Pregnenolone is not an acute-feel compound. Unlike modafinil (90 min onset) or phenibut (2-3 hr), effects emerge over days to 2 weeks as steady-state plasma levels and downstream metabolite ratios establish. No single-dose "is this working?" check.

At 5-30 mg/day (OTC microdose) in young man with normal levels — four phenotypes

1. "Alerting" (~25-30%): mild morning clarity, motivation lift. PregS / NMDA arm dominant. Subtle nootropic feel, not stimulant.
2. "Calming" (~25-30%): improved sleep depth, reduced background anxiety. 5α-reductase + 3α-HSD favoring allopregnanolone. Often PM-dosed by this group.
3. "No effect" (~25-30%): nothing felt over 2-4 weeks. Often substrate-saturation or unfavorable enzyme polymorphisms.
4. "Negative" (~10-15%): irritability, anxiety spike, brain fog, mild dysphoria. May be isopregnanolone blocking allopregnanolone, leaving PregS arousal unopposed.

At 50-100 mg/day

Conversion-direction drift becomes visible:

• Androgenic — oilier skin, acne, libido up, body-odor change. High 5α-reductase + CYP17A1.
• Estrogenic — nipple sensitivity, gyno signal, water retention, mood softening. Higher body fat / high CYP19A1.
• Cortisol — anxiety, sleep fragmentation, AM jitteriness.
• Mood elevation — ~10-20% report clean non-euphoric mood lift; most enthusiastic reviews come from this phenotype.

At 100-500 mg/day (psychiatric trial range)

Clinician-supervised only. Effects still gradual; broader side-effect surface (sleep architecture, fatigue, libido, GI). Brown 2014 / Marx 2009 / Marx 2020 effects emerged over 2-6 weeks.

Time course

Day 1-3: usually nothing. Week 1: sleep + dream changes first. Week 2-3: mood/cognitive stabilize, conversion-direction signs appear. Week 4-8: steady-state, bloodwork window. Discontinuation uneventful — no withdrawal syndrome; endogenous output recovers in 4-8 weeks.

Honest meta-frame

Subjective effects are a function of which downstream metabolite dominates in your body — can't be predicted without bloodwork. Community-data polarization (mood-elevation 45 vs fatigue 27; energy 35 vs anxiety 20) reflects conversion-direction variance, not placebo noise. For a 20yo at peak endogenous output, the most likely outcome at OTC dose is phenotype #3 (no effect) or #4 (mild negative).

Tolerance

Minimal direct receptor downregulation — unlike benzos or amphetamines, P5 doesn't deplete a transmitter pool. Three indirect mechanisms exist:

1. HPG/HPA axis adaptation — mild LH/FSH/ACTH downregulation at >50 mg/day for >8 weeks; endogenous output modestly drops. Reverses within 4-8 weeks of discontinuation.
2. Enzyme expression shift — chronic substrate provision can up-regulate downstream enzymes in favored arms. Explains common "first-week magic, then nothing" reports.
3. Allopregnanolone-specific tachyphylaxis — GABA-A modulator tolerance at high dose; more documented for brexanolone than parent P5.

Cycling

• Older deficient adults on replacement: often continuous; some endocrinologists prefer 6-9 months on / 3 months off for endogenous reassessment.
• Younger theoretical users: 8-12 weeks on / 4 weeks off. For Dylan: irrelevant — don't start.
• Psychiatric protocols: trial-defined 8-12 weeks; clinician decides continuation.

Reset

Discontinuation alone is sufficient. No withdrawal syndrome. Endogenous P5 returns within 2-4 weeks; HPG/HPA in 4-8 weeks. Post-cycle bloodwork at 4-6 weeks off confirms recovery. Chronic high-dose (>200 mg/day) users can taper over 2-4 weeks but rarely clinically necessary.

