Pete's Picks · Updated Oct 16

Best Fiber Supplement on Ozempic: Psyllium First

Q: Can fiber make Ozempic constipation worse?

It can. The 2025 joint advisory says high-fiber foods slow stomach emptying and can worsen constipation on GLP-1 medicines. Fluids matter, and your prescriber may suggest a different approach.

Psyllium has the trial record. The scoop size is the rest of the choice.

Pete's #1: NOW Psyllium Husk Powder

By Peptide Pete · Updated Oct 16

Fact-checked against van der Schoot 2022 and the Wegovy constipation figures.

Psyllium trials, not GLP-1 trials
3 products with buttons
No price per serving

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NOW Psyllium Husk Powder

Best plain psyllium: more fiber per scoop, no sweetener.

Pete's #1 pick · 9.4/10

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The short answer

The US Wegovy label says 24% of adults on the medicine reported constipation, against 11% on placebo. A 2022 meta-analysis found psyllium and pectin were the fiber types with a real effect in chronic constipation. Those trials weren't in people on GLP-1 medicines.

Both of my top two are psyllium. NOW ranks first because a tablespoon is 7 g of fiber and it's unsweetened. Metamucil is the familiar tub, 3 g a teaspoon, and the sugar-free one uses aspartame. I'm not ranking a wheat dextrin above psyllium because it mixes clear.

Picks at a glance

Compare them

Swipe for more

Product	Pete Score	Evidence	Scoop	Mix	Clean	Listing
NOW Psyllium Husk Powder	9.4	10	9	7	10	Check price
Metamucil Sugar-Free	8.9	10	8	8	7	Check price
Benefiber	8.0	8	7	9	8	Check price

How I ranked them

Constipation evidence (50%). Psyllium sits at the top of the 7.8 to 9.6 band. Wheat dextrin sits at the bottom of that band. The trials weren't GLP-1 trials.
Fiber per scoop (20%). More fiber in the scoop you'll take sits higher. The meta-analysis liked trials over 10 g a day.
Easy to mix (15%). A drink you can finish sits higher than a gel you abandon, still inside the band.
Clean label (15%). No sweetener sits higher. Aspartame sits lower in the band.

I didn't rank Nutricost psyllium. The Amazon slot isn't a confirmed button. Citrucel is methylcellulose, with less constipation evidence, and it isn't linked.

1Best for people who want plain psyllium

NOW Psyllium Husk Powder

Nutrition facts on the NOW psyllium label

9.4

Plain psyllium, 7 g of fiber per tablespoon, and it thickens fast.

Best for: you want the fiber type with the trial record and no sweetener.

Skip it if: you won't drink it immediately. It gels. That's the psyllium, and I can't talk the texture away.

Psyllium
7 g fiber per tablespoon
No sweetener

Pete's take

I'd buy the plain husk. A tablespoon is 7 g of fiber, which is closer to the doses in the constipation trials than a 3 g teaspoon. van der Schoot's review wanted more than 10 g a day for at least four weeks, so one scoop isn't a full day. Mix it and drink it. If it sits, it becomes a spoon you'll hate. Ask your prescriber before you push fiber hard on a GLP-1.

Score breakdown

Evidence 10 · Scoop 9 · Mix 7 · Clean 10

Full specs

Psyllium
7 g fiber per tablespoon
No sweetener

More pros and cons

It's the same fiber type as the stronger constipation trials.
A tablespoon carries more fiber than the Metamucil teaspoon.
There's no aspartame, so the tub stays unsweetened.

It thickens in the glass, so you have to drink it right away.
It still hasn't been tested in a GLP-1 trial.

Check Today's Price on AmazonAs an Amazon Associate, Straight Up Peptides earns from qualifying purchases.

2Best for people who want the smaller scoop

Metamucil Sugar-Free

8.9

Psyllium people recognize, 3 g a teaspoon, with aspartame.

Best for: you want psyllium in a milder scoop and you tolerate aspartame.

Skip it if: you avoid aspartame, or you need more fiber per spoon. NOW is the plainer tub.

Psyllium
3 g fiber per teaspoon
Aspartame

Pete's take

Metamucil is psyllium, which is why Evidence sits with NOW. I ranked it second because the teaspoon is only 3 g of fiber and the sugar-free powder uses aspartame. That's a real reason to skip it. The Amazon line that says GLP-1 friendly is advertising. I didn't find a trial of this tub in people on semaglutide. If the smaller scoop means you'll take it, buy this. If you want unsweetened, buy NOW.

Score breakdown

Evidence 10 · Scoop 8 · Mix 8 · Clean 7

Full specs

Psyllium
3 g fiber per teaspoon
Aspartame

More pros and cons

It's psyllium, so the evidence sits with NOW at the top of this page.
The smaller scoop is an easier drink for some people, which means they finish it.
The 180-teaspoon tub is the one I linked, so the button matches this powder.

