Hi, No interactions were found between Folic acid and Thyroxine. So, anyone can take Thyroxine tablet for hypothyroidism along with Folic acid tablet without any hesitation. Most importantly studies had been shown that in hypothyroidism, serum homocysteine level elevate and the elevated homocysteine level may damage vascular endothelium induces vascular smooth muscles proliferation, gives rise to hypercoagulability and finally increases the risk of cardiovascular diseases. But studies had confirmed that serum homocysteine level declined more markedly in treatment with Thyroxine plus Folic acid as compared to Thyroxine alone. So, Folic acid s administration along with Thyroxine can lessen the risk of cardiovascular disease by decreasing serum homocysteine level in hypothyroidism. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Zubayer Alam, General And Family Physician