So I've noticed that T3 is a very asked-about drug on these forums. I've been messing around with thyroid hormones for quite some time now and done a LOT of research and reading about them, and as I've discussed my experiences in recent months on these forums I've been asked a lot of questions about the various aspects of thyroid hormones, T3 in particular. I like to think myself knowledgeable on the topic and have been labelled so by several other forum users here, so I figured I'd make a write-up to answer some of the questions I get asked, or have seen asked, the most.
I'll try my best to make this FAQ as clear and concise as possible for the layman to understand - an informative article meant for the general public is confusing and therefore useless if it's full of complex information that's hard to understand for someone who isn't well versed in the matter of thyroid hormones. It's frustrating when loads of technical jargon is thrown in seemingly just to make it look like the author is all-knowing, so my aim is to avoid bamboozling my readers.
There are a lot of myths surrounding this drug, many of which have been long debunked by scientific research and testing but yet they still stand on some areas of the web, so I've taken it upon myself to help identify these myths and state what I believe to be the facts based on hard evidence and the experiences of myself and others. Naturally, some of the ideas here are going to fly in the face of seemingly popular current knowledge - however, I'm just going by my experience with this drug, my research and the good feedback I've gotten from others based on their results after I've given them advice, and will provide evidence and data where necessary. If you disagree with my interpretation of something here, feel free to disregard it and use your own judgement, other approaches do work (albeit to an overall less efficient degree IMO) and you may indeed find that a slightly different approach sits better with you
I'll be updating this FAQ with any new ideas and discoveries in my ongoing research and guinea-pigging of myself and my mates If there are any other questions I haven't answered that you'd like to see added or simply answered separately, feel free to comment. Please note that this will be a very long post, so I'd advise bookmarking it for future reference. This forum unfortunately lacks the features (anchoring, correctly functioning 'spoilers' etc) for me to clear this up to access certain questions more quickly, so sadly I can't make it any shorter or more accessible.
DISCLAIMER: The following is just advice. While T3 is generally a safe drug when used sensibly, it can be harmful and even deadly when used incorrectly. Use at your own risk and seek the advice of a qualified medical professional should you be concerned about your health before, during and/or after using thyroid drugs.
What is T3, and how is it of use to bodybuilders?
T3 is a thyroid hormone, and the main regulator of metabolism. In short, the higher your free T3 levels, the faster your metabolism and the more calories you burn as a baseline. When free T3 levels are low, the pituitary gland signals the thyroid gland to produce T4, which the body then converts to T3.
Synthetic T3 was (as with most drugs used by bodybuilders) designed as a drug for medicinal purposes, in this case for thyroid replacement therapy in those with thyroid problems. Bodybuilders have been using T3 for several decades now for its effects on the metabolism. The most popular use of T3 is to increase one's TDEE (Total Daily Energy Expenditure, i.e. calories burned) during a cutting phase or contest prep, and it does this very well.
Synthetic T3 is also proven to improve the way we process nutrients - it increases protein synthesis/protein turn-over rate and is also thought to improve the metabolism of carbohydrates. This obviously helps us during a dieting phase - however, because of this, the use of T3 is becoming increasingly popular during bulking cycles too. With the improved nutrient partitioning facilitated by T3, fat is less likely to be gained. The increase in protein synthesis also allows us to benefit more from a high protein diet, which in a caloric surplus can lead to increased gains.
Thyroid hormones also, in general, contribute to growth and development - seeing how us bodybuilding folk spend most of our time in a state of development and growth, it's not hard to see why high Free T3 levels can be of use to the bodybuilder whilst running a bulking cycle. I'll talk more on bulking cycles later.
Why T3, rather than T4? Isn't T4 used for thyroid replacement these days?
Yes, it is. The reason for this is simple - when we use T4, the thyroid won't convert it to T3 when there is already enough T3 in our system (unless there's a problem with the thyroid being overactive in its conversion of T4 to T3, which is at the root of most hyperthyroid conditions). This is great for thyroid replacement therapy as it ensures that T3 levels won't go too high, but for bodybuilders who are aiming for high T3 levels, this isn't what we're after. I also talked about the improved metabolisation of nutrients and so on with T3 usage - well, when we give the body T4 to convert to T3, it'll be our natural endogenous T3 and we won't get these extra benefits.
