Finasteride / Dutasteride
Post-Finasteride Syndrome (PFS) is a term used to describe a cluster of persistent symptoms that some people report after stopping finasteride or dutasteride—medications that inhibit 5-alpha-reductase and are commonly prescribed for hair loss and benign prostatic hyperplasia. Reported symptoms can include sexual dysfunction (reduced libido, erectile dysfunction, genital numbness), cognitive and emotional changes (brain fog, anxiety, depression, anhedonia), and broader physical complaints (sleep disruption, fatigue). While finasteride is taken orally, people also report similar issues after topical formulations, which can still be systemically absorbed in some individuals; as a result, PFS communities often emphasize that both oral and topical exposure may trigger problems in susceptible people.
Mechanistically, PFS remains an area of active debate and research, but two commonly discussed pathways involve androgen signaling and neurosteroid/GABA biology. One hypothesis centers on altered regulation of the androgen receptor (AR) and downstream gene expression after androgen signaling is disrupted, potentially leading to persistent changes in tissues that rely on androgen activity. Another hypothesis focuses on reduced synthesis of 5-alpha-reduced neurosteroids (e.g., allopregnanolone), which normally modulate GABA-A receptors and help regulate stress response, mood, and sleep; disruptions in this system could contribute to anxiety, insomnia, and emotional blunting reported by some patients. Importantly, these are proposed mechanisms—not settled facts—and anyone experiencing persistent symptoms after finasteride should seek medical evaluation and supportive care rather than self-treating based on any single theory.
Crash Anecdotes:
https://www.reddit.com/r/FinasterideSyndrome/
My Personal Risk Ranking:
Extreme Risk of Permanent Worsening (for PFS/PSSD/PAS):
If you currently have PFS/PSSD/PAS, this substance may carry an extreme risk of worsening symptoms—potentially in a lasting way—and is best avoided.
As a PFS sufferer myself, I have seen oral vs. topical not discriminate. In addition, cycling the medicine (going on and off anti-androgens) seems to be the highest risk factor vs. time on the anti-androgen.