Testosterone
Testosterone enanthate, Testosterone cypionate, Testosterone propionate, Testosterone undecanoate, Test E, Test C, Test Cyp, Test P
Forms: Esters: enanthate, cypionate, propionate, phenylpropionate, isocaproate, decanoate, undecanoate; blends such as Sustanon. The ester changes how long it acts, not the hormone itself. Medical forms also include gels, patches, a nasal gel, implanted pellets and oral undecanoate capsules; gel can pass to a partner or child through skin contact.
Injectable steroidsControlled substanceWADA S1.1 · prohibitedEvidence: approved medicine
The main male sex hormone and the base of most steroid stacks. Injectable esters differ only in how long they act; part converts to estradiol and DHT, which shapes both effects and side effects.
Legal status: Prescription medicine for hypogonadism; controlled as an anabolic steroid in many countries (US Schedule III, UK Class C); rules vary by country.
What it gives
What people use it for and what the sources report. Strength is a general category from the literature: mild, clear or strong.
Purpose
Athletes use it for muscle mass, strength and recovery, usually as the base of a stack. Medically it treats confirmed male hypogonadism, where the aim is normal levels rather than higher ones.
What people seek and what studies show
Muscle and strength effects are well studied: in a randomized trial a high dose enlarged muscles and raised strength even without training, more with it; gains and side effects rise with dose. In an observational study of men using it on their own, fat-free mass rose about 4.4 kg, but only about 1.2 kg remained three months after stopping. In healthy men high levels raised sexual interest but not sexual activity.
Effects
Evidence: Approved medicine — studied in people for its medical use
Sought effects by goal (as reported)
Mass
Sought for: muscle growth, strength, recovery
Cutting
Sought for: keeping muscle in a deficit
Recomposition
Sought for: muscle growth, keeping muscle in a deficit
Strength
Sought for: strength, recovery, muscle growth
Works against it: tendon / ligament injury risk
Endurance
Sought for: recovery
Works against it: fast heart rate / arrhythmia
Recovery & healing
Sought for: recovery
Health
Sought for: well-being & libido
Works against it: worse cholesterol (HDL↓ LDL↑), higher blood pressure
Possible side effects
Possible does not mean certain: whether they appear depends on dose, duration, individual response and monitoring. Below — what to watch for and how to notice it early.
19 possible side effects
level · how often it is reportedElevated
Suppression of natural testosterone & fertility
commonSuppresses natural testosterone and sperm output. Testosterone usually recovers within months and sperm within about a year; 1 in 10 still had low testosterone at one year, more after long use.
How to notice: Lower libido and energy, smaller testicles; low natural testosterone on tests after stopping.
In women: Menstrual changes or missed periods, lower libido and energy; reduced fertility.
Elevated
Thick blood (hematocrit) / clot risk
commonRaises red-cell mass in a dose-dependent way. On therapy, a hematocrit above 52% was linked to more major cardiovascular events and clots. A blood count shows it before symptoms do.
How to notice: Often silent; sometimes headaches, flushed face, itch after a hot shower.
Elevated
Black-market quality risk (fakes, contamination)
commonMost testosterone used in sport comes from underground labs: contents often differ from the label, and bacteria have been found in some black-market vials, which can cause abscesses.
How to notice: Unexpected effects, pain or infection, a stronger or weaker effect than expected.
Elevated
Heart strain / heart-muscle thickening
possibleA few months of use thickened the heart wall and slightly lowered pumping, recovering within a year off; after years of use, weaker pumping and coronary plaque are more common and partly persist.
How to notice: Shortness of breath on effort, lower endurance, palpitations.
Moderate
High estrogen (water, gyno risk)
commonPart converts to estradiol, more at higher doses and higher body fat. Nipple tenderness and water retention are typical signs; a sensitive estradiol test confirms it.
How to notice: Puffiness, sensitive or itchy nipples, mood swings, water weight.