T4 needs to be used in quadruple amounts compared to T3 to get the same amount of T3. Based on this, in my experience, I've found 75mcg of T3 alone to be more effective than a comparable stack of 37.5mcg T3 and 150mcg T4. This was to be expected as, again, the body will only convert as much T4 to T3 as it needs to maintain normal metabolic functioning in those with healthy thyroid function.
T4 is generally thought to be the superior choice if you're stacking it with Human Growth Hormone since they work synergistically, though that's a whole other topic and T3 is otherwise the better choice for the GH-free bodybuilder. A combination of T3 and T4 may even work well for the HGH user, though this isn't something I've bothered to look into so don't quote me on that!
Will T3 usage lead to thyroid damage?
Generally, no. Reports of thyroid damage from T3 use are extremely rare. Conversely, there are an astonishing number of studies that have proven that thyroid shutdown never actually occurs, and regardless of duration and dosage (within sensible limits) full thyroid function returns to normal within a few weeks in pretty much all cases. Studies date back to as early as the '50s, such as a study by a guy named M Greer, that found that people misdiagnosed with thyroid conditions had their T3 withdrawn after long term use (some as long as 30 continuous years) and had their thyroid fully functioning again within 2-3 weeks of cessation. Full article on this here - it's a pretty lengthy article, so here's the meat of what we're looking for:
The belief as to the reason that the thyroid is never really shut down, is because the thyroid gland was designed to go through periods of inactivity; when the levels of T3 in the body are low, the pituitary gland will send a message to the thyroid to produce T4 for the body to convert to T3. It's not producing T4 24/7 and invariably sits dormant for extended periods of time - it's designed to get working quickly after being inactive. The only likely reason it takes a few weeks to seemingly recover thyroid function is that, after the cessation of exogenous T3, there are going to be extremely low levels of T3 in the body, and it's going to be a gradual process to build it back up to acceptable levels again because the body won't want to just shoot its natural T3 levels back up immediately - it'd see this as a bit of a shock to the system, and the body doesn't like quick, dramatic changes.
Is T3 catabolic? Do I need to use AAS with it?
In short, the answer to both these questions is yes - however, I feel that the catabolic element of this drug is highly overstated. T3 will make you look flat at higher doses on a deficit, and when people see this they assume they've lost muscle. However, when you raise your calories again (particularly your carbohydrates), you'll regain some fullness pretty quickly and realise that the muscle was never actually lost.
The above isn't to say, though, that T3 isn't cataolic. It's mildly catabolic on its own, and is exacerbated when things like cortisol and a caloric deficit triggering overall weight loss are thrown into the equation. However, let's look at T3's mode of action - it increases both protein breakdown and synthesis. With T3 on its own, the breakdown of proteins (i.e. lean tissue) will outweigh the synthesis and you'll experience muscle catabolism. If, however, you introduce AAS (and we don't even need that much, as we'll look at shortly) then the breakdown/synthesis balance becomes fairly level and we no longer experience catabolism. If we then add in a caloric surplus with plenty of protein, the scales are tipped on to the side of synthesis, and T3 actually aids anabolism. Hence, it can be utilised for more favourable results on a bulk, i.e. improved lean gains and a decrease in the rate of fat gain. We'll talk more about this later, but for now let's look at the dosage of AAS we need in conjunction with our T3 (we'll use the old staple, testosterone, as our example drug here).
I recommend, if we're talking about testosterone usage, the formula of "mcg of T3 x 5 = grams of testosterone" to ensure the counteraction of the catabolic effect of T3. So, for example, taking 50mcg of T3, 250mg of test should be enough. Obviously, other steroids or pro-hormones can be stacked with, or replace, testosterone - the point was that you don't need as much AAS to counteract the catabolism as a lot of people might think. Something I've also heard a lot is that trenbolone as well as clenbuterol can both combat the flatness that T3 can create during a deficit, which makes sense as these compounds tend to harden up the physique and bring more blood into the muscles, but never having tried this I can neither confirm nor deny.
