Testosterone; Uses, Dosage, Side Effects, Interactions

Last updated: February 7, 2026Reviewed date: February 7, 2026Reading time: 6 min read
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Testosterone is a synthetic form of the endogenous androgenic steroid testosterone. In vivo, testosterone is irreversibly converted to dihydrotestosterone (DHT) in target tissues by the enzyme 5-alpha reductase. Testosterone or DHT ligand-androgen receptor complexes act as transcription factor complexes, stimulating the expression of various responsive genes. DHT binds with higher affinity to androgen...

For severe symptoms, danger signs, pregnancy, child illness, or sudden worsening, seek urgent medical care.

বাংলা রোগী নোট এখনো যোগ করা হয়নি। পোস্ট এডিটরে “RX Bangla Patient Mode” বক্স থেকে সহজ বাংলা সারাংশ যোগ করুন।

এই তথ্য শিক্ষা ও সচেতনতার জন্য। এটি ডাক্তারি পরীক্ষা, রোগ নির্ণয় বা প্রেসক্রিপশনের বিকল্প নয়।

Article Summary

Testosterone is a synthetic form of the endogenous androgenic steroid testosterone. In vivo, testosterone is irreversibly converted to dihydrotestosterone (DHT) in target tissues by the enzyme 5-alpha reductase. Testosterone or DHT ligand-androgen receptor complexes act as transcription factor complexes, stimulating the expression of various responsive genes. DHT binds with higher affinity to androgen receptors than testosterone, activating gene expression more efficiently. In addition, testosterone is irreversibly converted to estradiol by the enzyme complex aromatase, particularly in the liver...

Key Takeaways

  • This article explains Mechanism of Action of Testosterone in simple medical language.
  • This article explains Indications of Testosterone in simple medical language.
  • This article explains Contra-Indications of Testosterone in simple medical language.
  • This article explains Dosages of Testosterone in simple medical language.
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Emergency safety firstUrgent warning signs are highlighted below.

Seek urgent medical care if you notice

These warning signs are general safety guidance. Local emergency numbers and clinical judgment should always come first.

  • Severe symptoms, breathing difficulty, fainting, confusion, or rapidly worsening illness.
  • New weakness, severe pain, high fever, or symptoms after a serious injury.
  • Any symptom that feels urgent, unusual, or unsafe for the patient.
1

Emergency now

Use emergency care for severe, sudden, rapidly worsening, or life-threatening symptoms.

2

See a doctor

Book a professional medical evaluation if symptoms persist, worsen, recur often, affect daily activities, or occur in a high-risk patient.

3

Learn safely

Use this article to understand possible causes, tests, treatment options, prevention, and questions to ask your clinician.

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Definition

Testosterone is a synthetic form of the endogenous androgenic steroid testosterone. In vivo, testosterone is irreversibly converted to dihydrotestosterone (DHT) in target tissues by the enzyme 5-alpha reductase. Testosterone or DHT ligand-androgen receptor complexes act as transcription factor complexes, stimulating the expression of various responsive genes. DHT binds with higher affinity to androgen receptors than testosterone, activating gene expression more efficiently. In addition, testosterone is irreversibly converted to estradiol by the enzyme complex aromatase, particularly in the liver and adipose tissue. Testosterone and DHT promote the development and maintenance of male sex characteristics related to the internal and external genitalia, skeletal muscle, and hair follicles; estradiol promotes epiphyseal maturation and bone mineralization. Due to rapid metabolism by the liver, therapeutic testosterone is generally administered as an ester derivative.

Testosterone undecanoate is an androgen and anabolic steroid (AAS) medication which is used mainly in the treatment of low testosterone levels in men. It is also used in hormone therapy for transgender men. It is taken by mouth two to three times per day with food or given by injection into the muscle once every 12 weeks or so. Testosterone undecanoate is an esterified form of testosterone which is attached to a long fatty acid chain. The lack of a methylated site on the carbon 17 eliminates the adverse effects on the liver found in other testosterone analogs. It is currently getting further developed to be an alternative to testosterone enanthate or testosterone cypionate by Paddock labs, and this new injectable has an FDA status of tentative approval.

