Injectable Steroids
Kalpa Pharmaceuticals
Masteroxyl 100 mg
Product Information Compound Details
Active Substance Drostanolone Propionate Short-acting non-aromatizing anabolic steroid
100 mg/mLStrength 100 mg/mL
Package 10 mL Vial 1,000 mg total labeled content
Form Oil-Based Injectable
Estimated Half-Life Approximately 2–3 Days
Drug Class Androgen & Anabolic Steroid
Manufacturer Kalpa Pharmaceuticals
$142.00
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- Overview
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Product Overview
Masteroxyl 100 mg by Kalpa Pharmaceuticals
Masteroxyl 100 mg is an oil-based drostanolone propionate injectable manufactured by Kalpa Pharmaceuticals and dosed at 100 mg/mL in a 10 mL vial.
Drostanolone Propionate Injectable
Masteroxyl 100 mg is an injectable anabolic-androgenic steroid containing drostanolone propionate, a short-acting ester of the drostanolone hormone. Drostanolone is a derivative of dihydrotestosterone (DHT), which means it is not aromatized to estrogen and does not undergo 5-alpha-reductase conversion (since DHT itself is already the 5-alpha reduced form).
Drostanolone propionate is not currently marketed as an FDA-approved human pharmaceutical product in the United States. In non-medical bodybuilding settings, it is commonly referenced for its hardening and cosmetic effects during cutting phases, particularly because it does not cause water retention or gynecomastia.
Drostanolone promotes muscle protein synthesis through androgen receptor activation. When used at supraphysiologic levels for physique or performance enhancement, the potential for adverse effects also increases and such use falls outside approved medical indications.
Key Benefits of Masteroxyl 100 mg
- Non-aromatizing compound with no estrogen conversion
- Commonly referenced for hardening and cosmetic effects
- Short propionate ester for rapid onset and clearance
- Commonly stacked with testosterone during cutting phases
- MCT oil carrier for smooth, consistent formulation
Carrier Oil
MCT Oil Formulation
Masteroxyl 100 mg uses MCT oil as its carrier oil, providing the oil base for the drostanolone propionate formulation.
Product Profile
Drostanolone Propionate Profile
Drostanolone propionate is a short-acting ester of drostanolone, a DHT-derived anabolic steroid designed for non-aromatizing properties. Its lack of estrogen conversion distinguishes it from testosterone and other aromatizable compounds.
Short-Acting DHT-Derived Anabolic Steroid
The propionate ester releases drostanolone from the injection site relatively quickly, giving the compound a shorter duration of activity than longer-ester preparations. The half-life is approximately 2–3 days, which means drostanolone propionate requires more frequent injection than longer-ester compounds.
Drostanolone is a derivative of dihydrotestosterone, which lacks the ability to be aromatized to estrogen. This structural characteristic is why drostanolone propionate does not cause water retention or gynecomastia through the aromatization pathway. It also cannot be reduced by 5-alpha-reductase since it is already the 5-alpha reduced form of its parent compound.
These characteristics explain why drostanolone propionate is commonly referenced in non-medical cutting phases where a hardening, non-aromatizing compound is preferred.
Release Profile
Rapid Release, Short Duration
Drostanolone propionate releases drostanolone more rapidly than longer-ester preparations, with a half-life of approximately 2–3 days. This short duration of activity is why it is typically referenced as being administered every other day.
Masteroxyl 100 mg vs Other Kalpa Preparations
Kalpa Pharmaceuticals offers several injectable anabolic formulations built around different compounds. The main practical distinctions between these preparations involve the compound's aromatization rate, ester composition, and intended use context.
For a longer-acting drostanolone preparation, Masteroxyl 200 uses the enanthate ester. For multi-compound cutting blends, Cutaxyl 150 mg combines drostanolone propionate with testosterone propionate and trenbolone acetate. For users seeking a shorter-acting testosterone base to stack alongside drostanolone propionate, Testoxyl Propionate is commonly referenced.
