Bunions are an enlargement of the great toe or hallux joint of the foot and are frequently related to what is called hallux valgus that is a deviation of the big toe towards the outside. They may or may not be painful, however the potential for them to be painful is great. For this reason prevention and therapy is usually typically indicated. They certainly tend to be progressive and get worse with time. The only real method of getting rid of bunions is with surgery, but that's not necessarily a good solution at first. One of many ways in which they may be treated is with what is called bunion correctors, but they are frequently coupled with the question, can they work? They are splints or braces worn during the night to attempt to correct the angle of big toe to improve its appearance.
A great deal is determined by what is understood by “working”. There's a lot of thoughts and opinions as to them both working and not working with almost no scientific evidence. There's one published scientific study that did demonstrate that the angle of the hallux will be improved by a few degrees after one months use, but this was not a study of any longer than that one month. So, yes, it does look like that bunion correctors can work in the short term at improving the angle of the hallux valgus or bunion several degrees.
Apart from that study just about all we can count on is expert opinion. Most of that opinion is consistent with that scientific study. Nonetheless, it also looks like even if the use of the bunion corrector does not improve the angle of the big toe or hallux or only improves it a smaller amount, it can be feasible that the corrector will go quite a distance to preventing the problem from becoming worse. That is important as bunions are progressive. The splint might also be very useful at mobilizing the ligaments surrounding the joint which may be helpful with pain within the joint.