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T3 (Cytomel) Overview – What To Expect

T3, also known as Cytomel, Liothyronine Sodium, and Triiodothyronine, is one of the most commonly misunderstood drugs in not only bodybuilding, but in the medical community.

I have spoken with several individuals who have had major issues with fat loss, and having a weak metabolism who actually were walking around for years with an undiagnosed Thyroid deficiency (hypothyroidism).

Unfortunately, the method used to diagnose hypothyroidism, and autoimmune disorders that cause hypothyroidism is completely flawed, and 99% of physicians are utterly clueless as to what they are doing, or what their patients need to get healthy.

Sorry for the rant, but Thyroid hormones are a controversial topic for me as I have seen far too many doctors completely screw over their patients by being utterly clueless in the subject.

What Is T3?

In layman’s terms, T3 is the hormone in your body that regulates how fast your metabolism is.

The higher your T3 level is, the more calories you will burn, and the more fat loss potential you will have.

T3 is a drug that is prescribed to those with hypothyroidism, but it is commonly used by bodybuilders and recreational lifters who want to reach a level of body fat that would be difficult to achieve without drug assistance.

That isn’t to say that it is easy to get shredded on T3, it helps though.

Typical T3 Dosages

Determining the ideal T3 dosage will be based upon several factors.

Typically, T3 for bodybuilding/fat loss purposes involves purposely ingesting a supraphysiological amount of T3 in order to increase your metabolism to a level that would otherwise be impossible.

This can be achieved with as little as 25 mcg, however, not all T3 is created with equal quality.

Despite T3 being an inexpensive drug, for some reason, the quality varies wildly between different sources.

Ideally, you’d want to get your T3 from a pharmacy (and prescribed by your doctor of course), as that’s the only way to absolutely ensure it is dosed accurately.

The standard dose for fat loss purposes ranges between 25 mcg – 75 mcg of T3.

The standard starting dosage for treating Hypothyroidism is typically much lower (as low as 5-10 mcg per day), and may be titrated up based on your doctor's recommendation.

Personally, I never go above 50 mcg because T3 can be very catabolic at higher dosages, as it doesn’t discriminate between muscle and stored fat, so the higher your T3 dose is, the more muscle it will rip off your body.

50 mcg – 75 mcg should be more than sufficient for anyone to reap the benefits of a supraphysiological dose of T3.

Side Effects

Once you get to the 100 mcg + range, you put yourself at a much higher risk of side effects like Tachycardia, muscle loss, anxiety, and feeling weak.

Side effects that will be notable at any dose, but will be more pronounced the higher you dose T3 will be increased body temperature, increased hunger, and in some cases (I get this) constant muscle flatness.

By muscle flatness I mean it is a lot harder to get a pump, and your muscles lack that pop that they have when they are properly glycogen loaded and hydrated.

That is one of the first things I look for when I am determining if my T3 is legit or not.

I get a notable increase in body temperature, and I notice I am much flatter at the gym and it’s a lot harder to get a pump.

My appetite starts getting a lot more ravenous once I go above 50 mcg as well.

At 75 mcg I am hungry pretty much all day long.

Offsetting The Muscle Loss From T3

The only way you can offset the catabolism from a high dose of T3 is with anabolic assistance.

Whichever compounds are used to achieve that, the fact remains that a supraphysiological amount of Anabolics will almost always be necessary to maintain 100% of one's hard earned muscle tissue when venturing into the higher dosage range of T3.

Obviously it isn’t mandatory, but you will lose A LOT more muscle on T3 without any anabolic assistance than you would with it.

How Much Fat Loss Can You Expect From T3

I’m going to be completely honest with you as addressing this question specifically is the main reason why I wanted to write this article.

T3 is NOT some magical compound like some portray it to be that lets you eat whatever you want all day long and stay shredded.

Usually the individuals who perpetuate this myth about T3 consider “lean” as hardly visible abs.

For me though, being lean is being shredded at a single digit body fat %.

You CANNOT get to single digit body fat % by eating like crap on T3 just because you are on T3.

