How people get it: Sold over the counter.
The basics
What it is
Psyllium is a bulk-forming laxative.
Source: MedlinePlus (NIH): Psyllium: MedlinePlus Drug Information ↗
How it's thought to work
Psyllium soaks up liquid in the intestines and swells. This makes a bulky stool that is easy to pass.
Source: MedlinePlus (NIH): Psyllium: MedlinePlus Drug Information ↗
What people use it for
Psyllium is used to treat constipation. A doctor may also prescribe psyllium for diarrhea or high cholesterol.
Source: MedlinePlus (NIH): Psyllium: MedlinePlus Drug Information ↗
What the research has found so far
On Fiber supplements and aging, PubMed lists 142 trials in people, 57 studies that watched people over time, 6 animal and lab studies. See the counts and searches
Stage 2 because 142 published trials and 30 registered trials in people have been found, but no large ones yet.
A stage shows how far research has got, not whether it will work for you. How stages work
Side effects and risks
The page says to call a doctor right away for difficulty breathing, stomach pain, trouble swallowing, rash, itching, nausea, or vomiting.
Source: MedlinePlus (NIH): Psyllium: MedlinePlus Drug Information ↗
Who should be careful, and drug interactions
- Digoxin, aspirin-type drugs (salicylates), and nitrofurantoin should not be taken within 3 hours of psyllium.
- People with certain conditions are told to let their doctor know before taking psyllium.
- People who are pregnant, planning pregnancy, or breast-feeding are told to tell their doctor.
- People on a low-sugar or low-sodium diet are told to tell their pharmacist or doctor.
Source: MedlinePlus (NIH): Psyllium: MedlinePlus Drug Information ↗
Amounts used in studies
What studies or labels describe, not a recommendation.
- Psyllium comes as a powder, granules, capsule, liquid, and wafer taken by mouth, usually one to three times daily.
- The powder and granules are mixed with 8 ounces of liquid right before use.
- The page says psyllium should not be taken longer than 1 week unless a doctor says so.
Source: MedlinePlus (NIH): Psyllium: MedlinePlus Drug Information ↗
Roughly what it costs
The 4 products we list that contain Fiber supplements cost from $19.95 to $69.99, as read from the makers' pages. See the products
Questions to ask your doctor
- Is Fiber supplements a sensible option for me, given my health and the medicines I take?
- Could Fiber supplements interact with any medicine or supplement I already take?
- What side effects should I watch for, and when should I stop or call you?
- Supplements aren't checked by the FDA before sale. Is there a brand or a third-party test seal you would trust?
- How would we tell whether it is helping, and when should we review it?
This is general information gathered from the sources listed, not medical advice. Talk to your doctor before starting anything new.
Products that contain it
Read from each maker's page. The research stage is for the ingredient, not proof that a product works.
| Product | Form | Fiber supplements per serving | Price | Per serving |
|---|---|---|---|---|
| Psyllium Husk Caps 500 mg Veg CapsulesNOW Foods · maker's page ↗ | capsule | 1.5 gserving: 3 Veg Capsules | $23.0966 servings | $0.35 |
| Psyllium Husk SupplementDoubleWood · maker's page ↗ | — | See label | $19.95 | — |
| Fiber+ Vitamins C, D & B12 Sparkling Fiber PowderMetamucil · maker's page ↗ | powder | See label | $39.39 | — |
| Benefiber Original Powder Fiber SupplementBenefiber · maker's page ↗ | powder | See label | $69.99 | — |
Amounts, servings and prices are as each maker lists them on its own page, checked Oct 20, 2026. Price per serving is the price divided by the servings per container on the label; “—” means the page didn't say. A serving is the maker's serving size, not a recommendation.
What experts say
No expert views collected yet. Each one we add names the person and links to where they said it.
Recent research
New studies that mention Fiber supplements appear here after the morning update.
Trials
None of the registered trials of Fiber supplements is one we have linked as aging-related yet.
ClinicalTrials.gov lists 30 registered trials that mention Fiber supplements, for any condition (the count in The science below). Here we show the ones about aging. See them all ↗
The science
Counted from PubMed and ClinicalTrials.gov on Oct 30, 2026, using one search for Fiber supplements in relation to aging. Each link opens the exact search.
- Randomized trials in people
- 127 search ↗
- Large trials (multicenter or phase 3)
- 14 search ↗
- Phase 3 trials
- 2 search ↗
- Trials in people
- 142 search ↗
- Studies that watched people over time
- 57 search ↗
- Animal and lab studies
- 6 search ↗
- Registered trials
- 30 search ↗
PubMed search used
("fiber supplement*"[tiab] OR "fibre supplement*"[tiab] OR psyllium[tiab] OR "inulin supplementation"[tiab] OR "dietary fiber supplementation"[tiab]) AND (aging[tiab] OR ageing[tiab] OR longevity[tiab] OR healthspan[tiab] OR "older adults"[tiab] OR "older people"[tiab] OR elderly[tiab] OR "Aged"[mh])
Counts are search results, so they include some records that only mention Fiber supplements. How we count
Cite or share this page
Longevity Progress. (n.d.). Fiber supplements: Research stage and evidence. Retrieved October 30, 2026, from https://longevityprogress.com/treatments/fiber-supplements
<iframe src="https://longevityprogress.com/embed/stage/fiber-supplements" title="Fiber supplements: research stage on Longevity Progress" width="340" height="72" style="border:0" loading="lazy"></iframe>
The badge shows this treatment's current research stage and links back here. It updates by itself when the stage changes.