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Blood testosterone threshold for androgen deficiency symptoms
S Kelleher1, A J Conway, D J Handelsman
1Department of Andrology, Concord Hospital and ANZAC Research Institute, University of Sydney, Concord, NSW 2139, Australia.
The Journal of Clinical Endocrinology and Metabolism
|August 5, 2004
Summary
This study found that individual testosterone thresholds for androgen deficiency symptoms are consistent but vary between men. The mean threshold aligns with the lower end of the normal range for young men.
Area of Science:
- Endocrinology
- Men's Health
Background:
- Few studies systematically link blood testosterone levels to androgen deficiency symptoms.
- Short-term testosterone treatments create rapid fluctuations, hindering threshold definition.
- Subdermal implants offer stable testosterone levels for defining thresholds.
Purpose of the Study:
- To define blood testosterone thresholds for androgen deficiency symptoms.
- To investigate individual variability in testosterone thresholds.
- To compare thresholds between different types of hypogonadism.
Main Methods:
- 52 androgen-deficient men received 260 testosterone implantations over 5 years.
- Symptoms were monitored as testosterone levels gradually declined.
- Blood total and free testosterone concentrations were measured at symptom return.
Main Results:
- Individual testosterone thresholds for androgen deficiency symptoms were reproducible but varied significantly between men.
- The most common symptoms reported were lack of energy, motivation, and reduced libido.
- Symptomatic thresholds were lower in secondary hypogonadism compared to primary or mixed hypogonadism.
Conclusions:
- Each man has a consistent, yet individual, testosterone threshold for androgen deficiency symptoms.
- The average testosterone threshold for symptoms is at the lower limit of the normal range for young men.
- Further research is needed for implications in chronic diseases and aging.