Dosage & Usage
Masteroxyl 100 mg Dosage & Usage
The information below is provided for educational reference only. Drostanolone propionate is a prescription-class androgen in jurisdictions where it remains available; medical use requires appropriate diagnosis, clinical supervision and ongoing monitoring. Non-medical use falls outside approved indications.
Typical Dosage Ranges
In non-medical bodybuilding settings, drostanolone propionate is commonly referenced in the range of 50–100 mg every other day, or approximately 200–400 mg per week, though such use falls outside approved medical indications. Because of its short half-life, it requires more frequent administration to maintain stable blood levels.
| Use Case | Common Reference Range | Injection Frequency |
|---|---|---|
| Non-medical cutting phase | 50–100 mg per injection | Every other day |
| Weekly equivalent | 200–400 mg / week | Split into EOD injections |
| Pre-contest conditioning | Typically lower end of range | Every other day |
Stacking & Cycle Considerations
In non-medical bodybuilding contexts, drostanolone propionate is frequently referenced as a secondary compound stacked alongside a testosterone base during cutting phases. Because drostanolone does not aromatize, a testosterone base is often included to maintain physiological testosterone levels and provide a base level of estrogen. Kalpa offers several testosterone preparations that are commonly referenced in this context, including Testoxyl Propionate and Testoxyl Cypionate 250.
Drostanolone propionate may also be referenced alongside oral compounds such as Stanoxyl 10 or Oxandroxyl 10 during cutting phases. Cycle structure, duration and support compounds should be considered in the context of individual experience, health status and bloodwork where possible.
Managing Side Effects
Because drostanolone propionate does not aromatize, estrogenic side effects such as gynecomastia and water retention are not a concern through the aromatization pathway. However, drostanolone can contribute to androgenic side effects in predisposed individuals, including hair loss and acne.
Drostanolone propionate is not liver toxic in the way oral C17-alpha-alkylated steroids are, but cholesterol and hematocrit levels should be monitored during use. Aromatase inhibitors such as Arimixyl are typically less relevant with drostanolone alone, but may be referenced when stacking with aromatizable compounds.
Post-Cycle Therapy (PCT)
After completing a cycle with Masteroxyl 100 mg, post-cycle therapy is commonly recommended to help restore endogenous testosterone production and support hormonal recovery. Agents such as Clomixyl or Nolvaxyl are commonly referenced for this purpose.
Because drostanolone propionate has a shorter half-life than longer-ester preparations, some users reference a shorter waiting period between the last injection and the start of PCT. PCT protocols vary based on cycle length, compounds used and individual factors.
Important
Individual Response Varies
Dosing strategies, support compounds and recovery protocols should be adjusted based on experience level and bloodwork where possible. The information above is for educational reference and does not constitute medical advice.
Safety & Information
Drostanolone Propionate Safety Information
Drostanolone propionate is an androgen that can affect hormonal, reproductive, cardiovascular and hematologic function. Medical use requires appropriate diagnosis, clinical supervision and ongoing monitoring.
Important Safety Information
Drostanolone propionate is not currently marketed as an FDA-approved human pharmaceutical product in the United States. Its safety and efficacy have not been established through the clinical trial process required for current FDA human pharmaceutical approval.
Use of drostanolone propionate at supraphysiologic levels for bodybuilding or performance enhancement falls outside any approved indication and can increase exposure to androgen-related adverse effects.
Important
Non-Medical Drostanolone Use
Higher-than-physiologic drostanolone exposure can carry additional health risks. Product concentration and laboratory verification do not establish that non-medical use is safe or appropriate for an individual.
Potential Adverse Effects
Drostanolone can suppress endogenous testosterone production through negative feedback on the hypothalamic-pituitary-gonadal axis. This can lead to reduced testicular function and impaired fertility.
