a bottle of Synthroid 50 mcg tablets

Q. I have been on thyroid medication for the past year. Last fall I noticed my hypothyroid symptoms returning: fatigue, muscle cramps and stiffness after walking just a mile of my usual three-mile walk. I also felt extremely cold, while others were comfortable.

When I saw my doctor and told him about my symptoms, he checked my thyroid levels and gave me a month’s supply of Synthroid to tide me over. I had been taking generic levothyroxine.

A measure of thyroid function, my TSH level, was 3.7 on the generic. On Synthroid my TSH was 2.5 and all my symptoms disappeared even though the dosage is the same (50 micrograms). If there is such a difference from one brand to another, how can dosage be regulated properly?

A. The FDA maintains that all levothyroxine formulations (Levoxyl, Synthroid, etc) are identical. Physicians who specialize in treating thyroid disorders (The Endocrine Society) disagree. They worry that patients are put at risk when they are switched between branded or generic thyroid medicines.

For more information about symptoms, side effects, interpreting lab tests and treatment strategies we offer our Guide to Thyroid Hormones.

People who get switched need thyroid function tests afterwards. Doses may also need to be adjusted for seasonal variation (lower TSH during the summer).

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  1. AB

    It is true that there is a strong connection between thyroid problems and celiac disease, but PLEASE DO NOT ADVISE OTHERS TO GO GLUTEN FREE BEFORE BEING TESTED! If one eliminates gluten from his/her diet before testing is completed, the disease will not be able to be diagnosed. It’s always best to be tested FIRST, then go gluten-free.
    IF your test results for celiac disease are negative and you still are experiencing symptoms (there are about 300 of them and they are NOT all gastrointestinal!), THEN try going gluten-free. Connect with a local support group or veteran celiac to learn all you need to know. If you do not feel better after a while (keep a food journal and write down all you eat and any adverse reactions!), consider the possibility that you may have additional food sensitivities that need further investigation.
    Gluten-free does NOT mean taste free if you eat naturally GF foods and find out from those in the know what the best GF products are. I highly recommend Canyon Bakehouse Breads which are tasty and also nutritious compared to other GF brands.

  2. blkc

    I have been on a generic thyroid med for years without a problem. I was getting a generic from Target, the cost was $4.00 the dosage 125 mcgm. It worked fine all my levels were good and I felt great. The brand name was Mylan.
    Last April a Costco moved into our area I switched to their pharmacy. I got my thyroid med renewed and continued taking it. Within a few months I became very, very ill. I was sick all the time, I was depressed, I was constantly exhausted, I couldn’t see clearly at night. I became extremely anxious and even paranoid. I started the day off crying and couldn’t stop crying until I fell asleep at night. This effected all my relationships with family and friends. I was exhausted and totally wiped out.
    My doctor called me to remind me my six month check up was due and when I got my results back EVERYTHING WAS OUT OF WACK AND I MEAN SERIOUSLY SO. He wanted to know if I had changed my method of taking my pills, etc. I couldn’t even remember what I did. I knew I didn’t not take them deliberately but I was so confused at times I didn’t know what was going on. He told me I would have to make sure I took them at a certain time each day and give it five or six weeks to see what would happen. I called him within a week and asked if he couldn’t do something. I felt so horrible I couldn’t go on like this.
    At this point we were approaching fall so I had suffered for many months. As I layed on my couch one day totally wiped out I tried to go over what had changed in my life. Why would a medicine (generic) I had been taking for years suddenly stop working. The only thing I could think of was the manufacturer. Could that make a difference? Perhaps the one Target used was different than Costcos. I checked on the internet and began to realize there could be differences in generics and I could have stumbled onto something. I called my local Costco pharmacy and talked to a pharmacist who told me a thyroid condition has a very small window to medicate properly. The medicine has to be right on for you to get the proper effect of it.
    He actually told me that the one they sell could be giving me less of a dosage than I needed. I called target and found out what I had been on. I immediately asked my doctor to call a prescription in so I could go back to the mylan. Unbelievably I started to feel better within a week. It took me months to actually get back to where I had been. That actually only happened withing the last two months.
    Recently I went back to my local Costcos and asked to talk to the pharmacist who did the ordering. I told him what had happened to me and how I had suffered. He told me they are aware of the problem. By using their brand of generic I had been getting at least twenty percent less med and probably even more, depending on the time of the year and even the shelf life of the drug it could have been 30 or 40 percent less. A person with Hypothyroidism can not live a normal existence if not getting at least close to the proper dosage of medicine. This guy told me his own Mom went through the same thing.
    I asked why they are still selling the brand that doesn’t work. He said they are in a price war they are always looking for the best value for the consumer. I asked him how did that work? If Target could sell a brand of generic for $4.00 that actually did work and still make money on it. Why would Costco sell something they know isn’t working and not warn consumers? The cost to the consumer is still $4.00 but it doesn’t work. I am not kidding that I could have easily had an accident and died while taking this sub standard med. I think at the least Costco should pull the brand, or have to notify people of the danger of using it. They should have to put a label on it that you may have to have blood work within a month or so and you were at risk to get very ill if you don’t..
    I am posting this so someone doesn’t have to suffer as I did. What I found out is if you are on a generic that is working stay on that generic. DO NOT EVER GO TO ANOTHER GENERIC MANUFACTURER. If you have to do anything, go to the name brand until you can go back to the generic that works. I will never go from Mylan to another company. If I can’t get Mylan I will pay the extra cost for Synthroid. I have the paperwork, test results and unused tablets to prove this happened.
    PEOPLE’S PHARMACY RESPONSE: It is especially important not to switch generic manufacturers for medications like levothyroxine, where the margin of error for the dose is very small. Don’t think, though, that you can switch from Mylan to brand name Synthroid without consequences; sometimes that doesn’t go smoothly. Stick with just one maker.

