Estrogen , Oestrogen; Types, Uses, Contra Indications, Side Effects, Interactions

Last updated: February 7, 2026Reviewed date: February 7, 2026Reading time: 4 min read

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Estrogen, oestrogen, is the primary female sex hormone. It is responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens in females that have estrogenic hormonal activity: estrone, estradiol, and estriol. The estrane steroid estradiol is the most potent and prevalent of these. Estrogens are a pharmaceutical preparation containing a mixture of water-soluble, conjugated estrogens derived wholly or in part from URINE of pregnant mares or synthetically from ESTRONE and EQUILIN. It...

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This article explains Types of Estrogen in simple medical language.
This article explains Overview of actions in simple medical language.

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Estrogen, oestrogen, is the primary female sex hormone. It is responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens in females that have estrogenic hormonal activity: estrone, estradiol, and estriol. The estrane steroid estradiol is the most potent and prevalent of these.

Estrogens are a pharmaceutical preparation containing a mixture of water-soluble, conjugated estrogens derived wholly or in part from URINE of pregnant mares or synthetically from ESTRONE and EQUILIN. It contains a sodium-salt mixture of estrone sulfate (52-62%) and equilin sulfate (22-30%) with a total of the two between 80-88%. Other concomitant conjugates include 17-alpha-dihydroequilin, 17-alpha-estradiol, and 17-beta-dihydroequilin. The potency of the preparation is expressed in terms of an equivalent quantity of sodium estrone sulfate.

Types of Estrogen

Estrogens agonists

Steroidal: Alfatradiol
Certain androgens/anabolic steroids (e.g., testosterone, testosterone esters, methyltestosterone, metandienone, nandrolone esters) (via estrogenic metabolites)
Certain progestins (e.g., norethisterone, noretynodrel, etynodiol diacetate, tibolone)
Clomestrone
Cloxestradiol acetate
Conjugated estrogens (+medroxyprogesterone acetate, +bazedoxifene)
Epiestriol
Epimestrol
Esterified estrogens (+methyltestosterone)
Estetrol^†
Estradiol
Estradiol esters (e.g., estradiol acetate, estradiol benzoate, estradiol cypionate, estradiol enanthate, estradiol undecylate, estradiol valerate, polyestradiol phosphate)
Estramustine phosphate
Estriol
- Emmenin
- ProgynonEstriol esters
Estrone
- Estrone sulfate
- Estropipate (piperazine estrone sulfate)
- Estrone esters
Ethinylestradiol
- Ethinylestradiol sulfonate
Hydroxyestrone diacetate
Mestranol
Methylestradiol
Moxestrol
Nilestriol
Prasterone (dehydroepiandrosterone; DHEA)
- Prasterone enanthate
- Prasterone sulfate
Promestriene
Quinestradol
Quinestrol

Nonsteroidal: Benzestrol
Bifluranol
Chlorotrianisene
- Dienestrol diacetateDienestrol
Diethylstilbestrol (stilbestrol)
Diethylstilbestrol esters/ethers
- Dimestrol (diethylstilbestrol dimethyl ether)
- Fosfestrol (diethylstilbestrol diphosphate)
- Mestilbol (diethylstilbestrol monomethyl ether)
Doisynoestrol (fenocycline)
Hexestrol
- Hexestrol esters
Methallenestril
Methestrol dipropionate (promethestrol dipropionate)
Paroxypropione
Quadrosilan
Triphenylbromoethylene
Triphenylchloroethylene
Zeranol

Overview of actions

Structural

Mediate formation of female secondary sex characteristics
Accelerate metabolism
Increase fat store
Stimulate endometrial growth
Increase uterine growth
Increase vaginal lubrication
Thicken the vaginal wall
Maintenance of vessel and skin
Reduce bone resorption, increase bone formation

