Chitosan
Also known as: Deacetylated chitin
Chitosan is a fiber-like polymer made from chitin, which comes from the shells of shellfish such as shrimp and crab. It is discussed for its ability to bind dietary fat in the digestive tract, though human evidence for meaningful outcomes is limited. Because it is shellfish-derived, people with shellfish allergies should be especially cautious and speak with a professional.
Snapshot
Evidence level is outcome-specific; a supplement can have stronger evidence for one use and limited evidence for another.
What this page can tell you: Commonly discussed timing, food notes, caution categories, and an honest note on how much source review this entry still needs.
What it cannot: Whether this is appropriate for you personally, or that it treats, prevents, or cures any condition. Informational only — discuss with a clinician or pharmacist.
🕒 Timing
When: With a meal
Food: With food
Commonly taken with meals, since it acts on fats during digestion.
💊 Common use range
1,000–3,000 mg
Doses vary; higher intakes increase digestive upset — verify and follow product guidance.
Ranges are informational, not a recommended dose. Talk to a professional about what is right for you.
⚠️ Commonly noted interactions (supplements)
Often about absorption or timing rather than danger — separating doses is common. This list is not exhaustive.
🧭 Baseline caution
General caution for ordinary, common use — before accounting for your specific dose, medications, health history, or procedures.
No general caution factors flagged for ordinary use. See context alerts below for situations that may still apply to you.
Caution level is an informational summary of commonly discussed caution categories and doses — not a safety rating, approval, or medical advice. Low caution does not mean safe for you.
🔎 Context alerts to review
Context alerts may matter depending on your dose, medications, health history, or procedure plans — they do not mean the supplement is generally risky at ordinary use.
Spacing & absorption
- May affect absorption of other supplements/medications taken together
🩺 Medication caution categories
None flagged here, but always review your full routine with a professional.
🏥 Surgery & procedure caution
Not a well-established surgical concern; share your full supplement list with your care team.
If you have a procedure scheduled, bring your full supplement list to your surgical and anesthesia team. Do not stop prescribed medication unless your clinician tells you to. Do not start or stop supplements based only on this app.
✅ Quality checklist
- Prefer products with third-party testing or a certificate of analysis (COA).
- Check the label for the exact form and the elemental or active amount per serving.
🧩 Commonly paired with
🔁 Alternatives
🗣️ Questions for a professional
- I have a shellfish allergy — is chitosan safe for me to consider at all?
🔬 Evidence snapshot
A Cochrane review found chitosan produces only a small weight reduction vs placebo (~1.7 kg), and higher-quality trials show the effect is minimal and unlikely to be clinically significant (many trials were low quality). Its proposed mechanism is binding some dietary fat in the gut. It is not an effective weight-loss aid.
🧪 Forms & quality
Needs evidence review — no source-reviewed information yet. We only show dose and monitoring details after they have been checked against reputable sources.
See the supplement glossary for what form names like "L-", chelated, or standardized extract mean.
📏 Dose & monitoring
Needs evidence review — no source-reviewed information yet. We only show dose and monitoring details after they have been checked against reputable sources.
Evidence vs. burden: Not yet reviewed
😐 Commonly reported side effects
- Digestive upset
- Constipation
- Allergic reactions in people sensitive to shellfish
Non-exhaustive and individual.
🔄 Cycling & breaks
No established cycling pattern.
📅 Daily use notes
Because it binds fats, it may reduce absorption of fat-soluble supplements; space it away from products like fish oil or fat-soluble vitamins. People with shellfish allergies should be cautious.
📋 Source review status
Source-reviewed — last reviewed 2026-07-12
Reconciled 2026-07-12: Cochrane review + NIH ODS Weight Loss fact sheet. Weight effect minimal/clinically insignificant; binds dietary fat; GI effects (flatulence, bloating, nausea, constipation, heartburn); shellfish-allergy caution confirmed; space from fat-soluble vitamins/medications (mechanism-based precaution).
Research backlog (queries to verify):
- chitosan fat binding weight human trial evidence
- chitosan shellfish allergy caution
- chitosan fat-soluble vitamin absorption
📚 References
- Cochrane review — chitosan for overweight/obesityPubMed review — Weight reduction vs placebo WMD -1.7 kg, but high-quality trials show the effect is minimal and unlikely to be clinically significant; many trials poor quality.
- NIH ODS — Dietary Supplements for Weight Loss (chitosan)NIH ODS — Chitosan binds some dietary fat; weight effect ~1.7 kg 'probably clinically insignificant'; GI side effects; shellfish-derived → possible allergy.
Verified against the source shown. See the research-status page for how review works.
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