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 · IBS-D & loose stools

Best Fiber Supplement for IBS-D and Loose Stools: What Reddit Owners Report

Among fiber supplement options, Sunfiber (PHGG) has the best reports from people with IBS-D or loose stools: 15 of 18 rated owner comments were positive. We rank by a context rating that pulls small samples toward the average, so a handful of glowing comments cannot top the list. Only options with at least 5 rated comments in this context are ranked. This is a summary of self-reports, not a recommendation, and it is not evidence that any of them works for you.

#	Supplement	Context rating	Rated comments here	Positive	Negative	Unwanted effects	Overall score
1	PHGG (Sunfiber)	3.8	18	15	2	1	3.9
2	Wheat dextrin (Benefiber)	3.8	7	6	0	0	3.7
3	Psyllium husk	3.7	95	74	16	6	4.2
4	Acacia fiber	3.7	7	6	1	0	3.8
5	Inulin / FOS	3.5	6	5	1	1	3.5

Why each ranks where it does

1. PHGG (Sunfiber)

15 positive and 2 negative out of 18 rated comments from people with IBS-D or loose stools; 83% positive. See Sunfiber (PHGG) side effects. How people take it: Sunfiber (PHGG) dosage and timing.

4/5 Urgency & loose stools
“Been dealing with chronic diarrhea for months and my naturopath just recommended Tomorrow’s Nutrition brand SunFiber.”

owner comment via r/SIBO · 2025-11-13 · 5 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

2. Wheat dextrin (Benefiber)

6 positive and 0 negative out of 7 rated comments from people with IBS-D or loose stools; 86% positive.

4/5 Urgency & loose stools
“If I take benefiber every day, first thing I do when I wake up in the morning...my diarrhea symptoms are sooo much better”

owner comment via r/IBS · 2026-08-30 · 3 upvotes

3. Psyllium husk

74 positive and 16 negative out of 95 rated comments from people with IBS-D or loose stools; 78% positive. See Psyllium husk side effects. How people take it: Psyllium husk dosage and timing.

4/5
“Stick to Powdered psyllium husk it's purer (I take less then recommended for my IBS-D and it has been working wonders )”

owner comment via r/IBS · 2026-06-28 · 24 upvotes

2/5 Stopped workingUrgency & loose stools
“Psyllium absolutely makes my diarrhea worse.”

owner comment via r/IBS · 2026-10-19 · 18 upvotes

4. Acacia fiber

6 positive and 1 negative out of 7 rated comments from people with IBS-D or loose stools; 86% positive.

4/5 GentleStool form
“(Pelvic floor dysfunction can have emotional and physical causes, sometimes both.) Also I have been using Heather's Tummy Fiber (acacia senegal) - starting low and slow with 1/4 teaspoon, gradually increasing by 1/4 tsp per week.”

owner comment via r/IBS · 2025-11-23 · 2 upvotes

2/5 Regularity
“I do take acacia fiber regularly and I also eat kiwi from time to time, but unfortunately I can’t say that either of them has made a major difference.”

owner comment via r/SIBO · 2026-06-14 · 1 upvotes

Safety notes

Sunfiber (PHGG): Fermentable fibers can cause gas at first; most studies start at a few grams a day.^[PubMed]
Benefiber (wheat dextrin): It is made from wheat; check the label if you avoid gluten.^[PubMed]
Psyllium husk: MedlinePlus advises drinking at least 8 ounces (240 mL) of liquid with each dose, and keeping digoxin, aspirin and nitrofurantoin at least 3 hours apart from psyllium.^{[MedlinePlus]}
Acacia fiber: Start low and increase slowly; any fermentable fiber can cause gas.^[PubMed]

Check interactions with a pharmacist before starting, and see a doctor about new or severe symptoms.

Example Sunfiber (PHGG) products

Examples sold on Amazon, not ranked by Reddit. The score above is for the ingredient, not these products.

Example product · not Reddit-scored

Healthy Origins Healthy Fiber Powder 7.9 oz (225g), Featuring Sunfiber Partially Hydrolyzed Guar Gum (PHGG), Supports Digestive Regularity

Brand on Reddit: 4.0 from 147 owner comments · Sunfiber owner reviews

$18.99 on Amazon (price as of 2026-11-03). Prices change; check Amazon for the current price.

Check Price on Amazon