Best Fiber Supplements

Fact Checked: Yes

Written by: James Dixon

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Fiber is incredibly important. It plays a crucial role in maintaining digestive health, cholesterol levels, immune function, and overall health and wellbeing. We should all try to eat plenty of it from healthy food sources – greens, fruit, grains, pulses, and legumes are all fantastic sources. However, this is often easier said than done. We all have busy lives, and it can be hard to fully regulate or optimize your fiber intake.

Daily fiber supplements can be great for optimizing your intake and giving you all the health benefits associated with it. Today we are going to be looking at some of the best fiber supplements you can take to help fully optimize your health.

Fiber Supplementation

Fiber supplements can help with a wide range of symptoms, as well as simply protecting your health and wellbeing. They can allay the symptoms associated with diarrhea and constipation, often both, when needed.

Fiber sources that double as both foods and supplements can also decrease your risk of suffering from certain chronic health conditions, like type II diabetes, heart disease, and even certain cancer forms.

However, they aren’t all the same. No single supplement will do everything for everyone, not all forms will work for all symptoms, and not everybody needs to take them.

Therefore, you should try to pick a fiber supplement suitable for your specific symptoms. We’ve broken the four supplements in this list into categories, giving you the best in each, each with overlapping yet separate purposes.

You should also always consult your doctor if you are struggling with any symptoms of low fiber – largely, constipation and/or diarrhea – and/or if you’re looking to begin a new supplement. They will be able to advise you on the best course of action with your unique medical history in mind.

When choosing your fiber supplement, you should look for soluble fiber forms if you are suffering with diarrhea, with or without accompanying constipation. Soluble fiber dissolves in water, hence its name. As it dissolves, it forms into a thick gel which will then result in well-hydrated stools, or healthy stools.

In turn, this should mitigate or even get rid of symptoms of diarrhea and constipation.

Fiber supplements formed from soluble fiber have been found to help with all three forms of irritable bowel syndrome (IBS).

I would always recommend either psyllium husk and methyl cellulose or calcium-polycarbophil. The former are soluble fibers that have been found to be particularly effective in relieving symptoms of both diarrhea and constipation. The latter is actually a non-fermentable insoluble fiber. However, calcium-polycarbophil acts in a similar way to soluble fiber, giving you the benefits you need.

If you want to relieve constipation on its own, there are a few fiber supplement sources you should look out for. You will want insoluble fiber, which will encourage your colon to make mucus and water. This in turn should lead to softer, more easily passed stools.

Though most fiber forms will claim to benefit you (and most will, to a point), there are only a couple that have been clinically proven to work.

Coarse wheat bran and flaxseed are perhaps best. They are insoluble fibers that bring a laxative effect, stimulating that water and mucus in your colon to help you to overcome constipation.

Soluble fibers don’t have a great amount of clinical data backing up their efficacy for treating chronic constipation alone. These include fine wheat bran, as opposed to the coarse variety that you should be eating, alongside wheat dextrin, fructooligosaccharides, and inulin.

Who Should Avoid Fiber Supplementation

Fiber supplements should be safe and beneficial for most people, especially those struggling with IBS, and/or constipation. However, some people should be cautious when judging whether or not to take them.

If you have difficulty swallowing, pass impacted stools (hard and stuck), have a bowel obstruction (of the small or large intestine), suffer with intestinal inflammation, experience esophageal structuring (narrowing of your esophagus), suffer with slow transit constipation, gastroparesis, or pelvic floor dysfunction, or already get plenty of fiber from dietary sources, are severely backed up, or are on medication for your symptoms, you should think twice about taking a fiber supplement.

Again, if in doubt, it’s always best to talk with your healthcare provider before beginning a new supplement regime.

Our Top Fiber Supplements

As promised, we’ve got four different fiber supplements for you today. Each is the best at what it does in its individual category, except for the first, which is the best overall fiber supplement that we have been able to find.

Best Overall Fiber Supplement: Konsyl Daily Psyllium Fiber

Konsyl Fiber Supplement packet

Konsyl’s Daily Psyllium Fiber is amongst the best of the best. Psyllium is perhaps the most scientifically justified type of fiber going for digestive health benefits.

