T3: A complete guide to cycling T3 and how it works


Beast666 FanClub Pres
Here's the T3 thread for those that are interested.


There was a member earlier that was looking for a detailed T3 thread. We certainly have quite a few, but since this is one of my favorite compounds, I figured I'd post my thoughts on it and add it to the collection. My experience has only been with T3. I've had a short run with T4, and while I can tell you about it, my experience is very limited with T4. So I'll stick to T3. In order to understand what T3 does for us and how it works, we'll need to understand how the thyroid actually works. So that's where we're going to start.

Explanation of the Thyroid Gland

The thyroid gland sits in your neck just under the vocal cords and above your windpipe. So basically immediately below the "Adam's Apple" in your neck. Thyroid gland is part of your endocrine system. Recently, in my never ending search for vitamin D deficiency, I was led to the thyroid and had the pleasure of learning a whole lot about it. So let's get into its function...

The main purpose of this gland is to produce triiodothyronine (T3), thyroxine (T4) and Calcitonin (CT) hormones. It first collects both Iodine & Tyrosine (amino acid) from the bloodstream in order to produce the hormones. T3 & T4 are then delivered to just about every part of your body. Muscles, kidneys, liver, heart, brain, etc.. all get these hormones once they're pumped into the bloodstream by the thyroid gland. Your thyroid is the only gland that can make use of iodine.

The hypothalamus gland in your brain is the Big Boss of the operation. This is where metabolism function starts. When your thyroid hormone levels become low, the hypothalamus sends a message to the pituitary gland. This message is a hormone called 'thyrotropin releasing hormone' (TRH). The thyroid gland basically takes orders from its boss, the pituitary. When the pituitary receives the message that there is not enough T3 circulating in the blood, it sends a message to the thyroid gland that says "Crank up the heat!". This "message" is called the 'thyroid stimulating hormone' (TSH). It's actions are exactly what its name suggests, it stimulates your thyroid hormone production so that T3 and T4 are pumped out. And the opposite happens when there is too much thyroid hormones, where the pituitary slowly reduces how many messages (TSH) it sends until your levels stabilize again. So when you introduce exogenous T3, the messages slow down to a halt, and natural production stops. That's called Thyroid Shutdown. We'll get into that later...

When we reference T3 and T4, the "T" stands for Thyroid, and the numbers 3 and 4 represent the number of iodine molecules attached. The purpose of T3 & T4 is carry oxygen to various cells in the body for energy. Just about every cell in our bodies. This is why it's considered our metabolism regulator. It controls how much energy the cells in our bodies have and controls your body's temperature. The more you have, the more energy you have. Low T3 would cause fatigue and other issues. The gland produces much more T4 than T3, about 80% of production is T4. However, we can't utilize T4, so that 80% that was produced, is converted into T3 so that we can actually make use of it. This conversion happens in the liver by removing 1 molecule, so T4 minus 1 iodine molecule = T3.

So that's T3 and T4, but what about CT, or Calcitonin? In most cases you never have too worry about this one (I'm the only one on earth that has to, I think. ugh). Calcitonin basically counters over production by parathyroid. Parathyroid produced calcium, and when there's too much, Calcitonin works to give your body a balance.

What Happens When I Supplement With T3 or T4

As mentioned earlier, my experience is limited with T4. But I'll give you a general idea about it. T4 is converted in your liver into T3. You've seen these pills/liquids dosed in Micrograms. But 100 micrograms of T3 does not equal 100 micrograms of T4. The amount is tremendously reduced after conversion. So 100 mcg of T4 results in about 25 mcg of T3. So if I wanted to get 50 mcg of T3, but I only have T4 pills, I would have to take 200 mcg of T4. But even that calculation isn't spot on, because remember, not 100% of T4 is converted by the liver. So in fact, even more than 200mcg of T4 would be required to produce 50mcg of T3.

So how much T3 total does your body naturally produce? We've already established that when you supplement with T3 or T4, your pituitary begins to see the exogenous doses and shuts down production. You naturally produce approximately 25 micrograms of T3. So since we know that any oral administration of T3 is a replacement dose (meaning shuts you down), would it make sense to take 25 mcg of T3? Of course not! What's the point of replacing exactly what I produce? That would be a complete waste. Honestly, in my opinion, I think it's even a waste to start at that dose. I know some folks like to "ramp up" the dose. But it's not necessary.

The absolute minimum dose of T3 should be 40 mcg. I recommend a starting dose of 50 mcg; double what you normally produce.

When you use T3, you're basically creating the effect of an overactive thyroid. This will inevitably increase your serum levels, increase your metabolism and increase your body temperature. Since T3 reaches almost every cell and tissue in the body, that means it's affecting everything. Your body is in an unnatural state and overly active. So if there's a lot of energy for burning, it will utilize both fat and muscle. So yes, you will burn muscle while on T3 because it's not very picky as far as what it burns. This is the case naturally with folks who have hyperthyroidism. But I have a solution coming up...

