+ -Text Size


Other common name(s): none

Scientific/medical name(s): 3-hydroxypregn-5-en-20-one


Pregnenolone is a steroid the body makes as a precursor to other steroid hormones, such as progesterone, DHEA (see DHEA), mineralocorticoids (which regulate electrolyte balance), corticosteroids (which influence inflammation and metabolism), estrogens, and androgens.


Available scientific evidence does not support claims that pregnenolone can help treat conditions such as arthritis, multiple sclerosis, and cancer. Some research in animals has suggested that pregnenolone may help improve memory, but no research in humans has been reported.

How is it promoted for use?

Pregnenolone is mainly promoted as an alternative treatment that improves memory and alertness and reduces stress, depression, and fatigue. Some promoters claim pregnenolone also helps treat a variety of other conditions such as arthritis, cancer, osteoporosis, obesity, multiple sclerosis, premenstrual syndrome, and menopause.

What does it involve?

Pregnenolone supplements are sold in tablet and capsule form and as a topical cream. There is no standard dose, although it is available in strengths ranging from 5 to 50 milligrams.

What is the history behind it?

Pregnenolone was the subject of several animal and human studies during the 1940s. Some suggested potential clinical use for arthritis as well as for improving performance by reducing stress. Subsequent research demonstrated that pregnenolone is the precursor used by the body in producing all steroid hormones. As researchers learned more about these other hormones, interest in pregnenolone as a treatment decreased. For example, cortisol (another hormone made from pregenolone) is useful in treating inflammation of arthritis and other diseases, and doctors felt treatment with cortisol made more sense than treatment with pregenolone, which was used by the body in producing not only cortisol but also estrogens, androgens, and other hormones.

Chemically modified or synthetic versions of natural steroid hormones have been developed and tested as drugs in clinical trials, and those found to be more potent and to have more specific effects are now preferred in clinical medicine.

Interest in pregnenolone as a treatment has increased recently among some alternative practitioners, and a number of websites currently advocate its use for arthritis, Alzheimer disease, athletic training, and cancer.

What is the evidence?

Some promoters claim pregnenolone also helps treat a variety of other conditions such as arthritis, cancer, osteoporosis, obesity, multiple sclerosis, premenstrual syndrome, and menopause. Available clinical evidence does not support these claims. Studies in mice suggest possible enhancement of memory, but it is unclear whether this benefit would occur in humans.

Clinical studies done during the 1940s suggested that pregnenolone might enhance attention and physical and mental performance. These studies have not been replicated with modern clinical research methods, although a small study reported in 1997 as an abstract (but not a full article) found no effect on strength, balance, or memory. Some animal studies have suggested that pregnenolone may help improve memory, but no human studies have been reported in the available peer-reviewed medical literature to confirm this.

Are there any possible problems or complications?

Very little is known about the safety of the supplements or the effects of long-term use. Some laboratory studies in cancer cells and animals have suggested that pregnenolone may stimulate the growth of hormone-responsive cancers such as prostate and breast cancer. The body uses pregnenolone to make steroid hormones such as DHEA and testosterone. High doses may cause aggressiveness, irritability, trouble sleeping, and the growth of body or facial hair on women. It also may stop menstruation and lower the levels of HDL, or "good," cholesterol, which could raise the risk of heart disease. Other possible side effects include acne, heart rhythm problems, liver problems, loss of hair from the scalp, and oily skin.

Little is known about drug interactions, although some studies suggest it may interfere with the action of certain sleeping medicines or calming medicines (benzodiazepines). Always tell your doctor and pharmacist about any supplements or herbs you are taking.

Women who are pregnant or breastfeeding should not use pregnenolone. Relying on this type of treatment alone and avoiding or delaying conventional medical care for cancer may have serious health consequences.

Additional resources

More information from your American Cancer Society

The following information on complementary and alternative therapies may also be helpful to you. These materials may be found on our Web site (www.cancer.org) or ordered from our toll-free number (1-800-ACS-2345).

Dietary Supplements: What Is Safe?

The ACS Operational Statement on Complementary and Alternative Methods of Cancer Management

Complementary and Alternative Methods and Cancer

Placebo Effect

Learning About New Ways to Treat Cancer

Learning About New Ways to Prevent Cancer


Flood JF, Morley JE, Roberts E. Memory-enhancing effects in male mice of pregnenolone and steroids metabolically derived from it. Proc Natl Acad Sci U S A. 1992;89:1567-1571.

Grigoryev DN, Long BJ, Njar VC, Brodie AH. Pregnenolone stimulates LNCaP prostate cancer cell growth via the mutated androgen receptor. J Steroid Biochem Mol Biol. 2000;75:1-10.

Meieran SE, Reus VI, Webster R, Shafton R, Wolkowitz OM. Chronic pregnenolone effects in normal humans: attenuation of benzodiazepine-induced sedation. Psychoneuroendocrinology. 2004;29:486-500.

PDRhealth. Pregnenolone. Accessed at: www.pdrhealth.com/drug_info/nmdrugprofiles/nutsupdrugs/pre_0211.shtml on June 11, 2008.

Roberts E. Pregneolone--from Selye to Alzheimer and a model of the pregnenolone sulfate binding site on the GABAA receptor. Biochem Pharmacol. 1995;49:1-16.

Sih R, Morley JE, Kaiser FE, Herning M. Effects of pregnenolone on aging. J Investig Med. 1997;45:348A.

Tariq SH, Kamel H, Morley JE. Dehydroepiandrosterone and pregnenolone. In: Meikle AW, ed. Endocrine Replacement Therapy in Clinical Practice. Totowa, NJ; Humana Press; 2003: 307-368.

Note: This information may not cover all possible claims, uses, actions, precautions, side effects or interactions. It is not intended as medical advice, and should not be relied upon as a substitute for consultation with your doctor, who is familiar with your medical situation.

Last Medical Review: 11/01/2008
Last Revised: 11/01/2008