Moderate
Gynecomastia
commonDeveloped in about 1 in 5 men in a prospective study of real-world use. Early tenderness can settle, but established gland tissue usually needs surgery; early changes deserve a doctor's look.
How to notice: A tender lump or swelling under the nipple.
Moderate
Higher blood pressure
commonRaised blood pressure by about 7/3 mmHg on average in real-world use, reversing after stopping; all testosterone products have carried an FDA warning since 2025. Home readings show the trend.
How to notice: Often silent; sometimes headaches, flushing, nosebleeds — a home monitor shows it.
Moderate
Worse cholesterol (HDL↓ LDL↑)
commonLowers HDL and raises LDL and ApoB, more at higher doses and in stacks; values usually return to baseline within months of stopping. The changes are silent — only a lipid panel shows them.
How to notice: No symptoms — only visible on a lipid panel.
Moderate
Fast heart rate / arrhythmia
possibleIn the TRAVERSE trial even replacement doses slightly raised atrial fibrillation; AAS users have about twice the arrhythmia rate. Palpitations need an ECG.
How to notice: Racing heart, skipped beats, shaky hands.
Moderate
Androgenic hair loss
possibleConverted to DHT in skin, it can speed up hair loss in men with a genetic tendency; lost hair may not grow back.
How to notice: More hair in the shower, thinning at the temples or crown.
Moderate
Prostate growth / PSA rise
possibleDHT stimulates prostate growth and can raise PSA; most relevant after 40 or with urinary symptoms. A PSA test tracks it.
How to notice: More frequent urination or a weak stream, especially at night.
Moderate
Irritability, aggression, mood swings
possibleIn a placebo-controlled trial of a high dose most men changed little, but about 1 in 6 became hypomanic, mostly mildly. Irritability that others notice is a warning sign.
How to notice: Short temper, irritability, conflicts with others.
Moderate
Low mood, depression, lethargy
possibleAfter stopping, while natural testosterone recovers, low libido and fatigue are common (over half reported low libido in one study) and low mood is possible; a doctor can help.
How to notice: Flat mood, low motivation, tiredness.
Moderate
Tendon / ligament injury risk
possibleLong-term AAS users had about nine times more tendon ruptures than non-using lifters, mostly in the upper body; a quarter were preceded by local pain.
How to notice: Pain at tendon attachments under heavy load.
Moderate
Kidney strain
rareLong-term heavy AAS use has been linked to protein in urine and kidney scarring (FSGS) in bodybuilders, often improving after stopping. Cystatin C and a urine test help reveal it.
How to notice: Usually silent; foamy urine or swelling in later stages.
MenLow
WomenHigh
Virilization in women (often irreversible)
commonIn women: deeper voice, facial and body hair, clitoral enlargement and menstrual changes; voice and clitoral changes are often permanent.
How to notice: Hoarse or deeper voice, new facial or body hair, menstrual changes, clitoral enlargement.
Low
Water retention / bloating
commonReported by over half of men in a prospective study of real-world use; usually mild, from estrogen and sodium retention, and it can push blood pressure up.
How to notice: Puffy face and ankles, softer look, quick weight jumps.
Low
Acne, oily skin
commonAcne appeared in about a quarter of men in a prospective study, and oily skin is common; severe or scarring acne needs a dermatologist.
How to notice: Oily skin, spots on back, shoulders and face.
Low
Injection pain, infection, oil cough
commonSoreness after injection is common. Redness, heat, swelling or fever suggest infection and need a doctor. Undecanoate can rarely cause a coughing reaction from oil microembolism in the lungs.
How to notice: Soreness, lumps; a short coughing fit right after an injection.
What the levels mean
Lowbackground — just be aware
Moderatewatch for signs
Elevatedneeds regular control
Highcritical — can be life-threatening or permanent
Level: general category from the literature, not your personal risk
How often
- common
- reported often
- possible
- reported in some people
- rare
- reported occasionally
How to lower the risks
For 16 of 19 possible side effects there are specific ways to lower the chance: everyday measures, supplements and options a doctor may consider. For the rest — general advice. No measure removes a risk completely. Prescription medicines are listed only for a doctor to decide on, after tests — they have side effects of their own.
