Pregnenolone
"Master steroid" – endogenous steroid precursor (cholesterol → pregnenolone → all steroid hormones). OTC supplement. Evidence quality LOW: oral bioavailability poor (~5-10%), neurosteroid NMDA/GABA action drives small cognitive benefit. AAS-PCT niche use.
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WHAT IS PREGNENOLONE?
Detailed overview
Pregnenolone is the human body's "master steroid" precursor molecule – the first steroidogenic intermediate derived from cholesterol (via P450scc/CYP11A1 enzyme activity in mitochondria), from which the entire steroid hormone spectrum (progesterone, 17-OH-pregnenolone, DHEA, androstenedione, testosterone, cortisol, aldosterone) is synthesized. It is marketed in the OTC supplement market with a "natural hormone-precursor" claim – the theory being oral administration → systemic steroidogenesis substrate-loading → downstream hormone elevation (Test, DHEA). **Evidence quality LOW**: oral bioavailability is extremely poor (Roberts 1992, PMID 1610975 – serum pregnenolone <10% of administered dose at 4-hour peak, most undergoes first-pass hepatic progesterone conversion), downstream Test elevation in serum measurements is inconsistent. **The actual documented effect is neurosteroid-mediated**: pregnenolone directly in the CNS acts as an NMDA-receptor positive modulator + GABA-A-receptor negative modulator (Mosconi 2017, PMID 28259555 review) – this explains user-reported "mental clarity" + "brain fog reduction" effects, INDEPENDENT of the hormone-axis claim. **AAS-PCT context**: niche adjuvant role for mental recovery (post-cycle brain fog, cognitive haze) – but NOT a SERM-PCT replacement, NOT an HCG replacement, NOT an evidence-based axis-restart agent. Marx 2009 (PMID 19797577) Phase II schizophrenia trial used 500 mg/day dose for moderate cognitive benefit, which itself is a dose-magnitude warning vs typical AAS-PCT context 25-100 mg.
Mechanism
Endogenous steroid precursor (cholesterol → pregnenolone → all downstream hormones) + CNS neurosteroid NMDA/GABA-A modulator
Dosing
25-100 mg oral once daily in evening (OTC range); AAS-PCT niche protocol 50 mg/day × 4-8 weeks
Half-life
~30-45 min (parent; serum kinetics highly variable, rapid first-pass conversion)
Onset
Neurosteroid CNS effect 1-3 hours; downstream hormone effect (if any) 2-7 days chronic dosing
Legal status
OTC dietary supplement (USA DSHEA-1994 schedule); EU countries variable (food-supplement or unregulated); NOT WADA-banned
Data console
Lab data
Safety
Side effects, stop signs, contraindications
Side effects · 6
- Neurosteroid CNS effect: insomnia / heightened alertness in some users (GABA-A negative modulation), so evening dosing can worsen sleep in certain individuals.
- Headache, irritability, anxiety or restlessness in neurosteroid-sensitive individuals, dose-dependent.
- Mood swings and unwanted downstream hormonal effects (acne, increased sebum) since pregnenolone is a precursor to both androgens and estrogens.
- Indirect estrogen conversion (peripheral aromatization via downstream testosterone): water retention, nipple sensitivity. Magnitude is small as oral first-pass progesterone conversion dominates.
- Rare but documented liver enzyme elevation (ALT/AST) with chronic high-dose use (>50 mg/day for 6+ months).
- Highly variable, often absent effect: due to poor oral bioavailability (~5-10%), many users see no measurable hormonal or subjective benefit.
Contraindications · 6
- History or presence of hormone-sensitive cancer (prostate, breast): downstream steroid precursor loading poses a theoretical risk.
- Pregnancy and breastfeeding: pregnenolone crosses the placenta, theoretical effect on fetal HPG axis; theoretical risk also via partner contact.
- Does NOT replace evidence-based PCT: used as standalone PCT (instead of a SERM/HCG) in fully suppressed post-cycle state, axis recovery is undocumented.
- Pre-existing liver disease or elevated baseline ALT/AST: chronic high-dose use may worsen liver function.
- Concurrent GABAergic / anxiolytic medications (benzodiazepines, SSRIs): theoretical GABA-A negative-modulator antagonism, clinical relevance unclear, caution warranted.
- Unknown, uncontrolled hormonal disorder: due to the broad downstream steroid spectrum (testosterone, DHEA, cortisol, estrogen), not advised without medical supervision.
Related Performance Compounds
Same therapeutic category
Studies
Related research and clinical findings
Neurosteroids Progesterone and Dehydroepiandrosterone: Molecular Mechanisms of Action in Neuroprotection and Neuroinflammation.
Fedotcheva TA, Shimanovsky NL
Therapeutic potential of enzymes, neurosteroids, and synthetic steroids in neurodegenerative disorders: A critical review.
Servi R, Akkoç RF, Aksu F
Advancements in Non-Dopaminergic Treatments for Schizophrenia: A Systematic Review of Pipeline Developments.
Komatsu Y, Takehara M, Hart X
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The information here is for educational and scientific purposes only. Performance-enhancing compounds (AAS, prohormones, stimulants, doping agents) are illegal without prescription in Hungary and most of the EU, and carry serious health and legal risks. WADA bans them in competitive sport. This is NOT a usage guide, and we do not encourage any illegal use. If you do use them, medical supervision and regular bloodwork are ESSENTIAL. Severe endocrine, cardiovascular, hepatic and psychiatric side effects are possible.