FDA ApprovedFDA Approved

TRT

Testosterone Replacement Therapy | Testosterone Cypionate & Enanthate

Testosterone Replacement Therapy (TRT) is FDA-approved for treating male hypogonadism (low testosterone) caused by testicular failure or hypothalamic-pituitary dysfunction. Testosterone cypionate and enanthate are the most commonly prescribed injectable esters, providing sustained testosterone levels with weekly or bi-weekly dosing. The TRAVERSE trial (5,200+ participants) confirmed cardiovascular safety in high-risk men when used as indicated.

Daily dose

100-200mg weekly (injectable)

Frequency

1-2x weekly (injectable) or daily (topical/oral)

Cycle length

Ongoing (lifetime therapy for hypogonadism)

Storage

20-25°C (room temperature)

Key benefits

FDA-approved treatment for male hypogonadism restoring testosterone to physiological levels. Improves energy, libido, mood, muscle mass, bone density, and metabolic health. TRAVERSE trial confirmed cardiovascular safety in indicated patients.

How it works

Exogenous testosterone supplementation replaces deficient endogenous production. Binds androgen receptors throughout the body, modulating gene expression for anabolic (muscle, bone) and androgenic (libido, mood) effects. Suppresses HPG axis via negative feedback.

Dosage protocols

Goal

Standard TRT (Injectable)

Dose

100-200mg · Weekly or split 2x/week

Route

IM or SubQ

Goal

Topical Gel

Dose

50-100mg · Daily

Route

Transdermal

Goal

Oral (Jatenzo)

Dose

237mg · Twice daily with food

Route

Oral

Goal

Nasal (Natesto)

Dose

33mg · 3x daily

Route

Intranasal

Research indications

hormone Restoration

Hypogonadism Treatment — FDA-approved for primary and secondary hypogonadism with documented low testosterone and symptoms.

Symptom Resolution — Relieves fatigue, low libido, erectile dysfunction, depressed mood, and cognitive difficulties.

Quality of Life — Studies show significant improvements in overall quality of life and well-being measures.

body Composition

Increased Lean Mass — Meta-analyses show 3-6kg lean mass increase, with 10-13% strength improvements.

Reduced Fat Mass — 2-4kg fat mass reduction, particularly visceral adipose tissue.

Bone Health — Maintains bone mineral density in hypogonadal men, though TRAVERSE showed paradoxical fracture risk increase.

metabolic Health

Cardiovascular Safety — TRAVERSE trial: noninferior to placebo for major adverse cardiac events in high-risk men.

Diabetes Risk Reduction — May improve insulin sensitivity and reduce progression to type 2 diabetes.

Anemia Correction — Effective for unexplained anemia in hypogonadal men (41% correction rate vs 27.5% placebo).

Administration

injectable

oral

topical

nasal

Interactions

Synergistic

hCG — hCG maintains testicular function and fertility during TRT by mimicking LH. Commonly dosed at 250-500 IU 2-3x weekly.

Supportive

Anastrozole — Aromatase inhibitor that prevents testosterone-to-estrogen conversion. Used at 0.5-1mg weekly if estradiol elevates.

Synergistic

Growth Hormone Peptides — GH secretagogues (Ipamorelin, CJC-1295) may enhance body composition effects when combined with TRT.

Monitor Combination

Insulin — TRT may improve insulin sensitivity and reduce blood glucose; diabetics may need medication dose adjustments.

Monitor Combination

Blood Thinners — TRT can increase hematocrit and hemoglobin. Monitor closely if on anticoagulants due to altered blood viscosity.

Alternative

Clomiphene — SERM used as alternative to TRT or for PCT. Not typically combined during active TRT as they work through opposing mechanisms.

Safety notes

Requires diagnosis of hypogonadism with documented low testosterone plus symptoms

FDA black box warning: possible increased risk of heart attack and stroke

Regular monitoring required: testosterone, hematocrit, PSA every 3-6 months

Contraindicated in prostate cancer, breast cancer, uncontrolled heart failure

Suppresses fertility - hCG may preserve spermatogenesis if fertility desired

Topical products carry risk of secondary exposure to women/children

Research studies

TRAVERSE Cardiovascular Safety Trial (2023)

5,246 men | 45-80 years | Mean 33 months | FDA-mandated study

Landmark randomized trial in hypogonadal men with cardiovascular disease or high CV risk. Found TRT noninferior to placebo for major adverse cardiac events, establishing cardiovascular safety when used as indicated.

View study →

Testosterone Trials (TTrials) - Body Composition (2017)

788 men ≥65 years | 1 year | Multiple endpoints

Comprehensive NIH-funded study showing testosterone gel increased lean mass, improved sexual function, mood, and walking distance in older hypogonadal men.

View study →

Meta-Analysis: Muscular Responses to TRT (2018)

31 RCTs analyzed | Various formulations | Fat-free mass outcomes

Intramuscular TRT associated with 5.7% increase in fat-free mass and 10-13% improvement in muscle strength. Transdermal showed 1.7% fat-free mass increase.

View study →

Long-Term Safety Registry Study (2016)

1,000+ men | Up to 12 years | Real-world outcomes

Long-term registry data showing sustained improvements in metabolic parameters, body composition, and quality of life with continued TRT over many years.

View study →

Related compounds

HCG (Human Chorionic Gonadotropin)Testagen Kisspeptin PT-141