Is l-cartinte -l tartrate, creatine monohydrate, betaine anhydrous safe? those are my post supplements (weight lifting) do any of these cause cancer?

Quality control on most supplements is not terribly good no matter what it says on the label. An investigative study at a well known vitamin chain store showed that many of the tablets and capsules had little or none of the claimed ingredient. More concerning would be what other contaminants or natural substances are in the preparation. Work on a healthy diet with lean proteins, leafy vegetables

Agree with Dr Horn, as I too think you are taking potential risks, possibly not getting what you purchase, and of course, spending money for potential ineffective items. Talk to your doctor and a thoroughly trained physiatrist, as you would benefit from guidance in this area.