Estrogen definition

Estrogen can be defined as any substance (natural or synthetic) that simulates natural hormonal effects.

What is Estrogen?

What is estrogen?Estrogen is the main female sex hormone responsible for the development and regulation of the female reproduction system as well as the female secondary characteristics. The ovary is the main site of estrogen production in women. They are released from the ovarian follicles and are secreted by the corpus luteum following the release of an egg from the follicle and the placenta.

Though, several other metabolites of estradiol elicit estrogenic hormonal activity, 17Bestradiol (steroid) is the most potent and common endogenous estrogen.

Synthetic estrogens are contained in some oral contraceptives or estrogen replacement therapy used for post-menopausal women and in hormone replacement therapy (for trans-menopausal women).

Estrogen circulation in both men and women is in the lower level compared to androgens and are synthesized in all vertebrates. Types of estrogen include endogenous estrogens, pharmaceutical and non-steroidal estrogens.


These are the naturally occurring estrogens. Estrone, estriol (the weakest and the most plentiful estrogen) and estradiol (strongest; 80 times more potent than estriol) are the three main naturally occurring estrogens in women. Estrone and estriol circulates predominantly during menopause and pregnancy respectively as regards serum estrogen levels.

In paraphrase, estradiol is the primary form of estrogen in the body in non-pregnant females (those between the menarche and menopause stages of life). However, pregnancy shifts this role to estriol whereas estrone becomes the most important estrogen (primary estrogen) during the menopause stage of a woman’s life.

Estrogen and PregnancyEstetrol is another type of estrogen also produced during pregnancy. Androgens (testosterone and androstenedione) are the biosynthetic precursors of all forms of estrogens. This reaction is catalyzed by an enzyme called aromatase.

Additionally, some estrone metabolites (l6-hydroxyestrone and 2-hydroxyestrone) are weak estrogens. These are usually synthetic products. Longer acting synthetic esters of estradiol (estradiol valerate, estradiol cypionate, estradiol benzoate) have clinical indications. A more potent synthetic analogue of estradiol (ethinyl estradiol) is widely used in hormonal contraceptives.

Primarin (an estrogenic drug) contains equilin and equilenin (the natural steroidal estrogens), It also contains estrone sulfate which is an inactive form of estrogen. Estrone sulfate becomes active when it is converted to estrone.


Diethylstilbestrol is in this group but it is no more used in medical practice. There exist some classes of natural and synthetic substances that are known to possess estrogenic activity. Xenoestrogens, phytoestrogens and mycoestrogens are the names given to synthetic substances, plant products and substances produced by fungi that have estrogenic activity respectively. They are not steroids.

Low estrogen symptoms

Despite the variation in causes, the symptoms of low estrogen occur both in menopause (aged) women and in younger women. Causes may include menopause, genetic diseases, thyroid problems, anorexia, chemotherapy, hysterectomies and/or radiation therapy. Other causes include excessive exercise, eating disorders and insufficient body fat.

In older women, one of the major symptoms of low estrogen is sleep disturbances. This can cause extreme fatigue (another low estrogen symptom) in the day time. The subject(s) in question may as well experience night sweats, weight gain, cold sweats and palpitations. Other signs/symptoms include:

  • Symptoms of lack of estrogenHeadaches
  • Arthralgia (joint pain)
  • Bladder infections
  • Vaginal Infections
  • Decreased sex drive
  • Depression
  • Dry skin
  • Dry Vagina

In younger women, the most common symptoms experienced when estrogen level is low are lack of menstruation and delayed development. In younger women (below the age of 40), low estrogen levels can trigger early menopause which will result in hot flashes as well as night sweats. In this condition, the subject experience fatigue (a common complaint).

Similar symptoms can be seen in both groups such as forgetfulness, absence of sexual desire, insomnia, and pain during sexual intercourse. There could be irregularities in menstruation or a complete lack of menstruation, mood changes (crying, feeling depressed and irritability).

Additionally, a low level of estrogen can precipitate bone loss (osteoporosis) and an inability to conceive. In order to investigate and know when a subject’s estrogen level is low, a doctor will have to determine which type of blood or urine tests to carry out for that. Examples are Follicle Stimulating Hormone (FSH) test and chromosome testing.

The treatment for low estrogen and the symptoms of low estrogen is based on the underlying cause. That is, the cause determines the specific treatment plan to initiate. Treatment options may include lifestyle changes. That is, healthy dieting, lower carbohydrate intake and a higher consumption of fibers. Embarking on moderate exercises can also boost estrogen levels.

Hormone replacement therapy is a good alternative in many women. This is a form of estrogen supplementation and the hormones used are usually synthetic.

Estrogen dominance

A condition in which the body estrogen level is surplus could be referred to as estrogen dominance. In a clearer term, estrogen dominance is a common symptom of menopause. It can also be described as a condition where there is deficient, normal or excessive estrogen in the body with little or no progesterone to balance its effects in the body.

The roles and effects of estrogen

  • Estrogen and the menstrual cycleEnhances women’s physical and psychological wellbeing;
  • Transmits messages between cells;
  • Promotes the formation of female sexual characteristics;
  • Plays reproductive functions;
  • Accelerates metabolism;
  • Regulates menstrual cycle;
  • Promotes uterine growth;
  • Preserves the bone density
  • Decreases the risk of heart disease;
  • Preserves skin tension.

Estrogen has effects in the:

  • Brain – maintains body temperature and delay memory loss;
  • Breast – prepares the glands for milk production;
  • Heart and liver – Regulates liver functions;
  • Ovary – Stimulates the maturation of the uterus;
  • Bone – Preserves bone density;
  • Vagina – Maintains the vaginal lining.

High estrogen levels can cause atherosclerosis, headache, migraine, arthritis, vaginal infection, depression, panic, low self esteem, allergies, stroke, gall bladder disease, osteoporosis and thyroid dysfunction.

Estrogen is a very important hormone in the body of which if an imbalance occurs can lead to serious negative effects. So, a proper balance of this hormone should be monitored and maintained. In severe condition, subjects involved should seek the consent of a doctor.