Masteron Propionate 100

Masteron Propionate 100 by Vanguard Labs delivers 100mg/ml of high-quality drostanolone propionate, a fast-acting DHT-derived compound favoured during cutting and recomposition phases. Designed to promote a harder, drier physique with enhanced muscle density, this short-ester formulation allows for rapid onset and stable blood levels when administered every other day or daily.

Unlike aromatising compounds, Masteron Propionate from Vanguard Labs does not convert to oestrogen, making VGL Fitness Mast Prop 100 a popular addition to testosterone-based cycles where users seek improved cosmetic refinement, strength retention, and reduced subcutaneous water. Due to its strong androgenic profile and lipid impact, this compound is best suited to experienced users who understand cardiovascular monitoring, E2 management, and DHT-related risk considerations.

 

Masteron Propionate – Harm Reduction Crib Sheet

Compound: Masteron Propionate.
Chemical: Drostanolone Propionate
Class: DHT-Derived Anabolic-Androgenic Steroid (AAS)
Administration: Intramuscular injection (IM)
Common Concentration: 100mg/ml

 

Dosage

• TRT Use: Not suitable for TRT
• Performance Use: 300–500 mg/week
• Typical Protocol: 100 mg every other day (EOD)
• Advanced Use: Daily administration for stable levels
• High Risk: >600 mg/week (increased cardiovascular and androgenic strain)
• Commonly stacked with testosterone (not recommended as a solo compound)

 

Half-Life

• ~2–3 days
• Injection frequency: Every other day minimum
• Preferred: EOD or daily for hormonal stability
• Clears relatively quickly compared to long esters

 

Benefits

• Increased muscle hardness and density
• Dry, “grainy” physique look
• Reduced subcutaneous water
• Does not aromatise (no oestrogen conversion)
• Mild anti-oestrogenic properties (not a replacement for an AI)
• Strength retention during calorie deficit
• Synergistic effect when combined with testosterone

 

Side Effects

Oestrogenic

• Does not convert to oestrogen
• Can mask high E2 symptoms when stacked
• Low E2 risk if AI use is excessive

Androgenic

• Acne
• Oily skin
• Accelerated hair loss (genetic predisposition)
• Increased body hair growth
• Possible prostate enlargement

Cardiovascular

• Significant HDL suppression
• LDL elevation
• Negative impact on overall lipid profile

Suppression

• Strong suppression of endogenous testosterone production
• Requires testosterone base if used in a cycle

Other

• Joint dryness/discomfort (especially if E2 is low)
• Mood changes (irritability in some users)

 

Risks

• Cardiovascular strain due to lipid disruption
• Increased DHT burden (hair and prostate sensitivity)
• Infertility when stacked with testosterone
• Long-term cardiac risk if lipids are unmanaged
• Minimal hepatic impact (non-oral), but liver markers should still be monitored

 

Risk Mitigation

Bloodwork

• Pre-cycle bloodwork
• Mid-cycle bloodwork
• Post-cycle bloodwork
• Markers: CBC, lipids, liver function, kidney function, TT, FT, E2

Lipid Management

• Omega-3s (2–4 g EPA/DHA daily)
• 25–40 g fibre daily
• Limit saturated fats
• Regular aerobic conditioning (3–5x weekly minimum)

Oestrogen Management

• Do not intentionally crash E2
• Mast can mask elevated E2 symptoms
• Use AI only based on bloodwork and symptoms

Blood Pressure

• Weekly home monitoring
• Address sustained elevations promptly

Haematocrit

• Monitor via CBC
• Donate blood if >53%

Injection Hygiene

• Strict sterile protocol
• Rotate injection sites
• Short ester requires frequent injections

 

Post-Cycle Therapy (PCT)

Required if not transitioning to TRT

Assumes testosterone was used as a base compound

Start

• 3–5 days after final Masteron Propionate injection
• Base timing on the longest ester used in the cycle

Tamoxifen (Nolvadex)

• 40 mg/day (Weeks 1–2)
• 20 mg/day (Weeks 3–4)

Optional – Clomiphene (Clomid)

• 50 mg/day for 4 weeks

Follow-Up

• Bloodwork 4–6 weeks post-PCT