Synergistic with

• Magnesium (glycinate, threonate, malate) — modest GABAergic allopregnanolone-arm potentiation. Already in most canonical stacks.
• DHEA in older deficient adults (50+) — paired in post-menopause / late-andropause replacement. Not for users under 35.
• Progesterone in women (clinician-coordinated) — perimenopausal HRT protocols.
• Vitamin D3+K2, B-complex — substrate/clearance support; indirect.
• Psychiatric protocols (clinician-supervised) — combined with SSRIs, 2nd-gen antipsychotics, lithium, valproate, lamotrigine in Marx 2009 / Brown 2014.

Avoid

• TRT / exogenous androgens — exogenous T saturates AR + shuts endogenous output; added P5 aromatizes to E2 with no androgenic upside. Counterproductive.
• DHEA in young users (<35) — both upstream sex-steroid precursors; amplifies conversion-direction problem.
• Aromatase inhibitors without bloodwork — supraphysiological androgen load + E2 rebound risk on cessation.
• SERMs (enclomiphene/clomiphene) without coordination — combined estrogenic load via P5 → E2 layered on SERM-driven endogenous T rise.
• Exogenous progesterone in young men — duplicative; sedation, libido suppression.
• 5α-reductase inhibitors (finasteride, dutasteride) — block P5 → allopregnanolone conversion. Men on finasteride lose the calming arm entirely; relevant for post-finasteride syndrome users who try P5 expecting relief.
• Phenibut, alcohol, benzos, GHB, baclofen, gabapentin/pregabalin — additive GABAergic depressant load via allopregnanolone arm.

Neutral / safe

Omega-3, citicoline, Alpha-GPC, NAC, creatine, taurine, modafinil, bromantane, Selank, Semax, BPC-157, TB-500, caffeine, L-theanine — no meaningful interactions. Standard SSRIs/SNRIs/lithium co-administered in psychiatric protocols.

For Dylan: Skip. Canonical V4/V5 stack has zero P5 interactions to manage because P5 isn't in the protocol.

Mostly pharmacodynamic (conversion-arm-mediated) rather than CYP-mediated direct.

Pharmacokinetic

• CYP3A4 substrate — modest. Strong inhibitors (ketoconazole, ritonavir, grapefruit) can elevate P5 modestly. Strong inducers (rifampin, St. John's Wort, carbamazepine) accelerate clearance. Low clinical relevance at OTC doses.
• CYP17A1 inhibitors (abiraterone) — block Δ5 androgen arm; oncology context only.
• CYP19A1 inhibitors (anastrozole/letrozole/exemestane) — block P5 → E2. See Stacking.
• No significant CYP induction/inhibition by pregnenolone itself — clean profile; doesn't alter other drug metabolism at OTC doses.

Pharmacodynamic

• 5α-reductase inhibitors (finasteride, dutasteride) — block P5 → allopregnanolone. Men on finasteride lose the calming arm; relevant for post-finasteride syndrome users trying P5.
• SSRIs/SNRIs/TCAs — co-tolerable; SSRIs may upregulate 5α-reductase (theoretically synergistic at calming arm).
• Second-gen antipsychotics — co-administered in Marx 2009 / Kreinin 2014. No major interaction; some may modestly raise endogenous neurosteroids.
• Hormonal contraceptives — no documented direct PK interaction. Theoretical progestin-arm concern at OTC doses unsupported.
• Corticosteroids (prednisone, dexamethasone) — suppress endogenous CYP11A1 via HPA feedback; clinician coordination needed.
• Lithium, valproate, lamotrigine — co-administered Brown 2014 without major interaction.

Alcohol

P5-derived allopregnanolone potentiates GABA-A (same target as alcohol). Additive CNS depression possible at >100 mg P5 + alcohol. Not relevant at OTC doses or for Dylan (zero alcohol baseline).

P5 PGx is more relevant than for most compounds because the variability in clinical response is the genotype-mediated conversion-direction problem.

