At a glance
Effects
- Testosterone restoration: Raises serum testosterone to physiological range in hypogonadal men, relieving symptoms such as low libido, fatigue, low mood, and reduced bone density [1][2].
- Muscle anabolism: Promotes nitrogen retention and muscle protein synthesis via androgen receptor activation, supporting lean body mass accumulation [4].
- Strength and physical performance: Androgenic drive augments neuromuscular output and recovery; used as a performance base in athletic and bodybuilding contexts [6].
- Stable serum levels: The very long-acting ester produces steadier testosterone concentrations and fewer peaks and troughs than shorter-acting esters, which can reduce hormonal mood swings [7][8].
- Red blood cell stimulation: Testosterone stimulates erythropoietin, increasing haematocrit and haemoglobin — beneficial in anaemia of hypogonadism but a risk if levels rise excessively [9].
- Bone density: Long-term testosterone therapy has been associated with improvement in bone mineral density in men with hypogonadism [2].
Anabolic-androgenic steroid (AAS) / Schedule III controlled substance
Oral: ~1.6 h; IM injection: ~21–34 days (oil-dependent)
Intramuscular injection (Aveed/Nebido) or oral capsule (Jatenzo/Andriol)
Long: injectable depot detectable for several months
Low — injectable bypasses liver; oral uses lymphatic absorption
About Testosterone Undecanoate
Every point here is drawn from public medical and harm-reduction sources. A bracketed number after a claim — like [1]— is a reference: tap it to open the exact source it's based on (numbered list at the bottom). It is not a rating or score. Educational information, not medical advice.
Product specifics
- Est. delivery
- 3–7 business days · EU tracked
Product details as stated by the vendor (claims, not independently verified). Delivery is our standard EU estimate.
What it is
Testosterone Undecanoate is a long-acting ester of testosterone — a naturally occurring anabolic-androgenic steroid (AAS) — available in both injectable (Aveed/Nebido) and oral (Jatenzo/Andriol) forms, used medically for testosterone replacement therapy (TRT) in men with confirmed hypogonadism [1][2].
How it works
After administration, tissue esterases cleave the undecanoate side chain to release free testosterone [3]. The free testosterone then binds androgen receptors in target tissues, regulating gene transcription that governs muscle protein synthesis, red blood cell production, bone density, libido, and mood [4]. The injectable form is absorbed from an intramuscular oil depot over many weeks, producing a prolonged, stable release profile; the oral form is unusually absorbed via the intestinal lymphatic system, partially bypassing hepatic first-pass metabolism [5]. Because adjustments to dosing take weeks to reflect in serum levels, overshoot or undershoot can persist for extended periods [6].
Risks & side effects
Most important: Testosterone Undecanoate carries an FDA-mandated black-box warning: it can raise blood pressure, increasing the risk of serious major adverse cardiovascular events (MACE), including non-fatal myocardial infarction and stroke [1][9]. The injectable form also carries a rare but immediately life-threatening risk of pulmonary oil micro-embolism (POME) and anaphylaxis, which is why the FDA restricts its administration to enrolled healthcare settings with a 30-minute post-injection observation period [10].
Common
Serious
- Elevated blood pressure and cardiovascular risk (MACE: MI, stroke) — FDA black-box warning [1][9]
- Polycythaemia (excess red blood cells) — increases clot and stroke risk [9]
- Venous thromboembolism [9]
- Suppression of natural testosterone production and spermatogenesis — fertility may take months to recover after stopping [2][12]
- Worsening of benign prostatic hyperplasia (BPH) [1]
- Sleep apnoea exacerbation [9]
- Dyslipidaemia: lowered HDL cholesterol [9]
Rare
- Pulmonary oil micro-embolism (POME) — coughing, dyspnoea, hypotension immediately post-injection [10]
- Anaphylaxis immediately post-injection [10]
- Depression and suicidal ideation (reported in clinical trials of oral formulation) [9]
- Prostate cancer risk (insufficient long-term data in older patients) [1]
Safety & harm reduction
- Men with carcinoma of the breast or known/suspected prostate carcinoma [10]
- Pregnant women (testosterone is teratogenic) [10]
- Known hypersensitivity to testosterone undecanoate, castor oil, or benzyl benzoate [10]
- Elevated haematocrit/haemoglobin >50% — further polycythaemia risk [2]
- Males under 18 years of age — safety and efficacy not established [1]