It’s a mostly soluble fiber sourced from Plantago ovata plant seed husks. It takes on a lot of fluid as it gels, giving plenty of soft bulk to your stools and allowing for smooth transit through your digestive tract.

There is a strong body of research underpinning psyllium’s use in treating functional constipation and alleviating diarrhea. It will also go a long way towards improving blood sugar control and bringing down your LDL (or ‘bad’) cholesterol.

Psyllium is widely available across a range of supplements. So why go with Konsyl?

Konsyl Fiber Supplement nutrition information

Well, there are a few reasons.

Firstly, their ground psyllium husk is completely organic and free from any additives or other nasties like sugar alcohols or artificial sweeteners, which can often cause further irritation and make symptoms worse.

It’s also available in a couple of forms, which is nice – they sell it as a powder for those who want it, and in capsule form, which I generally prefer for sheer convenience.

However, if you do go with capsules, bear in mind that you’ll have to take quite a few to make up a solid dose – four or five capsules per day should do the trick. This should give you around 5-15 g.

If you use powder, don’t over-dilute it and make sure that you drink it quickly. It gets really thick and gelatinous if left for too long, especially in colder liquids. Instead, try downing it quickly in a smoothie, or eat it hot in something like porridge.

Konsyl’s Daily Psyllium Fiber Pros

  • It’s fully organic 
  • There is a good body of evidence underpinning it
  • It works well for both diarrhea and constipation
  • Stabilizes blood sugar levels and lowers levels of LDL cholesterol

Konsyl’s Daily Psyllium Fiber Cons

  • Gets gloopy when left in cold liquids

Best Fiber Supplement For Diarrhea: FiberCon Fiber Therapy for Regularity

FiberCon bottle

If you’re struggling with diarrhea alone, FiberCon is the way to go. It is perfect for whatever kind of stool difficulty you are experiencing.

It is a form of calcium polycarbophil. It’s a unique, synthetic fiber, formed to be perfect for what it does. It resists gut fermentation, meaning that it won’t make you gassy. Although it is completely insoluble, it actually works very similarly to soluble fiber – it takes on a lot of water in your colon, thus bulking out your stools.

In fact, the company itself claims that it can swell to nearly sixty times its starting weight in water. Even allowing room for exaggeration, this is pretty impressive.

This is very helpful for anybody struggling with diarrhea. It allows your stools to take on more shape, growing firmer, whilst also being able to add soft mass to dry or hard stools.

Fibercon ingredient label

FiberCon rests on a good scientific foundation with plenty of data supporting its claims and usage. It has been clinically proven to help those suffering with IBS-D (IBS with diarrhea), IBS-mixed type (alternation of diarrhea and constipation) and IBS-C (IBS with constipation). Basically, if you have any form of IBS, it should be able to relieve symptoms and discomfort whilst making you more regular.

Unfortunately, FiberCon contains additives. Combine this with the fiber’s synthetic nature and you have a product that is unsuitable for anybody looking for natural, whole food sources.

It comes in pill form, which is practical and useful. However, do bear in mind that the pills are pretty hefty – they may be hard to take for anybody who struggles to swallow larger tablets. You should take two pills daily for a workable dose.

FiberCon Pros

  • Resists fermentation in the gut, resulting in no gas
  • Mitigates symptoms of all forms of IBS, diarrhea, and constipation
  • Convenient pills, if hard to swallow
  • Great for bulking

FiberCon Cons

  • Not organic
  • Additives included
  • The pills are large, making them hard to swallow

Best Fiber Supplement For Occasional Constipation: Spectrum Essentials Flaxseed

Flaxseed is a fantastic source of fiber, perfect for overcoming the occasional bout of constipation.

Spectrum Essentials Flaxseed packet

It’s been clinically proven to work better than other fiber types, like psyllium, for improving frequency and quality of bathroom trips amongst constipation patients. In fact, one study showed that it’s better than lactulose, a leading laxative, for relieving constipation.

Spectrum’s flaxseed is simple, organic, ground flaxseed that should give you everything you want as you seek to alleviate your symptoms and benefit from the host of additional benefits on offer. The fact that it is milled makes it a fair amount more efficient than whole flaxseed. Milling improves the flaxseed’s ability to absorb water in the digestive tract, making it perfect for bulking out troublesome stools.

