Prescription-only medicine.
This page is educational: approved formats/strengths, what it’s used for, administration basics (label-first),
safety monitoring, side effects, FAQs, and official references. Always follow your local product leaflet and prescriber guidance.

Need help verifying labeling or format?

Ask about official leaflet links, strength confirmation, and general storage/authenticity checks.
We do not provide medical advice—TRT decisions and dosing must be handled by a licensed clinician.

Rx-only • Label-first • Clinician-supervised use

Testosterone undecanoate is a long-acting testosterone ester used in testosterone replacement therapy (TRT)
for men with confirmed hypogonadism (low testosterone) based on symptoms and repeat lab testing.
Compared with short-acting injections, long-acting formulations aim to reduce peaks and troughs—however, they still require
individualized follow-up and careful monitoring.

• Nebido: 1000 mg / 4 mL (i.e., 250 mg/mL) testosterone undecanoate.
• Aveed: single-use vial 3 mL containing 250 mg/mL testosterone undecanoate (total 750 mg).

Testosterone undecanoate long-acting products are generally intramuscular injections administered by a healthcare professional.
Do not self-inject unless your local label explicitly allows it and your clinician has trained you.

Important safety note (Aveed):
US labeling includes an observation period after injection in a healthcare setting due to rare but serious reactions (see FDA PI).

(This page intentionally does not provide a step-by-step injection technique guide. Follow your official leaflet and clinician training.)

TRT can cause side effects and is not appropriate for everyone. Seek urgent care for chest pain, severe shortness of breath,
signs of allergic reaction, or severe swelling.

• Injection-site discomfort
• Acne/oily skin, mood/libido changes
• Fluid retention in predisposed individuals
• Elevated hematocrit (requires lab monitoring)
• Product-specific warnings (see official PI/SmPC)

Is Nebido the same as Aveed?

Both are testosterone undecanoate injections, but labeling, packaging, and safety requirements can differ by region.
Nebido is commonly listed as 1000 mg/4 mL (250 mg/mL). Aveed US is 750 mg/3 mL (250 mg/mL) and has specific US safety warnings.
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What strengths are verified?

Verified formats include Nebido 1000 mg/4 mL and Aveed 250 mg/mL in a 3 mL single-use vial (750 mg total), based on official sources.
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Can I use this without blood tests?

No. TRT should be started only after appropriate diagnosis and continued with periodic monitoring.
The exact monitoring schedule is a clinician decision.

Where can I verify my leaflet?

Use national regulators (e.g., FDA PI / UK EMC / EU SmPC) or official databases. See the “Official References” section below.

• Nebido SmPC (UK EMC):
  medicines.org.uk (Nebido 1000 mg/4 mL)
• Nebido (NL regulator listing):
  geneesmiddeleninformatiebank.nl (250 mg/mL)
• Aveed FDA Prescribing Information (PDF):
  accessdata.fda.gov (Aveed 250 mg/mL, 3 mL vial)
• Aveed dosing page (manufacturer HCP):
  aveedusa.com (intervals per US label)

⚠️ Medical disclaimer

Educational content only. This does not replace medical advice, diagnosis, or treatment.
Testosterone undecanoate is prescription-only; only a licensed clinician can determine suitability, dosing, and monitoring.
Always follow your official patient leaflet and local regulations.