Cabergoline - Zyvex Pharmaceuticals
Cabergoline - Zyvex Pharmaceuticals Overview
Cabergoline by Zyvex Pharmaceuticals is a dopamine D2 receptor agonist - the same active compound found in the brand-name drug Dostinex. It suppresses prolactin secretion from the pituitary gland by stimulating dopamine receptors, which inhibit prolactin release. In a bodybuilding context, Cabergoline is used on cycles that include 19-nor compounds - Nandrolone (Deca, NPP) and Trenbolone - which can elevate prolactin levels and cause a specific set of side effects distinct from estrogen-related problems. Each tablet contains 2 mg of Cabergoline, which is a high-dose formulation suited to the twice-weekly dosing protocol standard in bodybuilding use.
Unlike aromatase inhibitors, which block estrogen conversion, Cabergoline acts on a completely different hormonal axis. Prolactin elevation from 19-nor compounds causes nipple sensitivity and lactation (progesterone-mediated gynecomastia), sexual dysfunction, and libido suppression that standard estrogen control cannot fix. Cabergoline is the targeted solution for this specific problem.
About the Compound: Cabergoline 2 mg
Cabergoline is a long-acting ergot-derived dopamine agonist with high selectivity for the D2 dopamine receptor. By binding to D2 receptors on pituitary lactotroph cells, it directly inhibits prolactin synthesis and secretion. The clinical indication is hyperprolactinemia and prolactinoma - conditions of abnormally elevated prolactin in the general population. In bodybuilding, the same mechanism is applied to manage the prolactin elevation that occurs when using 19-nor anabolic steroids, which bind to progesterone receptors and trigger prolactin secretion as a downstream consequence.
Zyvex Pharmaceuticals produces Cabergoline at 2 mg per tablet, 100 tablets per pack. The half-life of Cabergoline is approximately 63-68 hours - one of the longest of any compound used in bodybuilding. This pharmacokinetic profile means twice-weekly dosing (every 3-4 days) maintains stable prolactin suppression without daily administration. The long half-life also means effects accumulate over the first 1-2 weeks of use before reaching steady state.
What Cabergoline Does
Cabergoline's effects in a bodybuilding context are all derived from its ability to suppress prolactin. Prolactin elevation from 19-nor compounds produces a specific cluster of problems that require targeted intervention - standard estrogen control with AIs does not address them.
- Prolactin suppression - Cabergoline directly inhibits prolactin release from the pituitary. At 0.25-0.5 mg twice per week it reliably brings prolactin into the normal range during Nandrolone and Trenbolone cycles. This is the primary mechanism behind all its other benefits in this context.
- Prevention of prolactin gynecomastia - Prolactin-induced gynecomastia presents differently from estrogen gynecomastia: it causes nipple sensitivity, discharge, and tissue formation that SERMs like Nolvadex do not adequately block. Managing prolactin at the source with Cabergoline prevents this type of gyno from developing. Once established, prolactin gyno is harder to reverse than estrogen gyno.
- Libido and sexual function restoration - Elevated prolactin from 19-nor compounds is a primary cause of the libido suppression and sexual dysfunction (sometimes called "Deca dick") associated with Nandrolone use. Cabergoline normalizing prolactin levels resolves or prevents this problem for most users. Combined with adequate testosterone, prolactin management with Cabergoline restores normal sexual function during and after 19-nor cycles.
- Mood and wellbeing support - Dopamine pathway stimulation from Cabergoline can produce mild mood-elevating effects. Some athletes report improved drive and motivation, though this effect is secondary and variable. The primary value is prolactin control, not dopaminergic stimulation.
Not a replacement for estrogen control: Cabergoline manages prolactin. It does not control estrogen. Cycles that include aromatizing compounds (testosterone, Dianabol, Deca) still require an aromatase inhibitor (Arimidex, Aromasin) for estrogen management alongside Cabergoline for prolactin. The two problems require two separate solutions.
Dosing and Timing
Standard On-Cycle Dose
The standard dose is 0.25 mg twice per week - for example Monday and Thursday, or every 3-4 days. This is sufficient for most Nandrolone cycles at typical doses (300-600 mg/week Deca or NPP). The 2 mg tablet should be split into quarters for this protocol. For higher-aromatizing stacks or confirmed elevated prolactin on bloodwork, increase to 0.5 mg twice per week. Start with the lower dose - prolactin suppression with Cabergoline is potent, and over-suppression produces its own set of problems (excessive dopamine stimulation, nausea, hypotension).
