Hormones are crucial to a woman's reproductive health. The main hormones affecting the menstrual cycle and fertility are produced by glands in the brain and by the ovaries. Those hormones regulate menstruation, fertility and sex drive (libido) – any one of which can be adversely affected if the production of these hormones goes out of balance. As most women approach mid-life, hormonal changes gradually cause reproductive organs to shut down eventually leading to menopause.
Estradiol (E2) is the major estrogen and is recognised for producing the majority of the functions of estrogen in the body. It is critical for the development of female reproductive organs, for producing female secondary sexual characteristics and during the menstrual cycle and, with progesterone, prepares the endometrium for implantation. It helps vaginal lubrication, reduces urinary tract infections and increases sexual desire. It is also important for brain health, enhancing memory and mood. E2 is interconvertible with E1; E2 to E1 conversion being favoured.
Estrone (E1) is produced from the aromatisation of androstenedione and the reduction of E2 to E1. It has considerable estrogenic activity although it is less potent than E2.
Estriol (E3) is a metabolite of E1 and E2. It is a weaker estrogen which is capable of exerting either antagonistic or agonistic effects depending on dosage, or whether it is given alone or in conjunction with a stronger estrogen such as E2. It has been shown to be clinically effective for the treatment of menopause-related symptoms such as hot flashes, insomnia and poor memory. In addition, postmenopausal conditions of vaginal atrophy with accompanying dryness, vaginal infections and dyspareunia; and urinary tract changes resulting in recurrent UTIs, urgency, incontinence and frequent urination are helped considerably with E3.
Estradiol (E2) is about 10 times as potent as E1 and about 80 times as potent as E3 in its estrogenic effect. Except during the early follicular phase of the menstrual cycle, its serum levels are somewhat higher than that of E1 during the reproductive years of females. Thus it is the predominant estrogen during reproductive years both in terms of serum levels and estrogenic activity. During menopause E1 is the predominant circulating estrogen and during pregnancy E3 is the predominant circulating estrogen in terms of serum levels.
- Hot flushes
- Irregular menstruation
- Mood changes
- Vaginal dryness
- Bone loss
- Dry skin
- Low libido