I too have dry hair....not sure exactly why. In any event I have had some success with evening primrose oil as a supplement and Biotin (form of vit B). I stopped taking them a month or so ago and I have noticed a decline so I am going to try them again....Also, are you getting enough fat in your diet? I think that is a factor for many people so the 3 6 9 should help too.
My hair has always been very soft, thick and naturally curly. I do not dye or straighten or blow dry. I let it go naturally. Since I started on the Plaquenil/Prednisone/Was diagnosed with Lupus, my hair has slowly changed to the consistency or straw. I hate it. It doesn't even feel smooth when I'm taking a shower and it is wet with conditioner in it. I use salon products and have tried everything I can think of to no avail. My doctor thinks it is a hormonal effect of the various medications I have been on and believes that eventually it will even out. Another side effect I've noticed (not that I mind) is that my fingernails grow much faster and much stronger. I'm not sure I would have ever noticed this except that I've ALWAYS had short/brittle nails. Have any of you had this effect?