Testosterone Replacement Therapy (TRT): Benefits, Risks & Who Should Consider It

Testosterone Replacement Therapy (TRT): Benefits, Risks & Who Should Consider It

Low energy. Poor sleep. Shrinking muscle mass. A libido that's gone quiet. If you've been Googling these symptoms and wondering whether your testosterone is to blame — you're not alone, and the question is worth taking seriously.

Testosterone replacement therapy (TRT) is one of the most discussed topics in men's health today, and also one of the most misunderstood. This guide cuts through the noise: what TRT actually is, what the evidence says about its benefits and risks, and how clinicians decide who should — and shouldn't — use it.

What Is Testosterone Replacement Therapy?

Testosterone replacement therapy is medical treatment designed to restore testosterone levels in men whose bodies no longer produce sufficient amounts of the hormone. It is not a performance-enhancing shortcut. It is a clinically recognised treatment for a condition called hypogonadism — the medical term for inadequate testosterone production.

The Endocrine Society's 2018 Clinical Practice Guideline on testosterone therapy in men defines hypogonadism as a combination of:

• Consistently low serum total testosterone — generally below 300 ng/dL on two separate morning measurements
• Symptoms attributable to testosterone deficiency

Both criteria matter. Numbers alone don't tell the full story; symptoms without a confirmed hormonal deficit aren't sufficient justification for treatment either.

Citation: Bhasin S, Brito JP, Cunningham GR, et al. Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2018;103(5):1715–1744.

Forms of TRT

Testosterone is delivered in several formats, each with different absorption profiles and practical trade-offs:

• Intramuscular injections (testosterone cypionate or enanthate): Administered every 1–2 weeks, or more frequently at lower doses to reduce fluctuation. Cost-effective and reliable.
• Transdermal gels and creams: Applied daily to skin, providing steadier levels. Risk of transfer to partners or children if contact occurs.
• Transdermal patches: Daily application; some men experience skin irritation.
• Subcutaneous pellets: Implanted under the skin every 3–6 months; provides sustained release.
• Oral/buccal formulations: Less commonly used; some options carry liver considerations.

The choice of formulation depends on your lifestyle, preferences, monitoring access, and clinical factors your doctor will assess.

The Benefits of TRT — What the Evidence Shows

When prescribed appropriately for confirmed hypogonadism, TRT has demonstrated the following effects in clinical evidence:

Sexual Function

Multiple randomised trials show TRT improves libido and erectile function in men with documented low testosterone. The Endocrine Society guideline notes that improvements in sexual desire are among the most consistent findings in TRT research.

Body Composition

TRT reliably reduces fat mass and increases lean muscle mass in hypogonadal men. This is not equivalent to anabolic steroid use — effects are moderate and occur within normal physiological ranges when therapy is correctly dosed.

Bone Mineral Density

Long-term testosterone deficiency accelerates bone loss. TRT has been shown to increase lumbar spine and femoral neck bone density, reducing fracture risk in men with osteoporosis secondary to hypogonadism.

Mood and Cognitive Function

Men with low testosterone frequently report fatigue, irritability, low motivation, and depressive symptoms. Clinical evidence supports improvements in mood and energy following testosterone normalisation, though TRT is not a treatment for primary depression.

Metabolic Markers

Some evidence indicates that TRT in insulin-resistant or type 2 diabetic men with hypogonadism may improve insulin sensitivity and reduce HbA1c — though this remains an area of active research.

Important: Most benefits are tied to correction of a genuine deficit. Men with normal testosterone levels do not experience the same clinical gains, and the risk-benefit balance shifts accordingly.

The Risks of TRT — What You Need to Know

TRT is not without risk. Honest clinical guidance requires that these be communicated clearly.

Erythrocytosis (Elevated Red Blood Cell Count)

The most common clinically significant adverse effect. TRT stimulates red blood cell production; if haematocrit rises above 54%, the blood thickens and cardiovascular risk increases. Regular monitoring is essential. Dose adjustment or temporary cessation is required if haematocrit exceeds threshold.

Suppression of Sperm Production

Exogenous testosterone signals the brain to suppress the hormonal axis that drives natural testosterone and sperm production (the HPG axis). Men who wish to father children should not start TRT without first discussing fertility-preserving alternatives — typically clomiphene citrate or human chorionic gonadotropin (hCG).

