What are the true facts behind the "pump/tube vs. jar" skincare controversy? (Details follow)

Like many other women, I buy skincare products. Some have worked, some have not. What I am still wondering (after all these years) is whether your product will not be as effective if it is in a jar (and exposed to the elements) as it would be in a pump bottle or a tube (where it is more protected). I am particularly asking about moisturizers and serums and whether they lose their potency when in a jar vs. being in a tube.

I have heard that it makes a difference and others say…that it does not.

All I know is that if I am buying a high end product, I don’t want to bring it home in a jar….and have it lose its potency and not be effective.

I hope someone can shed light on this topic.

Thanks in advance!