T3 (cytomel) (Liothyronine sodium)
Cytomel is the most common synthetic version of the T3 or triiodothyronine. T3 is not produced directly by the thyroid gland but by the thyroid-stimulating hormone or THS. THS is also responsible for the production of T4 or thyroxine.

Drugs with thyroid hormone activity, such as Cytomel, are used for the treatment of obesity since they are effective fat-burning agents.
Cytomel exerts its fat-burning ability via the following metabolic pathways and processes.

Cytomel up-regulates the beta-2 adrenergic receptors in fat tissues. In lipolysis, or the breakdown of fat in fat tissues, the enzyme HSL (hormone sensitive lipase) plays a significant part. HSL controls the rate of lipolysis. For HSL to be activated, epinephrine and nonepinephrine (catecholomines) are necessary. These catecholomines bind to the beta-2 receptors, and thus when Cytomel up-regulates the beta-receptors, there is a corresponding increase in the ability of catecholomines to activate HSL, resulting to increased lipolysis.

This drug is likewise known to increase the UCP-3 or uncoupling protein-3. This process significantly increases lipolysis. Further, Cytomel also stimulates growth hormone (GH) production, as substantiated by several studies. And since GH is a thermogenic, it contributes to this drug’s fat-burning action. This is why when athletes are using Cytomel they find no need to use HGH.

Advantages of Cytomel therapy

With AAS use, the suppression occurs even after the therapy is stopped, sometimes in periods of weeks or months (especially in cases of long-term use). The same thing is observed during insulin intake, whereby the pancreas (the organ responsible for insulin production) ceases its production of insulin. Such is not the case with exogenous T3 hormone therapy. Several studies have concluded that thyroid therapy does not cause prolonged suppression of thyroid normal production. Thyroid function is normalized just days after medication is discontinued. In other words, there is no thyroid shutdown due to T3 supplementation; there is only a down-regulation of thyroid output during therapy.

Drawbacks of Cytomel therapy

Side effects of this class of drug include tachycardia and atrial arryhtmias, bone resorption, and loss of lean muscle tissue. Secondary side effects include insomnia, diarrhea, and nausea. These adverse reactions are highly possible if the user takes high dosages.

Notice that some of its major side effects relate to the cardiovascular system. This is because thyroid hormones have significant effects on cardiac structures (including cardiac muscles) and systems that alter cardiovascular hemodynamics.

Hyperthyroidism increases virtually all cardiac functions including heart rate and contractility, diastolic relaxation, and rate of ventricular pressure development. This results to an increased cardiac output by as much as 250 percent. These physiological changes are (most likely) the consequences of an increase in the expression of ATP and a decrease in the expression of ATP’s inhibitor, phospholamban.

Another drawback of Cytomel is its catabolic ability. When Cytomel exerts this ability on stored fats, this is an asset. However, this becomes a liability when it exerts this on bones and muscles. The negative result is bone resorption and muscle wasting (mentioned above). Moreover, this drug also diminishes GH’s nitrogen retention ability (although it stimulates GH’s production, as mentioned earlier).

Dosage

There is consensus among Cytomel users that the dosage protocol with this drug is to ramp it up, which means you start at the lowest dosage then gradually move upward. However, there are divergent opinions on how long the ‘gradually’ part should be. There are those who say it should be every three days, and then some pharmacological studies endorse it from 1 to 2 weeks. However, the user’s tolerance level ultimately determines the timeframe; that is, if the user reacts really well with Cytomel, then the dosage can gradually increase every three days.

Users are advised not to ramp up and down the dosage during therapy as this causes fluctuations in hormone levels, which further results to hormonal imbalance. The more prudent practice is to taper off the dosage. The minimum daily dosage of T3 is 5mcg and the maximum is 100mcg.

Cytomel intake is not dependent on bodyweight or gender, but rather on the individual’s blood level. This means that females can take the same dosage volume and schedule as males.

