In researching the benefits of lipoic acid (while not having noticed anyone else's mention of it here), I found this reference to bone density preservation by lipoic acid, from Life Extension (LEF.org):
Preserving Bone Density
Another area in which lipoic acid holds promise is in averting the bone loss that accompanies osteoporosis and other degenerative bone conditions. This multifaceted agent may help preserve bone health by quelling the oxidative stress that threatens to degrade healthy bone density.
When applied to bone marrow cells and osteoblasts (bone-forming cells) in the laboratory, lipoic acid suppressed the formation of bone-degrading osteoclast cells in a dose-dependent fashion.19,20 It also reduced the process of inflammation-induced bone loss in both laboratory and living systems.19 Scientists believe that lipoic acid’s ability in preventing the loss of bone is linked to its inhibitory effects on pro-inflammatory prostaglandin E2 and the inflammatory cytokine tumor necrosis factor-alpha.20,21
These promising preliminary findings suggest a therapeutic role for lipoic acid in preventing and managing osteoporosis and other conditions that threaten bone density.