As a bulk-forming laxative for the treatment of constipation, the adult dosage of powdered psyllium husk is typically 15 grams, 1–3 times per day, dissolved in water. Clinical trials have also used dosages ranging from 10.2–40 grams per day over two to eight weeks.^[1][2]

Dosages used for other conditions have ranged from 2.4–20.4 grams per day for cholesterol control, 7–15 grams per day for body composition, and 3.1–13.6 grams per day for glucose regulation.^{[3][4][5][6][7]}

Some studies also indicate that effects such as appetite suppression or reductions in blood glucose are more pronounced when psyllium is taken before or with a meal.^[8][9][10]

Generally, psyllium can be used at the recommended dosages without a risk of serious side effects.^[11] Psyllium at dosages of 5–10 grams taken three times per day generally seems to be well tolerated, and the most frequently reported side effects include transient stomach cramps and intestinal discomfort.^[12][13] For this reason, it is best to start with smaller doses and work up as individual response permits.

Psyllium should be taken with plenty of water to avoid bloating and decrease the potential of bowel obstruction.^[14] Therefore, psyllium is not recommended for use in people who are unable to maintain increased fluid intakes (for example, individuals who are confined to bed or who may have cognitive impairment).^[15]

People with known allergies to other members of the Plantaginaceae family should exercise caution, because there have been some cases of anaphylaxis after psyllium consumption.^[16][17] Occupational allergies are also reported to have developed due to the unintentional inhalation of or prolonged exposure to psyllium powder in people who work with psyllium regularly.^{[18][19][20][21][22][23][24]}