Why Do I Have To Wait 30 Days To Donate Blood After Stopping Propecia.

I ‘ve been taking propecia for the past 4 years but now I really wish to donate blood at least once in my lifetime.
As you know Finasteride users are not allowed to donate blood. According to one of your previous posts Finasteride is cleared from the blood stream within 48 hours.

So I planned to stop taking propecia for a week, donate blood and resume taking the pill. A week seemed a reasonable
amount of time also because according to the information I found on the internet, DHT levels take a whole week to be
back to normal once you stop taking it.

Unfortunately, however both on the Red Cross site and other sites, they state you need to wait at least 30 days after
the last dose of Finasteride.

Why do I need to stop for a whole month if Finasteride is cleared from my blood stream within a few days? Wouldn’t say,
two weeks be safe enough?

You need to wait a month because that is the policy of the Red Cross.  Two weeks may be “safe” but you have to follow the organization’s policy.