diffuse hairloss treatment

Using both, if you can, is always better than one or the other. But if you have to choose between them, go with finasteride (Propecia).

To be honest, I don't think any MPB regimen is worth your time unless it includes a proven DHT blocker (finasteride or dutasteride being the only two). No amount of vitamins, shampoos or even minoxidil (Rogaine) will help much beyond the first couple years if DHT is still blasting your follicles.
That said, if you take a DHT blocker, other treatments like minoxidil can definitely compliment it and improve your results.