  3. KC

    I too have been depressed, fatigued and had lower back pain (due to an injury) for many years. I also had reduced concentration, short/long term memory problems, low energy levels and a low threshold for anger and verbal outbursts (I’m 59 now).
    Based on various medical tests over the years, one of the layers of fatigue that put me in bed many times was due to low thyroid.
    From my experiences, (and my wife’s), thyroid medications take many weeks (months) to settle in and level out because your body is adjusting itself to working with it. In addition, how your body reacts to it will determine if the dosage needs to be adjusted in the future. The results can be subtle but if your body needs it, it needs it, even if you do not have any of the major symptoms. All the organs in your body need it to function properly with the right timing..heart rate, urination, brain processes…everything. I cannot urge you strongly enough to keep taking it and get your level tested every three months. No fasting required.
    Also, ask for a copy of your lab results each time and put them in a file for future review. Sometimes you can spot a trend before the doctor does. You can then look up each test on the internet to research what each one means and any associated symptoms.
    In addition to having my thyroid levels tested, I also had my vitamin B12 and D3 levels checked. My D3 level was in the “insufficient” range (23) and my B12 was in the middle range (545). My doctor stated that my B12 level was “okay” and offered no advice. My thought was: what’s the downside to increasing my B12 level to the top of the “normal” range? As it now stands, not only was there no downside, there as was a HUGE upside.
    By taking liquid (my preference) supplements I raised my B12 level to 1012, reducing my remaining fatigue and other problems substantially.
    I’ve also been taking D3 supplements (4k units) daily but have only been able to increase it by about 15 points. My biggest increase (to 67) was when I spent about 7-10 hours per week in the sun in addition to the supplement.
    Taking specific supplements was a change because for years I had been taking a daily vitamin which, based on my current results, was for decades just making expensive pee.
    I also was treated weekly with acupuncture/massage for 11 months and chiropractic for an additional 6 months to improve my lower back pain. I stopped wearing flip flops and purchased better shoes (Nike trail runners) and had inserts made that helped reduce my back pain even more, to near zero. I also have inserts for my slippers!
    I also suggest investigating your sleep/breathing quantity/quality (including the comfort/quality of your bed), diet (add more vegetables/reduce red meat), reduced salt intake, increased physical activity, vision and dental (especially your gums) care checkups . By improving and or changing each of these things has helped me feel 100% better.
    Based on all of the above, my behavior, memory, fatigue, energy, body comfort and sleep have all done a 180 for the better- just ask my wife :-).
    I still need to lose weight but at least I have the energy to start exercising!
    One thing to learn is the difference between fatigue and tiredness. Being tired includes yawning, fatigue does not. Sometimes you have both. It’s very important when describing your symptoms to the doctor.
    Also, I don’t think I’ve received proper medical care over the years because my weight gain was and is seen as the source of my problems and not a symptom of the underlying medical issues. Nearly all my doctors blame me as if I personally and intentionally have caused my medical problems! More than once I was told to seek mental health treatment as if thinking differently would change my thyroid or B12 levels or my allergies or my eyesight or some other actual physical problem they did not detect or consider.
    Though, based on my results, the solutions are out there. Keep reading, researching, investigating and trying different things until you feel better. Some things are simple, somethings are more complex. You CANNOT just try one thing and if it doesn’t work, give up. I could go on for many pages on all the things I’ve had to do to feel better and I’m still not done!
    You have to create a new “normal” for yourself if you want to feel better. It takes time and perseverance! Keeping up with things that don’t work is not the answer. DO NOT give up and especially, DO NOT accept as “normal” your usual negative behaviors/verbalizations, thoughts or feelings.
    If you don’t feel good or have behavioral problems, you must persist in educating yourself as much as possible about medical problems/symptoms so you can articulate the facts about your health more precisely. I’ve read many books and articles on many, many topics to be articulate enough to get the doctors to help me solve my problems.
    Most importantly, find a doctor that sees YOU and not just a number or a $$ or fat person or some other label that they may apply that keeps you from getting the treatment that you deserve and help you feel better. The medical mantra is “do no harm”. How is it that NOT investigating properly and not giving you proper treatment is not seen as violating this oath?
    Hope you feel better! You deserve it!

