I've been busy again answering questions on the Quora platform, where people ask the general public about anything and everything. This is the question I responded to:
Is there anything I can wear to correct my bad posture?
Yes and no. But mostly no, overwhelmingly so.
The first thing we have to question, or define, is what posture is in the first place, because if the underlying premise is flawed, so will be the solution.
The common view is that posture is a position, an alignment, and the majority of companies who provide wearable posture solutions appear to hold this view as well, but it's flawed, to the point of actually being an impediment to healthy functioning.
Posture is a balancing act, a movement, and if you try to hold a position against that natural movement you generate excess and unhelpful tension. The skeleton is an inherently unstable structure, and thankfully so, there's a trade off between mobility and stability, and human evolution has opted for wonderful mobility. If you want to be stable, be a tortoise. In order to stop toppling over we have to continually adjust and readjust to refind the support from the ground. You've no doubt seen articles on posture that show a plumb line connecting the ear, shoulder, hip, knee and ankle. The usual premise is that for good posture you're supposed to achieve this plumb line, but you're not. The picture can still be useful though as long as you interpret that picture as being an idealised line around which you wobble. Yes, with skill that movement can be minimal. Compare a well coordinated adult to a toddler who still displays a very pronounced wobble, but the aim isn't to eliminate it. Simply using your arms changes the whole balance mechanism, so you need to keep adjusting your posture.
This movement is innate, not something you need to think about, but you don't want to interfere with it either, and trying to achieve and hold an idolised posture will interfere. A more constructive word to use instead of posture is poise. Poise is a quality, you recognise it when you see it in others, and the problem with wearable posture solutions is they make no attempt to address poise, only posture. Poise is a quality of mind, a presence, including being present to the support your environment gifts you to aid your "posture". As counter-intuitive as it is for most, you aren't being pulled down by gravity (this is a longer conversation, but it's to do with Einstein's Theory of General Relativity), but pushed up by the ground, you "surf" that upwards thrust, and you do so by being dynamic, not by being in a fixed position. It's the by-product of millions of years of evolution, you don't need to do good posture any more than a fish needs to do buoyancy, you need to prevent interference and behaviours that lead to poor posture. If a posture corrector isn't addressing your mind, your thinking, it has no value.
Whilst most wearable posture solutions attempt to encourage a fixed position, there are some interesting electronic devices that connect to the skin on your upper back and sense your position in time and remind you when you've spent too long out of "alignment" with a vibration. The problem is that this only has value if you know how to experience poise, rather than mere posture, or a held position, in the first place. And if you do, you'll register the mild discomfort from being out of "alignment" for too long anyway, so the device is somewhat redundant.
Why expect inanimate objects to take responsibility for you in the first place? Better to have agency and be self empowered to look after yourself. In my opinion one of the best ways to do that is through Alexander Technique lessons which is famous for it's ability to improve posture and poise.