The sugar-free powder uses aspartame, which is a real reason to skip it.
The listing's GLP-1 friendly line is marketing, and no trial tested this tub in people on these medicines.

Check Today's Price on AmazonAs an Amazon Associate, Straight Up Peptides earns from qualifying purchases.

3Best for people who won't drink a gel

Benefiber

8.0

Wheat dextrin that disappears in water, with a weaker constipation record.

Best for: you've tried psyllium and you won't drink the gel.

Skip it if: you wanted the fiber type the constipation trials support. That's psyllium.

Wheat dextrin
3 g per stick
Doesn't thicken

Pete's take

I keep Benefiber on the list for the person who spat out psyllium and quit. Wheat dextrin mixes clear, and a stick is 3 g. van der Schoot didn't find the same constipation result for it that they found for psyllium. That's why Evidence sits at the bottom of this page's band. I wouldn't call it the best fiber on Ozempic. I'd call it the one you might finish. Severe pain or vomiting is a prescriber call.

Score breakdown

Evidence 8 · Scoop 7 · Mix 9 · Clean 8

Full specs

Wheat dextrin
3 g per stick
Doesn't thicken

More pros and cons

It dissolves clear, so you can finish a glass that psyllium would have gelled.
The stick packs travel, which helps on days you're not at the kitchen tub.
It's a reasonable pick when the only goal is a fiber you'll actually swallow.

The constipation trials are weaker for wheat dextrin than for psyllium, so it sits at the bottom of this list.
A 3 g stick is still a small add toward a 10 g day.

Check Today's Price on AmazonAs an Amazon Associate, Straight Up Peptides earns from qualifying purchases.

At a glance

1 NOW Psyllium Husk Powder

Best for people who want plain psyllium

Pete Score 9.4/10

Psyllium
7 g fiber per tablespoon
No sweetener

2 Metamucil Sugar-Free

Best for people who want the smaller scoop

Pete Score 8.9/10

Psyllium
3 g fiber per teaspoon
Aspartame

3 Benefiber

Best for people who won't drink a gel

Pete Score 8.0/10

Wheat dextrin
3 g per stick
Doesn't thicken

References: 5 · Products compared: 8 · Status as of Oct 10, 2026

Jump to: Ask your prescriber first · How common constipation is · What the fiber evidence says · Compare the picks · The picks · Using fiber safely · Common questions

Constipation affects up to about a quarter of people in the semaglutide trials. Fiber is the first thing most people reach for.

Psyllium has the strongest trial record for chronic constipation, so it leads our list. There is a clear note on when fiber is the wrong move.

"I haven't gone to bathroom in almost a week." That r/Semaglutide post drew 109 replies, and "backed up" threads are among the most active in the GLP-1 communities we track. Fiber came up more than 150 times in those threads.

Talk to your prescriber first

Before adding fiber or any laxative. The 2025 joint nutrition advisory lists fiber supplements, magnesium, polyethylene glycol 3350 (PEG 3350) and stool softeners as options when diet is not enough. Which one, and how much, is a decision for your prescriber, who knows your other medicines and conditions.
Fiber can make it worse. The advisory notes that foods high in fiber, protein or fat slow stomach emptying, which "can also worsen constipation."
Call right away if you have severe stomach pain that will not go away, vomiting, or nausea, vomiting or diarrhea that does not stop. The Wegovy patient information asks you to tell your provider right away about these.
Magnesium and kidneys. Magnesium products are not for everyone, including some people with kidney disease. Ask first.

On this page

Common constipation is on GLP
Fiber evidence says
Using fiber safely
Questions
Sources

A bowl of oatmeal topped with strawberries, blueberries, and banana. — Photo: thea a / Pexels

How common constipation is on GLP-1 medicines

In the US Wegovy prescribing information, 24% of adults on the medicine reported constipation, against 11% on placebo. The US label does not report how long those episodes lasted. The joint advisory puts constipation at 17 to 24% across GLP-1 trials and says it "should be managed proactively," starting with fluids and fiber from foods (Mozaffarian et al., 2025).

What the fiber evidence says

A 2022 meta-analysis pooled 16 randomized trials with 1,251 adults with chronic constipation. 66% of people responded to fiber, against 41% on control. Psyllium and pectin were the fiber types with significant effects, and the benefit showed up in trials that used more than 10 g of fiber a day for at least four weeks. Fiber also caused more gas than control (van der Schoot 2022, PMID 35816465). None of these trials were in people taking GLP-1 medicines.

The studies do not all agree. Here is where the results differ: the trials varied widely in fiber type, amount and length, and the authors call for caution because of that spread. Wheat dextrin and methylcellulose have less trial evidence for constipation than psyllium.