• CYP19A1 (aromatase) — high-activity variants (rs10046, rs1062033, rs700518) push P5-derived androgens → estradiol. Body fat multiplies the effect via adipose aromatase. Gyno signal, water retention, mood softening more likely.
• CYP17A1 — variants (rs743572, rs10883783) affect Δ5/Δ4 arm split. Strong activity favors DHEA → androgen; weak activity favors cortisol pathway.
• SRD5A1/SRD5A2 — type 1 brain-dominant; type 2 peripheral. Both govern P5 → allopregnanolone. Low-activity carriers (SRD5A2 V89L rs523349) get less calming arm, more PregS arousal. Finasteride mimics low-activity genotype.
• AKR1C2/AKR1C3 (3α-HSD) — controls 3α-reduction to allopregnanolone. Less studied but relevant.
• 3β-HSD2 (HSD3B2) — controls Δ5 → Δ4 conversion; shifts arm ratio.
• AR CAG repeat — modulates androgen-receptor sensitivity. Short CAG = more androgenic phenotype response (acne, libido); long CAG = milder.
• CYP11A1, StAR — affect cholesterol → P5 itself; baseline-level relevance.
• GABA-A subunit genes (GABRA1/2/6) — affect calming-arm sensitivity at receptor level.

23andMe coverage + practical implication

Most genes have partial 23andMe v5 coverage; specific SNPs inferable via Promethease. Bloodwork response testing is more informative than genotype prediction — genotype shifts conversion probabilities ~1.5-3x; bloodwork tells you what your body actually did. Use genotype to refine expectations, not substitute for empirical testing.

For Dylan: pending June 2026 23andMe + bloodwork will refine conversion-direction prediction but won't change the "endogenous peak, no indication, skip" calculus.

Legally OTC in US (DSHEA 1994 grandfathered); prescription-only in UK/Canada/Australia/most of EU.

Quality + WADA

Reputable brands publish third-party COAs (Pure Encapsulations, Thorne, Life Extension, Designs for Health). Adulteration risk is low — P5 is a commodity raw material. Capsule potency variance ±10-30% is the main concern; stick with COA-publishing brands.

WADA: P5 not specifically named, but downstream metabolites (DHEA, T, E2 ratios) trigger S1.1b. Practically disqualifying for tested athletes. Dylan currently untested; would become disqualifying if competition status changes.

For Dylan: Skip the sourcing question entirely. If revisited post-30 with bloodwork rationale, iHerb Life Extension 10 mg or Pure Encapsulations 10 mg are the cleanest starters (~$10-15 per 100-day supply).

P5 is more bloodwork-dependent than any other OTC compound in this wiki. If you can't do bloodwork, you shouldn't do pregnenolone.

Baseline panel

• Pregnenolone (serum, LC-MS/MS gold standard) — headline number
• DHEA-sulfate — Δ5-arm downstream marker
• Total + free testosterone, SHBG
• Estradiol (sensitive/ultrasensitive ECLIA or LC-MS/MS — NOT standard immunoassay)
• LH + FSH — HPG state
• Cortisol (AM) — Δ4 downstream; 4-point salivary if HPA in question
• Prolactin — rules out prolactinoma
• TSH + free T4 — thyroid confounder
• Lipid panel — cholesterol substrate
• CBC + CMP + LFTs

During use (week 8-12)

Repeat full panel. Look for: P5 elevation (absorption confirmed), DHEA-S elevation (Δ5 engagement), T/E2 shift direction (conversion preference), cortisol shift (Δ4 engagement), LH/FSH suppression (HPG adaptation — mild expected, severe = reduce or stop).

Post-cycle (4-6 weeks off)

Repeat panel to confirm HPG/HPA recovery.

Subjective tracking (daily during use)

Sleep VAS / Oura score, PHQ-9 weekly, GAD-7 weekly (if anxiety-prone), cognitive VAS daily + structured task weekly, libido VAS, skin photo log week 0/4/8, weekly weight + waist, resting HR + AM BP.

Genetic data (one-time)

23andMe + Promethease for CYP19A1, CYP17A1, SRD5A1/2, AKR1C2/3, 3β-HSD2, AR CAG. Refines but doesn't substitute for empirical bloodwork.

For Dylan specifically

Pre-supplementation baseline already planned for June 2026 bloodwork. If P5 lands in normal-young-adult range (likely), bloodwork itself resolves the question — no supplementation indicated. If low (unlikely at 20), endocrinology consultation; not a self-administered trial.