Mechanism of Action of Testosterone

The effects of testosterone in humans and other vertebrates occur by way of two primary mechanisms: by activation of the androgen receptor (directly or as DHT), and by conversion to estradiol and activation of specific estrogen receptors. Free testosterone (T) is transported into the cytoplasm of target tissue cells, where it can bind to the androgen receptor, or can be reduced to 5-alpha-dihydrotestosterone (DHT) by the cytoplasmic enzyme 5-alpha-reductase. The T-receptor complex undergoes a structural change that allows it to move into the cell nucleus and bind directly to specific nucleotide sequences of the chromosomal DNA. The areas of binding are called hormone response elements (HREs), and influence transcriptional activity of certain genes, producing androgen effects.

Indications of Testosterone

  • Hypogonadism, male
  • Gender dysphoria
  • Delayed puberty, male
  • Klinefelter syndrome
  • Breast cancer, palliative
  • Postpartum breast pain
  • Hypergonadotropic hypogonadism
  • Hypogonadotrophic hypogonadism
  • Deficient activity of the testis
  • Rare X chromosome abnormality – klinefelter syndrome
  • Deficient activity of testes or ovaries due to chemotherapy
  • Surgical removal of both testicles
  • Primary testicular failure due to torsion of both testes
  • Undescended testicle
  • Pituitary hormone deficiency
  • Absence of testicles
  • deficiency of gonadotropin releasing factor
  • Primary testicular Failure due to infection, or irritation, often causing pain, swelling, heat, or redness. সহজ বাংলা: শরীরের প্রদাহ; ব্যথা, ফোলা বা লালভাব হতে পারে।" data-rx-term="inflammation" data-rx-definition="Inflammation is the body’s response to injury, infection, or irritation, often causing pain, swelling, heat, or redness. সহজ বাংলা: শরীরের প্রদাহ; ব্যথা, ফোলা বা লালভাব হতে পারে।">inflammation of Testis
  • Deficiency of a substance that promotes masculinization
  • Male with unusually late sexual maturity

Contra-Indications of Testosterone

  • Cancer of the prostate gland
  • Polycythemia vera
  • Increased calcium in the blood from cancer
  • Diabetes
  • High cholesterol
  • Overweight
  • High blood pressure
  • Heart attack
  • Lung embolism
  • Chronic heart failure
  • Stroke
  • Blood clot formation in veins
  • Chronic lung disease
  • Liver Problems
  • kidney disease with reduction in kidney function
  • Enlarged Prostate
  • Enlarged Breasts
  • Temporarily stops breathing while sleeping
  • Visible water retention
  • Pregnancy
  • A Mother who is producing milk and breastfeeding
  • Abnormal increase in red blood cells

Dosages of Testosterone

Hypogonadism – Male

IM INJECTION

  • Testosterone Undecanoate: 750 mg (3 mL) IM injection followed by 750 mg (3 mL) injected after 4 weeks, then 750 mg (3 mL) every 10 weeks thereafter
  • Testosterone Enanthate and Cypionate: 50 to 400 mg IM injection every 2 to 4 weeks

IMPLANT

  • 2 to 6 pellets (75 mg each) implanted subcutaneously every 3 to 6 months.
  • The number of pellets to be implanted depends upon the minimum daily requirements of testosterone propionate administered parenterally. Thus, implant two 75 mg pellets for each 25 mg testosterone propionate required weekly.
  • Mucoadhesive Oral Patch: Apply a 30 mg patch to the gum region twice a day; morning and evening (about 12 hours apart).

Breast Cancer-Palliative

Testosterone Enanthate

  • 200 to 400 mg IM injection every 2 to 4 weeks

Delayed Puberty – Male

IM INJECTION

  • Testosterone Enanthate: 50 to 200 mg every 2 to 4 weeks for 4 to 6 months

IMPLANT

  • 2 pellets (each pellet contain 75 mg of testosterone) implanted subcutaneously every 3 to 6 months
  • Duration of therapy: 4 to 6 months

Side Effects of Testosterone

The most common

More common

Less common

  • Abnormal dreams
  • change in sense of taste
  • congestion
  • discouragement, feeling sad, or empty
  • Acting on dangerous impulses
  • Aggressive or violent behavior
  • Thoughts about suicide or dying
  • New or worse depression
  • New or worse anxiety or panic attacks
  • Agitation, restlessness, anger, or irritability
  • Trouble sleeping
  • An increase in activity or talking more than normal

Drug Interactions of Testosterone

Testosterone undecanoate  may interact with following drugs, supplements & may change the efficacy of the drug

Pregnancy & Lactation of Testosterone

Pregnancy

This medication is not recommended for pregnant women.

