Bulbine natalensis to Improve Testosterone - Quick Reference Sheet

Bulbine natalensis to Improve Testosterone

Created on 07/23/2026 – Quick Reference based on Evidence Review created using AI4L / Opus 4.8 Audit

A southern African herb traditionally used as a male aphrodisiac and now sold as a natural testosterone booster. The testosterone claims come from short rat studies, not men, where higher doses reversed the gains. The same animal doses strained the liver and kidneys. The only human study checked short-term safety, finding no clear harm. (Full Review)

Protocol

Dose
650 mg/day
ProLensis extract; commercial range 325–650 mg/day
Timing
325 mg twice daily
Morning and ~6 hours later, with food
Dose Ceiling
Cap, do not escalate
Higher dose reversed the gain in animals
Time to effect
Testosterone
Unknown in humans
Hormonal changes within 1–7 days in rats

Benefits

Contraindications
  • Pregnancy or breastfeeding
  • Pre-existing liver disease (transaminases above upper limit of normal)
  • Significant kidney impairment (eGFR below 60 mL/min/1.73 m²)
  • Hormone-sensitive cancers
  • Narrow-therapeutic-index CYP3A4 or CYP2C9 substrate drugs
Key Interactions
  • Prescription CYP3A4 and CYP2C9 substrates (statins such as simvastatin, calcium-channel blockers, benzodiazepines, warfarin, phenytoin, NSAIDs)
  • Hepatically metabolized OTC drugs (acetaminophen, high-dose NSAIDs)
  • CYP-active botanicals (St. John's wort)
  • Other testosterone or aromatase-modulating supplements (Tribulus terrestris, Fadogia agrestis, tongkat ali)
  • Alcohol and other hepatotoxins

Risk & Side Effects

  • High:
  • Medium: Liver toxicity
  • Low: Kidney toxicity; adverse blood lipid changes; herb–drug interactions
  • Speculative: Rebound testosterone suppression; altered white blood cell counts

Monitoring

Marker Target Why
Total testosterone ~500–900 ng/dL (men) Primary target outcome
Free testosterone ~15–25 pg/mL (men) Biologically active fraction
Estradiol ~20–30 pg/mL (men) Tracks conversion of testosterone to estrogen
Luteinizing hormone (LH) ~2–8 mIU/mL Shows whether any effect is central or testicular
ALT / AST ~10–30 U/L Detects liver-cell strain
ALP / GGT ALP ~40–100 U/L; GGT <30 U/L Sensitive liver signals seen in animal and human data
Creatinine / eGFR Creatinine ~0.8–1.1 mg/dL; eGFR >90 Detects kidney strain
Fasting lipid panel HDL >50 mg/dL; triglycerides <100 mg/dL Captures the adverse lipid shift seen in animals

Cadence: Liver and kidney panels at ~4 weeks; reassess hormones after a full cycle; repeat every 3–6 months if use continues, stopping earlier if liver enzymes rise

Qualitative Assessment

  • Libido and sexual function: subjective drive, erectile quality, and frequency of spontaneous interest
  • Energy and mood: daytime energy, motivation, and any irritability or aggression
  • Physical signs: acne, unusual fatigue, right-upper-quadrant discomfort, or dark urine
  • Strength and recovery: training performance and recovery