9. Low Testosterone
The amount of testosterone in your body determines the level of your sex drive. If your testosterone levels dip too low, your libido is likely to decline. Testosterone therapy is recommended for boosting your sex drive.
Related: Okay, No Hormones, But What Instead?
Depression is a double-edged sword because it saps sex drive, while antidepressants do so too. Seeking treatment for clinical depression is necessary; you can deal with the low libido once the depression is under control.
Related: 9 Physical Symptoms of Depression