I have kept a symptom diary against dose dates, which turns out to have been the useful thing.
Both of these get recommended confidently by different people, which suggests neither is obviously right.
My constraints are cost, measurement resolution and how much handling I am prepared to do — in roughly that order.
Under what conditions does the answer flip?
Adding fibre without adding fluid makes it worse, which is the most common self-inflicted error in this tag.
Soluble fibre — psyllium, oats, legumes — holds water and softens stool. Insoluble fibre adds bulk and speeds transit. In slowed-transit constipation the soluble kind is generally the more useful of the two.
| Event | Active arm | Placebo arm | Timing |
|---|---|---|---|
| Nausea | 40–45 % | 15–20 % | Peaks 1–2 wk after each step |
| Vomiting | 15–25 % | 5–8 % | Follows nausea |
| Diarrhoea | 20–30 % | 10–15 % | Early, variable |
| Constipation | 20–25 % | 8–12 % | Later onset, persistent |
| Discontinuation for GI events | 4–7 % | 1–2 % | Mostly during escalation |
Ranges span agents and doses; read the specific prescribing information for a specific figure.
Mechanically, osmotic agents such as macrogol draw water into the lumen and are the usual first pharmacological step; they work with the mechanism rather than against it.
The fibre-and-fluid relationship in functional constipation is established across intervention studies, and fibre without adequate fluid worsens symptoms.
Nothing here is medical advice.
Pain, distension and vomiting together are urgent. That is not constipation.
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Browse resultsAnswering this needs the actual fibre and fluid intake, and people are almost always taking less of both than they think.
Aim for 25 to 30 grams of fibre a day, which requires deliberate planning at a reduced total intake because fibre-rich foods are bulky and satiating exactly when appetite is suppressed.
On the detail: adding fibre without adding fluid produces a larger, drier, harder stool and makes the problem worse. The fluid is not optional and is the step people skip.
Osmotic laxatives such as macrogol have the strongest evidence base for chronic constipation and are first-line in most guidelines.
The caveat is that obstruction is a surgical emergency and presents as pain, distension and vomiting rather than as ordinary constipation.
This one does not attenuate with tolerance. Plan for it rather than waiting it out.
The short version: fibre to 25 to 30 grams a day, fluid to match, movement daily, and osmotic laxatives if that is insufficient.
Physical activity has a modest but real effect on transit time and is free, which makes it worth including even though it will not fix this on its own.
Red flags that change this from a management question to a clinical one: no bowel movement for several days with abdominal distension and vomiting, blood in the stool, or unexplained weight loss beyond what is expected.
Research-use compounds are not approved for human use.
Osmotic first, stimulant reluctantly, and not as a standing arrangement.
Ask PeptideStack is a static archive. Posting is closed, but the norms are worth stating: answer the question that was asked, show your working, cite the trial or the certificate, and say plainly where the evidence runs out.