ElevatedSuppression of natural testosterone & fertility
Check hormones before and after; if they stay low, see an endocrinologist.
Measure
Only if a doctor prescribes
How each option helps (6)
- Regular blood tests — LH, FSH and testosterone show how deep suppression is and whether natural production has recovered afterwards.
- Working with a doctor — Assesses how deep suppression is and guides recovery afterwards, including fertility testing.
- Clomiphene — A doctor may consider it after stopping, guided by hormone tests; recovery after long use can still take months. Risks: vision changes, mood swings, rare clots. Has side effects of its own.
- Human chorionic gonadotropin (hCG) — A doctor may consider it to preserve fertility (in men it keeps the testes working); it does not restart the pituitary, so natural LH still has to recover. Risks: higher estradiol, gynecomastia. Has side effects of its own.
- Tamoxifen — A doctor may consider it after steroids are stopped, guided by hormone tests; it has not been tested for this after steroid use. Risks: blood clots, vision changes. Has side effects of its own. Not offered to women: in the women’s view it adds to a risk this substance already carries.
- Follicle-stimulating hormone (follitropins, menotropins) — A fertility doctor may consider adding it to hCG when semen tests and FSH stay low; it does not restart the pituitary. Risks: gynecomastia, acne. Has side effects of its own.
ElevatedThick blood (hematocrit) / clot risk
Check the blood count regularly; if hematocrit stays high, a doctor decides — usually stopping or reducing the cause, sometimes therapeutic phlebotomy, never blood-bank donation. Avoid dehydration: it thickens the blood further.
Measure
How each option helps (3)
- Regular blood tests — A blood count shows hematocrit and hemoglobin climbing toward the range where clot and stroke risk rises.
- Therapeutic phlebotomy prescribed by a doctor — Only on a doctor's decision, never at a blood bank. Lowers hematocrit quickly but temporarily; repeated sessions drain iron, and a lower clot risk is unproven.
- Working with a doctor — Manages thick blood by changing what you use or, if justified, by therapeutic phlebotomy.
ElevatedBlack-market quality risk (fakes, contamination)
Products obtained without a prescription are often fake, mislabeled or non-sterile, and there is no way to check at home. For legal supplements, look for third-party testing (Informed Sport, NSF).
ElevatedHeart strain / heart-muscle thickening
Regular cardio, blood pressure control, an echo as a baseline and then yearly.
Measure
Only if a doctor prescribes
How each option helps (9)
- Heart screening: ECG and echocardiogram — Echocardiography shows wall thickening and reduced pumping early, while stopping AAS and treating BP can still help.
- Working with a doctor — Orders ECG and echocardiography and treats early heart changes.
- Home blood-pressure monitoring — Keeping BP controlled is one of the main ways to limit heart-wall thickening.
- Regular cardio training — Supports heart and vessel function, but does not reverse steroid-related heart thickening or weakening.
- ACE inhibitors (ramipril, perindopril, lisinopril) — Standard treatment for a weak heart (heart failure), and shrinks a thickened heart wall about as well as other BP drugs. Not studied in steroid users; the steroid risk remains. Has side effects of its own.
- Bisoprolol — In heart failure with weak pumping it lowered deaths in trials; doctors add it to standard therapy. Not studied in steroid users; the steroid risk to the heart remains. Has side effects of its own.
- Carvedilol — A doctor may add it when tests show weak heart pumping; in heart failure it lowered deaths. Not studied in steroid users, and it does not undo steroid damage. Has side effects of its own.
- Losartan / valsartan (angiotensin receptor blockers) — In high blood pressure, sartans shrink a thickened heart wall at least as well as other BP drugs. Not studied in steroid users; the steroid risk to the heart remains. Has side effects of its own.
- Telmisartan — In high blood pressure, ARBs shrink a thickened heart wall at least as well as other BP drugs. Not studied in steroid users; the steroid risk to the heart remains. Has side effects of its own.