Because drostanolone is a DHT derivative, it may contribute to androgenic side effects in predisposed individuals, including hair loss (androgenetic alopecia) and acne. Cardiovascular markers including lipid profile and blood pressure should be monitored during use.
Drostanolone does not aromatize to estrogen, so estrogenic side effects such as gynecomastia and water retention are not typically associated with its use through the aromatization pathway. Individual response and risk vary according to health status, exposure and other factors.
Conditions Requiring Medical Evaluation
Anabolic steroid use is not appropriate for everyone. Medical guidelines identify circumstances in which androgen therapy should be avoided or carefully evaluated, including known or suspected prostate or male breast cancer, elevated hematocrit, certain cardiovascular conditions, thrombophilia and near-term fertility plans.
Existing cardiovascular disease, abnormal blood counts and other medical conditions should be discussed with a qualified healthcare professional before any androgen use is considered.
Monitoring Considerations
Medically supervised androgen therapy typically involves follow-up assessment to evaluate treatment response, adverse effects and relevant laboratory markers. Monitoring may include testosterone concentrations, hematocrit, lipid profile, and prostate-related evaluation.
For non-medical use of Masteroxyl 100 mg, such monitoring is not typically performed, which increases the risk of unrecognized adverse effects.
Product Care
Storage & Handling
Keep the vial securely stored and protected from conditions that could compromise the product or container. Inspect the vial and solution before use and do not use a product that appears damaged, contaminated or otherwise abnormal.
Keep all medications and injectable products out of the reach of children. Follow the storage instructions provided with the product packaging.
Further Safety Information
Shipping & Authenticity
Shipping & Product Authenticity
Masteroxyl 100 mg is supplied through the official Kalpa Pharmaceuticals distribution chain and shipped in original manufacturer packaging with discreet, privacy-focused handling.
USA Domestic 3–5 business days
International 10–15 business days
Order Processing 24–48 business hours
Tracking Provided after dispatch
Direct Supply
Discreet Delivery & Original Packaging
The outer shipping package remains discreet, with privacy-focused handling and no unnecessary external product details. Products are supplied through the official Kalpa Pharmaceuticals distribution chain.
What to Expect
- Orders are processed after payment confirmation
- USA Domestic shipping is typically faster when local stock is selected
- International orders include tracking, though update frequency may vary by destination
- Multiple warehouses may result in separate shipments when applicable
Authenticity Verification
To verify your Masteroxyl 100 mg product, use the security code on the vial label and cross-check it on the Kalpa official site. Official Kalpa Pharmaceuticals presentation, batch-linked lab proof, and original packaging help reinforce product legitimacy and buyer confidence.
For complete delivery details, tracking policy, and reshipment terms, please see our Shipping Info page.
Storage
Masteroxyl 100 mg Storage
Proper storage conditions help preserve formulation stability and overall product integrity throughout shelf life.
Recommended Conditions
Store at controlled room temperature (15–25°C) and protect from excessive heat, moisture, and direct light. Maintaining stable conditions helps preserve the integrity of the oily formulation.
Keep the vial in its original packaging until use. Do not freeze. Before administration, inspect the solution and avoid use if it appears cloudy, discolored, contains particulate matter, or if the vial or seal is compromised.
Keep out of reach of children. Follow proper handling and sterile injection practices when administering the product.
Quick Reference
Do & Don't
- Do store at 15–25°C
- Do keep in original packaging
- Do inspect before each use
- Don't freeze the vial
- Don't expose to direct sunlight
- Don't use if solution looks abnormal
Frequently Asked Questions
Masteroxyl 100 mg FAQ
Answers to common questions about Masteroxyl 100 mg, drostanolone propionate, release characteristics, product strength and how it compares to other preparations.
What is Masteroxyl 100 mg used for?