Protein synthesis
- Increase hepatic production of binding proteins
Coagulation
- Increase circulating level of factors plasminogen
- Decrease antithrombin III
- Increase platelet adhesiveness
Lipid
- Increase HDL, triglyceride
- Decrease LDL, fat deposition
Fluid balance
- Salt (sodium) and water retention
- Increase cortisol, SHBG
Gastrointestinal tract
- Reduce bowel motility
- Increase cholesterol in bile
Melanin
- Increase pheomelanin, reduce eumelanin
Cancer
- Support hormone-sensitive breast cancers (see section below)
Lung function
- Promotes lung function by supporting alveoli (in rodents but probably in humans).
Uterus lining
- Estrogen together with progesterone promotes and maintains the uterus lining in preparation for implantation of fertilized egg and maintenance of uterus function during the gestation period, also upregulates oxytocin receptor in myometrium
Ovulation
- The surge in estrogen level induces the release of luteinizing hormone, which then triggers ovulation by releasing the egg from the Graafian follicle in the ovary.
Sexual behavior
- Promotes sexual receptivity in estrus, and induces lordosis behavior.In non-human mammals, it also induces estrus (in heat) prior to ovulation, which also induces lordosis behavior. Female non-human mammals are not sexually receptive without the estrogen surge, i.e., they have no mating desire when not in estrus.
- Regulates the stereotypical sexual receptivity behavior; this lordosis behavior is estrogen-dependent, which is regulated by the ventromedial nucleus of the hypothalamus.
- Sex drive is dependent on androgen levels only in the presence of estrogen, but without estrogen, free testosterone level actually decreases sexual desire (instead of increases sex drive), as demonstrated for those women who have hypoactive sexual desire disorder, and the sexual desire in these women can be restored by administration of estrogen (using oral contraceptive). In non-human mammals, mating desire is triggered by estrogen surge in estrus.

References

Estrogen , Oestrogen; Types, Uses, Contra Indications, Side Effects, Interactions

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Safe first steps

Avoid heavy lifting, sudden bending, and prolonged bed rest.
Use comfortable posture and gentle movement as tolerated.
Discuss physiotherapy, X-ray, or MRI only when clinically needed.

OTC medicine safety

For mild back pain, pain-relief medicine may be discussed with a doctor or pharmacist.
Avoid repeated painkiller use if you have kidney disease, stomach ulcer, uncontrolled blood pressure, or are taking blood thinners.

Avoid these mistakes

Do not start antibiotics without a proper medical decision.
Do not use steroid tablets or injections casually for quick relief.
Do not delay emergency care because of home remedies.

Get urgent help if

Back pain with leg weakness, numbness around private area, loss of urine/stool control, fever, cancer history, or major injury needs urgent care.

Medicine names, dose, and timing must be decided by a qualified clinician or pharmacist after checking age, pregnancy, allergy, other diseases, and current medicines.

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Write your symptoms, medicines already taken, test results, and questions before visiting a doctor. This note stays on your device unless you print or copy it.

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Tests to discuss with doctor

Basic vital signs: temperature, pulse, blood pressure, oxygen level if needed
Relevant blood, urine, imaging, or specialist tests only after clinical assessment

Questions to ask

What is the most likely cause of my symptoms?
Which warning signs mean I should go to emergency care?
Which tests are really needed now?
Which medicines are safe for my age, pregnancy status, allergy, kidney/liver/stomach condition, and current medicines?

Emergency warning signs such as chest pain, severe breathing difficulty, sudden weakness, confusion, severe dehydration, major injury, or loss of bladder/bowel control need urgent medical care. Do not wait for online information.

Go to emergency care if you notice:

New leg weakness, numbness around private area, or loss of bladder/bowel control
Back pain after major injury, fever, unexplained weight loss, cancer history, or severe night pain

Doctor / service to discuss: Orthopedic/spine specialist, physical medicine doctor, physiotherapist under guidance, or qualified clinician.

Step 1
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Step 2
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Step 3
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Step 4
Do only useful tests
Discuss neurological examination first. X-ray or MRI may be needed only when red flags, injury, nerve weakness, or persistent severe symptoms are present.
Step 5
Follow up and return early if worse
If symptoms worsen, new warning signs appear, or treatment is not helping, return for review quickly.

Rural patient practical tips

Take a written symptom diary and all previous prescriptions/test reports.
Do not hide medicines already taken, even herbal or over-the-counter medicines.
Ask which warning signs mean urgent referral to hospital.
Avoid forceful massage or bone-setting when there is weakness, injury, fever, or nerve symptoms.

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Frequently Asked Questions

Is this article a replacement for a doctor?

No. It is educational content only. Patients should consult a qualified clinician for diagnosis and treatment.

When should I seek urgent care?

Seek urgent care for severe symptoms, rapidly worsening condition, breathing difficulty, severe pain, neurological changes, or any emergency warning sign.

References

Add references, clinical guidelines, textbooks, journal articles, or trusted medical sources here. You can edit this area from the RX Article Professional Blocks panel.

Estrogen , Oestrogen; Types, Uses, Contra Indications, Side Effects, Interactions

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