Individualizing Injectable Testosterone Replacement Therapy in Primary Care: Pharmacokinetics, Symptom Stability, Safety Monitoring, and Injection Frequency.

Plain-language summary

This review looked at how to tailor injectable testosterone therapy for men with confirmed hypogonadism, meaning the testicles do not make enough testosterone, causing symptoms such as low libido, fatigue and loss of muscle. It covers the practical end: how often to inject, how to time doses, and what to monitor. The authors stress that injection frequency is often chosen out of habit rather than reasoning, and that it should only be considered once the diagnosis is properly established with repeat morning testosterone tests. Weekly dosing works well for many men. Some still get symptom cycling, acne, mood or sleep disturbance, breast tenderness, fluid retention, late-cycle fatigue or reduced libido, and for them the problem is usually the peaks and troughs rather than too little testosterone overall. Smaller doses more often can smooth that out, which in practice means twice weekly, three times weekly, every other day or daily rather than once a fortnight. The aim is steady symptom control, not the highest number on a blood test.

Key findings

• Weekly injections give stable symptoms and readable bloodwork for most men
• Splitting the same weekly dose into twice-weekly, three-times-weekly or daily injections reduces symptom cycling
• Redistributing the dose should be tried before raising it