I bought some capsules initially which were sodium borate
now I use some amino acid chelated ones which were cheaper.
I got my mother some too cause she had some arthritic pain in her fingers which the Iodine didn't do much for to begin with. Now though she says it's all gone including pain/stiffness in her shoulders at night.
I noticed they had taken the small amount of boron out of the multis she usually takes, now she takes 3-6 mg