HI Leopardtail, Rich was in the process of moving to mixed Cobalamins (B12) and mixed Folates (B9) when he sadly passed away and his protocol was op top, of other improvements (anti oxidants etc).. Yes. Rich and I were in ongoing private discussions. He had already posted that 1mg of MeCbl was a "reasonable" dose to change to if the SMP wasn't producing good results within 3 months. He was also giving much consideration to AdoCbl but hadn't reached a dose conclusion as of the last time I spoke with him. He was however moving away from folinic acid until a person had gotten things going and then testing if folinic acid improved, worsened or made no difference. You could need both Folinic Acid and Methylfolate. Rich found the pathway that allowed only Methylfolate to be used, since it obviously worked for a lot of us, if enough MeCbl was present. He posted that on the forum here somewhere. So folinic acid is not necessary or sufficient. He was moving away from any suggestion of folinic acid, especially to start with, as it introduces ambiguity in what is occurring since there may be two conflicting reasons why one was having folate insufficiency results with it; either it was working well and was causing donut hole folate insufficiency OR it was blocking methylfolate and causing methylfolate insufficiency symptoms. We were working on a migration pathway from the SMP to a much more complex modified Active B12/folate protocol. Rich was also looking into BH4 (as am I) and large amounts of Methyl-B9 could indicate the need for BH4. That would mean the need either for BH4 supplementation OR high doses of MethylFolate along with either hydroxocobalamin or very low dose MethylB12 once a day We hadn't started talking about BH4 at that time. However, low dose MeCbl is an impossibility for any length of time for everybody with low CSF cobalamin, elevated CSF-HCY and elevated CSF-MMA; which is to say FMS, CFS, Parkinson's, ALS, Supra Nuclear Palsy, Autism, Alzheimer's and no doubt a few more; until the problem of transport of cobalamins into the CSF and/or retaining cobalamin in the CSF. With low dose MeCbl I would be in a wheelchair, incontinent, and rapidly deteriorating cognitive abilities, mood and personality. I know. I was there 6 years ago and was able to claw my way back form the precipice. Right now much of the SACD is in remission, holding back at perhaps 6 months from that edge. If anything goes wrong with my MeCbl, my fault, manufacturers fault, nobody's fault, game over for me and quite a few others here, hiding quietly among us. I'm 3 days of high dose high quality MeCbl away from having trouble with word finding and other cognitive issues. If I sip up even a little I know about it fast., I hate it when my bleeding edge symptoms are my brain rotting out. I would rather it be something relatively harmless like IBS or Cheilitis or edema. I need 3 CNS penetrating doses of MeCbl/AdoCbl a day, or at least maintain my serum cobalamin level at an estimated 1000,000 to 200,000 pg/ml. I don't think it is the dose. There are others whose indicators is foot drop, or toe tripping. For me that comes a few days after the cognitive. Rich was only working on methylation and CFS/FMS/ME. He said that he knew nothing about these other more severe problems and made no pretense of the SMP being suitable for such. SMP makes things dangerously worse for people like me very rapidly. I don't have to take 3 doses if the two are even bigger and longer lasting. But then that probably would defeat the thinking behind a small dose. I have to get 30mg a day absorbed or I have deterioration. I've validated that amount with injections as have others. This is what the Japanese research points at with their 50mg trials. And the problem is there are a lot more people here in my boat than you, and even they, have any idea about. I wish I could have headed this off in 1978 when I first found the beginning of the answer. So, do you have suggestions for a workaround. What would BH4 do for me and those like me, and I am not that unusual here though I was one of the sickest 11 years ago.