I've been (ironically) too tired to concentrate on treatment possibilities for awhile, but I want to start supplementing with B12 again. I'm going to try a sublingual B12 methylcobalabin spray. I've been reading that a decline in Intrinsic Factor can result in poor absorption of B12. I've seen products that include Intrinsic Factor with B12, but I'm a little confused as to whether you can get IF separately, if you like your other B12 product. Do any of you have information &/or experience with Intrinsic Factor? TIA for any clues.