Propecia 1 mg sexual AEs: the year-one table, not the forum

01Year-one rates sit on a table, not a thread

Registration year-one tables put sexual adverse events in single digits, and they already had a placebo floor. Decreased libido 1.8% on Propecia versus 1.3% on dummy tablets. Erectile dysfunction 1.3% versus 0.7%. Ejaculation disorder 1.2% versus 0.7%, with decreased volume called out at 0.8% versus 0.4%.

Pooled sexual reports reached 36 of 945 men (3.8%) on 1 mg versus 20 of 934 (2.1%) on placebo. The p-value was 0.04. Drug-related discontinuations overall were 1.4% versus 1.6% for placebo. Sexual reasons for leaving sat at 1.2% versus 0.9%.

Hair forums drown those denominators because the men who feel fine rarely post. Low trial percentage is not zero patient experience. Both belong in the same visit.

02Semen quality and the six-week sample that bounds exposure

Thirty-five men on 1 mg for six weeks gave the semen numbers the pregnancy section leans on. Twenty-one of those samples had no detectable finasteride under 0.2 ng/mL. Mean was 0.26. The high mark was 1.52. The PI then assumes a 5 mL ejaculate and 100% vaginal absorption to put daily exposure at most 7.6 ng, which it compares to a 5 microgram oral amount that did not move circulating DHT in men.

That arithmetic exists to calm a fetal-exposure question. It does not certify that ejaculate volume, sperm count, or orgasm feel normal for the man in the chair. Postmarketing still lists infertility and poor seminal quality, with later improvement in some reports. Order the analysis if a child is the goal this year.

Rhesus work in the PI pushed maternal exposure far above semen estimates before male-fetus genital abnormalities appeared. That is animal context for handling and semen, not a sexual-AE incidence. Keep the two files separate so a couple does not hear 'the monkey study says you are fine' when he is reporting a month-two libido drop.

Hematospermia and testicular pain also sit in the postmarketing reproductive row. Blood in semen after a new 1 mg is a urology look, not a 'wait for hair month six' item. Pain that wakes him at night is the same. Date the first episode next to the first tablet.

03Why the loud rooms outrun the 945-man table

Selection bias is the quiet engine of hair boards. Men with no change have no story. Men with a change write it twice. The label already said resolution occurred in those who stopped for these effects and in most who stayed on therapy.

Fifth-year extensions saw each of those named sexual events fall to 0.3% or less. New reports did not pile up with longer exposure on the 1 mg hair program. That is the opposite of the 'it always gets worse' script.

Stockholm letters still treat a single man's diary as data for his visit. Population percentages do not veto a stop trial. They stop you treating a 2-point placebo-subtracted difference as a coin toss.

04Libido, erection, and ejaculate volume are the named trio

Decreased libido led the year-one list and is still the phrase most men use first. It is not the same complaint as a softer erection, and it is not the same as a smaller ejaculate. Chart them on separate lines or the follow-up becomes mush.

Erection change sat at 1.3% in that table. Vascular ED, alcohol, sleep debt, and performance fear sit in the same age band as androgenetic alopecia. A new PDE5 blister does not answer a finasteride question until the timeline is written.

Ejaculate volume fell in a dedicated semen study: median drop 0.3 mL (minus 11%) at 48 weeks on 1 mg versus 0.2 mL (minus 8%) on placebo. Five-milligram work showed a larger median drop near 0.5 mL (minus 25%) that reversed after stop. Fertility worry is a semen analysis, not a forum poll.

05How a household hears the sexual change

Partners often hear the forum version first: permanent, universal, hidden by the company. The visit version is narrower. A minority of men report a change. Most who stop for it improve. A smaller group reports persistence. Nobody in the room has to pick a team.

Semen exposure math on 1 mg is in the pregnancy section of the PI: highest measured semen level 1.52 ng/mL after six weeks in 35 men, with 60% of samples undetectable. That paragraph exists to bound fetal risk from semen, not to dismiss a man's sexual complaint.

Couples who want a child soon should say so before a long 1 mg course. Semen quality reports after stop include both improvement and lingering trouble. A reproductive clinic, not a hair board, owns that work-up.

