T3 and T4, Doses, Cycles for Cutting & Weight Loss

T3 And T4 Cycles

T3 and T4 have been recognized for their ability to enhance fat loss during cutting or dieting phases. However, due to their critical role as thyroid hormones, it is imperative to have a thorough understanding before considering supplementation with T3/T4 for bodybuilding purposes. In this article, we will outline the optimal dosage of T3/T4 for bodybuilding, side effects, supplements, cutting process, and discuss their significance in achieving desired physique transformations.

T3 vs T4

The thyroid gland, positioned at the base of the neck, exerts influence over various physiological functions such as brain development, heart function, and digestion. It produces biologically active hormones, T3 and T4, which are pivotal in regulating metabolism. T4, also known as thyroxine, is produced in higher quantities compared to T3, or triiodothyronine, and serves as a precursor to T3.

Approximately 40% of T4 in the body undergoes deiodination, a process that involves removal of an iodine group from its outer ring, to convert into T3. Once converted, T3 is utilized by cells in diverse tissues and glands of the body to facilitate oxygen delivery and energy generation. While the thyroid gland produces about 20% of the body's total T3, the remaining 80% is synthesized outside the thyroid gland in other tissues. On average, individuals secrete approximately 10-22 mcg of T3 and 94-110 mcg of T4 daily.

Cytomel Weight Loss

Some bodybuilders have turned to Cytomel, a synthetic form of T3, for its more potent effects compared to Synthroid, in order to achieve rapid weight loss and enhance their performance, meet weight requirements, or reduce body fat to attain their desired physique.

Individuals who do not suffer from hypothyroidism may obtain synthetic T3 from unofficial sources like the black market or websites that sell research compounds such as peptides and SARMs. T3 may be available in various forms, including Cytomel, as well as generic liquids, capsules, or tablets. However, it's crucial to note that the use of synthetic T3 for bodybuilding purposes should be approached with caution and under the guidance of a qualified healthcare professional, as it can carry potential risks and side effects.

T3 Dosage Bodybuilding

T3 40mcg

Athletes typically follow a dosing regimen of 25-50 mcg of T3 on average for an 8-week period to augment fat loss. When using tablets or liquid forms, they often start with a dosage of 12.5 mcg and gradually increase by 12.5 mcg every 3 days until reaching 50 mcg.

During the contest period, athletes may continue to use 50 mcg of T3, although some coaches may gradually reduce the dosage a few weeks prior to the competition to minimize loss of lean mass or prevent muscle flattening on the day of the show. After the contest, most competitors follow a tapering-off protocol, decreasing their daily dosage by 12.5 mcg every 3 days and concluding the T3 cycle with a total of 12.5 mcg for the final 3 days. Those using capsule forms may choose to run 25 mcg throughout the duration or adopt a similar tapering method, depending on the concentration of each capsule.

It is uncommon for bodybuilders or fitness modelps to purchase Synthroid or generic T4 for physique enhancement, as T3 is significantly more potent, with the body typically converting only up to 40% of T4 into T3 under normal conditions. Capsules with higher T3 concentrations, such as 50 mcg per capsule, can be challenging to accurately dose, hence their limited use in this context.

T4 Bodybuilding Dosage

T4 40 mcg

When opting for a combination of T3 and T4, it is advisable to select a product that maintains a 1:2 ratio. For instance, some athletes may choose to use a liquid form of this thyroid hormone combination. Each bottle generally contains around 30 mL, with each mL containing approximately 100 mcg of T3 and 200 mcg of T4. However, it is important to avoid exceeding the limit of 50 mcg of T3 and 100 mcg of T4. 

The Connection Between T3/T4 and Bodybuilding

T3 and T4 are important regulators of metabolism and have an effect on how the body breaks down fat, protein, and carbs. It can be simpler for people to reach a lower body fat percentage during a cut or diet when there is an excess of 73 and T4 in the body, which is why they are occasionally employed in the world of bodybuilding. Some people may decide to take exogenous T3 and T4 to achieve an incredibly low body fat percentage. While some might advise simply utilising T3, it's crucial to remember that when using supraphysiological dosages of these hormones, supplementing with T3 and T4 can be advantageous. 

Instead of depending exclusively on a larger dose of one of the hormones (T3 monotherapy), it is crucial to maintain the balance of both hormones. This is due to the fact that T4 acts as a precursor to T3 and aids in maintaining the body's normal thyroid hormone balance, which is essential for overall health and wellbeing. Consulting with a qualified healthcare professional and following recommended dosages and protocols is essential when using exogenous thyroid hormones to avoid potential risks and side effects.

T3 Side Effects Bodybuilding


T3, T4, or T3:T4 should always be done under the guidance and supervision of a qualified healthcare professional. Self-medicating with these compounds, especially for the purpose of fat loss or enhancing performance, can be dangerous and may worsen existing thyroid disorders or cause other adverse effects.

