Meta-analysis and construction of simple-to-use nomograms for approximating testosterone levels gained from weight loss in obese men.
Level 2 - randomized trial
Systematic review and meta-analysis of dietary and surgical weight loss interventional/cohort studies.
PubMed 37345263 · doi:10.1111/andr.13484
What was done
A systematic review and meta-analysis of 44 studies (1,774 participants, 2,159 datasets) evaluated changes in total testosterone (TT) and free testosterone (FT) in obese men following weight reduction. Interventions included low-calorie diet (LCD; 19 studies, 735 participants), bariatric surgery (BS; 26 studies, 1,039 participants), and both (1 study). Median follow-up was 26 weeks (interquartile range: 12–52 weeks). Parallel-scale, age-stratified nomograms were developed using baseline and target body mass index (BMI) values to estimate testosterone gains.
What was found
Weight loss through LCD increased TT by SMD = 2.5 nmol/L (95% CI: 1.9–3.1) and FT by SMD = 19.9 pmol/L (95% CI: 7.3–32.5). Bariatric surgery resulted in larger increases: TT increased by SMD = 7.2 nmol/L (95% CI: 6.0–8.4) and FT by SMD = 58.0 pmol/L (95% CI: 44.3–71.7). Combined across all interventions, TT gained 4.8 nmol/L (95% CI: 3.9–5.6) and FT gained 42.2 pmol/L (95% CI: 31.4–52.9). Testosterone gains were larger in men with higher baseline BMI or lower baseline SHBG, TT, and FT. Age-stratified analyses showed men over 40 gained relatively more TT, whereas men 40 and younger gained more FT for a given degree of weight reduction.
Why it matters
The study quantifies expected hormonal recovery following lifestyle or surgical weight loss in obese men and provides clinical nomograms to estimate testosterone changes based on target BMI.
Limits
The abstract does not distinguish randomized trials from single-arm cohort studies. Clinical symptom endpoints (e.g., changes in erectile function or libido) and long-term durability beyond the median 26-week follow-up were not reported.
Cited by
- supports Overweight men who lose excess body fat experience an increase in testosterone levels, whereas lean men who undergo severe caloric restriction experience a drop in testosterone.