For high homocysteine levels; is homocysteine supreme a good alternative for metanx?

Depends on how high: If you have diagnosed elevated homocysteine, you should be taking the preparation suggested or prescribed by your doctor. It is difficult to compare Homocysteine Supreme with Metanx as the forms of folate, (folic acid) B12 and B6 are not the same in both of them. Homocysteine Supreme does contain other vitamins and minerals including magnesium and zinc among others. It is also less expensive.

Homocysteine supreme: Metanx has a special type of folate (folic acid) that more readily enters the central nervous system at least according to the manufacturer. Homocysteine supreme does not have this type of folate (folic acid) but you could try it if your only goal is to lower homocysteine levels. If you have any neurological symptoms of folate (folic acid) deficiency( numbness, dizziness, fatigue, etc) the metanx might be a better choice

About the same: Metanx contains methylfolate, while Homocysteine Supreme contains a mix of methylfolate and folinic acid. Both have active B12 and active B6. Homocysteine Supreme also contains B2, magnesium, zinc, TMG, choline and serine, and provides support for all three of the biochemical pathways that metabolize homocysteine. Some CBS mutations are better supported by Homocysteine Supreme.