Dementia affects millions of people worldwide, and Alzheimer's disease remains its most common cause. Despite decades of research, no treatment currently reverses or cures the condition, and available medications offer only modest, short-term benefit. This has led researchers to look more closely at the earliest changes that occur in the brain, well before symptoms appear.
One area of focus is the mitochondria — small structures inside brain cells responsible for producing energy. Mitochondria are especially vulnerable to a type of cellular damage called oxidative stress, which occurs when harmful molecules called free radicals build up faster than the body can neutralise them. In Alzheimer's disease, this damage appears early and is thought to contribute directly to the loss of brain cells over time.
A recent scoping review published in the journal Antioxidants, led by researchers at Macquarie University including Professor Ralph Martins and Professor Hosen Kiat, examined the evidence on two types of antioxidant treatments studied in this context: natural vitamins, such as vitamins E, C, B and A, and a newer class of laboratory-designed compounds known as mitochondria-targeted antioxidants (MTAs). Professor Martins was among the first researchers to identify oxidative stress as a feature of Alzheimer's disease, nearly four decades ago — a finding that has since shaped much of the field's research into the condition's underlying biology. This latest review builds on that foundation, summarising what is currently known from animal and laboratory studies about how well each type of antioxidant protects brain cells and supports cognitive function.
The evidence on vitamins
Vitamins have long been studied for their antioxidant properties, and this review found encouraging results across several types. Vitamin E showed the most consistent benefit, improving markers of oxidative stress and memory performance in every study reviewed. Other vitamins, including forms of vitamin A, B and C, also showed positive effects, often by supporting healthy gene activity, reducing inflammation or lowering levels of a compound called homocysteine, which has been linked to brain cell damage.
These findings reinforce vitamins as a reasonable and well-studied starting point for supporting brain health. However, the review notes that these same benefits have been harder to reproduce in human clinical trials. Possible reasons include limited ability of some vitamins to reach the brain in sufficient amounts, due to the blood–brain barrier, as well as differences in trial design, dosing and how long treatments were administered.
A newer approach to mitochondrial protection
Mitochondria-targeted antioxidants were developed to address this delivery challenge directly. These compounds — including MitoQ, MitoTEMPO, SS-31 and SkQ1 — are designed to accumulate specifically inside mitochondria, where oxidative damage is thought to begin.
Across the studies reviewed, MTAs consistently improved cognitive performance, preserved mitochondrial structure and reduced hallmark signs of disease in animal models. SS-31 and SkQ1 showed particularly reproducible results across multiple independent studies and different stages of disease progression. Several of these compounds have also been tested in humans for unrelated conditions, such as vascular ageing and eye disease, with favourable safety profiles — an important consideration for future research.
Where the research goes from here
The authors describe these findings as an encouraging early step, though it is important to note the evidence reviewed here is limited to animal and laboratory studies, and further research, including human clinical trials, is needed before we know whether these benefits truly carry over.
Although some of the compounds discussed, such as MitoQ, are already available as supplements for other purposes, they have not yet been approved specifically for cognitive function, and anyone considering antioxidant supplements for brain health should speak with a qualified healthcare provider first.
Even so, this review paints a hopeful picture. Several MTAs already have established safety records in humans, giving researchers a strong foundation to build from. With continued research, mitochondria-targeted antioxidants may represent a promising new direction in the search for treatments to help protect the brain against Alzheimer's disease.
Source: Squillace, A., Fernando, M.G., Sullivan, K., Kiat, H., & Martins, R.N. (2026). Natural Vitamins and Novel Synthetic Antioxidants Targeting Mitochondria in Cognitive Health: A Scoping Review of In Vivo Evidence. Antioxidants, 15(1), 78. https://doi.org/10.3390/antiox15010078
