The human sex drive can vary greatly between individuals and is not constant in one individual throughout their life either. Low sex drive is caused due to several factors and remains an area of health that is seldom discussed, despite being common in both men and women. People who suffer from low libido may delay treatment, as they find it embarrassing to talk about their problems to their partners, doctors, or therapists.

Sometimes they consult alternative, dubious medical sources in search of under-the-table cures, which may end up doing more harm than good. A low libido is not to be confused with sexual dysfunction or erectile dysfunction. Although, other physical manifestations may appear in conjunction with it. Persistent and unexplained causes of low libido can result in the breakdown of intimate relationships, distress, psychological trauma, anxiety, and depression. The effects of low libido results include:

• Reduced interest in sex
• Fewer fantasies and thoughts about sex
• Inability to respond to stimulation
• Low engagement in sexual activity

Low sex drive in men may be the result of a single factor, or it may be due to a combination of different factors such as personal issues, biological factors, professional stressors, etc. Typical factors that cause low libido include:

1. Low levels of testosterone
Libido comprises a complex response that is regulated by several hormones. Testosterone is an important male hormone that is responsible for building muscle mass, bone, and promoting sperm growth. It also impacts libido. With age, testosterone levels tend to drop in men, resulting in a condition known as hypogonadism. This condition can also occur in men of all ages. According to the American Urological Association guidelines, testosterone levels are considered low if they fall below 300gm/nanoliter.

2. Chronic diseases and conditions
The debilitating effects of certain chronic illnesses like cancer, type-2 diabetes, heart or lung disease, high blood pressure, and obesity can affect the libido in men. Restless leg syndrome can also cause low libido and sometimes lead to impotency.

3. Disturbances in sleep
Men with obstructive sleep apnea tend to have lower testosterone levels, which in turn impact the libido. Sleeping fewer than five hours a night harms the sex drive in young, healthy men. Testosterone levels drop during the next day if the person has not had enough sleep, leading to a cycle of sleep deprivation and low libido.

4. Side effects of medications
Some medications can negatively affect sex drive. Blood pressure medications like beta-blockers and ACE inhibitors cause sexual dysfunction. Certain treatments for cancer like chemotherapy and radiation also lead to low libido. Opioids used for pain relief, certain antifungal medications, anabolic steroids, and antidepressants have also been observed to cause low libido in men.

5. Psychological factors
Depression and stress are major emotional reasons for lowered sex drive. Relationship problems, perceived lack of attractiveness in a partner, and infidelity may lead to a decreased libido. Some circumstances like the death of a loved one, job loss, the birth of a new baby can also be problematic.

A few other causes of low libido include stress, a busy work schedule, drug, or alcohol abuse. Tension and conflict about sex between the partners, anxiety, and poor body image are additional contributing factors.