You still need to diet hard in a calorie deficit, keep training hard, and do your cardio; T3 will simply magnify how much body fat the body burns up during your cut.

I honestly think I could reach very close to the same body fat % I do during my cutting phases without T3 at all (I’d probably end my cut at 1-2% higher than I usually would), it would probably take me a month longer or so though.

Basically, T3 speeds everything up and makes things a bit easier.

It IS NOT an excuse to eat like crap though.

You can get fatter even on T3 + DNP if you overeat.

Trust me, I have.

Does T3 Suppress Your Natural Thyroid Production?

Yes, taking exogenous thyroid hormone will absolutely stop your natural production.

Basically how your thyroid gland works is it has a stimulating hormone called TSH (thyroid stimulating hormone) that is present at a certain level to signal your thyroid gland how much T4 it needs to produce, which then will get converted to the active form of thyroid hormone (the one we want) T3.

When you take exogenous T3, your TSH plummets to near 0 because your body will recognize that there is already so much T3 in your system, that it has no need to produce any on its’ own.

So your thyroid essentially goes to sleep for the duration of time you are taking T3.

However, once you stop taking T3, your body will recognize there is no longer an excess amount of T3 in your system, and your TSH will skyrocket back up to signal your thyroid gland to start producing thyroid hormone again.

There is NO SUCH THING as complete thyroid shutdown.

Your thyroid will never be permanently destroyed from taking T3, and once you come off of T3, if you had a healthy thyroid to begin with, you will eventually recover to healthy natural thyroid function again.

Typically, this recovery process takes a few weeks, but for others it can take substantially longer.

It is all individually dependent.

Personally, I have never had my thyroid suppressed for more than a couple weeks, even after staying on 50 mcg T3 for nearly a year straight.

Why T3 Is My Favorite Fat Burning Agent

I  use it almost every single time I cut because it is one of the few things that works really great, and isn’t a stimulant.

Granted, both T3 and stimulants can create cardiovascular complications if abused, I simply prefer T3 if I had to only choose one thing to use as a fat burner.

I barely even notice T3 aside from slightly increased body temperature and a slightly faster resting heart rate, whereas with Clen my resting heart rate is borderline tachycardic and I can't combine it with any other stimulants that day without fearing some significant cardiovascular disaster.

I also prefer it to DNP simply because DNP makes me feel like I’m dragging so much ass I can barely get myself to the gym to train, and I’m actually twice as flat and my workouts are complete garbage on DNP.

Bottom line, T3 works, but it isn’t a magic pill that will get you shredded overnight.

How To Know If Your T3 Is Legit

Like I mentioned earlier, there are various sources for T3 and their quality varies.

Obviously the best place to get it would be a pharmacy after being prescribed it by a doctor for treating Hypothyroidism if you have it.

However, if you want to assess how potent your T3 is and see if the dose you are using is adequate for whatever you are using it for, then you need to get blood work to see how it is affecting your values, and know how to interpret them rather than trust some arbitrary dosage number that a doctor throws at you (doctors are notorious for doing this with hormone replacement therapy).

These are the main things you want to look at:

As you can see from my blood work, my TSH and T4 levels are absolutely tanked.

This is because I have so much exogenous T3 in my body from the T3 I’m using, that my thyroid gland has completely gone to sleep (temporarily).

This means that my body is HYPERthyroid (supraphysiological range of T3) during that test.

You want your T3 in range if you are treating Hypothyroidism.

In Canada they won't show you your T3 values in most cases (because most doctors here are clueless how to treat Hypothyroidism or anything hormone related) but if your TSH and T4 are in the toilet, you can be assured that your T3 is sky high (in most cases).

Now, if your TSH was in the normal range or high, then that's a different story.

