It's going to be hit and miss since all the "herbal" over-the-counter solutions have not been studied and their claims given the approval of the FDA, and there are so many out there.
If you have a regular physician, I'd recommend bringing up your concerns and see what kind of recommendations they give. If you're having difficulty getting fully hard (not necessarily like when you were in your 20s, but hard enough for vaginal penetration), then you may be developing ED or there might be something else going on that's worth bringing to your doctor's attention.