Testosterone can be measured in 2 ways, Total testosterone (TT) and Free testosterone (FT).
Although there is no clear cut off to what exactly constitutes low testosterone, its widely accepted that total testosterone <12nmol/L would benefit from treatment. (1)
If the TT levels are normal but there are symptoms of TDS (testosterone deficiency syndrome), FT can be measured and FT <250 pmol/L is considered low.
Symptoms of low testosterone can include but are not limited to:
erectile dysfunction
reduced libido (sexual desire)
increase in fat, reduced muscle mass
fatigue
depressed mood
impaired cognitive function
Prevalence of testosterone deficiency in Singapore is 25% or 1 in 4 (2)
There are some medical conditions in which low testosterone levels are more prevalent, such as diabetes and obesity.
Depending on the patient's age, looking out of contraindications for treatment and considering the possible side effects, patients suffering from symptoms of low testosterone can consider Testosterone replacement therapy (TRT).
TRT can be in the form of pills, Gels (Androgel) or intramuscular injections (Nebido) , each with their own set of pros and cons. The aim of TRT is to improve symptoms and not just to attain a "good level". We aim to correct the TT till it reaches the 3rd quartile of the normal physiological range or 15-20 nmol/L. Effects of treatment can been seen in as fast as 1 month depending on the type of symptoms experienced.
Hope this gives you some clarity, please seek help if you have more queries.
Regards
Dr Mark Lim
References
SMHS Testosterone Deficiency Syndrome Guideline.
Morgentaler A, Zitzmann M, Traish AM, Fox AW, Jones TH, Maggi M, Arver S, Aversa A, Chan JC, Dobs AS, Hackett GI, Hellstrom WJ, Lim P, Lunenfeld B, Mskhalaya G, Schulman CC, Torres LO. Fundamental Concepts Regarding Testosterone Deficiency and Treatment: International Expert Consensus Resolutions. Mayo Clin Proc. 2016 Jul;91(7):881-96. doi: 10.1016/j.mayocp.2016.04.007. Epub 2016 Jun 21. PMID: 27313122.
