Caffeine

Caffeine (in coffee/energy drinks) is a central nervous system stimulant whose main mechanism is blocking adenosine receptors (A1/A2A), which reduces “sleep pressure” and increases alertness; this also promotes catecholamine releaseand can raise arousal/stress signaling, which is why it can improve focus but also worsen anxiety, jitters, and sleep in some people (1). In hair-loss literature, caffeine is sometimes described as having mild 5-alpha-reductase–inhibiting potential (a theoretical DHT-lowering angle), but this is generally framed as modest and not comparable to finasteride-type effects (2).

For PFS/PSSD/PAS, caffeine is often “hit or miss” because it can push the nervous system toward higher sympathetic activation (more adrenaline-like tone) and disrupt sleep—both of which can amplify symptom sensitivity in already destabilized people. On hormones, the research on caffeine/coffee and testosterone is mixed across studies (some suggest increases in certain contexts, others show little association or different patterns by intake), so it’s not reliable to think of coffee as clearly raising or lowering androgens overall (3). Practically, if someone notices consistent flares with caffeine, the safest approach is to treat it as a personal trigger (reduce dose, switch to decaf, or avoid during stabilization), especially since “wired but tired” sleep disruption is a common way it backfires.

https://www.ncbi.nlm.nih.gov/books/NBK519490/

https://pmc.ncbi.nlm.nih.gov/articles/PMC11720832/

https://pmc.ncbi.nlm.nih.gov/articles/PMC9112543/

Crash Anecdotes:

https://www.reddit.com/r/PSSD/comments/v266y3/how_do_you_react_to_caffein/

My Personal Risk Ranking:

Very Low Risk of Permanent Worsening (for PFS/PSSD/PAS):
If you have PFS/PSSD/PAS, caffeine considered low to no risk for permanent worsening, but reports of symptom flares are not uncommon.