    • LAHs

      KC you are SO right on, you did all of the right things. I have been through a similar experience but for two years couldn’t get my stupid Endo to take very much interest in my situation. She just measured my T4 and TSH and said that because my TSH was low she wanted to reduce my T4! And I was screaming hypo by just sitting opposite her in her office. After I felt that I only had about 2 weeks to live (I am not exaggerating) I dragged myself to three doctors until I managed to get a sensible one who immediately put me on Armour thyroid (I had practically no T3). Within half an hour of taking my first dose I became normal. I feel that I was robbed two years of my life through a stupid Endo’s lack of familiarization of her specialized field.
      Finally, I wish that doctors and Endos would read all of the thousands of posts on the web to understand how many people are suffering from a) the wrong drug, b) the wrong dose or both.

  4. Oceanside Gal

    I’m confused! I was given Levothyroxine by my Dr. she had taken a blood test months earlier. The next time I had to pick up my Rx at Costco, about 2 mo. later, all of a sudden this new Rx was included. I called Dr.’s office to see why & the nurse told me that it was needed, I mentioned to the nurse that my older sister has a problem with her Thyroid, & she said “that is probably why I have the similar problem”. I just couldn’t by it, so I didn’t take it.
    Didn’t have any problems including the loss of hair, which ALL of my siblings (4 incl. my parents) have. Other than that there hasn’t been ‘other’ systems. Yes, tired have ‘chronic back pain, not constipated, have been depressed most of my life (now 67). The ONLY thing that I can truly say that has changed is my personality, and this way BEFORE I started taking the Rx. When I get angry, I get angry! No, I don’t swear or hurt anyone, I’m in way too tooo much in pain to go anywhere. I raise my voice quite LOUD! Which isn’t me, yes I get upset at times like so many of us, but not like that, my voice gets LOUD, & it’s just not me. Yes, I’ve been on Prozac way too long, but most of the depression Rx doesn’t work.
    Getting back to the Levothyroxine, have decided I’m not going to take it. I can’t tell any difference (about 3 weeks now) & the next time I see my Dr. I will tell her what I decided & why.
    Oh yes, the nurse at our local hospital told me, “that it was good for the memory, & she didn’t say anything else”. Hmmm, haven’t read anything in here about any memory loss.
    Re: the blood test, do you have to ‘fast’ or ‘?’ for it? Or just pull the blood & ask the tech. to look for anything abnormal?
    Any help WOULD be SOO appreciated. Again Thanks

