Testosterone is a hormone that is mostly associated with male characteristics. It is important for a host of functions. Women also produce testosterone but much less than men.
Testosterone production is highest in your teens. It peaks up in your early 20s and then gradually levels off. In your 30s, the levels start to decrease naturally.
Therefore, it is normal for testosterone levels to drop with age. However, if the drop is way too much, it is not normal. Very low testosterone can seriously affect your quality of life.
There can be many causes for low testosterone. It can be an infection and inflammation of the testes. It may be a problem in the glands that coordinate the production of testosterone. Gaining weight can lead to estrogen excess in the body. This can interfere with testosterone production. There are foods that can cause testosterone levels to drop.
To understand the causes of low testosterone, you first need to understand how testosterone is produced in the body.
Glands Involved in Testosterone Production
There are many glands involved in the production of testosterone in the body. The adrenals produce some amounts of testosterone, in both men and women.
But most of the production involves the hypothalamus, pituitary, and gonads. The testes in men and ovaries in women are reproductive organs. They are known as gonads.
A problem with any of these can cause Low T. To understand the causes of low T, it is important to first learn how testosterone is produced.
The hypothalamus produces a hormone called gonadotrophic hormone (GnRH). This stimulates the pituitary to secrete luteinizing hormone (LH).
LH prompts the gonads to produce testosterone.
When testosterone levels go higher than required, the hypothalamus stops sending signals to the pituitary. LH production stops, which in turn, halts testosterone production. When testosterone levels drop, the whole mechanism starts up again.
Causes of Low Testosterone in Men
All these glands work with each other and keep the testosterone levels balanced. Therefore, any problem with the adrenals, the hypothalamus, pituitary or gonads can cause low testosterone. Low testosterone is also referred to as ‘hypogonadism’ although this is a blanket term for low sexual hormones.
Depending on the glands that caused the low T, hypogonadism can be divided into two types:
- Primary hypogonadism
- Secondary hypogonadism
The normal range of testosterone is 300-1000 ng/dL in men. Hypogonadism is identified when the levels are below 300ng/dL. Free testosterone optimal range is 250 to 350 pg/ml while deficiency is from 0 to 180pg/ml. Some doctors say it is best to keep the testosterone levels at more than 600 for optimal health
In men, the actual production of testosterone occurs in the testis. Low testosterone resulting from a problem with the testis is called Primary Hypogonadism. This may be genetic or acquired. Testosterone production by the testis can be negatively affected by factors such as:
- Injury or trauma of the testes
- Infection of the testis such as seen in mumps orchitis
- Metabolic disorders such as a hemochromatosis
- Cancer treatment such as radiation, chemotherapy, or surgery
Most adults with low testosterone suffer from secondary hypogonadism. This happens when the hypothalamus and the pituitary glands malfunction. In most cases of secondary hypogonadism, there is no problem with the testis.
Secondary hypogonadism may be caused by:
- Medications: Opioids and steroids can affect the function of the hypothalamus and cause low T
- Inflammatory diseases: Sarcoidosis (an inflammation disease) in the testicles can cause testosterone deficiency
- Pituitary tumor or dysfunction of the pituitary: A tumor in the pituitary gland can result in the lesser or greater production of the pituitary hormones. This can result in testosterone deficiency.
- Extreme weight loss: Testosterone is made from cholesterol that is derived from fat. Rapid weight loss or a very low-fat diet can therefore hamper testosterone production.
- Uncontrolled diabetes mellitus: Type 2 diabetes or diabetes mellitus and low testosterone are strongly related. Diabetics are more likely to have low T whereas people with low testosterone are more likely to develop diabetes. The primary cause of type 2 diabetes is insulin resistance.
- Age-related decline: The testosterone-producing Leydig cells start reducing after the age of 18. There are about 1,15,000 Leydig cells lost per year. There is not only a decline in their number but also in function and efficacy with rising age.
Secondary hypogonadism can usually be reversed by identifying and treating its root cause.
Estrogen is the primary sex hormone in females. Men also need small amounts of estrogen for various functions in their bodies. Estrogen, along with testosterone regulates sex drive, erectile function, and sperm production in men (x).
In both men and women, fat cells make estrogen (x). So, in overweight men, estrogen levels can go higher than needed. Too much estrogen in males can lead to undesirable symptoms such as gynecomastia and erectile dysfunctions.
Testosterone is the main source of estrogen in males. So the body down-regulates testosterone production to prevent more estrogen synthesis. Thus being overweight and having estrogen excess can lead to low T in men.
Causes of Low Testosterone in Women
Testosterone, along with estrogen, supports growth and reproduction in women.
In women aged 19 years and up, the normal levels of testosterone are between 8-60 ng/dL. Some studies keep the range from 15-70 ng/dL. Levels lower than this are considered low testosterone. Free testosterone optimal level is 8pg/ml and deficiency is from 0 to 5pg/ml
The factors that can cause low testosterone in women are:
- Early menopause: The onset of menopause causes the ovaries to stop producing testosterone. Even though the adrenal glands produce some amounts of testosterone, early menopause can lead to an imbalance in testosterone production. This causes a significant drop in testosterone levels.
- Oophorectomy: This is the surgical process by which one or both ovaries are removed. This is also known as “surgically removed menopause”. As the ovaries are the primary producer of testosterone, this is a major cause of low T in females.
- Oral estrogen therapy: One of the common side effects of oral estrogen therapy is low T. Estrogen supplementation can lead to an excess of estrogen in the body. This disturbs the delicate balance between testosterone and estrogen.
Foods That Cause Low Testosterone
Certain foods can cause low testosterone in both men and women.
1. Food in plastic packages (with BPA): This is mainly true for foods that are canned or come in plastic packages. They contain chemicals called bisphenol A (BPA) that sip into the food. BPA can reduce the levels of free testosterone and androstenedione (which is a precursor of testosterone) (x).
2. Trans Fat: Processed foods, frozen foods, and prepackaged meals that contain trans fats can also cause low T (x). Trans fats can impair the function of the testicles. This leads to low testosterone levels.
The Final Note
Low testosterone levels can lead to several problems in both men and women. They can be minor changes in the body or major problems including infertility.
The gonads produce testosterone while the signal comes from the pituitary and hypothalamus. Infection, inflammation, disease, tumor, medicines, or metabolic disorders that affect these glands can lead to low T.
Understanding the cause can help your doctor decide on the right course of action. This can very well reverse the problem in most cases.