PROJECT

Testosterone and Fish Oil for Alzheimer’s Disease Prevention

HUMAN HEALTH
PROJECT

Testosterone and Fish Oil for
Alzheimer’s Disease Prevention

HUMAN HEALTH

Project summary

Alzheimer’s disease, hormones, and diet

Testosterone and fish oil (DHA) are promising supplements for reducing the risk of developing memory problems and Alzheimer’s disease. A clinical trial is underway to evaluate their influence on men with memory complaints by measuring the development of amyloid plaque in the brain — a hallmark of Alzheimer’s disease.

Background

  • There are various methods to reduce the risk of developing Alzheimer’s disease and dementia.
  • Supplements such as fish oil and the hormone testosterone have been considered as protective against Alzheimer’s.

Key points

  • Low testosterone levels have been related to memory problems.
  • Individuals with Alzheimer’s disease have lower DHA (omega-3 fatty acids found in fish oil).
  • A clinical trial on the use of testosterone and fish oil in men is underway to determine if there is any influence on cognitive decline.

Parsemus' role

  • The Parsemus Foundation provided early support for the clinical trial being conducted in Australia to evaluate fish oil and testosterone on the development of memory problems in men.
The Project in Detail

Topics

  1. Understanding the effects of testosterone and fish oil for Alzheimer’s disease prevention
  2. Clinical trial on testosterone and fish oil
  3. Take action on testosterone and fish oil for Alzheimer’s disease prevention
  4. Additional resources

Understanding the effects of testosterone and fish oil for Alzheimer’s disease prevention

Testosterone levels in both men and women decline with age, and low testosterone levels have been related to memory problems. Studies have shown that low testosterone levels have preceded cognitive impairment and the neuropathology of Alzheimer’s. Testosterone is also the likely reason that women carrying the apolipoprotein E4 (APOE4) genotype have a much higher risk of developing Alzheimer’s compared to men. The relationship between testosterone replacement therapy in men and women has been harder to quantify due in part to the small number of long-term, controlled studies available.

Another factor critical to brain function is omega-3 fatty acids, including DHA and EPA which usually come from fish oil. In the brains of older people, there is a depletion of long chain omega-3 fatty acids, and those with Alzheimer’s disease have lower DHA levels. DHA supplements can reduce markers of inflammation, which may influence Alzheimer’s disease. In dietary intervention studies, supplementation with DHA and/or EPA seems to be more effective in improving cognition in early stages of cognitive impairment.

Research on the impact of testosterone and dietary supplements is complex and studies frequently report conflicting results.  This may be due to the many individual factors that can affect outcomes, brief follow up, different methods, and lack of comparable imaging data. Long-term randomized clinical trials are needed before conclusions can be made.

Clinical trial on testosterone and fish oil

To help understand the influence of testosterone and fish oil for Alzheimer’s disease and memory, the Parsemus Foundation provided early support for a randomized controlled prospective trial on the impact of testosterone or DHA versus placebo on the onset of amyloid plaque associated with Alzheimer’s disease in men with memory complaints. The study is being conducted at Alzheimer’s Research Australia (formerly called the McCusker Alzheimer’s Research Foundation). Based on the results of a smaller non-placebo trial, the researchers led by Dr. Ralph Martins are optimistic that one or both treatments may slow the development of amyloid plaque and cognitive decline.

The trial has been screening men by completing a positron emission tomography (PET) amyloid scan prior to selection for the trial. The enrollment for the trial has ended in 2025 with participants undergoing completion of the study. In addition to the treatment arms, blood tests and retinal images from all participants will help to develop early diagnostic tests for Alzheimer’s disease.

Take action on testosterone and fish oil for Alzheimer’s disease prevention.

Learn more about dementia and Alzheimer’s disease — and what you can do to lower your risk. There are many lifestyle changes that can reduce the chance of developing Alzheimer’s disease, such as diet, exercise, and appropriate supplements. See Additional Resources below.

Additional resources

General information, research trials, and prevention information regarding Alzheimer’s disease

Scientific publications

See our searchable bibliography for a complete library of scientific publications on our projects.

Key publications on testosterone and fish oil for Alzheimer’s:

  • Kaufman J-M, Lapauw B. (2020). Role of testosterone in cognition and mobility of aging men. Andrology 8:1567–1579. (Free full text).
  • Thota RN, Rosato JI, Burrows TL et al. (2020). Docosahexaenoic acid-rich fish oil supplementation reduces kinase associated with insulin resistance in overweight and obese midlife adults. Nutrients 12(6), 1612. (Free full text).
  • Vlachos GS, Scarmeas N. (2019). Dietary interventions in mild cognitive impairment and dementia. Dialogues Clin Neurosci 21(1):69-82. (Free full text).
  • Tan S, Sohrabi  HR, Weinborn M et al. (2019). Effects of testosterone supplementation on separate cognitive domains in cognitively healthy older men: A meta-analysis of current randomized clinical trials. Am J Geriatr Psychiatry  27(11):1232-1246. (Abstract)
  • Martins RN, Villemagne V, Sohrabi HR, et al. (2018). Alzheimer’s disease: A journey from amyloid peptides and oxidative stress, to biomarker technologies and disease prevention strategies-Gains from AIBL and DIAN cohort studies. J Alzheimers Dis. 62(3):965-992. (Free full text).
  • Asih PR, Tegg ML, Sohrabi H, Carruthers M, Gandy SE, Saad F, Verdile G, Ittner LM, Martins RN. (2017). Multiple mechanisms linking type 2 diabetes and Alzheimer’s disease: Testosterone as a modifier. J Alzheimers Dis. 59(2): 445–466. (Free full text).
  • Wahjoepramono EJ,  Asih PR, Aniwiyanti V et al. (2016). The effects of testosterone supplementation on cognitive functioning in older men. CNS Neurol Disord Drug Targets. 15(3): 337–343. (Free full text)
  • Thomas J, Thomas CJ, Radcliffe J, Itsiopoulos C. (2015). Omega-3 fatty acids in early prevention of inflammatory neurodegenerative disease: A focus on Alzheimer’s disease. Biomed Res Int. 2015:172801. (Free full text).

Last updated on October 13, 2026

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