【中文名称】： 三碘甲状腺原氨酸钠

【简写拼音】： SDJZXYASN

【英文名称】： Liothyronine Sodium

【所属类别】： 甲状腺用药

药物说明：

【别名】 碘噻罗宁;甲碘安;甲碘氨;三碘甲状腺素钠;三碘甲状腺原氨酸钠 ,碘甲腺氨酸钠 ,三碘甲状腺氨酸钠

【外文名】Liothyronine Sodium

【适应症】 常用于粘液性水肿及其它严重甲状腺功能不足状态，还可用作甲状腺功能的诊断药。

【用量用法】 口服：成人开始时，１日１０～２０μｇ，分２～３次口服，以后逐渐增加至１日８０～１００μｇ为止。体重在７ｋｇ以下的儿童开始时１日２．５μｇ，７ｋｇ以上１日５μｇ。以后每隔１周，用量增加１日５μｇ，维持量为１日１５～２０μｇ，分２～３次口服。三碘甲状腺原氨酸抑制试验：用于对摄碘率高的病人作鉴别诊断。方法是：１日口服６０～１００μｇ，分３次服用，共６日，重复作放射性同位素碘摄碘试验，正常人及单纯性甲状腺肿者摄碘率受抑制数值超过服本品前基数的５０％以上，而甲状腺功能亢进者受抑制的数值低于５０％。

【注意事项】
同甲状腺素。
1.剂量过大可出现甲状腺功能亢进症状、多汗、体重减轻等。
2.神经兴奋性增高、失眠、呕吐、腹泻、发热。
3.糖尿病、高血压、冠心病及快速型心律失常病人禁用。

【规格】 片剂：每片２０μｇ。CYTOMEL TAB 25MCG 100
(LIOTHYRONINE SODIUM)

CYTOMEL TAB 5MCG 100
(LIOTHYRONINE SODIUM)

CYTOMEL TAB 50MCG 100
(LIOTHYRONINE SODIUM)

LIOTHYRON INJ 10MCG/ML X-G 1ML
(LIOTHYRONINE SODIUM)

三碘甲状腺原氨酸、甲状腺片（T3 Cytomel）药物说明

 中文全称

  三碘甲状腺原氨酸钠

 中文别号

  碘噻罗宁、甲碘安、甲碘氨、三碘甲状腺素、碘甲腺氨酸

 英文全称

  Liothyronine

 英文简称

  T3
  门类

  甲状腺素

 常见产品

  碘噻罗宁、甲碘安

 常见用量

  每天25-100微克（μg）

常见使用周期

  6-10周

剂型

  口服片剂

 原始用途

  治疗甲状腺性能减退等症

 活性/代谢清除时间（守旧估计）

  活性时间：2-3天；尿样清除时间：10天左右

 蛋白质合成代谢能力

  减脂剂量时多表现为分解蛋白质

 储脂/减脂

  减脂效果强

 副作用

  发烧；失眠、梦魇（睡前3小时内避免使用）；食欲减退/亢进；恶心、呕吐；烦躁、焦急；心律变态、心动过速。

三碘甲状腺原氨酸、甲状腺片（T3 Cytomel）药物简介

 1. 来源

  甲状腺素由甲状腺合成，合成及代谢过程中会产生多种产物，三碘甲状腺素（简称T3）是其中活性最强的一种，由甲状腺直接合成，也可由T4（四点甲状腺素）转化而成。

  甲状腺素是强力减脂药物，与CLEN同属第一线的减脂药物。

 2. 脂肪分解作用

  T3减脂的原理是加速身体燃烧储存的营养物质（碳水化合物、蛋白质以及脂肪）。一般甲亢病人都很消瘦、脂肪很薄，便是因为甲亢病人体内甲状腺素一直持续在高水平，体内的三种营养物质（碳水化合物、蛋白质以及脂肪）被远高于凡人的速度燃烧消耗掉了。因此，用T3减脂，即便不做有氧运动也是可以减的。