Some other common side effects of using T3 or T3:T4 combo for weight loss include:

  • Rapid heart rate (especially in those using over 50mcg/day)
  • Increased breakdown of muscle or exercise per muscle (why waste all of your hard work away?!)
  • Reduced insulin sensitivity can negatively impact individuals who are trying to replenish glycogen stores and "fill-back up" during a show or competition preparation, as it may impair the effective utilization of carbohydrates for energy.
  • Excessive sweating, including night sweats, can disrupt sleep and potentially lead to dehydration and electrolyte imbalances, which can affect overall health, recovery, and performance.
  • Impaired cognition and increased agitation can be particularly challenging to deal with when already experiencing hunger (commonly referred to as being "hangry"), as it can affect mental clarity, focus, and mood, potentially impacting adherence to a strict diet and training regimen, as well as overall well-being and quality of life.

T3 and Cytomel Supplements

T3 Structural Formula

Supplemets helps in better performance. T3 and T4 are also supplements for better performance. T3 (Triiodothyronine) is a hormone produced by the thyroid gland. T3 has a very powerful effect on a person’s metabolism and their ability to burn fat. Simply put, the more free T3 you have, the more fat you’ll burn.

Hypothyroidism, which is characterized by insufficient production of thyroid hormones, particularly affects females and can hinder weight loss efforts. Many bodybuilders turn to thyroid medications, such as Cytomel, to increase their T3 levels and achieve a shredded physique.

On average, the body naturally produces about 25mcg of T3 per day. However, if T3 levels are significantly lower, a doctor may prescribe exogenous T3 (Cytomel). Renowned bodybuilder Lee Priest has admitted to using T3 drugs in the past, typically at doses of 25-50mcg per day leading up to a competition.

One downside of using T3 is that it can suppress the body's natural production of the hormone, similar to the effects of steroids. This may result in difficulty in burning fat after discontinuing T3 use. However, endogenous T3 production should recover after several weeks or months of use.

Long-term abuse of T3 or inadequate time off the medication may result in sustained low T3 levels, which can blunt fat loss even if the person is in a calorie deficit. It is important to carefully manage T3 use and consult with a healthcare professional to minimize risks and maximize benefits.

T4 Cycle For Cutting Purposes

This cycle will provide an excellent basis for reducing body fat levels whilst protecting lean tissue and strength during a cut.

Week Anavar HGH Fragment 176 - 191 T4
1 N/A 500 mcg per day 50 mcg per day
2 N/A 500 mcg per day 50 mcg per day
3 N/A 500 mcg per day 50 mcg per day
4 N/A 500 mcg per day 75 mcg per day
5 N/A 500 mcg per day 75 mcg per day
6 N/A 500 mcg per day 75 mcg per day
7 N/A 500 mcg per day 100 mcg per day
8 N/A 500 mcg per day 100 mcg per day
9 80 mg per day 500 mcg per day 100 mcg per day
10 80 mg per day 500 mcg per day 125 mcg per day
11 80 mg per day 500 mcg per day 125 mcg per day
12 80 mg per day 500 mcg per day 125 mcg per day
13 80 mg per day 500 mcg per day 150 mcg per day
14 80 mg per day 500 mcg per day 150 mcg per day
15 80 mg per day 500 mcg per day 150 mcg per day
16 80 mg per day 500 mcg per day 175 mcg per day

T3 Cycle For Cutting Purposes (10 weeks)

This cycle is designed for individuals who have experience with steroid cycles and are looking to reduce their body fat levels while protecting lean tissue mass, enhancing strength output, and refining their overall conditioning and muscular visibility.

If you do not have prior experience with trenbolone, it is not recommended to perform this cycle. Instead, you could consider replacing trenbolone with anavar at an intake of 80mg per day due to its milder nature. In this case, you would need to integrate 7 caps of N2guard per day for liver protection.

For those with experience running steroid cycles, a T3 cutting cycle can be structured as follows:


Trenbolone Acetate Masteron Propionate Testosterone Propionate T3
1 200 mg per week 400 mg per week 100 mg per week 25 mcg per day
2 200 mg per week 400 mg per week 100 mg per week 25 mcg per day
3 200 mg per week 400 mg per week 100 mg per week 50 mcg per day
4 200 mg per week 400 mg per week 100 mg per week 50 mcg per day
5 200 mg per week 400 mg per week 100 mg per week 75 mcg per day
6 200 mg per week 400 mg per week 100 mg per week 75 mcg per day
7 200 mg per week 400 mg per week 100 mg per week 100 mcg per day
8 200 mg per week 400 mg per week 100 mg per week 100 mcg per day
9 N/A N/A N/A N/A
10 N/A N/A N/A N/A