Typically:

  • TSH in range = Thyroid functioning as normal and your T3 is probably bunk
  • TSH high and out of range = Thyroid is trying extremely hard to produce more T4 (to ultimately convert to/increase your T3 into a healthy range) becuase:
    • A) You are Hypothyroid at the moment because you either just came off of legit T3 within the last week or two and your Thyroid is in the process of recovering natural function (meaning the T3 you are currently using is bunk)
    • B) Or you have a crappy Thyroid gland and just have terrible natural thyroid production and likely require T4 or T3 to just maintain a healthy T3 level (meaning the T3 you are currently using is bunk)

Disclaimer: The information included in this article is intended for entertainment and informational purposes only. It is not intended nor implied to be a substitute for professional medical advice.

49 thoughts on “T3 (Cytomel) Overview – What To Expect”

  1. Thanks Derek, a very straight forward article that lays it all there. Checking my series of blood tests over the last few years shows I am at the low end of the TSH range and always have been. This may help explain my struggle to lose fat over the years. (I average 0.9 in a range from 0.3 – 3.5)

    Anyway, would a daily dose of 20mg of RAD-140 be sufficient to counteract the muscle loss from a cutting regime using T3?

    1. Typically a lower TSH indicates that your body isn’t working as hard to stimulate thyroid production because there is an adequate amount circulating in your body already.

      A sky high TSH would indicate poor Thyroid function typically where your body is scrambling to get itself up to adequate T3 levels.

      For your question, it depends on what dose of T3 you’re using and how much muscle you have on your frame. If you’re using around 50 mcg and have an average amount of muscle, it probably would suffice. If you were using 100 mcg+ of T3 though it probably wouldn’t.

    2. Being on the low end of TSH is actually better than the high end from a fat burning perspective. It’s counter intuitive. You don’t want to be in the high TSH range, this would lead to weight gain and hypothyroid symptoms.

  2. Thank you for great video.

    What about dosing in terms of frequency? what is the optimal? i have found so much in terms of peoples opinion on T3 half-life etc

    1. Ideally dosing should be in the morning and at night (split dosing), but honestly now I just take all of it at once upon waking and it seems to work exactly the same for me as split dosing did.

  3. Try to multi-dose the same 25mcg throughout the day, it’s great! Cut the pill into four pieces and take it every 5-6 hours.
    The Paleo Thyroid solution by Elle Russ is a great manifesto for people who suspect having a thyroid problems and the doctor keeps saying they are healthy. You can perfectly skip the paleo part if it’s not your method and still get great info

  4. Hi Derek,
    I have two questions concerning this topic.
    I understood that it is best to split the dosages (morning and evening). Is it best to take it on an empty stomach like before breakfast or after?
    You mentioned to minimise/prevent muscle loss you need to be on something anabolic. What do you feel is the minimum amount of test E per week to combat the muscle loss from 50mcg of T3?

    1. 1) I don’t notice a difference taking it with food or without, although some will argue that it is better on an empty stomach.

      2) That’s impossible to answer as different dosages will equate to different levels of total/free test in different individual’s blood work. E.G. 200mg of test won’t equate to the exact same serum levels in one individual that it will for another. Not every one is equal.

  5. Hey Derek, what are your thoughts on tapering up and down your dosages at the beginning and end of T3 cycle? And no tapering?

    I have noticed no difference. In fact, my thyroid recovered quicker when I just stopped using T3 instead of taking the 1-2 weeks to taper down.

    Thoughts?

    1. I couldn’t say for sure because I always tapered off in the past, however, if you think about it, regardless if you have exogenous T3 in your system, your Thyroid would be sleeping, so theoretically I would think coming off cold turkey vs. tapering would result in the same recovery process/time frame.

      I taper off just in case, however, I am skeptical that it makes any difference at all.

      1. What about if you take an eca stack, caffeine, or Dnp? Does it matter? Or start with the t3 as soon as waking up before anything else, vice versa?

        1. Don’t understand your question. If you take that other stuff it won’t influence when you should take your T3.

          1. Don’t see why not unless you had some underlying cardiovascular condition that was unaddressed.

  6. I have taken T3 in the past. Worked well. However, the last two times I started taking T3, I got several tendon related injuries. I stopped the T3 and healed and as soon as I started again I injured the tendons again. I’m am using real pharm-grade T3 and not research chems. I don’t know if it has something to do with my age (53) or what could have caused it. Maybe just a freak coincidence? Anyway, for now I’m using the EnhancedAthlete cardarine instead. I was able to get ripped from that (and to be honest a lot of trenbolone).