 3. 蛋白质合成作用

  T3低剂量时表现为加强蛋白质合成代谢，减脂剂量时，表现为蛋白质分解。故用T3减脂时往往会损失肌肉。

 4. 主要副作用及保护

  T3有精神高兴的副作用，故不建议睡前服用。T3特别忌讳剂量陡增陡减，否则易泛起恶心呕吐甚至心律变态。另外T3可能造成食欲亢进，这对减脂而言多少有些不利。

T3 Cytomel (Liothyronine Sodium) 100 Tabs/50mcg
PRODUCT NAME: T3 Cytomel
Pharmaceutical Name: liothyronine sodium
Chemical Structure: tri-iodio-thyronine (T3)
Molecular weight of base: 650.9776
CONTENT: 100 Tabs/50mcg
MANUFACTURER: Jones Pharmaceuticals Made in USA
Effective Dose: 25-100 mcg / day orally

Cytomel is not a steroid, but more a of a cutting aid. It's a synthetic form of the thyroid hormone tri-iodio-thyronine or T3, made up of a metabolite of the amino acid tyrosine and 3 iodine ions.

Characteristics:

Cytomel is not a steroid, but more a of a cutting aid. It's a synthetic form of the thyroid hormone tri-iodio-thyronine or T3, made up of a metabolite of the amino acid tyrosine and 3 iodine ions. In the body it in turn is made from another hormone, T4, which is secreted by the thyroid under influence of the pituitary hormone TSH (Thyroid stimulating hormone). If a shortage of either TSH or T4 is noted, usually doctors may opt for a replacement therapy. These days the most common prescription is synthetic T4 (synthroid), but in more severe cases of permanent thyroid dysfunction, the choice is given to Cytomel. Simply because T4 is mostly active through its conversion to T3 and T3 is 4-5 times stronger than T4 on a mcg for mcg basis.

In bodybuilding circles Cytomel is mostly used as fat-loss drug. Thyroid hormones are often referred to as the metabolic regulators of the body. High levels of T3 speed up the metabolism of an individual, allowing him to burn more calories and use calories more sufficiently. Generally ectopmorphic body-types have very high thyroid levels and in some cases a slight undiagnosed form of hyperthyroidism. Both hyper-and hypothyroidism can have severe consequences on an individual, such as goiters and other nasty stuff, so messing with your thyroid is not something I would advise to beginners. As with insulin, misuse of this compound can leave you dependent on exogenous T3 for the rest of your life (remember Frank Zane?). So some caution and research is required before putting Cytomel in your body. Generally cycles should be limited to 4-6 weeks tops, I recommend 3 and alternating cycles with 3-week cycles of clenbuterol. But most importantly, to avoid a crash or a shock to the thyroid function doses need to be built up over time and tapered off again. More so for cytomel than for any other drug in existence.

In his book, Anabolics 2002, Bill Llewellyn says that Cytomel is not a drug to start off on, and that use of milder drugs like T4 (Synthroid) or triacana can help ease a person into the use of T3. I'm inclined to disagree here however. Triacana is weak compound and I find of little use. Its not easily found anymore and not cheap either. T4 is basically similar to Cytomel except that its weaker. Something that users normally compensate with higher doses and sends them down a similar lane as simply using cytomel. Agreed, cytomel is NOT a drug for beginners, but with adequate research, experience with diet and some self-control, I don't see why cytomel shouldn't be the first thyoid compound used. But for recreational users looking for a fatburner, I still suggest using clenbuterol over cytomel for all intents and purposes. Cytomel is much more powerful, but clenbuterol is a lot safer for use. The results are easier to maintain with clenbuterol as well. Negative feedback in the thyroid may decrease natural levels of T3 in the body, causing a decrease of metabolic rate after coming off a cycle of T3. That can cause a rebound effect during which a lot of weight is gained back.

For competitive bodybuilders Cytomel is an almost unmissable aid in contest preparation, along with clenbuterol and non-aromatizing steroids such as stanazolol, trenbolone, methenolone and so forth...

