Which is better pull-ups or chin ups?

Both pull-ups and chin-ups are highly effective exercises for developing upper body strength, and they target slightly different muscle groups which makes them both valuable in a balanced fitness routine.

Pull-ups, with your palms facing away from you, tend to engage your latissimus dorsi (lats) and rhomboids more, which are the muscles in your back. They also work your brachialis and brachioradialis muscles (muscles in your arms) to a lesser degree.

Chin-ups, on the other hand, with your palms facing towards you, tend to engage the biceps more, and still work the lats, but to a lesser extent than pull-ups.

According to a study published in the Journal of Strength and Conditioning Research, chin-ups are slightly more effective at targeting the biceps brachii and the brachioradialis (a muscle of the forearm), while pull-ups are slightly better at targeting the lower trapezius.

So, the answer to your question depends on your fitness goals. If you're looking to develop your back muscles more, pull-ups may be the way to go. If you're looking to work your biceps more, then chin-ups may be a better choice. The best approach might be to include both exercises in your routine for a balanced upper-body workout.