How To Stave Off Muscle Waste from T3

Lot's of folks have looked at Clenbuterol, Albuterol and other similar compounds for their supposed anti-catabolic properties, to create a balance. Forget about all of that. They will not suffice and you're wasting your time. T3 will over power just about anything you're thinking of, except for steroids. So an attempt at running T3 alone would be detrimental to your muscle-tissue-retention ability.

Anabolic steroids will help stave off muscle waste. The problem is finding the right dose. Not all bodies have similar response, so the amounts would vary per individual. However, I've found that 250 to 350 mg of testosterone or equivalent of another compound, is enough to save your precious muscle tissue. Since Testosterone does not affect fat the same way it does muscle, you'll end up burning fat at a higher rate than you normally would, had you not introduced T3. So as a rule, I will say that T3 should never be used without a muscle-saving-dose of steroids.

Testosterone and other steroids when dosed right, will stimulate the muscle and speed up recovery at a faster rate than normal. You can expect that steroids are far more powerful at building, than T3 is at wasting. So although you will experience some counter-production, in my case, it's been quite negligible. And this is experimentation over the years while observing bod pod assessments to determine exact lean mass and body fat percentages. When I used to run bulking cycles, T3 was a must for me. I know many use it for cutting cycles to shed weight, but it can be a very powerful tool for your bulking cycle so that you minimize the chance of fat cells increasing in size.

How To Cycle With T3 On Board

To be quite honest, with T3, I don't ever pyramid or taper doses. I choose a dose, then I start and finish with the same dose. That being said, it takes a few trials and errors to find the sweet spot for T3. So it wouldn't hurt to start at 50 mcg to see if you get a good response. Increases would be ok to do in 20 to 25 mcg increments. But again, I never do. T3 is not like some other compounds that hit you in the face with side effects if you dose it a little off.

There's rarely a need to go over 100 mcg. I've done it, and many others have as well. But remember, that the more you use, the more you'll need to increase your steroid dose to protect your muscles. So don't get carried away with your doses. The highest I've done is not relevant to you as we've already mentioned individualism. So please don't ask because I won't tell. The point is, there is no need to go over 100 mcg.

If it's your first time with T3. Just start at 50 mcg daily. An ideal dose for most everyone after that first cycle is 75 mcg. That is 3 times what you normally produce. More than plenty to do the job. Once you go over 100 mcg, you'll need to adjust your testosterone dose to save your muscles. the 250 mg I suggested earlier is likely not effective enough at this stage.

You can run T3 for as long as you wish. There is no "Cut Off" point. Run it until you're satisfied with your results. Obviously these T3 cycles don't tend to last too long because we don't want to stay on steroids for too long either. So it's highly advised to discontinue use when you discontinue steroid use. Many have expressed concern that you have to taper down the dose before you come off of T3. This is false. You can stop cold turkey with no repercussions. Your thyroid gland will return to normal very quickly. I've used this compound for 6 months at a time alongside my testosterone replacement therapy (TRT) protocol. So for our "Cycles", you can expect your thyroid to return to normal function in a few days tops.

You can start T3 after you start steroid use. If using short esters, give it a week and start your T3. If using long esters, give it a couple weeks and start. Those periods really won't make that much difference, but it's a good idea to eliminate any possible issues.

There is no need to split your T3 dose into several doses daily. Just take your dose once a day, around the same time daily. You do not have to worry about what time of day, it does not matter. You do not have to worry about taking with or without food, it does not matter. Do not overthink this, please.

How to Know if Your T3 is Legit and Working

This is a tough one really. The truth is that a lot of people don't really feel anything from T3. And some others feel it in a couple days. There are only 2 ways of finding out that will work for everyone...

1. Body Temperature Increase.
2. Observe Blood work.

You should always have pre cycle blood work. If you do not get pre cycle blood work, you will not have anything to compare to. So your results would be worthless otherwise. This goes for cycling anything whatsoever.

After about a week or so of administering T3 doses, you should notice that your body temperature has slightly increased. After a couple weeks it most certainly should be elevated. You should not cycle T3 without a thermometer readily available so that you can check your temperature daily. I use an Omron ear thermometer and it takes a few seconds to give me a reading. As mentioned earlier, do not let your body get into dangerous temperatures. Always monitor and if it gets too high, you'll need to back off the dose in 20 to 25 mcg increments until your temperature is back at a safe point. How much, all depends on your normal body temperature. Not everyone is the same. Mine is normally 98.3 degrees fahrenheit, and I back off when I get too close to 99 degrees fahrenheit.

Blood work is the best method to check for T3 legitimacy. A good "normal" range for Total T3 is 76-181 ng/dL. And a normal range for Free T3 is 2.3-4.2 pg/mL. Where your levels would be is not a question that can be answered, so please do not ask me this. Too many factors will render comparisons potentially useless. It's easy to assume that your T3 is underdosed, but you could have an issue converting. Take T3, see your results, get blood work. That's how you know YOUR T3 is working for YOU. It should be obviously higher than range and you'll need to monitor and learn how your body takes to it. This is the tough part of testing if gear is underdosed. Either way, if you're in range, it's likely bunk. If you've been on for 4 weeks or so, and you're barely going over range, it's likely underdosed. Your Free T3 should also be elevated and your TSH should be very LOW. <~ aka shut down. TSH is really the big indicator.

