⁣ The Overhead Press is safe for your shoulders if you use proper form. It builds stronger, more muscular and healthier shoulders. It strengthens your rotator cuff muscles which hold you shoulder together and prevent dislocations. It also prevents muscle imbalances from the Bench Press by strengthening your rear shoulder muscles. But if you Overhead Press with bad form, you can hurt your shoulders

Probably one of the biggest questions people wonder when performing it

It actually depends on your forearm length: if your forearm is shorter/more proportionate to your humerus, you'll most likely feel comfortable at starting the exercise with the bar resting at your upper chest.

On the other hand (arm?), if the forearm results to be relativey longer, it'll feel better to start above.

What do I mean by "feeling better?"

Well, many people try to perform exercises by looking at the others, disregarding their own anatomical differences (see the deadlift set up):

In this case, a longer forearm would require the arm to travel excessively beyond underneath the bar for it to rest on the chest, if not that then it would require the wrist to be excessively extended. You simply can't cut your forearm length so..

The problem with this, is that it makes it a disadvantageous position to start the exercise from, and can increase the chances of getting injured: elbow/wrst/shoulder pain..

The above image shows the correct form of lifiting and to provide injury in wrist.

The injuries at wrist are very common in this exercise since if if there is a slight mistake in position then it can damage your hand for long term!

No moment arm (MA) from wrist to barebell allows a much more efficient force transfer from elbow up.