Some people find lipoic acid stimulating. So start at 50mg a day.
There are types that are tablets on iherb.com

That is what I did. If you get 100mg tablets you can break them in half. But this also comes in capsules which are less flexible in changing dosing.

If you don't find any stimulating effects that you don't like, you can slowly raise to 100mg twice a day. It may lower blood sugars for you, so if you are on diabetes drugs, you need to be testing your blood sugars.

You will want to get the r-lipoic form...as it is more potent and works in lower dosing than the older "alpha" type.

I would apply the Biofreeze to the Achillies tendon area and ankle too. That is where the nerves are, and where they may be compressed. Putting on thick skin of the bottom of the foot may not work. I really find Biofreeze helpful, I use it on my feet, knees and hands, for my arthritis too.

Dr. Smith had a very rapid response to lipoic acid...a couple of days or so. But I think 2 weeks is a modest expectation, or a month. He jumped in with high dose of 100mg twice a day to start, I believe.