Pregnenolone

The verdict

Is Pregnenolone worth taking?

Pregnenolone sits at the top of the steroid cascade. Every steroid hormone the body makes — cortisol, DHEA, testosterone, progesterone, the estrogens — descends from it. That is true, it is the entire marketing case, and remarkably little follows from it.

The premise of the category is that taking the precursor raises the products. One study has ever checked. Five men took a single 50 mg dose; urinary testosterone did not rise substantially, and no testosterone-to-epitestosterone ratio came close to the 4:1 threshold. Five men, one dose, 2005. That is the whole evidence base for the central claim of the category, and it points the wrong way. No study has measured estradiol, progesterone or DHEA-S as an outcome. No study of this question has included a woman.

What oral pregnenolone does reliably convert to, at the doses that have actually been studied, is allopregnanolone — a neurosteroid acting on GABA receptors. In the largest trial, 500 mg a day roughly tripled serum pregnenolone and raised allopregnanolone seven to eightfold. That is why the real research program is in psychiatry rather than hormone replacement, and why the findings that exist are about mood and anxiety rather than testosterone.

The trial record runs to roughly 500 randomized participants, almost all at 500 mg a day — ten times the tolerability ceiling WebMD gives, and three to fifty times what is sold in capsules. The clearest positive signal is in bipolar depression. Cognition has failed consistently, including in the largest schizophrenia trial. And the only trial ever run in healthy people at supplement-realistic doses, 15 to 30 mg for four weeks, found no effect on mood, memory, sleep quality or wellbeing.

A note for anyone subject to drug testing in sport: DHEA, the metabolite one step downstream, is named on the WADA prohibited list. Pregnenolone is not currently named on it. That list is revised annually, so check the current version rather than this page.

Emerging is the right grade and it is doing a lot of work. The pharmacology is real and genuinely interesting. What it does not support is anything on a pregnenolone label.

What it does

What Pregnenolone does in the body

Master steroid precursor support, cognitive function support (pregnenolone is the most concentrated steroid in the brain, several times higher than in plasma), mood improvement, and indirect downstream hormonal support through conversion to DHEA, progesterone, and ultimately testosterone or estrogens. Pregnenolone is synthesized from cholesterol in the mitochondria and converted by cytochrome P450 enzymes into the entire family of steroid hormones.

The evidence

What the research actually shows

Healthy people, realistic doses: null. A crossover trial in 17 healthy volunteers, 15 mg a day for two weeks then 30 mg for two weeks against four weeks of placebo, found pregnenolone was well tolerated and "by itself, had no significant effects on mood, memory, self-rated sleep quality or subjective well-being." It is the only trial matching how the supplement is actually bought and taken, and nothing happened.

Schizophrenia, five trials, roughly 370 participants — and cognition keeps failing. The largest, 120 patients on 500 mg a day for eight weeks, found no significant cognitive improvement over placebo on its primary measure. An earlier proof-of-concept study of 18 completers moved negative symptoms but not cognition. A trial of 52 completers at 50 mg found attention signals. A trial in 82 women was null on its primary endpoint, with nominal signals that did not survive correction for multiple comparisons.

Bipolar depression is the strongest result in the file. Eighty patients, 500 mg a day, twelve weeks — the longest trial anyone has run on this compound. Depression ratings improved over time against placebo, and remission on a self-rated scale reached 61 percent against 37 percent. Worth knowing, and worth noticing that it is an add-on treatment for a diagnosed illness at a dose nobody sells.

Chronic low back pain: significant and small. Ninety-four veterans, escalating to 500 mg a day over six weeks. The difference against placebo on daily pain was about half a point on an eleven-point scale. The investigator called the findings very preliminary.

Autism: one open-label study of twelve adults with no control group. The study medication was donated by a pregnenolone supplement manufacturer.

The cannabis story is the most misreported. The striking mechanism — pregnenolone blocking cannabinoid effects at the CB1 receptor — is rodent work. When a company took it toward human use they concluded pregnenolone itself is not usable as a medicine: short half-life, poor oral bioavailability, and rapid conversion into other active steroids. They built a non-metabolizable derivative instead. A drug developer looking hard at this molecule decided the oral compound does not work well enough to use, which is a verdict worth weighing against any supplement label.

Indications with no human trial at any quality: fatigue or energy in healthy adults since 1944, anti-aging, memory in healthy older adults, joint pain, menopausal symptoms, immune function, and raising testosterone, estrogen or DHEA as an endpoint. Nearly every claim on a vendor page falls in this list.

Safety, honestly stated. Across roughly 500 trial participants at 50 to 500 mg a day for up to twelve weeks, pregnenolone was consistently well tolerated with no excess of adverse events over placebo — in the largest trial, 55 percent versus 58 percent, with no severe events in either arm. Twelve weeks is also the longest human exposure ever studied. Beyond that, nothing is known, and people take this for years. Health Canada treats it as an unauthorized prescription product and seized a pregnenolone supplement from a distributor in 2017, warning about hormone-sensitive cancers; that warning is reasoning from the precursor relationship, not an observed signal.

Worth checking

The 60 percent decline belongs to a different hormone

Compounding pharmacies and hormone clinics repeat a specific figure: by the age of 75, people have about 60 percent less pregnenolone. It appears word for word across dozens of pages. It has no source. No citation is given anywhere it appears, and following it leads nowhere.