When to Start
For long-ester Nandrolone cycles (Deca 300, Deca 500), prolactin does not spike immediately - it rises as Nandrolone blood levels build. Start Cabergoline in week 3-4 of the cycle when using Decanoate esters, or from week 1-2 with shorter-ester NPP. For Trenbolone, which can raise prolactin faster and more sharply, start from week 1-2 regardless of ester. Many athletes prefer to start Cabergoline at cycle start for simplicity and consistent prolactin management throughout.
Splitting the 2 mg Tablet
At 0.25 mg twice weekly, one 2 mg tablet provides 4 doses (8 days of supply). Accurate splitting is important at this dose - a pill cutter producing uneven halves will deliver inconsistent amounts. Many athletes prefer to split into halves (1 mg) and take half-tabs twice weekly at confirmed elevated prolactin levels, then scale back to quarter-tabs (0.25 mg) for maintenance once prolactin is normalized.
Which Cycles Need Cabergoline
| Cycle | Prolactin Risk | Cabergoline Protocol |
|---|---|---|
| Testosterone only | None. Testosterone does not elevate prolactin through the 19-nor pathway. Estrogen management with an AI is all that is needed. | Not required. Do not use Cabergoline on non-19-nor cycles - unnecessary prolactin suppression has costs. |
| Testosterone + Deca (Nandrolone Decanoate) | Moderate to high. Nandrolone binds progesterone receptors and elevates prolactin in most users at standard bodybuilding doses. | 0.25 mg twice per week from week 3-4. Increase to 0.5 mg if libido issues or nipple sensitivity appear. Combine with an AI for estrogen control. |
| Testosterone + NPP (Nandrolone Phenylpropionate) | Moderate to high. Same mechanism as Deca; prolactin rises faster due to shorter ester and faster blood level buildup. | 0.25 mg twice per week from week 1-2. Monitor and adjust. NPP reaches peak levels faster, so prolactin management should begin earlier. |
| Testosterone + Trenbolone | High. Trenbolone is a potent prolactin elevator. "Tren dick" and prolactin-related gyno are common complaints without management. | 0.25-0.5 mg twice per week from week 1. Trenbolone's prolactin effect can be pronounced - confirm with bloodwork and adjust dose to keep prolactin in range. |
| Deca + Trenbolone stack | Very high. Two 19-nor compounds stacked produce the highest prolactin burden. This combination is advanced and requires active prolactin monitoring. | 0.5 mg twice per week from week 1. Get prolactin bloodwork at week 4 to confirm control. Adjust to 0.25 mg if levels drop below normal range. |
Side Effects and Risks
| What May Occur | Background | How to Handle It |
|---|---|---|
| Nausea and GI discomfort | The most common side effect, particularly at the start of use or when increasing dose. Dopamine receptor stimulation in the gut can cause nausea, especially on an empty stomach. | Take Cabergoline with food. Start at 0.25 mg twice weekly and titrate up if needed. Nausea usually diminishes after the first 1-2 weeks as tolerance builds. |
| Dizziness and low blood pressure | Cabergoline can cause orthostatic hypotension (blood pressure drop when standing). Dizziness is more common at higher doses or when first starting. | Take doses in the evening when lying down reduces the impact of hypotension. Rise slowly after taking. Avoid alcohol, which compounds the blood pressure drop. |
| Crashed prolactin / over-suppression | Prolactin has physiological roles in men including immune function and sexual response. Suppressing it below the lower limit of normal with excessive Cabergoline dosing causes its own problems: anorgasmia, emotional blunting, and immune suppression. | Use the minimum effective dose. Get prolactin bloodwork to confirm you are suppressing to normal range, not to zero. Target prolactin: within or slightly below the normal male reference range. |
| Cardiac valve concerns (long-term high dose) | High-dose chronic Cabergoline use (above the doses used for prolactinoma treatment) is associated with cardiac valve fibrosis in some studies. The doses used in bodybuilding (0.25-0.5 mg twice weekly) are below those linked to valve complications in clinical data, but the concern exists for very prolonged use at 0.5 mg twice weekly. | Use Cabergoline only during 19-nor cycles - not as a permanent baseline. Do not exceed 0.5 mg twice weekly. Avoid using it on cycles that do not require it. Periodic cardiac monitoring is prudent for heavy long-term users. |
Cabergoline and Post-Cycle Recovery
Cabergoline is not a component of standard PCT in the way SERMs and AIs are. Its role ends when the prolactin-elevating compound clears. For long-ester Nandrolone (Deca), this takes 4-6 weeks after the last injection. Prolactin typically normalizes on its own once Nandrolone clears and is no longer stimulating the pituitary. Cabergoline can be continued for 1-2 weeks into the post-cycle washout period if prolactin remains elevated, then discontinued.
