Randomized cross-over clinical trial of injectable vs. implantable depot testosterone for maintenance of testosterone replacement therapy in androgen deficient men

Clin Endocrinol (Oxf). 2010 Jul;73(1):102-9. doi: 10.1111/j.1365-2265.2009.03744.x. Epub 2009 Nov 5.


Background: Life-long testosterone replacement therapy (TRT) for younger men with organic androgen deficiency is best provided by depot testosterone (T) products. This study compared directly the two long-acting depot T products, subdermal T implants (TI) and injectable T undecanoate (TU) for maintenance of TRT.

Design, setting and participants: Men with organic androgen deficiency (n = 38) undergoing regular TRT at an academic Andrology centre were recruited for a two period, randomized sequence, cross-over clinical trial without intervening wash-out period of TRT maintenance.

Outcomes: For both depot T products, their pharmacokinetics and pharmacodynamics were evaluated using a range of androgen sensitive clinical, laboratory and quality of life measures as well as preference for ongoing treatment after experience of both products.

Results: The two depot T products had distinct pharmacokinetics and were not bioequivalent. However, there were no consistent clinical differences in a comprehensive range of pharmacodynamic measures reflecting androgen effects on biochemistry and haematology, muscle mass and strength, and quality of life, mood and sexual function. The majority (91%) of participants chose TU over TI at study completion.

Conclusion: Despite significant pharmacokinetic differences, the two depot T products are clinically interchangeable allowing for choice dependent on patient and physician delivery preference in practice but most patients preferred the injectable over the implantable form.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Androgens / deficiency
  • Cross-Over Studies
  • Drug Implants
  • Hormone Replacement Therapy / methods*
  • Humans
  • Hypogonadism / drug therapy*
  • Male
  • Patient Satisfaction
  • Quality of Life
  • Testosterone / administration & dosage*
  • Testosterone / analogs & derivatives
  • Testosterone / pharmacokinetics
  • Testosterone / therapeutic use


  • Androgens
  • Drug Implants
  • Testosterone
  • testosterone undecanoate