The likely explanation is that it is a real number borrowed from a different hormone. A 1994 study of 2,423 men aged 40 to 80 reported roughly 60 percent declines in adrenal C19 steroids — DHEA and its relatives — across that age span. Different compound, different age bracket, correct number.

The real data on pregnenolone and age exists and is better than the borrowed figure. A 2017 study measured 16 steroids by mass spectrometry in 525 people aged 18 to 81. Pregnenolone showed one of the steeper inverse correlations with age in the whole panel, and the upper reference limit fell from about 30 nmol/L at age 22 to about 8 nmol/L at age 70 — roughly a 75 percent drop, with no overall difference between men and women.

So the direction of the claim is right and the magnitude is, if anything, understated. The figure in circulation is still wrong, nobody who repeats it can say where it came from, and the actual measurement describes a shifting reference range rather than any individual's trajectory.

None of which answers the question that matters, which is whether a lower level causes anything or whether raising it helps. No trial has ever established a target range, shown that reaching one produces a benefit, or tested supplementation in people selected for low levels.

The claim that is simply wrong

The pregnenolone steal is not a real mechanism

The story goes like this: chronic stress makes the adrenals divert pregnenolone into cortisol production, "stealing" it from the pathway that makes DHEA and the sex hormones, so stressed people run low on testosterone and estrogen. It is everywhere in functional medicine content, and it is the usual reason given for supplementing pregnenolone.

It does not appear in the endocrinology literature as a validated mechanism, and the objections to it are specific rather than vague.

There is no shared pool to steal from. Pregnenolone is made inside each individual cell's mitochondria, from cholesterol, by the enzyme CYP11A1. Steroidogenic cells store very little hormone. There is no circulating or glandular reservoir that one cell type could draw down at another's expense.

The bottleneck is upstream of pregnenolone, not at it. The rate-limiting step in steroid production is the transport of cholesterol into the mitochondrion, before pregnenolone exists. Pregnenolone availability is therefore not what constrains output, so running out of it is not a coherent failure mode.

Cortisol and DHEA are made in different cells. The terminal cortisol enzyme is expressed in the zona fasciculata; DHEA is the major product of the zona reticularis. No mechanism has been described for transferring mitochondrial pregnenolone between those zones.

And empirically they rise together, not at each other's expense. DHEA and cortisol are normally released simultaneously under ACTH. The clinical proof is Cushing's disease, where chronic ACTH excess produces high cortisol alongside normal-to-elevated DHEA sulfate. If the steal were real, maximal cortisol drive would flatten DHEA. It does the opposite — so reliably that the DHEA sulfate level is used to tell ACTH-driven Cushing's from the adrenal kind.

Precursor shunting does happen in one setting: congenital adrenal hyperplasia, where a missing enzyme physically blocks a pathway and redirects precursors. That is a genetic lesion, not a consequence of a stressful year. The parent concept the steal belongs to, adrenal fatigue, was examined in a systematic review of 58 studies and found not to exist.

Food first

Getting Pregnenolone from food

There is no food-first route here, and it is worth being plain about why rather than listing foods that supposedly help.

Pregnenolone is not a dietary compound. The body makes it on demand inside the mitochondria of steroid-producing cells — adrenal cortex, gonads, brain — by cleaving the side chain off cholesterol. It is not stored, and it does not travel to those cells from a meal.

The obvious next thought, that eating more cholesterol gives the body more raw material, does not follow either. The step that limits steroid production is not the supply of cholesterol but its transport across the mitochondrial membrane, which is hormonally controlled. Adding substrate upstream of a regulated gate does not open the gate.

So the honest answer to "how do I get more pregnenolone from food" is that you do not, and the things that plausibly support steroid production generally — enough total energy, enough dietary fat, enough sleep, not being in a chronic deficit — are the same unglamorous list that supports everything else. None of it has been tested against a pregnenolone level as an outcome.

What the guide adds

The part that is not on this page

Everything above is the assessment. What the guide adds for Pregnenolone is the protocol:

• Optimal Form
• Dose Range
• Bioavailability
• Purity Red Flags
• Stack With / Avoid

147 entries across nine categories, every one graded against the clinical literature the same way.

Get The Complete Supplement Guide →

About the author

Who graded this

Daniel Edlund is a Le Cordon Bleu-trained private chef in Los Angeles, a certified personal trainer and strength coach, and an internationally licensed massage therapist. Thirty years of strength training and fifteen years cooking in private estate kitchens. He is the author of The Complete Supplement Guide, which grades 147 entries against the clinical literature, and of The EASY Way to Organic Cooking, first published in 2013.

More about Daniel →

This page is information, not medical advice. Supplements interact with prescription medication and with each other, and the right answer depends on your own bloodwork and history. Talk to your doctor before starting anything, particularly if you are pregnant, nursing, managing a health condition, or already taking medication.

Also in Hormonal Support & Vitality

Related entries

• Calcium D-Glucarate — Emerging evidence
• Black Cohosh — Moderate evidence
• Stinging Nettle Root — Emerging evidence
• Red Clover Isoflavones — Moderate evidence
• Fadogia Agrestis — Overhyped
• Fenugreek — Moderate evidence

All 147 entries, graded →