Supplement analysis backed by scientific evidence · PT

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Limited evidenceLongevity & antioxidants

Catalase

An enzyme sold on the theory that hair goes grey because hydrogen peroxide builds up in the follicle. The mechanism has some support; swallowing catalase to reverse grey hair has none.

Evidence last reviewed: August 2026

What the science says

  • Reversing grey hair Limited evidence

    The rationale comes from work showing that hair follicles accumulate hydrogen peroxide with age and lose catalase activity, which bleaches hair from within. That finding is about enzyme activity inside the follicle; no trial has shown an oral catalase supplement reaches follicles or changes hair colour.

  • Antioxidant supplementation for hair Limited evidence

    A review of oxidative stress in age-related greying describes multiple contributing pathways and notes that topical or systemic antioxidant interventions have not been demonstrated to restore pigment. Orally administered catalase is a protein and is digested into amino acids like any other.

Dosage & safety

Studied doseNo dose has any efficacy evidence. Products typically list 5,000–10,000 IU of catalase, often combined with saw palmetto, biotin or copper.
SafetyNo serious risks reported at label doses, largely because the enzyme is digested. Some products are derived from bovine liver or Aspergillus, which matters for allergies and dietary restrictions. Do not use it to delay evaluation of sudden or patchy hair colour or hair loss changes, which can have medical causes.

Scientific references

Where to buy

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