Primobolan (Methenolone Acetate)
Active Substance: Primobolan
Description
Primobolan, also known by its chemical name Methenolone Acetate, is an oral anabolic-androgenic steroid (AAS). It has also been marketed under other brand names such as Nibal. There is also an injectable version, Methenolone Enanthate, sold under the brand name Primobolan Depot.
Medical Use and History
Methenolone Acetate was originally developed for medical use, primarily in the treatment of anemia caused by bone marrow failure. It was also used to treat muscle wasting diseases. However, its medical use has largely been discontinued in many countries.
Anabolic and Androgenic Ratio
The anabolic-to-androgenic ratio of Primobolan is 88:44-57. This means it has moderate anabolic effects (muscle-building) and weak androgenic effects (masculinizing). The lower androgenic rating is one of the reasons it is often considered a milder steroid.
Side Effects
While Primobolan is often considered a "mild" steroid, it is not without potential side effects. These can include:
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Androgenic side effects: Due to its androgenic nature, it can cause acne, increased body hair growth, and in genetically predisposed individuals, male pattern baldness. In women, it can lead to virilization, which includes deepening of the voice, increased body hair, and clitoral enlargement.
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Cardiovascular side effects: It can negatively impact cholesterol levels by increasing LDL ("bad") cholesterol and decreasing HDL ("good") cholesterol, which can increase the risk of cardiovascular disease.
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Hormonal suppression: Like other anabolic steroids, Primobolan can suppress the body's natural testosterone production. This can lead to issues such as reduced libido and fatigue. Post-cycle therapy (PCT) is often used to help restore natural hormone levels.
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Liver toxicity: While considered one of the milder oral steroids in terms of liver toxicity, prolonged use or high doses can still lead to liver damage.
Benefits
The purported benefits of Primobolan for physique and performance enhancement include:
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Lean muscle gains: It is known for promoting slow, steady, and high-quality muscle gains.
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Reduced fat: It can help in reducing body fat, making it a popular choice for "cutting" cycles.
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Minimal water retention: It does not lead to significant water retention, which can be a desirable trait for those seeking a more "hard" and defined look.
Pros and Cons
Pros:
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Relatively mild with a low androgenic rating.
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Does not aromatize into estrogen, so it does not cause estrogenic side effects like gynecomastia.
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Known for producing high-quality, lean muscle gains.
Cons:
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Can still cause a range of side effects, including androgenic and cardiovascular issues.
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Suppresses natural testosterone production.
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The oral version (Methenolone Acetate) may have some degree of liver toxicity, though it's considered less severe than other oral steroids.
Dosage and Frequency
There is no medically established dosage for performance enhancement. In clinical settings, the oral version was typically administered at a dose of 10-20mg per day. However, users in the bodybuilding community may use different dosages. The injectable version (Primobolan Depot) was often administered every one to two weeks.
Half-Life and Detection Time
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Half-Life: The half-life of Methenolone Acetate (oral) is relatively short, with some sources suggesting it's around 24 hours. The injectable version, Methenolone Enanthate, has a much longer half-life of approximately 10.5 days.
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Detection Time: The detection time for Primobolan is significant. Urinary metabolites of Methenolone Acetate can be detected for several days after a single oral dose. Due to the long-lasting metabolites, some sources suggest a detection time of 4-5 weeks for Methenolone Acetate and up to 6-8 weeks or even longer for Methenolone Enanthate.
Sterogenic, Progestronic, and Prolactin Effects
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Estrogenic: Primobolan does not aromatize (convert to estrogen) and therefore has no estrogenic effects. This means it does not cause gynecomastia or significant water retention.
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Progestronic: Primobolan does not have progestogenic activity.
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Prolactin: Primobolan is not known to directly cause increases in prolactin levels.
Pharmacological Properties
Half Life
4.8 hours
Active Dose
87%
Detection
1.00 days
Concentration
10 mg/tab
Anabolic/Androgenic Profile
Usage Effectiveness
Activity Profile
Estrogenic
None
Progestanic
None
Water Retention
None
Aromatization
No
Benefits
Dosage Recommendations
Beginner
20-40 mg/week
Intermediate
40-60 mg/week
Advanced
60-100 mg/week
Evidence-based planning resources
Dive deeper into Primobolan (Methenolone Acetate) cycle design, stacking options, and harm-reduction checklists available inside Anabolic Planner.
- Primobolan (Methenolone Acetate) compound database overviewCompare Primobolan (Methenolone Acetate) with other steroid agents in the structured compound index.
- Primobolan (Methenolone Acetate) stack and cycle templatesReview evidence-based cycle outlines, dose progressions, and PCT pairings that incorporate Primobolan (Methenolone Acetate).
- Harm-reduction guide for Primobolan (Methenolone Acetate)Refresh safety monitoring, lab work, and countermeasure strategies tailored for Primobolan (Methenolone Acetate) protocols.
Peer-reviewed reference material
Validate mechanisms, contraindications, and regulatory guidance for Primobolan (Methenolone Acetate) with trusted clinical databases.
- Primobolan clinical research on PubMedSearch peer-reviewed human and veterinary studies discussing efficacy, endocrine impact, and contraindications.
- Primobolan pharmacology via Drug Information PortalReview mechanisms, synonyms, regulatory status, and toxicology summaries from the U.S. National Library of Medicine.
Side Effects
Common
Rare
Safety Information
Liver Toxicity
Moderate
Kidney Toxicity
Low
Cardiovascular Risk
Moderate
Disclaimer: This information is for educational purposes only. Always consult with a qualified healthcare professional before using any compounds.