Hello, Yes, Meth can cause bones to weaken. Methamphetamine is associated with disruption of normal bone metabolism and increases the risk of osteoporosis and subsequent fractures. There are experiments conducted on animals (mice) which have shown the increase of risk of osteoporosis following meth administration. The deteriorating effects on bone formation processes were higher the higher the dose of methamphetamine. In humans, only a few studies have been conducted. However, available data suggest a clear negative effect of meth use on bone mineral density and increased risk of osteoporosis compared to non-users of methamphetamine. Therefore, your son is at increased risk of bone fractures because of use of meth, and he needs to take extra care in order to avoid or prevent future bone fractures. Ideally, he should quit meth and enter a rehabilitation program. This is the best way to reverse negative bone formation processes that have taken place until now and ensure healthy bones for his future life. Hope I have answered your query. Let me know if I can assist you further. Regards, Dr. Ervin Toçi