NON-RESPONDERS: Although rare, I have certainly heard of folks that do not respond to T3. Unfortunately they flood internet forums complaining about "fake gear" without providing any blood work. T3 is one of the cheapest powders to buy and the chances of someone faking it or even underdosing it is slim to none. Although I've used some bunk stuff from random chem sites. But I can vouch for ar-r.com, our sponsor for their quality and effectiveness of the compound. There's also a really good chance that you're iodine and/or Tyrosine deficient. Although it's exogenous T3 and doesn't need to be "produced", iodine is still useful for proper metabolism. You don't want to deplete your iodine levels because it makes for a longer, more cumbersome recovery. Leaving you fatigued for a while. Iodine deficiency results in hypothyroidism.

Finally, many folks are not aware of drug interactions that could hinder progress when coupled with T3.

Adverse Drug Interactions

I recommend that you avoid coupling T3 with the following drugs:

Ephedrine: Risk of cardiac issues. So avoid ECA+T3.
Lemon Balm: Blocks thyrotropin receptors, making recover longer.
Insulin: Combo may result in hyperglycemia. (glucose excess)
Iron: Discontinue iron supplementation (food is enough), as it will decrease efficacy of T3.
Magnesium Citrate: Same as above. Keep magnesium doses at or under 100 mg.
Raloxifene: Combination can force TSH to become over productive, even in the presence of exo T3.
Red Yeast Rice: This is used to help cholesterol levels, unknown mechanism interferes with T3.

Above interactions are from epocrates, you need a membership to access the data so I cannot link to it.

Side Effects Of T3

Many people, including myself experience a level of fatigue and even some achiness. This generally (for me at least) goes away after a week or so or when your body adjusts to all the T3. That is all I personally experience (as far as feeling something) from T3, and I get great results from it. Of course I get a temperature increase but it doesn't make me feel hot all the time. It's not like Trenbolone.

Other issues you might experience are developing an irregular heartbeat (this is not as dangerous as it sounds), shakiness, shortness of breath, headaches and sweating.

If your symptoms persist beyond 2 weeks, you should either lower your dose or abort the cycle.

Hope this article helps. Have a powerful day,

~ Austinite
Hey Dre. Aus told me he left this forum.
But did he delete his account? and all his threads are now gone?

No man, screw up happened and its causing a debate in another thread. So as to not go against the wishes of 3J all I'm saying is that they will be back up in due time.
Has anyone else used T3 for lean gains while on a bulking cycle? I would like to hear more first-hand accounts.
Question for the big brains:
If an individual is sub-clinically hypothyroid and supplementing with T3 to bring them back into "normal" range; will it still be as muscle wasting as a healthy individual supplementing T3?

If a sub-clinical hypothyroid case were to supplement with T3 bringing them back into the "normal" range, how would they compare with a healthy individual who's serum T3 was the same without supplementing?
Last edited:
Question for the big brains:
If an individual is sub-clinically hypothyroid and supplementing with T3 to bring them back into "normal" range; will it still be as muscle wasting as a healthy individual supplementing T3?

No, the catabolic effects aren't the same as clinically induced hyperthyroidism.
No I answered before the ninja-ness lol. In what aspects are you wanting to know how the two compare?

Their muscle building/wasting characteristics, just a general guideline.
My assumption is that they would be the same in that regard.
"Everyone is different" <- There, you can't use that one now :p
Their muscle building/wasting characteristics, just a general guideline.
My assumption is that they would be the same in that regard.
"Everyone is different" <- There, you can't use that one now :p

Yes, I believe that you're correct. The one supplementing would very similar to the one with endogenous source.
I was using it on my cycle and bulking at the time. What specifically are you after?

Do you believe you put on less fat or had better lean mass gains as a result of doing so? Will you use it again next time you go on a bulking cycle? What dosage did you use?

Do you believe you put on less fat or had better lean mass gains as a result of doing so? Will you use it again next time you go on a bulking cycle? What dosage did you use?


I did not use it for the whole 15wk cycle, probably only 4-5wks in total. I developed sides to the clen I added at the same time so I cut both trying to find which one caused the sides and just never got back on the T3. I didn't run it that long but i definitely feel as if it helped burn the fat I had at the time. Within a few days use I noticed a much leaner look in the mirror but didn't measure. BF%. After stopping it I got a slight weight rebound but that wore off after a few days when my thyroid started producing hormones again (my assumption). I do plan on using it again in my next cycle though and for the whole cycle to experiment on myself with it further. I was dosing it at 50mcg at first and bumped that up to 80mcg. After reading Austin's article above and the formula he came up with, I'll probably be doing 100-125mcg next time around.

Cliffs: although I didn't run it for too long, It left a very positive impression on me in terms of fat loss and I'm anxious to try it again.

Depending on the level of caloric surplus you're in during your bulk, you will need to adjust your food intake bc you will be burning more calories so a cycle that starts off as a low surplus/lean bulk could very easily turn into a cutting cycle if you don't adjust for calories burned. Hope that helps you some.
Should someone with controlled hbp mess with t3 or t4 supplementation? Is there an increased risk I cardiac issues with t3?