I also recommend at LEAST a gram of protein for every lb of bodyweight you carry. I've never been an advocate of massive amounts of protein, but with T3 I truly believe you'll benefit from a very high protein diet - not only is it essential to get plenty of protein to favourably swing the balance between the increased protein breakdown and synthesis T3 will cause, but because more protein generally becomes usable by the body when using T3, then generally, the higher the percentage of your diet that is protein (meaning less carbs and fats), the more likely you are to lose fat and less likely to store it (some people may disagree with this claim, which obviously is fine but I feel it obligatory to at least provide what I feel is a well-performed and relevant study (here) to back up my view).
When should I take T3? How often?
Take it first thing in the morning once a day and on an empty stomach, regardless of the dose. T3 is thought to have a couple day half life, so makes no sense to split the doses. It also makes even less sense to take it multiple times a day when we consider that it's best taken on an empty stomach because calcium and iron will interfere with the absorption of the med.
Best case scenario is to allow at least two hours before ingesting food, though I've found that you can get away with waiting a bit less than an hour. If you're eating a meal low in calcium and iron, you can take your T3 with it - just note that even pretty small amounts of iron will affect the absorption of T3, whereas the threshold for impaired absorption of some nutrients and meds by calcium is thought to be around 200-300mg of calcium. If you enjoy a cup of coffee first thing and can wait at least half an hour before eating breakfast, go for it, but no more than just a splash of milk! 250mg of cooked rice also has only around 1mg of iron and is pretty low in calcium, so it might be a good meal to start the day if you're not able to allow a gap for whatever reason. Just be aware that some sauces will contain iron and/or calcium, as will many meats and veggies, so it'd be wise to do a search-around and see what you can and can't have based on what you like.
How should I dose my T3 whilst cutting? Do I need to ramp up?
I always recommend 50mcg as a maximum dose if it's your first cycle. I'd recommend 25-50mcg as a dose for metabolic optimisation and stabilisation, the latter of which really comes into good use during prolonged dieting when metabolic slowing would otherwise occur. 75mcg at a push in some cases, but it'd be wiser to just drop a few hundred calories from your diet instead if it was for cutting. T3 should be used to optimise one's metabolism, rather than being used as a fat burner in itself. The tendency whilst dieting is for the body to reduce your Basal Metabolic Rate to conserve your body's stored fuel, and using a replacement dose of T3 essentially stops that from happening. There are also other benefits you don't get with your own T3, such as improved carbohydrate tolerance and greater protein synthesis rates when used with AAS, which is also why I like to use a high-replacement dose when I'm bulking.
Typically, I'd say start with a dose of 25mcg, and bump it up a little every few days until you reach a max 50mcg dose.
Do you recommend high doses of T3 at 100mcg or more?
No. I used to, but over time I've come to realise that it's not worth it. Do I believe such a dose is safe? If the person is healthy and they monitor their symptoms, then yes, absolutely. I've followed the work of late thyroid specialist Dr. John C. Lowe for a few years now and he regularly had some of his patients on 100mcg of T3 (yes, T3 - not T4) or more - their health was monitored and they felt good on these doses, and of course their thyroid function was great (some interesting reading here http://web.archive.org/web/20101224224855/http://drlowe.com/QandA/askdrlowe/t3.htm). I've tried up to 150mcg myself, felt very good on it and my TDEE was obviously high.
On a previous cut, I added in an extra 25mcg every three weeks. By doing this, I didn't have to lower my caloric intake at all - I kept my intake consistent, and by adding in the extra T3 as I dropped bodyweight, the would-be lowering of my TDEE due to the decrease in weight was counteracted by the increase in TDEE by the introduction of more T3. In other words, my TDEE was pretty much kept constant throughout the last 10 weeks so there has been no need to adjust my calories to keep losing 2-3lbs a week, week-in week-out. It definitely worked well.
...so why don't I recommend it if it works so well and is safe? Well, I've noticed over time that I seem to gain weight back quickly when relying on high doses of T3 to lose it. When I thought about it, it makes sense - weight loss via hormonal changes, is always going to be reset if those hormones are reset. So, in other words, the results are temporary unless you stay on that high dose permanently, which I'd of course never recommend. As I said in the previous question, T3 is best used for metabolic optimisation/stabilisation purposes.
Do I need to taper down at the end of the cycle?