ModerateHigh estrogen (water, gyno risk)
Check estradiol by blood test before acting on symptoms; keep salt and body fat in check.
Measure
How each option helps (2)
- Regular blood tests — A sensitive estradiol test shows whether water retention or nipple tenderness really comes from high estrogen.
- Working with a doctor — Prescription estrogen control is safer when adjusted by lab results than by guesswork.
ModerateGynecomastia
React early: see a doctor at the first lump, check estradiol and prolactin.
Measure
How each option helps (1)
- Working with a doctor — Early assessment of breast-tissue growth allows treatment before the change becomes permanent.
ModerateHigher blood pressure
Less salt, regular cardio, good sleep; home readings; a doctor if it stays high.
Measure
Supplement or OTC product
How each option helps (8)
- Home blood-pressure monitoring — Seated, rested readings on several days show your true BP; persistently high values are a signal to see a doctor.
- Regular cardio training — Regular aerobic training lowers resting BP by a few mmHg, more in people with high BP.
- Working with a doctor — Diagnoses persistent hypertension and prescribes treatment when needed.
- Avoiding alcohol and other liver stressors — Regular drinking raises blood pressure; cutting it out lowers it.
- Coenzyme Q10 — Inconsistent: some analyses show a small systolic drop in cardiometabolic disease, but a Cochrane review found no clinically meaningful effect.
- Magnesium — Meta-analysis of trials: about 2 mmHg lower systolic pressure on average.
- Omega-3 (fish oil, EPA/DHA) — Small drop of a few mmHg, mainly in people with untreated high blood pressure.
- Taurine — Meta-analysis of 20 small trials: about 4 mmHg lower systolic pressure on average.
ModerateWorse cholesterol (HDL↓ LDL↑)
Avoid combining several oral steroids; regular cardio, soluble fiber (psyllium), less saturated fat and alcohol; if LDL/ApoB stay high, a doctor may consider a statin. Omega-3 only lowers triglycerides.
Measure
Supplement or OTC product
How each option helps (8)
- Regular blood tests — A lipid panel with ApoB shows how far HDL has dropped and LDL risen — changes you cannot feel.
- Working with a doctor — Interprets lipids and ApoB and decides whether a statin or other therapy is warranted.
- Avoiding alcohol and other liver stressors — Alcohol raises triglycerides; its small HDL bump does not lower heart risk.
- Regular cardio training — Raises HDL a little and lowers triglycerides; it cannot offset a steroid-driven fall in HDL on its own.
- Berberine — Placebo-controlled meta-analysis: LDL about 0.5 and triglycerides about 0.4 mmol/L lower; HDL unchanged. Trials are mostly small; no statin substitute.
- Citrus bergamot — Pooled small trials show lower LDL and triglycerides, but certainty is low to very low; it is no replacement for statins.
- Omega-3 (fish oil, EPA/DHA) — Clearly lowers triglycerides but does not fix the steroid HDL drop, the main lipid harm; DHA-containing oils may even raise LDL slightly.
- Psyllium husk fiber — Lowers LDL by about 0.2–0.3 mmol/L (roughly 5–10%), also on top of doctor-prescribed statins; no effect on HDL.
ModerateFast heart rate / arrhythmia
Limit caffeine and other stimulants; with palpitations, stop the suspected drug and get an ECG. Don't add potassium on your own (supplements, Asparkam/Panangin, salt substitutes): it is dangerous with spironolactone, ARBs/ACE inhibitors or kidney problems; a blood test shows the level.
Measure
How each option helps (1)
- Heart screening: ECG and echocardiogram — An ECG reveals arrhythmias, conduction problems and QT changes — important with stimulants, clenbuterol, thyroid hormone or diuretics.
ModerateAndrogenic hair loss
Ketoconazole shampoo, minoxidil, a dermatologist early if you are prone to it.
Supplement or OTC product
How each option helps (1)
- Minoxidil (topical) — Slows thinning and regrows some hair; scalp itching and early temporary shedding are common, unwanted facial hair possible. Gains fade once stopped.
