Deca/NPP and Sexual Side Effects: Why It’s Not Just Prolactin (Full Breakdown)

[sciroxxonline]

Deca-Durabolin and its close relative nandrolone phenylpropionate (NPP) are among the most widely used anabolic steroids for a reason. That said, they also have some well-known potential downsides—and the most infamous is “deca dick.” Just to be clear on definitions, we’re talking about lower libido, weaker erections, reduced sensitivity, and that overall “disconnected” feeling.


What’s interesting is how most threads online follow the same script: one-word explanation—prolactin—and one-word fix—caber (Dostinex). The real physiology is usually more complex than that.


I published a full article that lays out the mechanisms behind nandrolone and sexual function in a clear order, without relying on the typical shortcuts:


👉 Full article: Deca dick myth and truth


What the article covers (and why it matters):

• Why the “Deca = prolactin” narrative is not only simplified, but often way off
• Why cabergoline can improve symptoms without proving prolactin was the main driver (dopamine effects matter)
• The true foundations:
  • Deca and its progestin-like/progesterone-like effect
  • The Deca-specific metabolic twist: nandrolone converts to DHN (dihydronandrolone → very weak androgen) while testosterone converts to DHT (dihydrotestosterone → the most potent androgen in the human body)
• Why this can leave you under-androgenized where it matters most: penile tissue / prostate / brain
• Does Deca convert to estrogen? And where estrogen actually fits (Deca-only vs Deca + testosterone is often a completely different story)

If you’re thinking about Deca/NPP, already using it, or you simply want to understand why the reputation exists, it’s worth checking out:


👉 Full article: Deca dick myth and truth