Not in the way that most people think. If you gradually lower the dose, you're still supplying the body with T3. When you're still supplying the body with an adequate level of T3, the recovery process cannot begin, and even 25mcg can be an adequate amount that will mean no more thyroid hormone is needed and so the thyroid won't need to get back to work. When we factor in that the half life of T3 is thought to be around a couple of days, it makes more sense to cease the cycle and the levels of exogenous T3 in our blood will gradually decrease as the days pass. So in effect, there's enough tapering down going on anyway.
However, there's a more efficient approach than coming off completely. Coming off completely will leave our metabolism at rock-bottom since there's 0 thyroid hormone and if we're not very careful, we risk the chance of gaining back fat. So how do we go about ending our cycle?
We run a low dose of 12.5mcg for 2-3 weeks from the end of the cycle.
Running a continued dose of 12.5mcg of T3 at the end of the cycle sort of acts like a post-cycle therapy. 12.5mcg is enough to provide a bit of T3 to the body and keep the metabolism half-decent, yet at the same time isn't nearly enough to replace what the body normally produces. So, the thyroid gland has to get back to work to make up the rest and the recovery process can begin while the 12.5mcg keeps an acceptable level of metabolic function going.
As I said above, there is no need to taper down and it would be a waste of time. Just drop down to 12.5mcg from day 1 after the cycle, and run it for 2-3 weeks. This time period will allow the thyroid to recover to normal levels whilst providing a baseline metabolism during the early stages of the recovery. IDEALLY, you'd get bloods done after this few week bridging period to see where you're at and make sure you're recovered.
Here are my experiences with this protocol by way of blood test results:
Before ever using T3:
Serum TSH level: 4.28 mu/L (0.35 - 5.50)
Serum Free T4 level: 18.5 pmol/L (10.3 - 22.7)
Serum Free T3 level: 4.7 pmol/L (3.5 - 6.5)
After a year on T3, having been on 50mcg for the last month:
Serum TSH level: 0.15 mu/L (0.35 - 5.50) "Abnormal"
Serum Free T4 level: 5.7 pmol/L (10.3 - 22.7) "Abnormal"
Serum Free T3 level: 6.1 pmol/L (3.5 - 6.5)
Exogenous T3 causing suppression of my TSH and T4 levels due to replacement, 50mcg appears to be a high-replacement dose for me and is higher than my normal level theoretically meaning a boost in TDEE
3 weeks later, 3 weeks of running the 12.5mcg protocol:
Serum TSH level: 3.81 mu/L (0.35 - 5.50)
Serum Free T4 level: 15.6 pmol/L (10.3 - 22.7)
Serum Free T3 level: 5.7 pmol/L (3.5 - 6.5)
Despite still being on 12.5mcg, TSH and T4 are normalised, albeit possibly mildly suppressed due to still being on 12.5mcg. T3 levels fully recovered and higher than before T3 was ever used.
I'd call my recovery a total success based on the above. I ate at what would normally be maintenance for me and gained 2lbs in weight between the start and the end of the protocol. I'd advise eating a bit below maintenance for the first week of the protocol.
Note: Here is some blood work of another UK-M user (thread here) who recently tried this protocol, suggesting full thyroid recovery:
TSH: 2.07 (0.27 - 4.2) Free T4: 16.1 (12.0 - 22.0) Free T3: 7.1 (3.1 - 6.8)
What should my diet be like when I start the above recovery protocol?
The metabolism will be fairly low on 12.5mcg. In order to ensure that you don't get fat in the 2-3 weeks it will take to recover, you need to stay at what would normally be a mild deficit for you, so you need to plan this wisely. Some prefer to maintain the deficit for a few weeks until thyroid function has been restored, whereas others like to gradually increase their calories over the weeks as thyroid function returns to normal and TDEE gradually increases.
Some people like to use iodine supplements, such as sea kelp, to help recover their thyroid function. Iodine deficiency generally leads to poor thyroid function, so this idea makes sense and sea kelp is dirt-cheap.
Shouldn't you check your temperature to establish how much T3 you need?
This is an approach that has been talked about by some experts of the past. I won't go into detail, but in short your temperature is generally an indicator of thyroid function, and the temperature measurements are used to ensure that you're taking the right amount of T3, as well as to establish whether or not you've reached the point at which thyroid function recovery will take a few weeks rather than a few days to return to normal.
