Clayton's Health Facts: Pregnenolone.

Clayton South, SPN (ISSA), is a recognized expert in the bodybuilding / fitness industry with over 150 bodybuilding, fitness and nutrition publications to his credit.

What Is It?
And Where Does It Come From?

Pregnenolone (3-Hydroxypregn-5-en-20-one; delta 5-pregnen-3 beta-ol-20-one, and 17 beta-(1-ketoethyl)-delta 5-androstene-3 beta-ol) is a steroid hormone that is manufactured from cholesterol by cellular mitochondria.

It is found in human nervous system tissues1, including the adrenal glands, the skin, the retina of the eye, the brain, the testicles in males and the ovaries in women.

Pregnenolone can exist in the blood as pregnenolone or the more stable pregnenolone-sulfate.

What does it do?
What scientific studies give evidence to support this?

Pregnenolone is an endogenous (naturally produced) steroid hormone that is a precursor to every bodily hormone. Pregnenolone is produced primarily in the testicles in males and the ovaries in females.

Pregnenolone was originally used in the 1940's to treat arthritis, and it proved remarkably effective for relieving arthritic symptoms. Studies show that pregnenolone may relieve the symptoms of rheumatory and osteo arthritis and increase the range of motion of arthritic joints. However, benefit was noted only when patients were given intramuscular injections of pregnenolone.2 No data has been obtained on the effects of oral pregnenolone administration on arthritis symptoms.

Although pregnenolone is a precursor hormone to every other hormone made by the body, the site of pregnenolone manufacture will chiefly determine the results of pregnenolone hormone conversion.

In males, for example, pregnenolone produced in the testicles has a high probability of converting into testosterone, and pregnenolone produced in the ovaries in females has a high probability of converting into estrogens. In both sexes, pregnenolone produced in the adrenal glands has a high probability of converting into aldersterone, cortisol or DHEA. Pregnenolone supplementation may help to correct any existing hormone imbalances.

"Probability" and "high conversion" must be defined. Although the pregnenolone manufacture site does influence the conversion of pregnenolone into, for example, testosterone, it does not always follow that pregnenolone MUST convert into testosterone or any other hormone. In the worst case, pregnenolone may convert into stress hormones, thereby creating a catabolic environment that could lead to muscle breakdown instead of muscle gain (atrophy instead of hypertrophy).

Furthermore, the term "high conversion" is relative. Many hormones convert to their target hormone at a rate of about ten percent. While this conversion rate is clinically significant and while pregnenolone can improve hormone profile, and quality of life, a pregnenolone to testosterone conversion rate of ten percent would still fall far short of delivering the results seen with prescription anabolic steroid drugs.

Aside from its use as a hormone booster, pregnenolone has also been used as an immune system booster and stress reliever. Anecdote indicates that pregnenolone helps improve energy levels, helps to combat stress, and helps to improve sleep length and quality.3 It may also combat the skin ageing (through an increase in hydration) when topically applied.4

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Pregnenolone also improves mental function in a dose dependant manner. It has been shown to affect working, short-term and long-term memory, and may result in increased motivation to learn new information, and an improvement in the ability to acquire new knowledge.5

Who needs it?
What are some symptoms of deficiency?

No daily requirement or allowance (RDA) exists. Everyone can benefit from pregnenolone supplementation.

Pregnenolone is an appropriate supplement for men and women of all ages.

How Much Should Be Taken?
And Are There Any Side Effects?

Follow label directions.

Pregnenolone has an impressive record with very low levels of toxicity and is safe for human use.

Do not use pregnenolone if you are supplementing DHEA.

Do not use if you suffer from seizure disorders, as pregnenolone can suppress GABA activity, resulting in an increase in central nervous system activity which may lead to seizures in those with epilepsy.6

Consult with a physician before using any nutritional supplement.


  1. Morfin R, Young J, Corpechot C, et al. Neurosteroids: pregnenolone in human sciatic nerves. Proc Natl Acad Sci 1992;89:6790-3.
  2. McGavack TH, Chevalley J, Weissberg J. The use of D 5-pregnenolone in various clinical disorders. J Clin Endocrinol 1951;11:559-77.
  3. Steiger A, Trachsel L, Guldner J, et al. Neurosteroid pregnenolone induces sleep-EEG changes in man compatible with inverse agonistic GABAA-receptor modulation. Brain Res 1993;615:267-74.
  4. Sternberg TH, LeVan P, Wright ET. The hydrating effects of pregnenolone acetate on the human skin. Curr Ther Res 1961;3:469-71.
  5. Isaacson RL, Varner JA, Baars JM, de Wied D. The effects of pregnenolone sulfate and ethylestrenol on retention of a passive avoidance task. Brain Res 1995;689:79-84.
  6. Maione S, Berrino L, Vitagliano S, et al. Pregnenolone sulfate increases the convulsant potency of N-methyl-D-aspartate in mice. Eur J Pharmacol 1992;219:477-9.

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