Bunions are an enlargement of the big toe joint of the foot and are commonly associated with what is called hallux valgus which is a deviation of the great toe or hallux towards the outside of the foot. They may or may not be painful, nevertheless the prospect of them to be painful is high. Because of this prevention and therapy will be typically justified. They certainly tend to be progressive and get worse with time. Really the only way to get rid of them is with surgery, but that is not always a good option in the beginning. One way in which they is often dealt with is with what is known as bunion correctors, but they are usually accompanied by the question, do they work? These are splints or braces worn during the night to attempt to correct the deviation of big toe to improve its appearance.
A lot is determined by what is meant by “working”. There's a lot of thoughts and opinions as to them both working and not working with minimal scientific research. There is certainly one published study that did show that the angle of the big toe can be improved by a few degrees after one months use, but this was not research of any longer than that one month. Thus, yes, it does seem that bunion correctors can work in the short term at improving the angle of the hallux valgus or bunion a few degrees.
Apart from that one study just about all we can rely on is expert thoughts and opinions. Most of that opinion is consistent with that study. However, it also appears that even if the use of the bunion corrector doesn't improve the angle of the big toe or hallux or just helps it a tiny amount, it is entirely possible that the corrector will go a long way to preventing the problem from becoming worse. That is important as bunions are progressive. The splint can also be very useful at mobilizing the ligaments around the joint and that might be useful with pain within the joint.