Using fiber safely

Fluids. Psyllium Drug Facts labels say to mix the powder with at least 8 oz of liquid and drink it promptly, and warn that taking it without enough liquid may cause choking. Do not take the dry powder. Do not use it if you have trouble swallowing.
Space it from medicines. The Metamucil label says to take it at least 2 hours before or after prescribed drugs, because fiber can affect how they are absorbed. Ask your prescriber how this applies to your medicines.
Go slow. Adding fiber gradually can limit gas and bloating.
Stop and call if you get chest pain, vomiting, or trouble swallowing or breathing after taking it, or if constipation lasts longer than your label allows.

Also on this site

Semaglutide vs tirzepatide: one lost 20.2%, the other 13.7%.SURMOUNT-5 put both drugs in the same 72-week trial. Tirzepatide took the bigger number. The gap is real. What it leaves out matters too.See the head-to-head

We did not find reliable interaction data in the sources reviewed. That does not mean there are no interactions.

A woman walks a tree-lined park path on a sunny day. — Photo: Reynaldo Yodia / Pexels

Common questions

What is the best fiber supplement on Ozempic?

Psyllium has the strongest evidence for chronic constipation. My top pick is NOW Psyllium Husk Powder, because the scoop is larger and it has no sweetener. Metamucil is the familiar smaller scoop. Ask your prescriber before starting.

Can fiber make Ozempic constipation worse?

It can. The 2025 joint advisory says high-fiber foods slow stomach emptying and can worsen constipation on GLP-1 medicines. Fluids matter, and your prescriber may suggest a different approach.

Should I take MiraLAX or magnesium for Ozempic constipation?

The advisory lists PEG 3350, magnesium and stool softeners as options when diet is not enough. Ask your prescriber which fits you, because these are medicines with their own cautions.

How long does constipation last on Ozempic?

The US Wegovy label reports constipation in 24% of adults on the medicine and 11% on placebo. It does not say how long an episode lasts. Call your prescriber if it is severe, painful or comes with vomiting.

Does psyllium affect how my medicine is absorbed?

Fiber can affect absorption of oral medicines, and the Metamucil label says to take it at least 2 hours before or after prescribed drugs. Semaglutide injections are not swallowed, but other medicines you take may be.

Is Benefiber or Metamucil better on a GLP-1?

Metamucil is psyllium, which has the stronger trial record for constipation. Benefiber is wheat dextrin, which dissolves clear and does not thicken. No trial has compared them in people on GLP-1 medicines.

If I could only buy one

If I could only buy one, it's NOW psyllium. Same evidence class as Metamucil, more fiber in the scoop, no aspartame.

Best for people who want plain psyllium: NOW Psyllium Husk Powder

Check Today's Price on AmazonAs an Amazon Associate, Straight Up Peptides earns from qualifying purchases.

If you want the familiar smaller scoop, get Metamucil Sugar-Free.
If you refuse a gel, get Benefiber.

What changed: Oct 16, 2026. Pete Scores now sit between 7.8 and 9.6. NOW stays first on scoop size and no sweetener.

This page includes affiliate links. If you buy through them, we earn a commission at no extra cost to you. As an Amazon Associate, Straight Up Peptides earns from qualifying purchases.

Research information, not medical advice. Nothing on this page recommends starting, stopping or changing any medicine, laxative or supplement. Talk to your prescriber before adding fiber or a laxative while on a GLP-1 medicine.

Sources, methodology, and changes

Methodology. Literature search on 2026-10-10: PubMed (fiber, psyllium, constipation, meta-analysis), the 2025 joint GLP-1 nutrition advisory, and the Wegovy prescribing information and patient information. On the same day we priced eight fiber products on Amazon US and recorded fiber per serving from labels and listings. We did not test any product. Reader quotes come from Reddit threads collected for our reader research.

Primary sources.

van der Schoot A et al., 2022, Am J Clin Nutr. Fiber supplementation for chronic constipation, meta-analysis: PMID 35816465
Mozaffarian D et al., 2025. Nutritional priorities to support GLP-1 therapy for obesity: a joint advisory: PMID 40673264
Wegovy (semaglutide) US prescribing information and patient information, Novo Nordisk. Adults on the medicine: constipation 24%, placebo 11%. The US label does not report episode length.
Metamucil Drug Facts, DailyMed: https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=a9824f73-5ea2-4a65-a926-3a57561441b8
Amazon US listings, Oct 10, 2026: B003CT2YQY, B000052Y5Q, B002RWUNYM, B07MKZD9LR, B07LGH45K2, B01CTFZFE4, B015VBRIXE, B07GC6QPY4

Changes. Oct 10, 2026: first published. Oct 11, 2026: constipation figures set to the US Wegovy label (24% vs 11% of adults). The 47-day median is not on that label, so it was removed. Benefiber stick packs stated at 3 g of fiber per packet after checking the product label. Oct 17, 2026: shortened the top of the page so the product photo shows on a phone.

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