Here's my issue with this approach. Firstly, a lot of people, myself included, discover that certain (or all) types of AAS influence their body temperature. So, given that T3 is generally used with AAS for bodybuilding purposes, this can obviously skew the results of these measurements significantly. Secondly - and this is somewhat linked to my first issue - is that, if you're going by these readings, it seems to be suggested that most people need 100mcg of T3 just as a baseline replacement dose! This is insanity if you ask me. I had bloods done whilst on 50mcg of T3 just to satisfy my curiosity - my free T3 levels came back right on the high end of normal, not far off what would have been considered hyperthyroidism, and TSH and T4 came back suppressed meaning that the thyroid was no longer working to produce T4 since there was more than enough T3 in the body already. So in other words, 50mcg for me was enough to be a high-replacement dose - I'm a tall and pretty heavy lad, so it's of no relation to the theory that less bodyweight = less of the drug needed. Others I've spoken to who have had bloods done on similar amounts have had similar results. Besides that, I've heard of women getting the impression from temperature readings that 100+mcg is needed as a baseline even at their low bodyweights. Also, it's suggested that once you reach a certain temperature, you'll start experiencing thyroid shutdown and should come off to prevent recovery problems - this is completely unnecessary, for reasons established earlier in this FAQ.
So yes, I'm going against what qualified science professionals have said since steroids weren't factored in and I always advise using AAS with T3. Instead, I'm going by my own, and several others' I know, practical experiences and saying that doses of 50mcg or maybe lower are indeed useful. I'm sure pretty much every thyroid specialist you'd ask would also tell you that doses of above 50mcg are going to see your free T3 levels start going out of the normal range, unless you're an elderly person with abnormal thyroid function.
I've heard of the 2 days on/2 days off approach - is this useful?
Not really. The idea behind this approach is to avoid adaptation by the body to the amount of T3 you're talking - by taking your T3 two days in a row, and then having two days off, you get a high level on day 1, an even higher level on day 2, and then it gradually lowers by about half over the next 2 days before being raised again. This up and down dosing is thought to stop the "homeostasis" response and keeps the body off-balance, i.e. not allowing it to adjust to the T3.
I firmly believe the above, however, to be unnecessary. I've personally run the same dose for several weeks and seen no "adjustment" effect whatsoever - the results after the extended period were the same as they were on the first week. I've also known of several people besides myself to run the same dose for several months and not "adjust" to it. Fellow UK-M'er SelflessSelfie has ran 100mcg for 8 weeks straight and can confirm it's still as effective on week 8 as it is on week 1.
I believe the adjustment theory comes from steroids generally being adjusted to by the body, but T3 however is different. There are also probably some that have said that the same dose will lose its effectiveness after a few weeks - however, I'd imagine that these people haven't taken into account the drop in bodyweight and subsequent lowering of TDEE during T3 use.
So, to summarise, the 2 on/2 off approach works, but is unnecessary. It'd be easier on your system and produce identical results to just use a regular daily dose rather than doubling up for a couple of days and then having a couple off.
I'm prepping for a contest - is it a good idea to use T3?
Absolutely. However, it's worth noting that, as discussed above, T3 may make you look temporarily flat whilst cutting, so it's not ideal to be on a significant dose when it comes to getting on stage. I'd strongly advise coming off the T3 at least a month in advance, following the recovery protocol (info to follow) and then have a timely refeed to allow yourself to fill back out. Really, if you're not in tune with how T3 works for you, might not be the best idea to use it during contest prep - gain a bit more experience with it first.
Is it okay to use underground lab (UGL) T3 rather than pharma?
I've known many to use UGL T3 and have great results. It's certainly effective. However, you're taking a bit of a risk. Just a bit of a risk, but a risk nonetheless, and the point of this article is to make you aware.
T3 is taken in mcg. That's a 1000th of a mg, and needs serious regulation to ensure completely accurate dosing, something that UGLs generally don't have in place. Granted, in general, some of the best UGLs do a good job of getting their dosing on point, maybe out by a mg here and there but this isn't going to make much difference with most drugs. However, with a drug that's taken in mcg's, there's always the potential for a dose that's way off the mark.