- Blood pressure — monitor periodically throughout therapy [1]
- Serum testosterone levels — check mid-interval (e.g., 4–6 weeks post-injection) [6]
- Full blood count / haematocrit — monitor for polycythaemia [2]
- PSA and prostate assessment — baseline and periodic [9]
- Lipid panel (HDL/LDL) — testosterone can lower HDL [9]
- Liver function tests — particularly with oral formulation [5]
- Anticoagulants (e.g., warfarin) — testosterone may potentiate; more frequent INR/PT monitoring required [9]
- Insulin and anti-diabetic agents — androgens may alter insulin sensitivity; glycaemic monitoring recommended [9]
- Corticosteroids — combination may increase fluid retention, especially in patients with cardiac, renal, or hepatic disease [9]
- Other antihypertensives — concomitant blood-pressure-raising drugs increase MACE risk [9]
- Injectable (Aveed): stay at the healthcare facility for at least 30 minutes post-injection; REMS-enrolled prescribers only [10]
- Estrogen management: monitor oestradiol; aromatase inhibitors (e.g., anastrozole) may be required if symptomatic gynaecomastia or elevated oestradiol develops [6]
- Post-cycle therapy (PCT): exogenous testosterone suppresses the HPG axis; after stopping, a PCT protocol (SERMs such as clomiphene or tamoxifen) is commonly used to restore endogenous testosterone and spermatogenesis — recovery may take months [2]
- Oral form must be taken with a fat-containing meal for adequate lymphatic absorption [5]
- Due to the very long half-life of the injectable form, dose adjustments have a delayed effect — allow at least one full inter-dose interval before re-assessing serum levels [6]
Dosage context
Commonly reported clinical dosing (not a prescription — presented for harm-reduction context only): **Injectable – Aveed (USA):** 750 mg IM at initiation, again at 4 weeks, then every 10 weeks thereafter [11]. **Injectable – Nebido (EU/international):** 1,000 mg at initiation, with an optional 1,000 mg dose at 6 weeks, then 1,000 mg every 10–14 weeks [4]. **Oral – Andriol/Jatenzo:** 80–160 mg/day in 2–4 divided doses taken with a fat-containing meal [5]. Performance use at doses or frequencies above these clinical ranges substantially increases all risks, particularly cardiovascular and haematological.
Sources
- 1.DailyMed – Jatenzo (testosterone undecanoate) Prescribing Information
- 2.PMC – Safety Aspects and Rational Use of Testosterone Undecanoate
- 3.USPTO / Clinical literature – TU pharmacokinetics and ester hydrolysis
- 4.ScienceDirect – Testosterone Undecanoate overview (Nebido dosing)
- 5.Wikipedia – Pharmacokinetics of Testosterone (half-life data)
- 6.SteroidsEU – Testosterone Undecanoate complete guide (performance context)
- 7.ClinicalTrials – Oral TU ABPM Extension Study (cardiovascular risk)
- 8.ClinicalTrials – Testosterone Undecanoate Replacement in Boys (pharmacokinetics)
- 9.The Lancet Healthy Longevity – Cardiovascular events meta-analysis
- 10.Aetna / RxList – Aveed (injectable TU) REMS, contraindications, dosing
- 11.FDA / RxList – Aveed prescribing information (adverse reactions, dosing)
- 12.GoodRx – Aveed (POME and anaphylaxis patient information)
- 13.DailyMed – Undecatrex (oral TU) capsule prescribing information
This information is provided for educational and harm-reduction purposes only. It is not medical advice. These substances can carry serious health risks; effects and safe use vary by individual. Consult a qualified healthcare professional before use. Legal status varies by country — it is your responsibility to know your local law. We do not encourage misuse.
Other options for Testosterone Undecanoate· 12 offers
Same compound from different labs/brands and pack sizes. Tap a row to switch brand — the price and buy button update instantly.
This compound comes in different forms (e.g. injectable vs oral vs topical). Cost per mg is only comparable within the same form.
| Brand | Form | Strength | Pack | Price | Per mg |
|---|---|---|---|---|---|
Generic | vial | 250 mg/ml | 10 ml | 43,90 € | €0.018/mg |
Generic | — | — | 54,90 € | — | |
GenericSelected | cap | — | 60 cap | 54,90 € | — |
Testoheal | gel-tube | 5 g | 3 tube | 69,90 € | — |
Testoheal | capsule | 40 mg/cap | 60 cap | 72,90 € | €0.030/mg |
Cernos | cap | 40 mg/cap | 60 cap | 79,90 € | €0.033/mg |
Testoheal | cap | 40 mg/cap | 50 cap | 89,90 € | €0.045/mg |
Testoheal | cap | 40 mg/cap | 100 cap | 94,90 € | €0.024/mg |
Generic | blister-pack | 40 mg/cap | 30 cap | 94,90 € | €0.079/mg |
Generic | blister-pack | 25 mg/tab | 100 tab | 114,99 € | ★€0.046/mg |
Testoheal | cap | 40 mg/cap | 200 cap | 189,99 € | €0.024/mg |
Testoheal | cap | 40 mg/cap | 500 cap | 419,99 € | ★€0.021/mg |