The length of a man's penis can decrease to up to an inch. This is due to many reasons. Here are some of them.
1) physical erection problem - to keep a penis in shape a man needs to have regular erection, this strengthens muscles of the penis but if a man has erection problem, the penis might shrink and this can lead to a decrease in the length of the penis.
Obesity and increase in age can cause it too. Deposits of fat can decrease the size of a flaccid penis.
Some medication can cause this too, examples are a type of hypertensive drugs. The condition can be reversed if medication is stopped.
Unfortunately, penises can shrink or get shorter. Usually, this is caused by age or most likely medications. Certain medications can make the penis get smaller. The reaction of a medication to certain body parts can enlarge or shrink them based on the ingredients that are in the medications. There are certain medications that cause penis shrinkage and these include those medications that block calcium. Most people take these medications in order to lower their blood pressure. Other causes include drugs that decrease the testosterone levels.
The amount of shrinkage depends on the individual himself as well as the amount of medication that was taken and probably the man’s age should also be taken into account. Reading the side effects of certain medications would be beneficial.