ModerateProstate growth / PSA rise
PSA as a baseline, especially after 40; a urologist if urination changes.
Measure
How each option helps (1)
- Regular blood tests — PSA tracks prostate changes on androgens — most relevant after 40 or with urinary symptoms.
ModerateIrritability, aggression, mood swings
Good sleep, fewer stressors, tell someone close to you what to watch for.
Measure
How each option helps (2)
- Avoiding alcohol and other liver stressors — Alcohol and other drugs on top of steroids explain much of the link between steroid use and violence.
- Sleep hygiene — Enough sleep lowers irritability and improves impulse control.
ModerateLow mood, depression, lethargy
Keep routine and social contact; talk to a specialist if low mood persists.
Measure
How each option helps (2)
- Working with a doctor — Mood problems, especially after stopping steroids, are treatable; a doctor can refer you to mental-health care.
- Sleep hygiene — Good sleep supports mood, especially in the low-hormone phase after stopping steroids.
ModerateTendon / ligament injury risk
Progress weights gradually — strength rises faster than tendons adapt.
ModerateKidney strain
Drink enough water, control blood pressure, avoid regular painkillers (NSAIDs).
Measure
How each option helps (3)
- Fluid & electrolyte management — Good hydration eases kidney stress from heavy training and heat; dehydration plus NSAIDs is a classic cause of acute kidney injury.
- Regular blood tests — Creatinine reads high in muscular people and with creatine; cystatin C and a urine test give a truer picture of the kidneys.
- Working with a doctor — Investigates protein in the urine or falling kidney function and can start treatment that slows kidney damage.
MenLow
WomenHigh
Stop at the first voice change and see a doctor — early stopping matters.
Measure
How each option helps (1)
- Working with a doctor — Steroid labels say to stop at the first mild signs (hoarse voice, facial hair, clitoral growth) to prevent permanent change; checks catch them early but do not make use safe.
Low-level side effects
Water retention
Steady salt and water intake, cardio, check estradiol.
Measure
How each option helps (1)
- Working with a doctor — Tells harmless water retention from swelling due to heart, kidney or liver trouble; steroid labels warn that edema can come with heart failure.
Acne
Gentle skin care, cleansing after training, a dermatologist if it spreads.
Supplement or OTC product
How each option helps (3)
- Adapalene — Reduces spots in many users. Redness, scaling, dryness and stinging are common early and usually ease; acne may look worse at first. Rarely, allergic swelling.
- Benzoyl peroxide — A first-line acne option. Dryness, redness and peeling are common at first; it bleaches hair and fabric; rarely, serious allergic reactions. Severe steroid acne needs a dermatologist.
- Zinc — Trials show a modest drop in inflamed spots, weaker than antibiotics; steroid acne is driven by androgens.
Injection site
Sterile technique, never share needles, vials or pens; see a doctor for a hot, swollen site. If equipment was ever shared, test for HIV and hepatitis B/C and ask about hepatitis B vaccination.
Check-ups and blood tests
Which tests and check-ups to do and when. This is a guide — agree the exact schedule with your doctor.
