Nandrolone Decanoate, primarily known as Deca-Durabolin (from Organon), is an anabolic-androgenic steroid chemically related to Testosterone. It possesses a higher anabolic effect but a weaker androgenic one. It is a Testosterone derivative lacking a methyl group at the C-19 position (hence its technical name: **19-Nortestosterone**).

Half-Life and Injections:

• The **Decanoate** ester is a fatty acid that slows down the release of Nandrolone into the bloodstream.
• The half-life is **5 days**, making injections sensible every 7–10 days to avoid a cumulative effect.

The primary action of Nandrolone in bodybuilding is to initiate anabolic processes crucial for muscle growth and regeneration:

1. Nitrogen Retention: Nandrolone significantly increases nitrogen storage in muscles. A positive nitrogen balance equates to an **anabolic (building) state**.
2. Protein Production: It binds to androgen receptors, initiating protein synthesis, which leads to faster muscle growth.
3. Bones: In medicine, it is used to combat **osteoporosis** due to increased calcium accumulation in the bones.

⚠️ **Important:** For Nandrolone to be effective in muscle building, a **positive energy balance** (calorie surplus) and sufficient protein intake (2.5 – 3 g per kg of body weight daily) are necessary. It is not a steroid that significantly builds muscle on a calorie-restricted diet.

Benefits for Joints:

Nandrolone Decanoate causes water accumulation in the joints, acting as a "lubricant." This is a **true blessing** for athletes complaining of shoulder and knee pain, often allowing for pain-free training. However, this addresses the symptom, not the cause—joint issues return after discontinuation.

Nandrolone is often used in long cycles, primarily combined with Testosterone esters (e.g., Testosterone Enanthate), as both are non-toxic to the liver.

Typical Weekly Dosing (Injections):

• Beginners: 200–400 mg per week.
• Experienced Users: Up to 600 mg per week (always under supervision).

"Deca" + Testosterone Bulking Cycle (Example):

Weeks 1–6: Testosterone Enanthate 500 mg + Nandrolone Decanoate 400 mg.

Weeks 7–12: Testosterone Enanthate 700 mg + Nandrolone Decanoate 550 mg (optional dose increase).

Low Androgenic Impact (Advantage):

Nandrolone does not convert into the potent DHT (dihydrotestosterone), making problems like hair loss, prostate issues, or acne the exception rather than the rule. It is the only steroid that DHT-sensitive individuals can use without confronting typical DHT-related problems.

Progesterone and "Deca Dick" (Disadvantage):

Nandrolone unfortunately has a progesterone-like effect, binding to progesterone receptors in about 18% of cases. This can lead to:

• **Gynecomastia** (breast gland growth, similar to estrogen).
• **Increased water and fat retention**.
• **Loss of libido and impotence** (colloquially "Deca Dick" – inability to sustain an erection).

This issue **cannot be resolved** by estrogen blockers (Tamoxifen, Clomid) as they do not affect progesterone levels. **Cabaser (Cabergoline)**, which effectively lowers prolactin levels, is required to restore sexual function.

Other Side Effects:

• Blood thinning, elevated blood pressure, nosebleeds.
• In women: deepening of the voice, menstrual and ovulation disturbances.