Stacking and Use:

It can be stacked or alternated with clenbuterol. We usually recommend to alternate, three weeks clen with three weeks cytomel, since clen loses most of its benefits after a short period of time and using cytomel for extended time-periods will increase the risk of permanent thyroid failure. Neither drug is terribly expensive so We see no problem in this. Some opt to use them together for 3-4 weeks, and then use an over the counter ECA stack to bridge with for an equal period of time, but we're not big fans of that. Which naturally doesn't mean its not effective, that's just a personal opinion. Running it for three weeks, one could choose for a schedule as follows:

25 /25 /25 /50 /50 /50 /75 /75 /75 /100 /100 /100

/75 /75 /75 /50 /50 /50 /25 /25 /25 mcg/day.

If taken for 4 weeks, then run each dose for 4 days, 5 weeks then each dose for 5 days and so on. It is extremely important that the doses are tapered on and off and that a cycle never exceeds 6 weeks at the most.

As far as adding products, no ancillaries are needed, but its highly recommended that this is only used when anabolic/androgenic steroids are also being used. First of all the extra free calories work with the steroids to enhance results, but also because an increased level of thyroid hormones can be extremely catabolic and the use of anabolic compounds to counter muscle loss is a requirement here.

Cytomel® (liothyronine sodium)

Cytomel® is the popularly recognized brand name for the drug liothyronine sodium. This is not an anabolic steroid but a thyroid hormone. It is used medically to treat cases of thyroid insufficiency, obesity, certain metabolic disorders and fatigue. Specifically this drug is a pharmaceutical preparation of the natural thyroid hormone triiodothyronine (T-3). When administered, Cytomel® increases the patient's metabolism. The result is an increased rate of cellular activity (noted by a more rapid utilization of carbohydrates, fats and proteins). Bodybuilders are particularly attracted to this drug for its ability to burn off body excess fat. Most often utilized during contest preparation, one can greatly decrease the amount of stored fat without being forced to severely restrict calories. To this end Cytomel® is commonly used in conjunction with Clenbuterol and can produce extremely dramatic results. This combination has become very popular in recent years, no doubt responsible for many "ripped" on-stage physiques. It is also noted by many that when thyroid hormones are taken in conjunction with steroids, an increased anabolic effect can be seen (noticeably greater than if the steroids are used alone). This is likely due to faster utilization of proteins by the body, increasing the rate for new muscle accumulation.

One should take caution if considering using this drug. Cytomel® comes with an extensive list of warnings and precautions which are not to be ignored. Side effects include, but are not limited to, heart palpitations, agitation, shortness of breath, irregular heartbeat, sweating, nausea, headaches, and psychic/metabolic disorders. It is a powerful hormone, and one that could potentially alter the normal functioning of the body if misused. When administering Cytomel®, one must remember to increase the dosage slowly. Generally one 25mcg tablet is taken on the first day, and the dosage is thereafter increased by one tablet every three of four days for a maximum dosage of 100mcg. This will help the body adjust to the increased thyroid hormone, hopefully avoiding any sudden "shock" to the system. The daily dose is also to be split evenly throughout the day, in an effort to keep blood levels steadier. Women are more sensitive to the side effects of Cytomel® than men, and usually opt to take no more than 50mcg daily.

It is important to stress that a cycle should last no longer than 6 weeks and it should never be halted abruptly. As slowly as the dosage was built up it should also be lowered, one tablet every 3-4 days. Taking Cytomel® for too long and/or at too high a dosage can result in a permanent thyroid deficiency. After doing such, one might need to be treated with a drug like Cytomel® for life. It is also a good idea to first consult your physician and have your thyroid function tested. An undiagnosed hyperfunction would not mix well with the added hormone. An athlete should also be sure never to purchase an injectable form of the drug. It is generally an emergency room product, much too powerful for athletic use. Since T-3 is the most powerful thyroid hormone athletes are using, this is generally not the starting point for a beginner. Before using such a powerful item, it is a good idea to become familiar with a weaker substance. The highly popular Triacana is very mild, allowing the user much more latitude (from severe side effects) than Cytomel®. An in-between point is Synthroid (synthetic T-4), still weaker in action than Cytomel®. Once the user is ready however, the fat burning effect of this hormone can be extremely dramatic.