At a glance

Muscle growth
Strength output
Rapid pre-workout performance
Libido enhancement
Cardiovascular / blood-pressure risk
Aromatisation (oestrogen / gynaecomastia)
Injection pain & infection risk
HPTA suppression
Polycythaemia / raised haematocrit· class-derived
Mood / neuropsychiatric· class-derived
Androgenic skin / hair effects· class-derived
Water / fluid retention· class-derived
BenefitSide effectHealth risk· more & brighter bars = stronger

Effects

  • Rapid muscle protein synthesis: Fast androgen-receptor binding and protein synthesis upregulation begins within the workout window when used pre-training [1].
  • Strength increase: Enhanced anabolic environment promotes gains in muscle mass and strength within a short timeframe after injection [4].
  • Acute pre-workout CNS drive: The rapid testosterone spike produces neurotransmitter modulation that many users report as heightened aggression and focus during training [1].
  • Elevated libido: Supraphysiological testosterone transiently raises libido; increased or decreased libido is among the very common reported effects of testosterone injection [5].
  • Erythropoiesis stimulation: Testosterone increases red blood cell count (erythrocytosis), which can temporarily raise oxygen-carrying capacity but also increases blood viscosity risk [5][6].
Classification

Anabolic-androgenic steroid (AAS), Schedule III (US)

Active half-life

Complex: initial ~2–4 h acute phase; terminal elimination can extend considerably due to depot absorption [1]

Route

Intramuscular injection (water-based suspension) [1]

Onset

Peak testosterone within 30 min – 2 h post-injection [1]

Detection time

Approximately 12–24 h urine clearance; T:E ratio may normalise faster than longer esters [10]