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Limited evidenceBrain & cognition

Idebenone

A synthetic CoQ10 analogue that is a licensed drug for a rare mitochondrial eye disease. For the memory and general 'mitochondrial support' claims it is sold under, the trial record is negative.

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What the science says

  • No benefit for Alzheimer's disease Moderate evidence

    A multicentre randomized double-blind trial found that idebenone failed to slow cognitive decline in Alzheimer's disease at any of the doses tested. Earlier comparative work against tacrine was inconclusive, and no trial supports use as a memory enhancer in healthy adults.

  • Vision in Leber hereditary optic neuropathy Moderate evidence

    A systematic review and meta-analysis found that idebenone improved the chance of clinically relevant visual recovery in Leber hereditary optic neuropathy compared with untreated controls. This is a prescription indication at 900 mg/day under specialist care, not a supplement use.

  • Respiratory function in Duchenne muscular dystrophy Moderate evidence

    The DELOS phase 3 randomized placebo-controlled trial in patients not using glucocorticoids reported a slower decline in peak expiratory flow over 52 weeks. Again a supervised drug indication rather than a nootropic effect.

Dosage & safety

Studied doseClinical trials used 900 mg/day (300 mg three times daily) in eye and muscle disease and 120–360 mg three times daily in the negative Alzheimer's trials. Supplement labels typically give 45–150 mg/day, a dose no study supports for cognition.
SafetyCommon effects in trials were diarrhoea, nasopharyngitis and back pain; liver enzymes may rise. It is a prescription medicine in several countries and its legal status as a supplement varies. Do not use as a self-directed treatment for a diagnosed mitochondrial or neurological disease, and avoid in pregnancy and breastfeeding.

How to take it

TimingThree divided doses with meals, as in the trials that used 900 mg/day.
With food?With food, which substantially increases idebenone absorption - taking it fasted wastes most of the dose.
Worth knowingSupplement labels give 45-150 mg/day, which is a fraction of any trial dose and has no cognitive evidence behind it; idebenone is also a prescription medicine in several countries, so its legality as a supplement varies.

Frequently asked questions

Does idebenone improve memory?

No. A multicentre randomised trial found idebenone failed to slow cognitive decline in Alzheimer's disease at any dose tested, and no trial supports it as a memory enhancer in healthy adults.

What is idebenone actually used for?

Idebenone is a synthetic CoQ10 analogue licensed at 900 mg/day for Leber hereditary optic neuropathy, a rare mitochondrial eye disease, where it improved the chance of visual recovery. It has also been studied in Duchenne muscular dystrophy; these are supervised drug uses, not supplement uses.

Is idebenone better than CoQ10?

There is no evidence for that in general health or cognition: supplement labels give 45-150 mg/day of idebenone, a fraction of any trial dose, and no study supports it for cognition. Its legal status as a supplement also varies by country.

Does idebenone have side effects?

In trials, idebenone commonly caused diarrhoea, nasopharyngitis and back pain, and liver enzymes may rise. Take it with food, which substantially increases absorption, and avoid it in pregnancy and breastfeeding.

Scientific references

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