Finasteride vs Testosterone
FDA Approved vs FDA Approved
compatible 5-alpha reductase inhibitor that reduces conversion of testosterone to DHT. Used concurrently for hair loss prevention or prostate health. May reduce some androgenic benefits (body hair, libido in some individuals). Standard dose is 1 mg daily for hair loss.
Molecular Data
Finasteride Testosterone
Weight 372.54 Da 288.42 Da (base)
Half-life 6-8 hours (DHT suppression persists ~24 hours) ~8 days (cypionate)
Type Synthetic 4-azasteroid compound Steroid hormone (C19H28O2)
Key Benefits
Finasteride
01 Reduces scalp DHT by approximately 66% at 1mg daily
02 Slows or stops hair loss progression in roughly 90% of men
03 Produces visible hair regrowth in approximately 48% of men within 1-2 years
04 FDA-approved with over 25 years of clinical use and long-term safety data
05 Convenient once-daily oral dosing with no injections required
06 Well-characterized side effect profile with low incidence of adverse events
07 Can be combined with minoxidil for enhanced efficacy
Testosterone
01 Restoration of normal testosterone levels in hypogonadal men
02 Increased lean muscle mass and strength
03 Improved bone mineral density and reduced fracture risk
04 Enhanced libido, sexual function, and erectile quality
05 Improved mood, energy, motivation, and cognitive clarity
06 Reduction in body fat percentage, particularly visceral fat
07 Increased red blood cell production and oxygen-carrying capacity
08 Improved insulin sensitivity and metabolic health markers
Dosing Protocols
Finasteride
1mg/day (hair loss) or 5mg/day (BPH) / Once daily
Testosterone
100-200 mg/week (TRT) / 1-2x per week (injectable)
TRT - Standard Replacement 100-200 mg/week 1-2x per week
TRT - Conservative Start 80-100 mg/week 2x per week (40-50 mg per injection)
TRT - Propionate Protocol 25-50 mg every other day Every other day or 3x per week
Performance Enhancement - Moderate 300-500 mg/week 2x per week
Performance Enhancement - Advanced 500-750 mg/week 2-3x per week
Side Effects
Finasteride
Decreased libido (reported in 1.8% of men in clinical trials vs 1.3% placebo)
Erectile dysfunction (reported in 1.3% vs 0.7% placebo)
Decreased ejaculate volume (reported in 0.8% vs 0.4% placebo)
Testosterone
Acne and oily skin (increased sebum production via DHT)
Water retention and bloating (estrogen-mediated)
Mild mood changes (irritability, increased assertiveness)
Increased hematocrit and hemoglobin (erythrocytosis)
Testicular atrophy (suppression of LH/FSH from exogenous testosterone)
Injection site pain, redness, or irritation
Increased body hair growth
Mild elevation in blood pressure
Contraindications
Women who are pregnant or may become pregnant (finasteride is teratogenic and can cause abnormalities of external genitalia in a male fetus; even handling crushed tablets poses a risk)
Women who are breastfeeding
Known hypersensitivity to finasteride or any component of the formulation
Severe hepatic impairment (finasteride is metabolized by the liver)
Pediatric patients (not indicated for use in children)
Prostate cancer (active or history of hormone-sensitive prostate cancer)
Breast cancer in males
Polycythemia (hematocrit above 54% at baseline)
Uncontrolled severe heart failure
Untreated severe obstructive sleep apnea
Desire for near-term fertility (without concurrent HCG/FSH)
Pregnancy or potential exposure to pregnant women (Category X)
Hypersensitivity to testosterone or any formulation components
Research Evidence
Finasteride Testosterone
Status FDA Approved FDA Approved
References 5 studies 5 studies
Latest — June 2023
FDA Approved Yes Yes
This comparison is for educational and research purposes only. Consult a healthcare professional before use.