The short answer
Psyllium is the most widely used soluble fibre supplement, and the question is not the brand, it is the format. As a powder, 10 g of husk costs 0.28 EUR at KoRo. As capsules, the same 10 g would cost 4.14 EUR at Bioptimal, fifteen times more, and you would have to swallow 31 of them. The capsules compared provide about 1 g a day, ten times less than the dose used in studies and than the one Bioptimal recommends for its own powder.
The comparison
| Brand and format | Type | Price | Price per kilo | Recommended daily dose | Cost per day |
|---|---|---|---|---|---|
| KoRo, organic psyllium, 500 g | husk, powder | 13.75 EUR | 27.50 EUR | not specified | 0.28 EUR for 10 g |
| Bioptimal, organic psyllium powder, 1 kg | husk, powder | 27.95 EUR | 27.95 EUR | 10 g | 0.28 EUR |
| Bioptimal, organic psyllium powder, 150 g | husk, powder | 8.95 EUR | 59.67 EUR | 10 g | 0.60 EUR |
| Dieti Natura, psyllium, 200 capsules | seed, Plantago indica | 12.50 EUR | 208 EUR | 1.2 g | 0.25 EUR |
| Bioptimal, organic psyllium, 60 capsules | husk | 7.95 EUR | 414 EUR | 0.96 g | 0.40 EUR |
What this table tells us
Capsules cannot provide a useful dose
Psyllium works by swelling in the gut, and the doses studied are counted in grams. The US FDA authorises a cardiovascular health claim from 7 g of soluble fibre from psyllium husk a day, or about 10 g of husk. Bioptimal in fact recommends 10 g a day for its powder. Its capsules, at three a day, provide less than 1 g. Dieti Natura’s provide 1.2 g.
Seed or husk: not the same product
The husk, or seed coat, concentrates the mucilage: it is what swells and provides the soluble fibre. KoRo states 90 g per 100 g, Bioptimal 86.5 g. Dieti Natura’s capsules contain the whole seed of Plantago indica, black psyllium, and not the husk of Plantago ovata, the blond psyllium used in the studies. They are also made with bovine gelatine and are not organic.
The powder is easy to take
Two teaspoons in a large glass of water, a yoghurt or a compote, to be drunk quickly before the mixture thickens. You need to drink enough during the day: taken with too little water, psyllium can on the contrary hinder transit. Start with one spoonful a day to let your gut get used to it, as bloating in the first few days is common. Take it apart from medicines, as it can reduce their absorption.
What about dietary fibre?
It remains the foundation: Anses recommends 30 g of fibre a day for an adult, and most people in France eat clearly less. Pulses, wholegrain cereals, fruit and vegetables provide it. A 60 g portion of rolled oats alone provides about 6 g, as our comparison of rolled oats shows. Our guide to dietary fibre gives the best sources. Psyllium complements, it does not replace.
Our verdict
Buy blond psyllium husk powder, organic, in a large format: KoRo at 27.50 EUR a kilo and Bioptimal at 27.95 EUR are the cheapest, within 2% of each other, and Bioptimal also comes in 150 g for trying it out. Forget the capsules: you would need about thirty a day to reach the dose used in the studies.
Morning or evening, how much water, which medicines to space out: the full official instructions are in our guide psyllium before bed, good or bad idea?
Our sources
- Official KoRo, Bioptimal and Dieti Natura pages, consulted on 24/09/2026.
- FDA, 21 CFR 101.81: health claim on soluble fibre from psyllium husk and the risk of coronary heart disease.
- Anses, benchmark of 30 g of fibre a day for adults.