Glucomannan Vs Psyllium

Studies show time and again that we are just not eating enough fibre each day for optimum health. The average daily intake in the UK (according to the NHS) is just 18 grams per day, when we should be aiming for at least 30 grams of daily fibre. Meanwhile, in the USA the National Institute of Diabetes and Digestive and Kidney Diseases claims that around 42 million Americans are affected by constipation, making it the most common digestive complaint in the United States.

With this in mind, taking a fibre supplement may suit many people. Glucomannan and Psyllium are two popular options, but have slightly different benefits and clinical support. Read on to find out which fibre may suit you best.


Glucomannan Vs Psyllium - Shirataki NoodlesGlucomannan is a fibre that is extracted from the root of the Konjac Plant, which is native to Asia. It absorbs water to become a thick gel, making it ideal for appetite suppression. It has been used in East Asian traditional medicine for thousands of years, and also has an incredibly long history as a food.

Glucomannan absorbs water, like other soluble fibres, but it appears to be the most absorbent and viscous option available. Best results are seen when taking three daily doses of 1 gram each, about an hour before each meal.

It is the primary ingredient in shirataki noodles, also known as zero calorie noodles. Because the fibre is not digestible, these noodles have almost no calories per serving.

Some brands may have more calories if they have been mixed with rice flour or other ingredients to provide a better texture. They are incredibly plain noodles, and so suit strong flavours and spicy sauces.


Psyllium is a fibre taken from the husk of the psyllium plant, called Plantago ovata. Its branded name is Metamucil, but it is widely available as a non-branded supplement. It is a soluble fibre, and so it absorbs water and passes through your digestive system largely unchanged.

Dosages vary, and doses of up to 30 grams are generally well tolerated if enough water is drunk alongside the supplement. A dose of 5 grams appears to be a good starting point for treating constipation; it can be adjusted higher or lower as needed.

Weight loss – fat binding

Glucomannan and Psyllium both bind with fats in the digestive system, essentially reducing the calorie count of a meal. Studies have also found that increasing fibre intake decreased fat and protein digestibility, again reducing the calorie value of a meal.

Weight loss – appetite suppression

Glucomannan Vs Psyllium - Appetite Suppression, Refuse FoodPsyllium may have a very small effect upon the consumer’s appetite, but studies show that it is not enough to lose any significant amount of weight.

Glucomannan, on the other hand, has far more clinical support to show that it does suppress the consumer’s appetite.

In one eight week study, obese consumers who were taking three 1 gram doses of glucomannan each day (1 hour before each meal), lost 5.5lbs. They were not following a calorie restricted diet, and were not taking any other weight loss measures!


Both Glucomannan and Psyllium appear to be effective supplements to take for preventing and treating constipation. Unlike some other constipation treatments such as senna, they do not cause the walls of the intestine to spasm, and so may be a more comfortable option. As they are both types of fibre, they absorb water, adding bulk and moisture to stools, allowing them to pass through your intestines easier. In Japan, Glucomannan has a nickname that translates to “the broom of the intestines”, due to its effects in increasing stool size and preventing constipation.

Other Health Indicators

Because glucomannan and psyllium both bind with cholesterol and dietary fats, they both can lead to lowered cholesterol levels, especially in people who have high cholesterol levels to start with. Psyllium may lower HDL cholesterol levels though, which are the good type of cholesterol. Glucomannan, on the other hand, does not affect HDL cholesterol levels at all. Glucomannan supplementation also appears to reduce triglyceride levels.

For anyone who wants to take a fibre supplement but is worried about increased flatulence, psyllium may be the best option. It does not ferment in the digestive system unlike many other fibres, and so it does not cause “excessive flatulence”. Some studies even indicate that it can reduce gas.

Glucomannan also helps to regulate blood sugar levels. Because it slows down digestion, including the emptying of the stomach after a meal, it causes a more gradual rise in blood sugar levels, rather than a sharp rise. This may mean reduced snacking, but it also may help to treat pre-diabetes, and could help to prevent and treat hyperglycaemia in diabetics. Diabetics and Pre-diabetics should only take glucomannan supplements with the approval and supervision of their doctor, as their medication may need to be altered as a result of taking this supplement.

Side effects

Glucomannan Vs Psyllium - Side EffectsGlucomannan can cause a range of side effects, but it appears that the majority of side effects dissipate after the first few days of use, as the body quickly gets used to an increased fibre intake. Studies repeatedly report that the majority of glucomannan’s side effects, primarily increased flatulence, stomach cramps, and bloating, stopped after the first three days of taking a glucomannan supplement, if they occurred at all.

Glucomannan can cause constipation if not enough water is drunk when taking the pill; we recommend at least one glass of water with the capsule, and then sipping another glass of water over the next half an hour.

Increased bowel movements, both size and frequency, are to be expected when increasing the amount of fibre in your diet, and starting to take a fibre-based appetite suppressant is no exception. There is a very small risk of choking, as the product does swell on contact with water. This is why the product comes in capsule form, not as a tablet. Obviously, like all supplements, the product should be kept out of reach of children.

Glucomannan also affects blood sugar levels. Diabetics should consult their doctor before taking any glucomannan-based product.

Psyllium can also potentially cause a range of side effects. Stomach cramps and increased bowel movements are possible. It should be taken with plenty of water to prevent constipation. Severe allergic reactions, such as anaphylaxis, are a reported side effect of taking psyllium, although are overall a rare occurrence. Possible signs of allergic reactions include vomiting, chest tightness, breathing difficulties, rashes and hives. Stop taking the product and report any of these symptoms to your physician if they occur.

Neither of these supplements are suitable for people who have had intestinal blockages in the past, unless approved of by your doctor.

Unlike many other products with a laxative effect, there is no time restriction for how long you can supplement psyllium and glucomannan for. Other products such as senna cause the intestines to contract, which pushes faecal matter through the bowels; taking a product such as senna for more than a week at a time is not advisable, as it can cause dependency. This is not an issue that occurs with glucomannan or psyllium, as they are fibre-based.

So, which is better?

Glucomannan Vs Psyllium - PsylliumIt really depends what your goals are. Psyllium is great for treating constipation, but glucomannan also increases the volume and number of bowel movements.

As for weight loss, here is where glucomannan clearly stands out as the superior product, suppressing the consumer’s appetite, reducing the amount they eat, slowing digestion down (reducing snacking between meals), and ultimately aiding weight loss. It is also useful as a tool to stave off hunger when you are following a low calorie diet, helping you to stick to the meal plan.

Disclaimer: Our reviews and investigations are based on extensive research from the information publicly available to us and consumers at the time of first publishing the post. Information is based on our personal opinion and whilst we endeavour to ensure information is up-to-date, manufacturers do from time to time change their products and future research may disagree with our findings. If you feel any of the information is inaccurate, please contact us and we will review the information provided.

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