I consider 200mcg to be a pretty safe upper limit and you can get away with taking more T3 than a lot of people realise. However, all it takes is for someone working on tabs in a UGL to mess up, accidentally slip another half a mg in there and all of a sudden you're taking 500+mcg in one sitting. Overdoses like this can lead to thyrotoxic crisis or "thyroid storm", which is considered to be a life threatening medical emergency that can lead to irreversible heart damage or even death.
Now, it's an extremely rare case, in fact practically unheard of, for a lab to screw up T3 dosing to the degree that it can cause such a huge and lasting problem or even kill you, and chances are that you'll be fine using a trusted/reputable UGL. However, the risk is always there, and this FAQ is here to make you aware of the risks, and I'm not here to bash any labs but one of them is particularly good otherwise and a reputable lab, yet I and several others I've spoken to have had problems with their T3 being WAY overdosed. So just goes to show that even reputable labs get it wrong when it comes to mcg dosing.
I mostly go pharma grade with T3 so I know I'm gonna get what I'm intending to take, but I've used UGL labs in the past with good results. Certain pharma brands are some of the cheapest you can pick up and are available from tried and trusted online pharmacies. Always look up the reviews.
You've discussed using T3 whilst bulking and I've seen others mention it - any advice?
As I've indeed discussed above, the use of T3 during bulking cycles is becoming increasingly popular. It increases protein synthesis and turnover rate and is thought to improve carbohydrate metabolism, and when combined with a high protein diet and AAS can lead to improved gains and minimised fat gain.
I've known several people to use T3 during a bulk cycle and they were very impressed with it, whilst I've also known a couple to not be so impressed. I think, though, that some people run maybe 50mcg and think they can go gung-ho with their diet and not put on any fat - this isn't the case. Whilst you're taking a decent dose, it will help you keep the fat at bay, it will only help - it won't stop you getting fat eating twice what you'd normally eat on a bulk and getting a ridiculous amount of carbs and fats. It should be taken to optimise your metabolism and aid protein synthesis.
I believe 50mcg to be the sweet spot for bulking. This dose is well tolerated by most and optimises your metabolic function and protein turnover.
T3 makes me hungrier! Is this normal?
Generally, if you're experiencing increased hunger on T3, you're using a dose that increases your thyroid hormone level significantly and I'd recommend a lower dose whilst dieting. T3 improves the body's ability to process nutrients - when used at the correct dose, this will generally mean less hunger due to the fact that the body is getting more of the micronutrients it needs from your food and macronutrients are processed more efficiently - this though can be overridden by taking a dose that increases your TDEE by a considerable margin therefore increasing your body's requirements for food. Appetite suppressants like Sibutramine or ECA can help, but lowering the dose is the most advisable approach.
I blast & cruise with my steroids - can I also run a low dose of T3 whilst I cruise?
Yes, you can. In fact, I run 32.5mcg between blasts and have found it to work well (you may wish to run 25mcg to be conservative), eliminating the need to "reverse diet" after finishing a blast cycle. This is a good dose to keep your free T3 levels at normal levels and the metabolism decent. As we've established, running T3 for long durations has no lasting effect on the thyroid.
I tend to drop my calories down to maintenance whilst I'm cruising as well as consuming more normal levels of protein - a gram of protein per lb of bodyweight or a bit more works well.
Speaking of blasting and cruising - would you advise using T3 to cut during a cruise?
Absolutely. Slightly off-topic, but I prefer to cut during my cruises these days, saving my blasts for building muscle. I cruise on 250mg of testosterone - I've ran as much as 150mcg of T3 on this dose and I've not experienced any notable level of muscle loss. As I've already stated, I think the catabolic element of T3 is way overstated and almost non-existent when a good dose of AAS is thrown into the mix, but then I also gave a sensible guideline above because not everyone will be able to maintain on 150mcg and a cruise dose of test, and indeed a lot of people won't even be able to tolerate such a high dose of T3 and I certainly advise against using it. However, a sensible dose of T3 on a cruise dose of testosterone will absolutely aid a mid-cruise cut without sacrificing muscle mass where protein intake is adequate and training is good. Be prepared for increased muscle flatness due to glycogen depletion, of course.
I've heard of people using T3 for a post-contest/post-cut "anabolic rebound" - good idea?
I've had experience with this myself and think it's a superb idea.