  5. mdy

    I’ve taken Synthroid and the mail order pharmacy I use switched me to a generic. It was in the accompanying information with the prescription, but I don’t remember if it was Synthroid or the generic that said the dose should be taken at least an hour before eating or several hours after eating.
    Also, an important note I thought — do not take thyroid meds with calcium (food or pills). I had been taking thyroid med at bedtime with two calcium pills. Now I take the thyroid pill first thing in the morning so I can wait an hour before eating. It takes juggling so maybe this is why the midnight dose or the 2am dose that others mentioned works so well.

  6. Ron

    My wife had been on levoxyl for years. She noticed that she still had the same symptoms that warranted her being prescribed levoxyl. I did some internet investigating when her blood pressure became uncontrollable. I urged the doctors to put her on T3-Levrothronine and Armour thyroid. within a few weeks she became her old self.

  7. jt

    My mom read this posting and became so worried she stopped taking her thyroid medication completely. Does anyone know of a lab I can send her medication to to have it tested to see if it is safe to take???

  8. RMG

    Several years ago my insurance drug provider switched me from Synthroid to levothyroxine. My hair started to fall out severely, but I didn’t connect the two acts until I visited an older dermatologist. When I told him my symptoms, he immediately said, “It’s the generic. I’ll switch you back to Synthroid—same dose—and we’ll see what happens.” Well, within two weeks the hair had stopped falling. I now seldom notice any hair in the shower drain instead of a handful!

  9. KL

    After the mess with Armour thyroid (it disappeared from the market) my doctor found a pharmacy that compounds. I’ve been on compounded thyroid (porcine) and although I still have these blasted ups and downs, much prefer this. I have to pay out of pocket for it, but it’s $20 a month, which is affordable. I also want to pass this on to other folks with hypothyroid problems–if you have any GI issues at all, if you have anemia or low vitamin D, GO GLUTEN FREE.
    Don’t bother with the expensive tests, just try for 6 weeks to go without gluten in your diet and see how you feel. There is a connection between gluten intolerance and hypothyroidism. My energy level has improved as has my general health by getting gluten out of my diet and for the first time in years I’m not anemic.

  10. KC

    Last week our pharmacy gave my wife a refill of her generic Cytomel (liothyronine) and the pills were from a different manufacturer. They were also smaller than her original generic pills.
    She started taking them and crashed with debilitating fatigue after 3 days. She returned to the pharmacy and her original pills from the previous manufacturer were restored to her. She’s feeling a bit better after 3 days of catch-up. She’s taking the extra 3 pills, 1 per day, 12 hours after taking her regular dose.
    She made no other changes in medication/supplements so it appears that her fatigue is due to the change in manufacturer of liothyronine.
    It appears that there are major manufacturing differences among manufacturers of generic meds despite what the courts rule on.

