Cabergoline Guide: Dosage, Uses and Side Effects

Cabergoline is a dopamine D2 receptor agonist that suppresses prolactin production, making it the essential ancillary compound for any steroid cycle containing Trenbolone or Nandrolone (Deca-Durabolin / NPP). At a standard dose of 0.25-0.5mg twice per week, Cabergoline prevents prolactin-related side effects including erectile dysfunction, reduced libido, nipple lactation, and mood disruption. According to clinical data published in the Journal of Clinical Endocrinology and Metabolism, Cabergoline reduces serum prolactin levels by 80-90% within 2-4 weeks of administration at therapeutic doses.

Key Takeaways

• Only needed with 19-nor compounds: Trenbolone and Nandrolone (Deca/NPP) raise prolactin. Testosterone, Dianabol, Anavar, Winstrol, and Masteron do not
• Standard dose: 0.25mg twice per week for prevention. 0.5mg twice per week if symptoms appear
• Half-life: 63-69 hours (very long acting, twice-weekly dosing is sufficient)
• Not an aromatase inhibitor. Does not affect oestrogen. Use alongside an AI if running aromatising compounds
• Continue for 2-3 weeks after last 19-nor injection as prolactin can remain elevated while the compound clears
• Available from SteroidShop: Cabergoline 0.5mg

What Is Cabergoline?

Cabergoline is a synthetic ergoline derivative that was originally developed for the treatment of hyperprolactinemia (abnormally high prolactin levels) and prolactin-secreting pituitary tumours (prolactinomas). It is prescribed under brand names including Dostinex (Pfizer) and is listed in the British National Formulary as a first-line treatment for prolactin disorders. In the bodybuilding community, it became an essential ancillary once the mechanism behind “Deca dick” and Trenbolone-related sexual dysfunction was identified as prolactin elevation rather than oestrogen.

Unlike aromatase inhibitors (Aromasin, Arimidex) which control oestrogen, and unlike SERMs (Nolvadex) which block oestrogen at specific receptor sites, Cabergoline operates through an entirely different pathway. It stimulates dopamine D2 receptors in the pituitary gland, which directly inhibits prolactin secretion at the source. This mechanism is why AIs and SERMs cannot resolve prolactin-related side effects, and why Cabergoline is irreplaceable when running 19-nor compounds.

Why 19-Nor Steroids Raise Prolactin

Trenbolone and Nandrolone belong to the 19-nortestosterone (19-nor) family, defined by a missing carbon atom at the 19th position of the steroid molecule. This structural modification gives them powerful anabolic properties but also introduces progestogenic activity: the ability to activate progesterone receptors. When progesterone receptors in the pituitary are activated, they stimulate the lactotroph cells to release prolactin into the bloodstream.

At normal physiological levels (2-18 ng/mL in men according to NHS reference ranges), prolactin is harmless. But at the elevated levels caused by 19-nor steroid use, prolactin directly impairs several systems:

• Erectile dysfunction: elevated prolactin suppresses GnRH pulsatility and reduces dopamine activity, both of which are required for normal erectile function. This is the mechanism behind “Deca dick” and “Tren dick”
• Reduced libido: prolactin directly antagonises the dopamine-driven reward circuits that underpin sexual desire
• Nipple lactation (galactorrhoea): prolactin’s primary biological function is to stimulate milk production. At sufficiently elevated levels in men, visible discharge can occur
• Mood disruption: dopamine suppression from high prolactin can cause anhedonia (inability to feel pleasure), low motivation, and depressive symptoms
• Refractory period extension: prolactin spikes after orgasm are responsible for the refractory period. Chronically elevated prolactin extends this significantly

Standard aromatase inhibitors (Arimidex, Aromasin) do not address prolactin because prolactin is not produced through the aromatase pathway. You can have perfectly controlled oestrogen and still experience all of the above symptoms if prolactin is left unmanaged. This is a common mistake among users who assume “Deca dick” is an oestrogen problem.

Cabergoline Dosage Protocols

Take with food to reduce the mild nausea that some users experience with the first 1-2 doses. Evening dosing may help if nausea or dizziness is experienced, as you sleep through the initial peak.

Which Compounds Require Cabergoline?

If your cycle does not contain Trenbolone, Nandrolone, or NPP, you do not need Cabergoline. For oestrogen control on non-19-nor compounds, use Aromasin or Arimidex instead.

Cabergoline Side Effects

At the doses used in bodybuilding (0.5-1mg per week for 8-16 week cycles), Cabergoline is generally very well-tolerated. The cardiac valve fibrosis risk that appears in medical literature is associated with Parkinson’s disease dosing (3-6mg per day, continuously for years), which is 20-40x higher than bodybuilding doses. At 0.5-1mg/week for a few months, this risk is not considered clinically significant.

Cabergoline vs Pramipexole

Cabergoline is the overwhelming first choice in bodybuilding due to its long half-life (twice-weekly dosing), predictable prolactin suppression, and manageable side-effect profile. Pramipexole is rarely used because its short half-life requires daily dosing and its stronger dopaminergic activity can cause impulse control issues at higher doses.

How to Use Cabergoline in a Tren or Deca Cycle

Here is a practical example of integrating Cabergoline into a Trenbolone cycle:

Note that Cabergoline continues for 2-3 weeks after the last Trenbolone injection. This is because Trenbolone Enanthate has a 7-10 day half-life, and prolactin can remain elevated while the compound clears. Stopping Cabergoline too early risks a late-onset prolactin flare.