 [ Symptoms ] took a dose of 50mcg levothyroxine can this cause harm  should i be concerned since it is a natural hormone produced effects if any it may cause [ Disease ] the answer to your question depends on a lot of information you did not include i will try to give you some general guidance in the united states levothyroxine is a regulated drug you can not obtain it without a prescription so i am wondering if you mean you took someone else is prescription medicine which is always a bad idea or if you obtained some sort of natural supplement type product that claims to contain levothyroxine or a related product dessicated pork thyroid levothyroxine is a thyroid hormone thyroid hormones are important for regulating many body functions people who have had their thyroid gland removed or destroyed with radioactive iodine or who do not produce enough thyroid hormone generally receive therapy with supplements like levothyroxine no one should take levothyroxine or any other thyroid hormone unless they have been diagnosed with a thyroid disorder taking unneeded thyroid hormone can cause problems with the thyroid gland and can interfere with many bodily functions so in short taking a single 50mcg dose of levothyroxine on a one time basis probably is no cause for alarm but do not take this medication unless it has been prescribed for you by a health care provider hope this helps it was given in a pass med for a weekend trip and was not for me i took the medication then realized it was not mine pharmacy put someone elses in the bag i cannot find where there is any real adverse reactions to a single dose of it and since i have not had any of the alergic reactions noted on the label i figure i am ok dont want to make a trip back to doctor if not necessary thanks for information