Sleep Apnoea

TRT may worsen pre-existing obstructive sleep apnoea. Men with undiagnosed or untreated sleep apnoea should be assessed before starting therapy.

Cardiovascular Effects

The relationship between TRT and cardiovascular risk has been extensively studied. The evidence is nuanced. The large TRAVERSE trial (2023) found no significant increase in major adverse cardiovascular events in hypogonadal men with pre-existing cardiovascular disease treated with testosterone. However, men with recent myocardial infarction or stroke warrant careful clinical assessment.

Skin and Hair

Acne and oily skin are common, particularly in the early months. Accelerated hair thinning can occur in men genetically predisposed to androgenic alopecia.

Prostate Health

TRT is contraindicated in men with known or suspected prostate cancer or breast cancer. PSA should be measured before starting therapy and monitored regularly. The Endocrine Society guideline recommends against offering TRT to men with a PSA >4 ng/mL without urological evaluation.

Who Should Consider TRT?

According to the Endocrine Society 2018 guidelines, TRT is recommended for men who have:

1. Confirmed hypogonadism — two fasting morning testosterone readings below 300 ng/dL
2. Clinical symptoms — at least one of: low libido, erectile dysfunction, fatigue, depressed mood, decreased muscle mass, or increased body fat
3. No contraindications — no prostate or breast cancer, no desire for fertility in the short term, no severe untreated sleep apnoea, haematocrit within normal range

It is not a treatment for age-related testosterone decline in men whose levels remain within the normal reference range, nor is it appropriate for men seeking athletic enhancement.

Who Should NOT Take TRT?

The Endocrine Society guideline lists clear contraindications:

• Prostate cancer (active or high risk)
• Breast cancer
• Haematocrit >54%
• Uncontrolled congestive heart failure
• Desire for fertility (without concurrent fertility management)
• Untreated severe obstructive sleep apnoea

What Does TRT Monitoring Look Like?

TRT is not a set-and-forget treatment. Responsible management includes:

• Serum testosterone at 3–6 months, then annually
• Haematocrit at 3–6 months, then annually
• PSA at 3–6 months, then annually in men over 40
• Symptom reassessment at each visit
• Bone density scan in men with osteoporosis at baseline

If you are offered TRT without a monitoring plan, seek a second opinion.

Frequently Asked Questions

Q: How quickly does TRT work? Most men notice changes in libido and energy within 3–6 weeks. Body composition improvements typically appear at 3–6 months. Bone density changes require 12+ months of consistent therapy.

Q: Is TRT permanent? No. TRT can be discontinued. However, natural testosterone production may remain suppressed for weeks to months after stopping, particularly after prolonged use.

Q: Does TRT cause prostate cancer? Current evidence does not support a causal link between TRT and prostate cancer development in men without pre-existing cancer. TRT is contraindicated in men with active prostate cancer.

Q: Can I take TRT if I want to have children? Not without specific management. Standard TRT suppresses sperm production. Men wishing to preserve fertility should discuss alternatives (clomiphene, hCG) with their doctor before starting any testosterone therapy.

Q: What's the difference between TRT and anabolic steroids? TRT aims to restore testosterone to normal physiological levels (300–1000 ng/dL). Anabolic steroid use involves supraphysiological doses — far above normal — for performance enhancement. These are fundamentally different contexts with different risk profiles.

Q: Do I need a prescription for TRT in Singapore? Yes. Testosterone is a Schedule III controlled drug in Singapore. It requires a valid prescription from a licensed physician following appropriate diagnostic workup.

Taking the Next Step

If you recognise these symptoms in yourself and want a structured assessment — not a generic health quiz, but actual clinical evaluation — Noah offers medically supervised hormone health consultations designed for men in Singapore.

A qualified doctor will review your full clinical picture, order appropriate blood work, and walk you through options that are right for you — not a protocol off a shelf.

→ Start your assessment at ofnoah.sg

This article is for educational purposes only and does not constitute medical advice. Consult a licensed physician before starting, stopping, or changing any medical treatment.

Reference: Bhasin S, et al. Testosterone Therapy in Men With Hypogonadism: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab. 2018;103(5):1715–1744.