Masteroxyl 100 mg contains drostanolone propionate, a non-aromatizing anabolic steroid. In non-medical bodybuilding settings it is commonly referenced during cutting phases for its hardening and cosmetic effects, though such use falls outside approved medical indications.
How often should Masteroxyl 100 mg be injected?
Because of its short half-life of approximately 2–3 days, drostanolone propionate is typically referenced as being administered every other day. This frequency is necessary to maintain stable blood levels with the propionate ester.
Does Masteroxyl 100 mg require PCT?
What does drostanolone propionate do?
Drostanolone propionate is a derivative of dihydrotestosterone. Once released, drostanolone binds to the androgen receptor and promotes anabolism in skeletal muscle. Because it is a DHT derivative, it is not aromatized to estrogen and does not cause water retention or gynecomastia through the aromatization pathway.
How long does drostanolone propionate take to work?
Drostanolone propionate is a short-acting ester, so circulating drostanolone rises relatively quickly after administration. Its effects are correspondingly shorter-lived between injections.
The time required to notice a change depends on what is being evaluated, the individual's starting hormone levels, treatment circumstances and other biological factors.
Is drostanolone propionate the best compound for cutting?
There is no single best compound for cutting. Drostanolone propionate is commonly referenced during cutting phases because it does not aromatize, but it is often stacked with a testosterone base and other compounds rather than used in isolation.
Kalpa Pharmaceuticals offers several products that are commonly referenced in this context, including Cutaxyl 150 mg as a multi-compound cutting blend and Stanoxyl 10 as an oral cutting compound.
What is the difference between Masteroxyl 100 mg and Masteroxyl 200 mg?
Both contain drostanolone, but with different esters. Masteroxyl 100 mg uses the propionate ester, which is short-acting and requires more frequent injection. Masteroxyl 200 uses the enanthate ester, which is longer-acting and requires less frequent injection.
What is the difference between drostanolone propionate and testosterone propionate?
Both use the propionate ester, but the active hormones differ. Drostanolone is a DHT-derived compound that does not aromatize to estrogen. Testosterone does aromatize, meaning it converts to some degree of estrogen. Kalpa offers Testoxyl Propionate as a testosterone propionate preparation for users seeking an aromatizable short-acting testosterone.
Is 100 mg of Masteroxyl a lot?
A milligram amount cannot be classified as appropriate or excessive without considering the medical indication, individual response, laboratory results, treatment schedule and the specific product being used. In non-medical contexts, drostanolone propionate is commonly referenced in the 50–100 mg per injection range.
It is also important to distinguish a dose in milligrams from a product's concentration in mg/mL. Masteroxyl 100 mg is labeled at 100 mg/mL; that concentration does not by itself specify how much should be administered.
What strength is Masteroxyl 100 mg?
Masteroxyl 100 mg is labeled at 100 mg of drostanolone propionate per mL. It is supplied in a 10 mL vial, giving 1,000 mg of total labeled drostanolone propionate content per vial.
Does drostanolone propionate cause hair loss?
Drostanolone is a DHT-derived compound. DHT is associated with androgenetic alopecia in predisposed individuals. Because of this, drostanolone propionate may contribute to hair loss in individuals who are already predisposed to DHT-related hair loss.
Individual response varies. Anyone concerned about androgen-related hair loss should discuss this with a qualified healthcare professional.
Why is Masteroxyl 100 mg dosed at 100 mg/mL?
Drostanolone propionate is typically formulated at lower concentrations because the propionate ester is a shorter-chain ester that can be more difficult to keep in stable solution at higher concentrations. The 100 mg/mL concentration is a practical formulation choice for this ester.
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June 14, 2019
I used this in the middle of my last cycle. 1ml every other day/400mg wk.
The mast I was using before this was quality and I didn't feel a drop off when I switched to this one.
Same heightened libido, aggressiveness in gym and sparring sessions, and continued low dose usage of aromasin as before switched. Great quality product. I've used their test e before as well and saw results as expected with diet and training on point.