Let's look at the idea behind the "anabolic rebound" first. After being depleted of calories for a considerable period, when you switch all of a sudden to a high calorie diet again the muscles act like sponges. They'll suck up water, retain glycogen and the body will generally be in a state in which excess nutrients are absorbed and used for lean tissue as opposed to fat gain. That's the theory anyway, one which a lot of competitive bodybuilders apparently swear by.
Here's the downside of the above, though. After an extended period of dieting, chances are the metabolism is going to be running low. This means a low TDEE not leaving us much room to play with in terms of calories, and poor partitioning of nutrients. Overall, this can negate the anabolic state that the body would have been in whilst "rebounding".
This is where T3 really shines - it keeps the metabolism revving and, as I've talked about already, helps put the body in an anabolic state when combined with AAS and a caloric surplus. If done correctly, within a week of finishing your diet and reverting from a cut to a bulk, you can regain as much as 15lbs of intra-muscular water, glycogen and a bit of lean tissue, and be looking fuller AND leaner. As for how to do it correctly, you literally just transition straight into a bulk. You can find instructions on how to bulk with T3 above in terms of recommended doses and nutrition.
The whole "rebound" effect is generally thought to last a couple of weeks. Do with that information what you will. I'd of course recommend you stay on AAS whilst continuing your T3 use, so maybe extend your cutting cycle to allow the bulk - either that, or if you're going to cut during a cruise as I discussed above, then maybe cut at the end of your cruise so you can start your blast by way of a rebound bulk.
Will I experience strength loss whilst using T3?
I've noticed that this one is purely down to individual response and happens in a dose-dependent manner, so you may or may not. However, the more of a deficit you're in, particularly if you're running low carbs, the higher the likelihood that you'll experience general muscle weakness and loss of glycogen retention within the muscle which will both temporarily lessen your levels of strength, and if you're running 100mcg or more then you'll very likely experience an increased level of glycogen depletion even in a small deficit. Might not be the best of ideas to use T3 on the run-up to a powerlifting or strongman comp (which I can't imagine most people would want to do anyway since staying lean isn't usually a priority for a lifting comp prep), but other than that any strength loss should indeed be temporary.
Isn't T3 bad for your heart?
If you have a pre-existing heart condition, I wouldn't recommend you using T3. This abstract 20 year observational follow-up study (full paper is available at ResearchGate but you need to be a member and request the full text) does demonstrate that there is no increased risk of atrial fibrillation, cardiovascular problems or death associated with long term T3 use with sensible dosing - however, this is no guarantee that nothing will happen to you if you have pre-existing conditions, as T3 does increase cardiac output in a dose-dependent manner, especially the longer you run higher doses. You should ideally have gotten your cardiac function fully checked, and have it checked regularly, if you're using performance and image enhancing drugs either way.
You shouldn't have a problem if your heart is healthy, though. If you do start getting symptoms that you wouldn't normally experience, such as recurrent palpitations, tachycardia (abnormally fast heart rate) etc, then discontinue your use. However, I believe T3 to be less stressful on the heart than stimulants, such as ephedrine and clenbuterol as used in cutting cycles - it's quite telling that these two meds were taken off the market because of their adverse effects on the heart, whereas T3 is prescribed all over the world, with an abundance of research behind it, and the doses prescribed might not be as low as many think. Just be careful, especially when combining T3 and stimulants, and stop using everything if you feel something isn't right with your heart and run the recovery protocol as detailed above. Problem should quickly disappear with discontinuation - visit your doctor if the problem still persists after a week or two.
I do find that the longer you run a higher dosed cycle then high blood pressure may become an issue, and when this happens the more likely it is that side effects like palpitations and so on are likely to start presenting themselves, but running sensible cycles like this for a few months at a time generally hasn't been a problem for myself or others I've spoken to - those with a healthy cardiovascular system should be able to run T3 for the entire length of any steroid cycle of a sensible duration throughout the entirety of the cycle with no issue unless you're running very high doses, but I must stress that if you start getting cardiovascular side effects then drop it. Ignoring the problem could potentially lead to permanent damage of the heart/cardiovascular system. Any issues should subside over the next few weeks after cessation if the use of T3 is ceased when the problems first start arising.
