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Limited evidenceGut health

Cellulase

An enzyme that breaks down plant cell-wall cellulose, sold to reduce gas from vegetables. Humans do not digest cellulose anyway, and there are no trials of cellulase on its own in people.

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What the science says

  • Gas and bloating from vegetables Limited evidence

    No published human trial has tested cellulase alone for gas. The only human data come from multi-enzyme blends that happen to include cellulase; a randomised placebo-controlled trial of one such complex in functional dyspepsia reported less bloating, but the effect cannot be assigned to cellulase.

  • A different enzyme has the actual evidence Moderate evidence

    For gas from beans and cruciferous vegetables, the enzyme with randomised evidence is alpha-galactosidase, not cellulase. Placebo-controlled crossover trials found it reduced breath hydrogen and gas-related symptoms after an oligosaccharide-rich meal, though a later trial in irritable bowel syndrome found no symptom benefit.

  • Digestive rationale Limited evidence

    Cellulose passes through the human gut largely intact and is fermented by colonic bacteria rather than digested. A capsule of cellulase spends minutes in the stomach and small intestine, which is a poor match for where fibre fermentation actually happens.

Dosage & safety

Studied doseNo studied dose. Labels state activity units (typically 100-3,000 CU) taken with meals, as part of a blend.
SafetyNo serious adverse effects reported. Occupational inhalation of enzyme dust can cause sensitisation, but oral use appears well tolerated. People with known enzyme or mould-derived-product allergy (cellulase is usually produced from Aspergillus or Trichoderma) should avoid it.

How to take it

TimingWith meals containing plant fibre.
With food?Always with food.
Worth knowingHumans make no cellulase at all, so this genuinely adds something we lack — but breaking fibre down earlier can mean more gas, not less.

Frequently asked questions

Does cellulase reduce gas from vegetables?

No human trial has tested cellulase on its own for gas, so the evidence is limited; the only data come from multi-enzyme blends where the effect cannot be assigned to cellulase. Breaking fibre down earlier could even mean more gas, not less.

What enzyme actually helps with bean gas?

For gas from beans and cruciferous vegetables, the enzyme with randomised evidence is alpha-galactosidase, not cellulase; placebo-controlled trials found it reduced breath hydrogen and gas symptoms after an oligosaccharide-rich meal. A later trial in IBS found no symptom benefit.

How much cellulase should I take?

Cellulase has no studied dose; labels state activity units, typically 100–3,000 CU, taken with meals containing plant fibre, usually as part of a blend. People with allergy to mould-derived products should avoid cellulase, which is usually made from Aspergillus or Trichoderma.

Scientific references

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