It is also a whole food, meaning that it has all the micronutrient benefits this entails, and it makes a great addition to porridge, overnight oats, pancakes and other baked goods. The flavor you will get from it is also lovely – nutty, warm, and deep.

Do note that it gels very efficiently (hence the benefits), but this means that you should start with a small amount if you’re cooking with it. Otherwise, you could end up with either a dry or gloopy mess!

Flaxseed is particularly good at improving blood sugar control and lowering levels of bad cholesterol, and is also a fantastic source of omega 3 fatty acids. Though the latter won’t have much impact on your constipation, it’s still a lovely bonus to gain as a bit of an added extra.

Two tablespoons make up one serving, giving you a healthy helping of 3g of dietary fiber.

Spectrum Essentials Flaxseed Pros

  • Completely organic
  • Great for overcoming occasional constipation
  • Milled for efficacy
  • Whole food source
  • Contains omega-3 fatty acids
  • Great for use in cooking

Spectrum Essentials Flaxseed Cons

  • It can cause gas and bloating
  • Not convenient to use
  • May aggravate symptoms of IBS-D

Best Fiber Supplement For Alternating Constipation & Diarrhea: Citrucel Methylcellulose Fiber Therapy Caplet for Irregularity

If you have the patience to make it through that name, you’re onto a winner. 

Citrucel Methylcellulose Fiber bottle

Citrucel is a great remedy for occasional or alternating constipation and diarrhea. Each dose gives you a couple of grams of methylcellulose, a completely water soluble, gelling fiber known for its ability to mitigate symptoms of various bowel concerns.

Methylcellulose is a synthetic fiber that forms into soft bulks when mixed with water. This makes it perfect for overcoming constipation, as it will give stools the softness they need to pass.

The bulking factor will, however, also be great for overcoming diarrhea, as a watery, runny stool is given shape and form, thus slowing them down. It has a very low fermentation rate in the gut, which means you won’t experience much by way of gas or bloating.

Methylcellulose is slightly less well-studied than some of the other fibers in this list. There are better researched products out there. However, tentative data suggest that methylcellulose may well be the answer you’re looking for if you alternate between struggling with both diarrhea and constipation.

Citrucel provides this methylcellulose in a very handy pill.

Citrucel Pros

  • Perfect for overcoming both occasional diarrhea and occasional constipation
  • Non-fermentable, meaning no gas or bloating
  • Convenient to take
  • Can tackle several forms of IBS

Citrucel Cons

  • Clinical research is limited
  • You need to take quite a few capsules per dose
  • Not great for those suffering solely with IBS-C

How Much Fiber Do You Need?

We all need plenty of fiber in our diets… but what exactly does that mean? Some of the products we’ve seen give you a gram or two. Some go higher. But how much is enough?

Our needs are quite changeable. They can vary depending on a few factors, including your age, gender, overall digestive health, activity levels, and any pre-existing medical issues you may have. As a good rule of thumb, you should be aiming for around 25 to 34 grams of fiber today, preferably as much as possible from whole food sources.

Alternatively, you can think in terms of energy expenditure. Aim for about 14 grams of fiber for every thousand calories you consume. For instance, someone with low body mass and activity levels may need 1500 calories per day. They would therefore need around 21 grams of fiber per day. Somebody with more muscle mass and an active lifestyle may need 3000 calories, which would be 28 grams per day.

As above, age is a factor you can think in terms of. Children aged 2-3 will need about 14 grams of fiber, whilst girls aged 4-8 will need more like 17, with boys the same age needing more like 20. This jumps to 22 and 25 respectively when you get to the 9-13 range, 25 and 31 for 14-18, and thereafter about 25 and 31 (though requirements may tail off slightly as you age).

These guidelines all assume that fiber intake is at least predominantly sourced from whole food sources, i.e. not from supplements. This should always be your first port of call – fresh fruit and vegetables, legumes, nuts, and whole grains should form the bulk of your fiber intake.

Supplements should be used as their name suggests – they should supplement you dietary fiber intake, not form it, not even most of it. Aim for as much natural fiber as you can. If this isn’t enough – if you are experiencing any of the symptoms associated with low fiber levels, like constipation or diarrhea – then it is likely time to supplement. Take 1-5 grams per day from the kinds of sources we have listed in this article, whilst taking the remainder from decent, whole foods.