06Depression ink and the PSA drop sit beside the sexual table

Mean PSA in young trial men (ages 18-41) moved from 0.7 to 0.5 ng/mL at month 12 on 1 mg. Older BPH studies at 5 mg cut PSA by about half. Any confirmed rise from the on-drug nadir needs evaluation even if the number still looks 'normal' for untreated men.

Depression and suicidal ideation entered the postmarketing psychiatric row. Mood change is same-week medicine, not a 'wait for hair month six' project. The sexual AE and the mood AE can travel together. Chart both dates.

Breast tenderness and enlargement in the 1 mg trials did not differ from placebo. Postmarketing still asks men to report lumps, pain, or nipple discharge. That sentence is counseling, not a claim that 1 mg causes male breast cancer at a measured rate.

07A stop trial is a dated plan, not a weekend dare

There is no prize for enduring a sexual AE to keep a hairline. Plan the pause with the prescriber: last-dose date, which function you are watching, and when you return. Hair reversal after withdrawal is a twelve-month label clock, not a three-day shed panic.

Restart only if the sexual function recovered enough to make the trade clear. Jumping from 1 mg to a borrowed 5 mg because 'maybe more DHT block will somehow spare sex' is backwards chemistry.

Document alcohol, new SSRIs, and sleep in the same fortnight. Those confounders wreck more erections than the 0.6-point ED gap in Table 1. Clean the confounders before you retire the molecule.

Stop-trial pocket list

• Name the function that changed: desire, rigidity, volume, orgasm
• Write the week it started relative to the first 1 mg
• Pause with a return date, not an open-ended vanish
• Do not split leftover 5 mg tablets as a homemade 1 mg

08What the next clinic hour should already hold

Bring a two-month diary with dose time, alcohol, sleep hours, and which sexual function moved. One angry memory of 'it broke in March' wastes the slot.

List every other drug that touches desire or rigidity: SSRIs, spironolactone, residual 5 mg finasteride, borrowed tadalafil. The parent letter holds the full lock. This postscript only annotates the sexual row.

09Persistence after stop is a 2012 warning, not a second percentage

April 2012 the US label added sexual dysfunction that continued after discontinuation: erection, libido, ejaculation, and orgasm disorders. FDA said it had not reviewed a new controlled trial that measured how often that happens or how long it lasts.

Causality for lasting symptoms is still argued in journals. Postmarketing lists also carry male infertility or poor semen quality, with reports of later improvement, plus testicular pain and hematospermia. Those lines are signals, not incidence.

Stop-trial planning belongs with the prescriber who wrote the 1 mg, not with a leftover 5 mg prostate split. See the paired duration myth postscript for what hair does after the last tablet. Sexual recovery and hair reversal run on different clocks.

10Hair 1 mg is not a leftover Proscar 5 mg conversation

Five-milligram prostate tablets live on a different indication, a different age band, and a different AE conversation. PLESS at 5 mg saw 3.7% leave for sexual-function reactions versus 2.1% on placebo over four years. Do not paste that paragraph onto a 28-year-old on Propecia.

PCPT used 5 mg in men 55 and older. Gleason 8-10 cancers were 1.8% on finasteride versus 1.1% on placebo. The hair label says the meaning of that finding for 1 mg use is unknown. Do not volunteer a prostate-cancer lecture as if it were a hair-dose fact.

Splitting a 5 mg BPH tablet to improvise hair dosing is a compounding habit, not a labeled 1 mg course. Strength, film coat, and counseling all change. Ask the pharmacy for the 1 mg product the letter names.

11Crushed tablets and pregnancy sit outside this AE letter

Coated tablets keep intact film between fingers and the 5-alpha block. Pregnant women, or women who may be pregnant, must not handle crushed or broken 1 mg tablets. Wash with soap and water if contact happens. Propecia is not indicated in women.

Male-fetus genital development needs DHT. That is a Type II 5-alpha-reductase story, the same enzyme this tablet prefers. It is a handling rule, not a sexual-AE rate. Keep broken crumbs out of a shared bathroom cup.

12Seal on the sexual-AE despatch

Nora Lindqvist seals this sexual-AE note on 21 August 2026. Year-one tables stay on the desk. Forum volume stays in the margin. Persistence after stop stays a labeled possibility without a second percentage attached.

Change nothing about the 1 mg without the clinician who can also read mood, PSA, and fertility plans. Questions to [email protected]. This thread educates. It does not prescribe.