Finasteride Brain Fog: What Is It and Why Does It Occur?

In this article, we will consider finasteride as a potential trigger of brain fog. We will do so by explaining what brain fog is, looking at its association with other diseases, and then exploring the effects of finasteride and its effect on our brain.
Frederika Malichová

Frederika Malichová

Neuroscientist at the University Of Cambridge.

A blue image with text saying "Finasteride Brain Fog"

Can Finasteride Cause Brain Fog?

Finasteride, a prescription medicine used primarily for treating hair loss and prostate cancer, can indeed influence the brain. It can modulate oxidative stress, acetylcholinesterase activity, and gene expression in the brain, showing regionally selective effects. It reduces neurogenesis and was found to negatively impact cognitive functions, which may be translated into brain fog.

A study found a significant association between finasteride use and reports of cognitive dysfunction (reporting odds ratio of 5.43). Most cases were considered serious (65.83%), with no signs of recovery (58.37%).


What Is Brain Fog?

Brain fog is a term used to describe symptoms related to cognitive dysfunction and mental symptoms [1, 2].

Awareness about brain fog increased with the COVID-19 pandemic as some patients affected by COVID-19 experienced brain fog for an extended period after recovering from the viral infection [2].

Brain fog can be observed in a variety of conditions ranging from COVID-19, major depressive disorder to diseases like multiple sclerosis or celiac disease [1, 3]. Although it is also prevalent in disorders like hypersomnolence, narcolepsy, or idiopathic hypersomnia [1, 3].

The symptoms of brain fog are [4, 5]:

  • Difficulty focusing
  • Forgetfulness
  • Problems with decision-making
  • Mental fatigue
  • Disconnection from reality
  • Cloudy or daydreamy feeling

However, the symptoms may vary from person to person and from the condition they are complementing [2].

Brain fog can also be caused by other medications, such as Ozempic or Wellbutrin.

What Diseases Are Associated With Brain Fog?

Brain fog, as an umbrella term for cognitive difficulties, has been associated with many medical conditions.

Most frequently, we can observe brain fog as an accompanying syndrome in Chronic Fatigue Syndrome. There, it is characterized by persistent fatigue. In other conditions like Fibromyalgia (a condition resulting in widespread pain and tenderness), anemia, depression, or diabetes, we can see patients experiencing brain fog [6, 7, 8].

Interestingly, some patients affected by Parkinson’s disease with freezing of gate have found to have a higher risk of cognitive decline, which could manifest as brain fog [11].

However, in general, chronic stress, poor sleep quality, hormonal changes, certain diets, and some medications can all contribute to brain fog [6].

Can The Use Of Finasteride Cause Brain Fog?

Although there is no direct cause-and-effect relationship between finasteride and brain fog, there have been studies reporting the effect of finasteride on cognitive dysfunction.

Finasteride is a prescription drug blocking the conversion of testosterone to 5alpha-dihydrotestosterone, which inhibits the production of neurosteroids [12]. Neurosteroids have the ability to influence neural plasticity, and influencing their levels may have pathophysiological implications, for instance, in diseases like depression [12].

However, finasteride is also used as a treatment for androgenic alopecia (excessive hair loss) or benign prostate hyperplasia and prostate cancer [12].

Unfortunately, finasteride treatment has been reported to be associated with cognitive dysfunction, particularly among young alopecia patients [13]. Such cognitive dysfunction could contribute to the development of brain fog.

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Frederika Malichová

Frederika Malichová

Frederika is a postgraduate researcher at the University of Cambridge, where she investigates new biomarkers for Frontotemporal Dementia and other tauopathies. Her research has been published at prestigious conferences such as the Alzheimer’s Association International Conference 2023. She obtained her BSc in Biomedical Sciences from UCL, where she worked closely with the UK Dementia Research Institute.