Thread Magic is the same formula as the discontinued Thread Heaven we used to sell: a synthetic thread conditioner that stops tangling and fraying. Seriously. Run the thread on your needle through this and it makes a slick coating that works like ball bearings. Works especially well on metallics, silks, and rayon threads to make them more pliable and easier to use. Thread Magic is chemically inert and will not react with the fibers.
So yeah, thread lube, right? Makes stitching more pleasurable. Especially with those pesky metallics.