Lactation

This medication is not recommended for breastfeeding women. The safety and effectiveness of using this medication have not been established for children. This medication is not recommended for children under 18 years of age.

References

Testosterone; Uses, Dosage, Side Effects, Interactions

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A simple rural-patient checklist to help you explain symptoms clearly, ask better questions, and avoid unsafe self-treatment.

Safety note: This is not a prescription or diagnosis. For severe symptoms, pregnancy danger signs, children with serious illness, chest pain, breathing difficulty, stroke-like weakness, or major injury, seek urgent care.

Which doctor may help?

Start with a registered doctor or the nearest qualified health center.

What to tell the doctor

  • Write when the problem started and how it changed.
  • Bring old prescriptions, investigation reports, and current medicines.
  • Write allergies, pregnancy status, diabetes, kidney/liver disease, and major past illnesses.
  • Bring one family member if the patient is weak, elderly, confused, or a child.

Questions to ask

  • What is the most likely cause of my symptoms?
  • Which danger signs mean I should go to hospital quickly?
  • Which tests are necessary now, and which can wait?
  • How should I take medicines safely and what side effects should I watch for?
  • When should I come for follow-up?

Tests to discuss

  • Vital signs: temperature, pulse, blood pressure, oxygen saturation
  • Basic physical examination by a clinician
  • CBC, urine test, blood sugar, or imaging only when clinically needed

Avoid these mistakes

  • Do not use antibiotics, steroid tablets/injections, or strong painkillers without proper medical advice.
  • Do not hide pregnancy, kidney disease, ulcer, allergy, or blood thinner use.
  • Do not delay emergency care when danger signs are present.

Medicine safety and first-aid guide

This section is for patient education only. It does not replace a doctor, pharmacist, or emergency care.

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.

For rural patients and family caregivers

Patient health record and symptom diary

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.

Doctor to discuss: Orthopedic / spine specialist, physical medicine doctor, or qualified clinician
Tests to discuss with doctor
  • Neurological examination for leg power, sensation, reflexes, and straight leg raise
  • X-ray only if injury, deformity, long-lasting pain, or doctor suspects bone problem
  • MRI discussion if severe nerve symptoms, weakness, bladder/bowel problem, or persistent symptoms
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?
  • Is physiotherapy, posture correction, or activity modification needed?

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.

Safe pathway to proper treatment

Care roadmap for: Testosterone; Uses, Dosage, Side Effects, Interactions

Use this simple roadmap to understand the next safe steps. It is educational and does not replace examination by a doctor.

Go to emergency care if you notice:
  • Severe or rapidly worsening symptoms
  • Breathing difficulty, chest pain, fainting, confusion, severe weakness, major injury, or severe dehydration
Doctor / service to discuss: Qualified healthcare provider; specialist depends on symptoms and examination.
  1. Step 1

    Check danger signs first

    If danger signs are present, seek emergency care and do not wait for online information.

  2. Step 2

    Record the symptom story

    Write when symptoms started, severity, medicines already taken, allergies, pregnancy status, and test results.

  3. Step 3

    Visit a qualified clinician

    A doctor, nurse, or qualified healthcare provider can examine you and decide which tests or treatment are needed.

  4. Step 4

    Do only useful tests

    Do tests after clinical assessment. Avoid unnecessary tests, random antibiotics, or repeated medicines without diagnosis.

  5. 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.

This roadmap is for education. A real diagnosis and treatment plan requires history, examination, and clinical judgment.

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Write your symptom story. A health professional or site editor can review it before any answer is prepared. This box is not for emergency care.

Emergency first: Severe chest pain, breathing trouble, unconsciousness, stroke signs, severe injury, heavy bleeding, or rapidly worsening symptoms need urgent local medical care now.

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

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