Supplement analysis backed by scientific evidence · PT

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Limited evidenceBrain & cognition

Pregnenolone

Pregnenolone is the upstream neurosteroid precursor, marketed for memory and mood on essentially no data in healthy people. The modest positive trials are in psychiatric populations at 400-500 mg/day, and they are small, inconsistent and unreplicated.

What the science says

  • No evidence for memory or cognition in healthy adults Limited evidence

    There are no controlled trials showing pregnenolone improves memory, focus or cognition in healthy people. The memory claims trace back to 1940s-era industrial studies and rodent work, not modern clinical research.

  • Schizophrenia adjunct: mixed at best Limited evidence

    In the largest RCT (120 participants randomized, 8 weeks of adjunctive pregnenolone), the primary cognitive endpoint - the MATRICS composite - was not improved. A secondary measure of functional capacity (UPSA-B) did improve (p = 0.03), and negative symptoms did not change because baseline scores were already very low. Other small add-on trials report negative-symptom benefits while several are null.

  • Bipolar depression: one promising but unreplicated RCT Limited evidence

    Eighty adults with bipolar depression were randomized to pregnenolone titrated to 500 mg/day or placebo for 12 weeks as add-on therapy. There was a significant treatment-by-week interaction on the Hamilton Depression scale (p = 0.025) and higher remission by self-report (61% vs 37%), but the effect did not appear consistently across all scales and has not been replicated.

Dosage & safety

Studied doseTrials use 100-500 mg/day, with the bipolar depression study titrating to 500 mg/day for 12 weeks. Consumer supplements typically contain 10-50 mg - doses with no efficacy data whatsoever.
SafetyPregnenolone is converted into progesterone, DHEA, androgens and estrogens, so it can produce hormone-related effects: acne, irritability, headache, insomnia and menstrual changes. Short-term trials up to 500 mg/day report good tolerability, but long-term safety is unknown and effects on the endometrium and prostate are unstudied. Avoid with hormone-sensitive cancers and in pregnancy or breastfeeding. Its status under anti-doping rules is ambiguous - related prohormones including DHEA are banned outright - so tested athletes should avoid it. Prescription-only or unapproved as a supplement in many countries outside the US.

Scientific references

Where to buy

Double Wood Supplements, Pregnenolone, 120 Capsules (50 mg per Capsule)

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