  11. KC

    My wife started on Synthroid and did very well for about 4 years. Her hair grew back, gained energy, no disturbed sleep and her cold intolerance was greatly reduced…..
    After 4 years, all the hypothyroid symptoms came back so we changed Docs when her original one could/would not offer anything but Synthroid.
    She asked for and received Armour. She felt a bit better but still no relief of fatigue.
    Changed Docs again. New Doc started adjusting Armour until T3 and T4 were in “normal” range, TSH was still high. Added/increased Cytomel until TSH was in normal range. While her lab work says everything is “normal”, she still suffers debilitating fatigue, continuing hair loss, cold extremities and dry skin, as if she was not on any meds……
    Note: she’s lost 65 pounds(diet/exercise) and now people want to know if our 4 y.o. grandson is “her son”. Her sleep apnea is gone. She lowered her cholesterol over 100 points (250 to 140). She walks regularly despite the fatigue. She’s been treated by 4 doctors over that past 5 years. None of them have been able to do anything about her symptoms….
    She is also on Bromocryptine for a benign pituitary micro-adenoma (microscopic cyst).
    Note: We tested her symptoms by stopping the bromocryptine for 3 months. No change in symptoms.
    At the end of the three months she stopped Synthroid as another test. For about 3 weeks she felt “normal”-good energy, etc. Then the hypothyroid kicked back in and she started feeling fatigued, etc. so back to the meds again. This has been going on for over 6 years.
    After all this, she still has all the same symptoms. Her hair is getting very, very thin and really worries her.
    Now what should she do?

  12. MS

    I had been on Armour thyroid for years after surgery when I was 19 for a goiter. Never had any side effects. Then when I was in my 40’s a new Dr. put me on Synthroid and then I was switched to the generic. I became so tired that I wanted to take naps and was dead tired by 5 p.m. I finally asked to be switched back to Armour thyroid and my quality of life improved dramatically.

  13. KC

    Archives of Internal Medicine published a study in 12/2010 indicating taking thyroid medications at night before bedtime is more efficacious.
    Here’s a link to a general report on the topic:
    After reading the original report( http://archinte.ama-assn.org/cgi/content/abstract/170/22/1996 ), I take my Synthroid at about midnight everyday because taking it early enough in the morning before breakfast did not fit within my sleep schedule. My sleep was being ruined by my alarm every morning to get up and take my Synthroid. This way I get good sleep and better results with the Synthroid.
    While I have not been on any generics, I suspect that taking them at night may increase their effectiveness, possibly by taking them on an empty stomach and being digested more slowly during the night allows them to be digested more completely.

  14. MD

    Similar experience. Found out the pharmacist took the liberty of switching me to generic. Bad move, even though it was cheaper. Back to the actual synthroid and all was well again.

  15. PF

    I wonder if anyone else has had the following result with Synthroid? After taking it for 20 years I was switched to a generic, and immediately developed an awful metallic taste in my mouth that even overode food flavors, and never abated. My doctor and I tried all the generics with the same result. I then went back on Synthroid, and got a slightly different but equally awful taste in my mouth.
    I wounder if the manufacturing process or source chemicals have changed? I was depressed, because I couldn’t even enjoy food anymore. Finally she put me on Armour thyroid and together with painting my forearms or neck with iodine twice a day, all my low thyroid symptoms are controlled and my taste is back to normal! The Armour by itself didn’t control my allergies and runny nose, but painting with iodine does. I know painting with iodine is looked upon with skepticism by some, but it is working for me.

  16. Martha I.

    I must comment on this column. Years ago I asked my pharmacist to fill my Synthroid prescription with generic. It caused significant problems, was ineffective and my physician advised me to never take generic again. In spite of all this, I am in a constant battle with my drug insurance carrier and sometimes even convincing my current physician.
    I have even offered to pay full price to be able to continue Synthroid. At the same time I had problems, I was working in an internal medicine clinic and there were many other patients who reported problems at that time. So, bottom line, in my opinion generic levothyroxine is not a good replacement for the brand name, Synthroid.

  17. KC

    I guess no one at the FDA takes thyroid medication!

  18. bloomergal

    My mother had been on Levothyroxine for quite awhile and did not notice much improvement in her condition until she changed her routine. As she invariably has to get up in the middle of the night to go to the bathroom between 2:00-3:00 am, she keeps a glass of water and one Levothroxine pill on the bedside table and takes it when she gets back into bed. She started noticing a real effect within a few days of making this change in routine.

  19. deb t.

    I have many of these concerns although I haven’t noticed a difference between Synthroid and generic. Neither of them make me feel any better. I plan to seriously discuss Armour thyroid with my physician. I’ve also been taking sea kelp (iodine) and a thyroid supplement every other day to see if I noticed a difference.

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