Why do dips have such a bad reputation for shoulders?
Ask ten gym-goers about dips and at least three will tell you they stopped doing them because of shoulder pain. This is not the exercise's fault. It is almost always a technique problem combined with a mobility deficit and an over-aggressive loading timeline.
The dip is a compound movement that takes the shoulder into extension past neutral while bearing load. The anterior capsule of the shoulder joint, the ligamentous tissue at the front of the joint, is under tension at the bottom of every dip rep. That tension is a training stimulus in a healthy shoulder and a pain source in one with restricted mobility or pre-existing anterior tightness.
The two most common technique errors accelerate this problem. First, descending past ninety degrees of elbow flexion without adequate shoulder mobility to handle the range. Second, allowing the shoulders to roll forward at the bottom of the movement, which shifts the load from the intended muscles to the anterior capsule and bicep tendon. Both errors feel like nothing for the first few weeks and produce significant pain in weeks four to eight.
The shoulder pain reputation is also partly a selection effect. People who train dips with good technique and adequate mobility do not stop doing them. People who train them carelessly stop when they get hurt and then tell others the exercise is dangerous. The exercise is not dangerous. The approach is.
A second source of bad reputation is inappropriate loading progression. The dip is a bodyweight movement and many people treat that as a fixed load. Bodyweight is not a fixed load for everyone. A ninety-kilogram person doing full range dips is lifting significantly more absolute load than a sixty-kilogram person. Adding bodyweight through a dip belt before building the connective tissue tolerance for the movement at bodyweight is a reliable path to injury.
Fix the technique. Build the shoulder mobility. Progress the loading gradually. The dip becomes one of the most effective upper body exercises available without a barbell.