Is it possible to narrow broad shoulders through botox?

I would not recommend Botox to alter the shape of your shoulders. Discontinue shoulder exercises as a best option to decrease muscle mass. Best of Luck!

Botox stands for Botulinum TOXIN. You cannot possibly inject enough toxin and for enough years to cause sufficient atrophy of muscles. Shoulder muscles are not ornamental or cosmetic and you may need them to perform functions such as raising your arms or straightening your back. I wouldn't recommend paralyzing important functional muscles for temporary cosmetic improvement that muscle atrophy may give you.There are no pictures to tell the cause of "broad shoulders". Are you male or female? Generally, broad shoulders are not an undesirable cosmetic characteristic as they create pleasing proportions in both men and women. It would generally be due to bony skeletal size and not muscle unless you are extremely muscular. If its skeletal then there is no surgery. beauty is all about proportion and proportion is a visual illusion. if you are bothered by the proportions of your torso, then you may be able to address it by changing what you can by moving fat around rather than paralyzing muscles or cutting bones.

Botox should not be used to alter the shoulders. So much would be needed and it would alter your ability to move your arms correctly. This is not a good or advisable treatment. "This answer has been solicited without seeing this patient and
cannot be held as true medical advice, but only opinion. Seek in-person
treatment with a trained medical professional for appropriate care."