  7. What were your TSH levels before taking T3? Mine are 4.3, trying to find a good dosage (first timer), not sure if it would vary whether you’re at a 1.0 or a 5.0+

  8. Hey Derek, I was on T3 for a week at 100mcg and now I am having random spurts of chest tightness and heart palpitations, I have stopped taking the T3 for the last day. Obviously, this isn’t enough time to see whether the sides discontinue, do you have any suggestions as to what to do?

  9. I am considering using T3 right now to finish my cut . I have been going natural for a couple months now which is how long i have been back in the gym . I had a rare genetic issue that destroyed my ability to eat and i was out of the gym a long time , lost my tissue and when i finally could get off a liquid shake diet … you can imagine how fast the weight came . Now i am not obese or anything but i am trying to get my abs back and they aren’t here just yet , slightly showing the top ones in the right lighting ( the shadows of them ) and so i wanna get this cut done sooner than later not because of patience , simply i don’t like to be in a deficit longer than needed as well ill need time to taper my calories up before my bulk leading into the summer . I’d love to be beach ready and now that i am on anxiety medicine , actually enjoy my summer this year . My question for you is , will T3 be an issue for me? during my surgery my phrenic nerve took some damage which affects my diaphram , this coupled with anxiety can cause me shortness of breathe . I also like i just mentioned have anxiety that i medicate for , i began a DNP cycle but tapped out right away as i was feeling anxious about it and think honestly it was probably just all in my head . I know T3 can be a lot safer and not so much to worry about so i wonder , if high doses causes anxiety and shortness of breathe , would a low 25 MCG dose still get the job done without the sides? I have no issue with diet or training , i have will power and discipline and have not fallen off my diet yet , i am 20 lbs down with zero cardio in place and just good diet and training however my weight has stalled and now cardio is in place this week starting … thoughtz?

    1. I can’t predict if it will be an issue for you, but putting yourself into a supraphysiological level of T3 levels (the point of using exogenous T3 to burn fat at a supraphysiological rate) absolutely can cause an increase in resting heart rate, and cause some shortness of breath. Using 25mcg is probably not going to push your body too far into the supraphysiological fat burning zone if you have a healthy functioning Thyroid right now, which is why most individuals use around 50-75mcg during cut phases. The higher your dose, the higher your resting heart rate and shortness of breath could be from the T3 though.

  10. I plan on dosing my T3 at 50MCG per day, I’ve been running 30mg of Ostarine. Do you think 30mg of Ostarine is sufficient to reduce muscle wasting sides?

  11. Dosage questions:
    How should you lead up to 50 mcg a day. Would you start with 25 mcg a day? Would you start with half a 25 mcg a day? At what rate do you increase it to 50 mcg?

    1. I ramp from 25 mcg up. At what rate would depend on your assessment of your individual response to a lower dose, and if you determine you can handle more without any negative side effects (e.g. if you have a massive increase in heart rate/blood pressure you wouldn’t increase it ever).

  12. Hi,
    I’m a female 33
    My tsh 5.5 30 ( high) should be 0.400-4.100
    My T4. 6.3 (Normal) Should be 4.5-10.5
    My T3 2.8 (Low) Should be average of 4.5

    My doctor put me on Naturethroid . I was wondering on your input for T3 and if I should be taking that with my levels?

      1. If I was told correctly it’s a very low amount . That is why I was wondering if it wouldn’t hurt to Strickly add T3 Cytomel At 25 mcg

          1. Get a blood test done and check reverse T3 as well as thyroid peroxidase antibodies. I’ve dated 2 girls now who had undiagnosed Hashimotos Thyroiditis and were also poor converters of T4 to T3.

            What you need would become more clear based on those results.

    1. Yes there are several interactions with T3. I took it on an empty stomach always well before my other daily supplements to avoid any potential interference.