Blasting a very high dose for a few weeks also tends to be very tolerable for myself and others I've spoken to, but as I've pretty much stated above, I've noticed that the higher doses seem to come with side effects the longer you run them, with the side effects coming in quicker the longer you run them. I can run 150mcg pretty much side effect free for a few weeks, then I start noticing my heart rate increasing, palpitations, feeling hot and a bit tight-chested - the symptoms went away once I discontinued the cycle, though it's obviously not good to get to this point at all, so I'd never run a high dose for more than a few weeks again, and as I've said above I don't recommend using T3 as a fat burner, only a drug for metabolic optimisation at a high-normal replacement dose. If you're after a large boost in your metabolic rate, I'd actually say it's safer to run a mild dose of DNP than it is to run a high dose of T3 (this is another topic, however, and I'd strongly advise you to research DNP fully before considering using it).
Can using T3 cause hair loss?
In short, yes. The link between abnormal thyroid hormone levels and the effects on our head of hair is well documented. However, it's also well documented in the matters of thyroid replacement that once your thyroid levels are returned to normal, if the problems were thyroid related then it's highly likely that your hair problems will subside (how long this takes will depend on how long your cycle was, though I've personally done an 8 week 150mcg cycle for example and noticd my hair regrowing within a few weeks after running the recovery protocol detailed in this FAQ) . I personally notice significant hair thinning and pattern baldness on higher doses of T3 (75mcg upwards), which are reversed when my T3 levels are normalised.
As with most T3 side effects, this effect comes from having abnormal thyroid hormone levels in the blood as opposed to from the med itself. Hair loss can also be caused by low levels of T4 - since taking T3 suppresses T4, if you're experiencing hair loss as a side effect, you may consider running T4 along with your T3 on future cycles.
I've seen a few posts around the internet that suggest that Finasteride (AKA Propecia or Proscar) can be used in conjunction with T3 in order to combat this hair loss - however, this is not the case. Finasteride simply stops the conversion of testosterone to DHT, the primary cause of male pattern baldness, via the prevention of action of the 5-alpha reductase enzyme. Since hair-related side effects from high thyroid levels are in no way linked to DHT levels, Finasteride will not work.
What about other T3 side effects?
The potential side effects of T3 generally come from there being excess thyroid hormone in the body (i.e. hyperthyroid symptoms) as opposed to coming from the actual med itself. The potential sides are listed HERE, however, they're only potential sides. Myself and many I've known to use T3 in doses of 100+mcg have generally found our T3 usage to be mostly side-effect free or at least tolerable, but as I've mentioned the longer you run these higher doses then side effects can start creeping in - towards the end of a lengthy high dosed cycle I started to notice hair thinning and palpitations, for which I would have came off anyway but luckily I was already approaching the end of the cycle, and these side effects subsided once I lowered the dose to a maintenance dose of 37.5mcg. I advise you to keep note of the potential side effects and cease use of T3 if you become aware of any cause for concern. Of course, if the side effects persist, see your doctor.
One side effect that does bother me with T3 is heat sensitivity or intolerance. If you're prone to this side effect (you'll feel considerably warmer than normal at all times, and generally feel weak and dizzy in hot conditions) then you may wish to avoid taking T3 during the summer months. I'm normally a lover of the hot summer months but on T3 I just can't seem to tolerate the hot weather. Another is susceptibility to headaches - I'm normally fairly prone to them anyway, but on high doses T3 I was getting them pretty regularly.
Just to reiterate - the higher the doses and the longer you run them, the worse the side effects tend to get. A sensible dose of 50mcg should be very tolerable.
I'm approaching PCT - when should I come off the T3?
I'd advise coming off the T3 a couple of weeks before you start PCT, using the recovery protocol discussed earlier. In my view, it's a bad idea to have your metabolism recovering at the same time that you're also trying to restore your other hormone levels, in terms of maintaining your current body composition. Protein synthesis will be poor at this time as it is, the last thing you'd want is to make it even worse by going into PCT with a slowed down metabolism and even worse protein synthesis.
Will I still get fat drinking alcohol whilst using T3?
In my experience, yes. Alcohol supposedly slows down all other processes in the body in order to prioritise ridding the body of the alcohol - this seemingly includes the metabolism, even with exogenous thyroid hormones circulating in the body. Drink cautiously