Baseline tests
your own starting values — every later result is compared with them
Lipid panel (HDL, LDL, triglycerides, ApoB)cholesterol
Complete blood count (hematocrit, hemoglobin)hematocrit
Kidney panel (creatinine, eGFR, cystatin C)blood pressure, kidneys
Electrolytes (potassium, sodium, magnesium)heart rhythm
Testosterone (total, free), LH, FSH, SHBGnatural testosterone, low mood
Estradiol (sensitive assay)high estrogen, gynecomastia
Prolactingynecomastia
PSAprostate
Home blood-pressure logheart, blood pressure, kidneys
ECGheart, heart rhythm
Echocardiogram (heart ultrasound)heart
Urinalysiskidneys
While taking
about 4–6 weeks in, then every 6–8 weeks — agree the exact schedule with your doctor
Lipid panel (HDL, LDL, triglycerides, ApoB)cholesterol
Complete blood count (hematocrit, hemoglobin)hematocrit
Kidney panel (creatinine, eGFR, cystatin C)blood pressure, kidneys
Electrolytes (potassium, sodium, magnesium)heart rhythm
Estradiol (sensitive assay)high estrogen, gynecomastia
Prolactingynecomastia
Home blood-pressure logheart, blood pressure, kidneys
Urinalysiskidneys
After stopping
4–8 weeks after stopping (later after long-acting injections), then until values return to baseline
Lipid panel (HDL, LDL, triglycerides, ApoB)cholesterol
Complete blood count (hematocrit, hemoglobin)hematocrit
Kidney panel (creatinine, eGFR, cystatin C)blood pressure, kidneys
Testosterone (total, free), LH, FSH, SHBGnatural testosterone, low mood
Semen analysisnot earlier than 3 months after stopping, then every 3 months until normalnatural testosterone
Every year
with regular or repeated use
PSAprostate
ECGheart, heart rhythm
Echocardiogram (heart ultrasound)heart
Which doctors can help
Cardiologisthematocrit, heart, cholesterol, blood pressure, heart rhythm
Endocrinologistnatural testosterone, high estrogen, gynecomastia
Psychotherapist / psychiatristmood, low mood
Urologistprostate
Nephrologistkidneys
Sports physiciantendons
Dermatologisthair loss
Gynecologistvirilization, natural testosterone (women)
At home
- Home blood pressure: 2–3 times a week in the morning, keep a log
Get medical help at once if
- Swelling, pain or redness in one leg; sudden shortness of breath or chest pain; sudden one-sided weakness or numbness, trouble speaking or seeing — seek urgent care.
- Chest pain or pressure, breathlessness on light effort, swollen ankles, fainting — seek urgent care.
- A painful lump under the nipple or nipple discharge — see a doctor early, while it can still regress; a hard, painless or fixed lump, skin dimpling or bloody discharge — see a doctor promptly.
- Difficulty or pain when urinating, blood in urine; unable to pass urine at all — urgent care.
- Sudden severe headache, vision changes, numbness or weakness on one side, trouble speaking — call emergency services.
- Racing or irregular heartbeat that does not settle at rest, dizziness, fainting, chest pain — call emergency services.
- Much less urine than usual, cola-colored urine, new swelling, flank pain — see a doctor now.
- Losing control of anger, thoughts of harming yourself or others — stop and get help today.
- Thoughts of suicide or self-harm — contact emergency services or a crisis line right now.
- A snap and sudden sharp pain in a tendon, inability to load the limb — stop training and get it examined.
- Deepening voice, new facial hair, clitoral enlargement — stop and see a doctor: changes can become permanent. (women)
In an emergency, call your local emergency number.
For women
Testosterone virilizes women: deeper voice, facial and body hair, clitoral enlargement and menstrual changes can appear quickly, and voice and clitoral changes are often permanent. No level above the female range is free of this risk.
Myth & fact
Myth
“The FDA dropped its heart warning, so testosterone is safe for the heart.”
Fact
That change rests on TRAVERSE — replacement doses in men with low testosterone. Sport doses are higher, and at the same time the FDA added a blood-pressure warning for all testosterone products.
Combinations
No specific combination notes for this substance yet. The stack check still adds up side effects that several substances share.
Sources
Bhasin S et al. The effects of supraphysiologic doses of testosterone on muscle size and strength in normal men. N Engl J Med 1996 (opens in a new tab)Smit DL et al. Health effects of androgen abuse: a review of the HAARLEM study. Curr Opin Endocrinol Diabetes Obes 2022 (opens in a new tab)Windfeld-Mathiasen J et al. Cardiovascular Disease in Anabolic Androgenic Steroid Users. Circulation 2025 (opens in a new tab)
Check how Testosterone combines with your stack
Possible side effects by body system, combinations, how to lower the risks and which tests to do — free.
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