Telling The Difference Between Low Fiber Intake And Dehydration

The symptoms associated with low fiber intake can also come from a lack of fluid in your diet. Even minor dehydration can lead to constipation. Chronic minor dehydration (consistently slightly under consuming fluid) can result in chronic, ongoing digestive complaints.

Therefore, if you think you’re getting enough fiber in your diet, consider drinking more water. You can aim for a certain amount of fluid per day.

Alternatively, simply take note of how often you pee, and the color of that pee. If you’re going every couple of hours and it’s clear, great. If it’s yellow or darker and you’re only going a couple of times per day, you probably need to drink more. This alone may fix your digestive concerns.

You should also consider upping your fluid intake when using fiber supplements. They work by gelling with water, which will need to be found from somewhere. Not replacing the water used in the gelling process could leave you dehydrated.

Most supplements will recommend you drink an extra 8 ounces of water per day, preferably with your fiber supplement. However, individual instructions may vary, so always be sure to check the label.

Fiber Supplementation FAQs

When is it best to take fiber supplements?

There is no particularly good or bad time to take in fiber. In fact, total consumption is far more important than timing, though it may be a good idea to spread your total consumption all out a bit.

For fiber supplements, consider your routine to be the main variable. It has to work for you. Figure out when you would usually have your main daily bowel movement – or when you would like it to be, if you are struggling to go at all. Take your fiber supplements around five or six hours before this point to give the fiber enough time to make it through to your colon. If you generally go to the bathroom first thing in the morning, consider taking your fiber supplement at night to get you ready for the right time.

Timings may be longer for some people or be shorter for others. Make note of timings and adjust accordingly. As ever, drink plenty of water with your fiber supplement.

Do fiber supplements cause gas?

Some fiber supplements can cause gas. On our list above, flaxseed is a particularly bad culprit for causing gas and bloating, though even this isn’t too bad. However, each type of fiber will have a different degree of fermentability – our gut bacteria’s digestion of it. As our bacteria feed on the fiber, they cause stomach gas.

Most of the items on our list are quite good for fermentability. Even flaxseed is pretty mild. Other forms are far worse, including common fiber types like guar gum, polydextrose, and inulin.

Do note, however, that even lower fermentable fiber sources can cause a bit of gas or bloating at first. For instance, it’s quite common to experience bloating when first beginning a course of super greens, which are incredibly rich in different forms of fiber. This is because your gut may take a little while to adjust to the new fiber load. However, this should usually improve over a few days or weeks. If in doubt, begin with half- or quarter- doses, building up slowly.

In addition, some additives in certain fiber supplements may cause bloating and gas. Our list is pretty solid, though. There are few additives involved, meaning far fewer variables to potentially interfere with your gut.

Do fiber supplements make you poo?

Technically, no. Digestive waste from your diet makes you poo. However, fiber certainly helps the whole process out a great deal. It absorbs water through the digestive process. Rather than breaking down, as other nutrients do, it therefore bulks up. This gives your stools a lot of bulk.

If you’re struggling with diarrhea, this can stem the tide as your stools become less fluid. If you struggle with constipation, fiber can give your stools soft bulk so that you can pass it more easily.

Most fiber supplements will be designed with an eye to improving your bowel movements. Insoluble fiber sources like ground flaxseed and coarse wheat bran have quite significant laxative effects, meaning that they make you pass stools far more ably, far more quickly. Bulking agents like psyllium and polycarbophil are there more to retain water in your stool, which may slow down your bowel movements.

Do fiber supplements cause constipation?

Fiber supplements can help you to overcome constipation. However, too much fiber can cause fiber-related constipation, as can ingesting fiber too quickly. Alternatively, taking a fiber supplement without drinking enough fluids can cause blockages, whilst some fiber supplements can dry out your stools.

In particular, finely ground wheat bran and wheat dextrin products may cause constipation.

If you are worried about fiber-related constipation, or if this is why you are taking a fiber supplement in the first place, consider a supplement with a decent capacity for holding water. Psyllium is a good bet, as are both polycarbophil and methylcellulose. These should keep you regular.