r/Constipation · 2026-03-17 · 1 upvotes

2/5 Side effects
“I'm mixed (more methane) and can't tolerate PHGG.”

owner comment via r/SIBO · 2025-11-07 · 1 upvotes

Frequently asked

What side effects do people report with Sunfiber (PHGG)?

18 of 507 Reddit owner comments about Sunfiber (PHGG) (4%) describe an unwanted effect; the ones mentioned most were gas or bloating. These are self-reports, not a measured side-effect rate.

Is Sunfiber (PHGG) safe?

Safety depends on your health and medicines. The NIH and other sources listed on this page note specific cautions. Ask a doctor or pharmacist before starting, especially if you take other medicines or are pregnant.

More on Sunfiber (PHGG)

Compare side-effect reports: Psyllium husk vs PHGG (Sunfiber) · PHGG (Sunfiber) vs Inulin / FOS