  13. Maybe you should mention, that SHBG levels rise with elevated fT3 levels, which can leave you with a lower free test level. Im on thyroid medication myself and i saw this many times when i too to much of T3.

  14. Brady Baumgartner

    Hey Derek, you answered my question about a week ago on your Winter Bulk 2017 sarm cycle page. I am currently on 20mg S23, 20mg LGD 4033, 25mg Mk677, 25mg Ostarine, and 500mg test. I am starting a ten day mini cut today during my spring break. I am going to use 700-800mg dnp (I have used this dose before), work up to 140mcg clen (used before), and this is my first time with T3, I am going to take 50mcg a day.
    I have two questions, I am going to up my sarms on this cycle eventually to 50mg LGD and 40mg S23, and I was wondering if I should start now possibly to stave off muscle catabolism on the cut. Maybe to 30mg LGD, and 30mg S23 for now. Thoughts?
    Also, what do you think I should do with the diet on this cut for maximal fat loss? Keto, high carb low fat, or just kinda normal with some fats and carbs.
    Stats: 6’2 252lbs, 14%BF

    1. Also thinking about throwing in yohimbe in morning, ephedrine pre workout, and yohimbe once more per day. Thoughts?

    2. You’re on 500 mg of test, boosting your SARMs an extra 20 mg each won’t make a difference imo.

      Maximal fat loss would be whatever you could adhere to easiest. On DNP, sticking to a strict calorie allotment is the biggest challenge.

      I would never use carbs on DNP personally as it always just made me hungrier (blood sugar fluctuations caused brutal cravings on DNP which are already bad as is) and you will probably overheat on that much DNP with carbs in your system.

      I think that DNP dosage is unnecessarily high as well and you’re in danger territory.

      1. Do you stop t3 before a show or event to fill out from being flat? Or a heavy carb load while still taking the t3?

        1. I would drop at least down to 25 mcg during peak week. Will prevent you from filling out if you’re on too much T3 and you shouldn’t need to lose more fat during peak week anyways.

  15. Derek, I have been on T3 for the past 16 weeks for a BB show. Started at 25 and went to 50 for most of the prep. The last week i boosted it up to 75. The show just ended. How should i tapper down?

    1. I’d drop down to 25 mcg right away and then slowly titrate down over the next week or two and then come off.

  16. former pro athlete, now i do print work for boxing magazines, tradeshows, exhibitions etc.. just got hydrostat #s and pushing just over 9.7% but now i want to go into the extreme orbit of ripdness. is there any benefit in t4 at all? just got cytomel and wondering if it is worth stacking it with ndt. putting your tsh to sleep and lowering your t4 seems to be the optimum situation for the physical apperance.. by the way, you got your knowledge down real good doggy!! as an athlete i have acess to top sports doctors and they nothin but clowns when its about thyroid…. good job, sure helps out dudes like me that want to learn the best ways…

    1. NDT has T3 in it. Your TSH would be asleep regardless which exogenous source of T3 you use if you push yourself into supraphysiological range.

  17. I should have been more clear, the reason i would stack it is to get any benefit out of the t4 in ndt… does the t4 in ndt convert to t3 in the same percentages that the body does it naturally? and just taking t3 would basically spike my levels rather than it being created in the serum from the conversion from t4 to t3.. so if im taking 25 mcg of cytomel and 2 grains of ndt, which has about 18 mcg of t3 and about 74mcg of t4.. is that conversion going to yield me another 60- 70% t3.. thank you

    1. Get blood work and see. That’s impossible for me to figure out. Conversion rate depends on a myriad of factors and your diet.

  18. Hi Derek,

    These TSH levels are confusing I recently took test and the results came back indicating that my TSH level is 2.666. according to my dr chart that’s normal range. however it doesn’t show the t3 or t4 likes yours. My nutritionist suggested that I T3 25mcg which i am taking now is that dosage high enough based on my level? I am trying to do another figure show in the fall so i really need this to work. I have been having a hard time to cut this time around and i am thinking it has to do with my thyroid or other hormones (i got test done for that too currently waiting on the results). Should i be on a higher dosage or should i wait?

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