RESEARCH MONOGRAPH · KDC-MN-158

Pregnenolone

May 9, 2026 Kodiac biolabs Research Revised May 30, 2026 2 min read

Our opinion on this compound

61/100

The grandparent steroid that gets sold as a finished neurosteroid, which it isnt

Pregnenolone sits at the top of the steroidogenic tree. Cholesterol gets converted to pregnenolone in mitochondria by CYP11A1, and from there everything branches: progesterone, allopregnanolone, DHEA, cortisol, testosterone, estrogens, the works. So when you read a marketing page that says pregnenolone does X, what they're really claiming is that you can dose the parent compound and selectively get one downstream metabolite, which is not how steroid biochemistry works.

The interesting pharmacology is that pregnenolone itself (and its sulfate, PREGS) does seem to be a direct CNS modulator. It's a positive allosteric modulator at NMDA receptors and a negative modulator at GABA-A, which is opposite to its allopregnanolone metabolite. There's preclinical work showing pro-cognitive effects via this NMDA mechanism, and a handful of small human studies in schizophrenia and bipolar showing modest signal on cognition and negative symptoms.

But here's the thing. When you give oral pregnenolone you get a downstream metabolite cocktail that varies a lot person to person depending on CYP17A1 activity, 5-alpha reductase, sulfotransferase activity, sex, age. The same dose in two people produces very different DHEA, allopregnanolone, and progesterone responses. So the clinical literature is honestly all over the place.

Mechanism is well-mapped at the receptor level, terrible at the systemic-pharmacokinetic level. Reliability of effect is low for that reason. Safety is reasonable at the doses studied but you're shifting an entire steroid axis, which means it interacts with anything else hormone-related you're doing.

Sourcing is straightforward, it's a cheap commodity steroid that's been made at scale forever, HPLC purity is easy to verify, and most research-grade material is fine.

What we like: the NMDA-PAM angle is genuinely interesting and underexplored. What we dont like: marketing pages that talk about pregnenolone like it's a single-target nootropic when it's a precursor pool that turns into half the steroidome. Treat it like a research tool for studying steroid biosynthesis, not a finished molecule.

Evidence: 50
Mechanism: 65
Reliability: 40
Safety: 68
Sourcing: 80
Value: 70
Signal: 55
Staying power: 60

Plain-language summary Intrigue 65 / 100

Pregnenolone is the master neurosteroid: the body makes it from cholesterol and uses it as the precursor to all other steroid hormones. Beyond hormonal precursor, pregnenolone itself is neuroactive and is investigated for cognitive enhancement and mood. Not stocked by Kodiac. This monograph is provided for research and educational reference.

Intrigue 0–100 blends mechanism novelty, evidence strength, and translational potential. Kodiac editorial, not peer-reviewed.

Endogenous neurosteroid precursor

An endogenous steroid hormone synthesized from cholesterol; the precursor of all other endogenous steroid hormones and a neurosteroid in its own right.

Abstract

Pregnenolone (CAS 145-13-1; molecular formula C21H32O2; molecular weight 316.48) is the metabolic precursor of all endogenous steroid hormones (corticosteroids, mineralocorticoids, gonadal steroids) synthesized from cholesterol by the side-chain cleavage enzyme CYP11A1. Pregnenolone is also a neurosteroid acting at sigma-1 receptors and as a positive allosteric modulator of NMDA receptors at micromolar concentrations. Plasma and CNS pregnenolone decline with age. The compound has been studied for cognitive enhancement, depression, and schizophrenia (where some Phase 2 trials have shown modest effects). The compound is sold as a dietary supplement. Reported research dose ranges in the literature span 10 to 100 mg. Investigators should be aware that pregnenolone elevates downstream steroid hormones (DHEA, cortisol, sex steroids) through metabolic conversion, with potential clinical implications.

Mechanism of action

Sigma-1 receptor activity; NMDA receptor PAM. Precursor for downstream steroid hormone synthesis.

Reported research dose ranges

Reported research dose ranges in the literature span 10 to 100 mg.

References

Marx CE, et al. Pregnenolone as a novel therapeutic candidate in schizophrenia. Mol Psychiatry 2009.

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KDC-MN-158

The full reference document is provided strictly for research use only. It reports research dose ranges from the published literature, not instructions for use in humans or animals.

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FOR RESEARCH USE ONLY. Not for medical, diagnostic, or therapeutic purposes. Not for human consumption. All information is provided for research and educational purposes only.

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Pregnenolone

Abstract

Mechanism of action

Reported research dose ranges

References

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Abstract

Mechanism of action

Reported research dose ranges

References

Read the full monograph

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