| Product | Role in Recovery |
|---|---|
| Cabergoline | Continue briefly post-cycle if prolactin is still elevated (check bloodwork). Discontinue once prolactin normalizes - typically 2-4 weeks after last Nandrolone or Trenbolone injection. Not required in PCT itself. |
| Nolvadex (Tamoxifen) | Standard SERM for HPG axis recovery. Note: Nolvadex can elevate prolactin in some individuals. If running Nolvadex in PCT after a 19-nor cycle and prolactin-related symptoms return, continue Cabergoline at 0.25 mg twice weekly alongside Nolvadex until PCT is complete. |
| Aromasin (Exemestane) | If AI is needed during PCT for estrogen control, Aromasin is compatible with both Nolvadex and Cabergoline without interaction issues. |
Bloodwork at 4-6 weeks post-PCT should confirm both testosterone and prolactin have returned to baseline. If prolactin remains elevated after PCT without ongoing 19-nor use, consult a healthcare provider to rule out a non-cycle cause.
Frequently Asked Questions
What is cabergoline and why do bodybuilders use it?
Cabergoline is a dopamine D2 receptor agonist - a drug that stimulates dopamine receptors in the pituitary gland and suppresses prolactin secretion. The brand-name version is Dostinex; Cabergoline is the active compound in both. In clinical medicine, it treats hyperprolactinemia and prolactinomas. In bodybuilding, it serves a specific and targeted purpose: controlling prolactin elevation caused by 19-nor anabolic steroids (Nandrolone compounds like Deca and NPP, and Trenbolone). These compounds bind to progesterone receptors, which triggers prolactin secretion as a downstream effect. Elevated prolactin causes a distinct cluster of problems - nipple sensitivity and discharge (prolactin-mediated gynecomastia), severe libido suppression, and sexual dysfunction often called "Deca dick" - that standard estrogen control with aromatase inhibitors cannot fix. Cabergoline at 0.25-0.5 mg twice per week suppresses prolactin into the normal range and prevents or resolves these issues. It is not used on cycles that do not include 19-nor compounds, because testosterone-only cycles do not elevate prolactin through this pathway.
Which steroid cycles require cabergoline?
Cabergoline is required on cycles that include 19-nor compounds - steroids derived from 19-nortestosterone that bind to progesterone receptors and elevate prolactin. The compounds that trigger this are Nandrolone Decanoate (Deca), Nandrolone Phenylpropionate (NPP), Trenbolone Acetate, and Trenbolone Enanthate. Any cycle that includes one or more of these compounds should include Cabergoline for prolactin management. Testosterone alone, DHT-derived compounds (Masteron, Proviron, Anavar, Winstrol), and oral-only cycles not including Nandrolone or Trenbolone do not require Cabergoline. The practical rule: if your cycle has Deca, NPP, or any form of Trenbolone, have Cabergoline on hand and use it. If your cycle is testosterone-based without 19-nors, Cabergoline is unnecessary and carries its own risks if misused.
What is the correct cabergoline dose for bodybuilding?
The standard starting dose is 0.25 mg twice per week - taken every 3-4 days, for example Monday and Thursday. This is the correct starting point for most Nandrolone cycles at typical bodybuilding doses (300-600 mg/week Deca or NPP). At this dose, most users achieve adequate prolactin control without over-suppression. For heavier cycles - high-dose Nandrolone, Trenbolone, or a combination of 19-nor compounds - increase to 0.5 mg twice per week. The Zyvex 2 mg tablet should be split: each tablet provides 4 doses at 0.5 mg or 8 doses at 0.25 mg. Do not use more than 0.5 mg twice per week for bodybuilding purposes - higher doses are for prolactinoma treatment and carry increased risk of side effects without additional benefit for cycle support. Get prolactin bloodwork at 4-6 weeks into the cycle to confirm the dose is working.
