Caffeine

Caffeine (found in coffee, tea, energy drinks, and many pre-workouts) is a central nervous system stimulant whose primary mechanism is adenosine receptor antagonism (A1/A2A). By blocking adenosine signaling, caffeine reduces “sleep pressure” and increases alertness, and it can also increase catecholamine/adrenaline-type activity—one reason it can improve focus but also worsen jitters, anxiety, palpitations, and sleep in some people.

In hair and dermatology literature, caffeine is sometimes discussed as potentially supporting hair growth in certain models, and some sources mention a theoretical 5-alpha-reductase–related angle. However, this is generally presented as modest and not comparable to finasteride-like effects, and much of the discussion is model- or context-dependent.

In PFS/PSSD/PAS discussions, caffeine is often described as “hit or miss” because it can push the nervous system toward higher sympathetic activation and disrupt sleep—both of which may amplify symptoms in already sensitized or unstable individuals. Human research on caffeine/coffee and testosterone is mixed across studies (varying by dose, timing, population, and study design), so it’s not reliable to treat caffeine as clearly raising or lowering androgens overall.

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 (Community Reports):

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

How to Interpret This Page

This page summarizes anecdotal reports and community observations, not medical evidence. “Risk” here refers to how frequently severe or prolonged symptom worsening is reported, not to proven causation or population-wide probability. Individual responses vary widely, and absence of issues in some users does not rule out significant reactions in others.

Risk Signal Based on User Reports

Reports of Symptom Flares Are Not Uncommon (for PFS/PSSD/PAS):
Among individuals who already have PFS/PSSD/PAS, caffeine is commonly mentioned as a trigger for symptom flares—most often involving anxiety, “wired but tired” overstimulation, sleep disruption, and next-day worsening. Many people tolerate caffeine well, and it is not typically discussed as a frequent cause of long-lasting worsening, but sensitivity appears highly individual. Community risk cues often include high doses, energy drinks or stimulant stacks, late-day intake, and use during an already unstable baseline.

For individuals without these conditions, caffeine is widely used and generally well tolerated, though anxiety and sleep disruption are still common side effects at higher doses. Given the variability described in anecdotes, some people with PFS/PSSD/PAS choose to treat caffeine as a personal trigger—reducing dose, switching to half-caf/decaf, or avoiding it during stabilization.

Evidence basis: Anecdotal reports (online forums, self-reports); established caffeine pharmacology; mixed human endocrine data; no controlled studies examining PFS/PSSD/PAS-specific outcomes.