Prolactin is a pituitary hormone best known for milk production. In men, high prolactin lowers libido, weakens erections and can cause breast tenderness. It can rise in some people using “19-nor” steroids like nandrolone and trenbolone.
- Test prolactin if you have sexual side effects on nandrolone or trenbolone.
- Cabergoline is the usual medical treatment, at low doses twice a week.
- Very high prolactin needs a doctor to rule out a pituitary tumour.
“Deca dick” is the crude nickname for a real problem: loss of libido and erectile function in some men using nandrolone. Prolactin is often blamed, sometimes correctly, sometimes not. Understanding what prolactin does, how to test it and what the medical treatment involves helps you avoid both ignoring a real problem and treating one that is not there.
What “19-nor” means
Nandrolone and trenbolone are 19-nortestosterone derivatives: they lack a carbon atom at position 19 of the steroid structure. That small change gives them strong anabolic effects and also some activity at progesterone receptors. Progestogenic activity and other hormonal changes may contribute to higher prolactin and to sexual side effects in some users, although the exact mechanisms are still debated. Products include Deca (nandrolone decanoate), NPP (nandrolone phenylpropionate) and trenbolone acetate and enanthate.
Symptoms of high prolactin in men
- Low libido
- Erectile dysfunction or difficulty reaching orgasm
- Breast tenderness or, rarely, discharge from the nipple
- Low mood and fatigue
- Over time, lower testosterone and reduced bone density
These overlap with low or high estrogen, low testosterone and simple fatigue, so do not assume prolactin is the cause without testing.
Testing prolactin in Canada
Prolactin is a simple blood test, best taken in the morning after a calm start: stress, intense exercise, poor sleep and even a difficult blood draw can raise it temporarily. Canadian labs report it in micrograms per litre (µg/L) or mIU/L depending on the lab; normal male values are usually under about 15–20 µg/L. Your doctor can order it, or you can pay privately at LifeLabs or Dynacare. Test estradiol and testosterone at the same time so you can see the whole picture. Our bloodwork guide explains timing.
Other things raise prolactin too, including some antidepressants and antipsychotics, opioids, an underactive thyroid and kidney disease. A doctor will consider these.
Medical treatment
When prolactin is genuinely high, doctors use dopamine agonists, because dopamine is the brain’s natural brake on prolactin.
Cabergoline is effective but not trivial. Side effects include nausea, dizziness on standing and, rarely, impulse-control problems such as compulsive gambling or spending. At the high doses once used for Parkinson’s disease, it was linked to heart valve damage, which is why doctors keep doses low for prolactin and may order a heart ultrasound with long-term use. It is a prescription drug in Canada.
When prolactin is very high
Other causes of sexual side effects on 19-nors
Prolactin gets the blame, but it is often not the culprit. Before treating anything, rule out these more common causes:
- Low testosterone relative to the 19-nor. Nandrolone suppresses your own testosterone strongly. If little or no testosterone is used alongside it, libido and erections often suffer.
- Low estradiol. Nandrolone converts to estrogen far less than testosterone does, and an aromatase inhibitor on top can push estradiol too low.
- High estradiol from a high testosterone dose alongside.
- DHN instead of DHT. Nandrolone is converted by 5-alpha reductase into a much weaker androgen than DHT, which may contribute in some men.
- Stress, poor sleep and relationship factors, which affect everyone.
A single blood panel covering testosterone, estradiol and prolactin usually shows which one is out of range.
Lowering the risk
- Get baseline prolactin before starting a 19-nor, so you know your normal.
- Keep doses moderate; side effects rise with dose.
- Keep estradiol in a healthy range. Estrogen also stimulates prolactin, and high estradiol makes sexual side effects worse. See estrogen management.
- Make sure testosterone is adequate alongside. Many sexual side effects blamed on nandrolone are really low testosterone or low estradiol.
- Sleep well and manage stress, both of which affect prolactin.
For a comparison of the two nandrolone esters, read NPP vs Deca, and for each compound’s risks see the compound profiles.
Frequently asked questions
Does nandrolone raise prolactin?
It can in some users, possibly through its progestogenic activity and effects on other hormones. Not everyone is affected, which is why testing matters.
What prolactin level is high for men?
Most labs consider male values above roughly 15–20 µg/L high, but check your lab’s range and repeat the test before acting on one result.
Is cabergoline available in Canada?
Yes, as the prescription drug Dostinex and generics. It is used for high prolactin under medical supervision.
Photo: rawpixel (public domain).
General information, not medical advice. Cabergoline is a prescription drug; use it only with a doctor’s guidance and monitoring.
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