Does cabergoline cause weight gain?
No - cabergoline does not cause weight gain and in the context of bodybuilding cycles, it typically has the opposite effect. Elevated prolactin from 19-nor compounds contributes to water retention and fat accumulation in some individuals. Cabergoline normalizing prolactin levels reduces these prolactin-driven effects. The weight gain commonly associated with Deca and Nandrolone cycles is primarily from estrogen-driven water retention (managed with an AI) and increased appetite, not from prolactin directly. Cabergoline is not associated with fat gain in any clinical data. If you are gaining unwanted weight on a cycle that includes Cabergoline, the causes are estrogen control, caloric surplus, or the anabolic compounds themselves - not the Cabergoline.
What are the side effects of cabergoline?
Cabergoline's most common side effects in bodybuilding use are nausea and dizziness, both of which are typically mild and dose-dependent. Taking Cabergoline with food and in the evening (when lying down reduces the hypotensive impact) minimizes these. Other reported effects include headache, fatigue, and mild mood changes. More serious concerns include orthostatic hypotension (blood pressure drop when standing) and, with long-term high-dose use, cardiac valve fibrosis - a concern documented in studies of patients on doses significantly higher than the 0.25-0.5 mg twice weekly used in bodybuilding. At standard bodybuilding doses for defined cycle lengths, the cardiac concern is theoretical rather than documented at the dose ranges in question. One significant risk specific to bodybuilding use is over-suppression of prolactin: going below the normal range with excessive dosing causes anorgasmia (inability to reach orgasm), emotional blunting, and immune effects. Use the minimum effective dose and confirm levels with bloodwork.
What should I avoid while taking cabergoline?
Several interactions and behaviors increase the risk of side effects with Cabergoline. Alcohol significantly potentiates the blood pressure drop caused by Cabergoline - combining the two increases the risk of dizziness, fainting, and hypotension, particularly in the hours after taking the dose. Antihypertensive medications (blood pressure drugs) combined with Cabergoline can produce excessive blood pressure reduction; disclose Cabergoline use to any physician managing your blood pressure. Serotonin-affecting drugs - including some antidepressants (SSRIs, SNRIs), certain antiemetics, and triptans - can interact with dopamine agonists; combined use should be done with medical oversight. Macrolide antibiotics (erythromycin, clarithromycin) can elevate Cabergoline blood levels by inhibiting its metabolism and should be avoided during use if possible. Practically: avoid alcohol on dose days, do not combine with other dopaminergic drugs or antihypertensives without guidance, and disclose use to any prescribing physician.
Is cabergoline a prescription drug?
Yes, in the United States cabergoline (Dostinex) is a prescription-only medication approved for the treatment of hyperprolactinemia and prolactinomas. It cannot be legally dispensed without a prescription at a licensed pharmacy. It is not a controlled substance under the Controlled Substances Act and is not classified as an anabolic steroid. Bodybuilders obtain it as a research chemical or through gray-market sources outside the licensed pharmacy system. WADA does not specifically list Cabergoline as a prohibited substance for competitive sport, though athletes subject to drug testing should consult the current WADA prohibited list and their sport's specific rules. From a practical standpoint: a physician can prescribe it if you present with elevated prolactin confirmed by bloodwork, which some athletes use as a legitimate route to obtaining it.
How long do cabergoline side effects last?
Cabergoline's side effects are generally tied to its active presence in the body. With a half-life of approximately 65 hours, meaningful blood levels persist for several days after each dose. Acute side effects like nausea and dizziness that appear shortly after taking a dose typically resolve within 4-8 hours as peak plasma levels subside. Initial side effects in the first week of use - particularly nausea - often diminish over 1-2 weeks as tolerance to the dopaminergic effects develops. If you stop Cabergoline entirely, side effects clear as the drug washes out over 5-7 days (roughly 2-3 half-lives to meaningful clearance). One exception: if Cabergoline has caused over-suppression of prolactin, the recovery of normal prolactin levels after stopping takes 1-2 weeks as the pituitary resumes normal secretion. Persistent or worsening side effects that do not diminish with dose reduction are a reason to discontinue and consult a physician.
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