Treatment category · 3 delivery methods · FDA-approved · Requires testing
Testosterone Replacement
Therapy — injections,
creams & pellets explained
TRT corrects clinically low testosterone — improving libido, energy, mood, body composition, and sexual function in men with diagnosed hypogonadism. The delivery method matters significantly: each has different hormone stability, convenience, cost, and lifestyle implications.
TRT requires confirmed low testosterone on blood testing before starting — not just symptoms. Symptoms of low testosterone overlap with many other conditions. Proper diagnosis is essential, and treatment requires ongoing monitoring by a physician.
Overview
What TRT does — and who it’s for
Testosterone replacement therapy restores testosterone to normal physiological levels in men with clinically confirmed hypogonadism — low testosterone caused by testicular failure (primary hypogonadism) or insufficient pituitary/hypothalamic signaling (secondary hypogonadism).
When testosterone is genuinely low, restoring it to normal range reliably improves libido, sexual function, energy, mood, bone density, muscle mass, and body composition. These are established, well-documented benefits with decades of clinical evidence.
The key qualifier is “clinically confirmed.” Symptoms of low testosterone — fatigue, reduced libido, mood changes — are non-specific and overlap with many other conditions including sleep disorders, depression, thyroid dysfunction, and normal aging. A blood test is required before TRT is appropriate.
If you are experiencing several of these, discuss testing with your physician — not starting TRT without testing.
Reduced sexual desire or libido
Erectile dysfunction
Persistent fatigue and low energy
Depressed mood or irritability
Reduced muscle mass or increased body fat
Brain fog or difficulty concentrating
Reduced bone density
Loss of morning erections
TRT suppresses the HPG axis, reducing LH and FSH — the hormones that drive sperm production. Men who want to preserve fertility should not start TRT without discussing alternatives such as clomiphene, hCG, or kisspeptin with a reproductive endocrinologist or urologist.
The three delivery methods
Injections, cream, or pellets — choosing the right fit
Each delivery method achieves the same goal — restoring testosterone to normal range — but with meaningfully different pharmacokinetics, convenience, and lifestyle implications.
Testosterone Injections
Self-administered subcutaneous or intramuscular injections — typically weekly or twice-weekly. The most widely used TRT method. Flexible dosing, easy monitoring, lowest cost. Peaks and troughs between injections are manageable with frequent smaller doses.
Testosterone Cream
Compounded testosterone cream applied daily to skin — typically inner thighs, scrotum, or upper arms. No injections. Stable daily levels. Scrotal application produces significantly higher absorption. Transfer to partners or children is a real risk requiring care.
Pellet Testosterone Therapy
Small pellets implanted under the skin every 3–6 months by a physician. No daily application or weekly injections. Highly convenient — but dose cannot be adjusted once inserted, and removal requires a minor procedure. Most expensive option.
Side-by-side comparison
All three methods compared
| Feature | Injections | Cream | Pellets |
|---|---|---|---|
| Frequency | Weekly or bi-weekly | Daily | Every 3–6 months |
| Self-administered? | Yes | Yes | No — physician procedure |
| Hormone stability | Peaks and troughs (manageable with frequent dosing) | Stable daily levels | Stable — then declines toward next insertion |
| Dose adjustable? | Yes — easily | Yes — change daily dose | No — fixed until next insertion |
| Transfer risk? | No | Yes — skin-to-skin contact | No |
| Cost | Lowest | Moderate | Highest |
| Best for | Most men — best value, most flexibility | Men who want stable levels without needles | Men prioritizing convenience above all else |
Common questions
Frequently asked questions
Do I need a blood test before starting TRT?
Yes — always. TRT should only be started after confirmed low testosterone on at least two morning blood tests (testosterone levels are highest in the morning). Testing should also include LH, FSH, and ideally a full hormonal panel to identify whether the cause is primary or secondary hypogonadism. Starting TRT without testing is inappropriate and potentially harmful.
Will TRT affect my fertility?
Yes — TRT suppresses the HPG axis, reducing LH and FSH and therefore dramatically reducing or eliminating sperm production. This effect is typically reversible when TRT is stopped, but recovery can take months and is not guaranteed. Men who want to father children should not start TRT without discussing fertility preservation with a reproductive urologist or endocrinologist. Alternatives including clomiphene citrate and hCG can maintain fertility while supporting testosterone.
Once I start TRT, is it forever?
Not necessarily — but in practice, many men continue long-term. When TRT is stopped, natural production resumes over weeks to months, but may not fully recover to pre-treatment levels — particularly if TRT was used for an extended period. Some men restart TRT after a break; others use clomiphene or hCG as a “restart” protocol to stimulate natural production. Discuss the long-term plan with your physician before starting.
Can TRT improve erectile dysfunction?
If low testosterone is contributing to ED, restoring it to normal range typically improves erectile function — particularly desire and libido. However, TRT alone is not always sufficient for ED if there is also a vascular component. Many men with low testosterone and vascular ED benefit from TRT alongside shockwave therapy, PRP, or ED medications. Always address both hormonal and vascular dimensions when both are present.
Find a TRT provider
TRT requires physician evaluation, blood testing, and ongoing monitoring. Search our directory of vetted physicians — or join the forum to hear from men navigating TRT.
PhallusMD is an informational resource and does not provide medical advice. TRT requires blood testing, physician evaluation, and ongoing monitoring. All forms of TRT suppress natural testosterone production. Do not start TRT without confirmed low testosterone on laboratory testing. PhallusMD does not sell or prescribe medications.