T3 25μg/tab 100tabs

Liothyronine is a synthetic form of triiodothyronine (T3), an active thyroid hormone involved in regulating metabolism, energy production, and nutrient utilization. It is manufactured to be chemically identical to endogenous T3 and is available as the sodium salt.

Chemical Description

• Chemical name: L-tyrosine, o-(4-hydroxy-3-iodophenyl)-3,5-diiodo-, monosodium salt

• Form: Oral tablets

Each tablet contains liothyronine sodium, along with inactive ingredients such as calcium sulfate, gelatin, starch, stearic acid, sucrose, and talc.

Hormonal Equivalence

• 25 mcg of liothyronine ≈

  • 1 grain of desiccated thyroid (thyroglobulin)

  • 0.1 mg of levothyroxine (T4)

How Liothyronine Works

T3 is the biologically active thyroid hormone responsible for most thyroid-related metabolic effects. While the thyroid gland primarily secretes thyroxine (T4), T3 is produced mainly through peripheral conversion of T4 under the influence of thyroid-stimulating hormone (TSH).

Liothyronine directly binds to nuclear thyroid hormone receptors, influencing DNA transcription and protein synthesis, which leads to increased metabolic activity in nearly all tissues.

Medical Uses

Liothyronine is prescribed to:

• Treat hypothyroidism

• Prevent or manage certain types of goiter

• Alleviate symptoms of thyroid hormone deficiency, including:

  • Fatigue

  • Weight gain

  • Cold intolerance

  • Hair loss

  • Dry or thickened skin

  • Slowed speech and growth

By restoring adequate T3 levels, liothyronine helps normalize metabolic function and relieve these symptoms.

Effects on Fat Metabolism

Thyroid hormone therapies, including liothyronine, are known for their fat-burning properties due to multiple metabolic mechanisms:

Beta-2 Adrenergic Receptor Activation

Liothyronine increases the expression of beta-2 adrenergic receptors in adipose tissue. These receptors enhance the action of catecholamines (epinephrine and norepinephrine), which activate hormone-sensitive lipase (HSL)—the key enzyme responsible for lipolysis.

Increased Lipolysis

By enhancing catecholamine responsiveness, liothyronine accelerates the breakdown of triglycerides into free fatty acids, leading to increased fat utilization.

UCP-3 Stimulation

Liothyronine stimulates uncoupling protein-3 (UCP-3), increasing thermogenesis and energy expenditure, further supporting fat loss.

Use in Athletic Contexts

Athletes may use liothyronine to increase metabolic rate, resulting in faster utilization of carbohydrates, proteins, and fats. Its primary interest lies in fat reduction, particularly during cutting phases.

Liothyronine is sometimes combined with anabolic agents to counterbalance metabolic slowdown. However, because T3 increases protein metabolism, maintaining a high-protein diet is essential to minimize muscle loss.

Dosage Information

General Use Pattern

• Starting dose: 25 mcg per day

• Increase by 25 mcg every 5–6 days

• Maximum dose: 100 mcg per day

• Daily dose should be divided throughout the day

Typical Ranges

• Average dose: 25–100 mcg per day

• Cycle length: 5–7 weeks

• Break between cycles: At least 6 weeks

Common Pyramidal Protocol

• 25 → 50 → 75 → 100 → 75 → 50 → 25 mcg

This gradual increase and decrease helps reduce side effects and supports recovery of normal thyroid function after discontinuation.

Possible Side Effects

Most adverse effects are dose-related and occur with excessive intake.

Rare but Serious Effects

• Heart rhythm disturbances

• Tremors

• Symptoms of heart failure

• Breathing difficulties

• Glucose in urine

• Severe sweating

• Diarrhea

• Rapid weight loss

• Psychiatric disturbances

• Hypersensitivity reactions

More Common Effects

• Hand tremors

• Nausea

• Headaches

• Increased sweating

• Elevated heart rate

Reducing the dosage often alleviates these effects.

Important Precautions

Blood Sugar

Liothyronine may raise blood glucose levels. Individuals with diabetes should monitor blood sugar closely and consult a healthcare professional if abnormalities occur.

Cardiovascular Conditions

Liothyronine increases cardiac workload. People with angina, arrhythmias, or other heart conditions should use extreme caution and seek medical guidance before use.

Pregnancy and Breastfeeding

• Pregnancy: Considered safe when thyroid hormone replacement is required

• Breastfeeding: Small amounts pass into breast milk; continued therapy is generally necessary

Older Adults

Elderly individuals may be more sensitive, especially to cardiovascular effects, and should be monitored closely.

Storage Instructions

• Store at room temperature

• Keep away from moisture and direct sunlight

• Keep out of reach of children and pets