Androstenedione
Also known as: A4, Andro
What Does Androstenedione Measure?
Androstenedione (also called A4 or Andro) is a sex hormone precursor produced primarily in the adrenal glands and the gonads (ovaries in women, testes in men). Blood tests measure the concentration of this steroid hormone in the bloodstream, typically reported in nanograms per deciliter (ng/dL) or nanomoles per liter (nmol/L). It serves as a key intermediate in the biosynthesis of more potent sex hormones, including testosterone and estrogen, making it an important marker for evaluating hormonal balance.
Why Does Androstenedione Matter?
Androstenedione plays a critical role in the hormonal cascade that produces androgens and estrogens throughout the body. Abnormal levels can signal underlying conditions such as polycystic ovary syndrome (PCOS), congenital adrenal hyperplasia (CAH), adrenal tumors, or ovarian dysfunction. In clinical practice, measuring androstenedione helps evaluate causes of hirsutism (excess hair growth), irregular menstrual cycles, infertility, and early or delayed puberty. It is also used to monitor the effectiveness of treatments for hormone-related disorders and to investigate suspected androgen excess in both men and women.
Normal Ranges
Males
75–205 ng/dL (2.6–7.2 nmol/L) for adult males
Females
85–275 ng/dL (3.0–9.6 nmol/L) for adult females; levels vary with menstrual cycle phase and drop significantly after menopause (30–140 ng/dL)
Children
Varies by age and pubertal stage; prepubertal children typically <50 ng/dL; rises progressively during puberty
Causes of High Levels
- Polycystic ovary syndrome (PCOS) — one of the most common causes of elevated androstenedione in women
- Congenital adrenal hyperplasia (CAH) — particularly 21-hydroxylase deficiency, leading to overproduction of adrenal androgens
- Adrenal tumors or adrenocortical carcinoma — abnormal adrenal tissue producing excess hormones
- Ovarian tumors — certain ovarian neoplasms can secrete excess androstenedione
- Cushing's syndrome — excess cortisol production often accompanied by elevated adrenal androgens
- Anabolic steroid or androstenedione supplement use — exogenous intake directly raises blood levels
Causes of Low Levels
- Primary adrenal insufficiency (Addison's disease) — damaged adrenal glands produce insufficient steroid hormones including androstenedione
- Hypopituitarism — reduced ACTH stimulation leads to decreased adrenal androgen production
How to Improve Your Androstenedione
Diet
- Adopt a low-glycemic index diet rich in vegetables, legumes, and whole grains to help regulate insulin levels, which directly influence androgen production
- Reduce refined sugars and processed carbohydrates, as insulin spikes can stimulate ovarian androstenedione secretion
- Include anti-inflammatory foods such as fatty fish (salmon, sardines), berries, and leafy greens to support adrenal and hormonal health
- Consume adequate zinc-rich foods (pumpkin seeds, beef, chickpeas) which support healthy steroidogenesis
- Limit alcohol intake, as excessive consumption can disrupt adrenal hormone regulation and liver metabolism of androgens
Supplements
- Inositol (myo-inositol 2–4 g/day or combined myo/D-chiro-inositol) — clinically studied to reduce androgen levels in women with PCOS
- Spearmint extract or spearmint tea — shown in studies to have anti-androgenic properties; 2 cups of spearmint tea daily or standardized extract
- Zinc (25–40 mg/day) — supports enzyme regulation in steroidogenesis; useful when levels are deficient
- Magnesium (200–400 mg/day as glycinate or citrate) — helps improve insulin sensitivity, indirectly reducing androgen excess
Related Biomarkers
Frequently Asked Questions
What is androstenedione and why is it tested?
Androstenedione is a precursor hormone produced by the adrenal glands and gonads that the body converts into testosterone and estrogen. It is tested to investigate symptoms of androgen excess (such as unwanted hair growth, acne, or irregular periods in women), to evaluate suspected adrenal or ovarian disorders, to help diagnose conditions like PCOS or congenital adrenal hyperplasia, and to assess puberty-related concerns in children.
What does high androstenedione mean for a woman?
Elevated androstenedione in women most commonly signals polycystic ovary syndrome (PCOS), congenital adrenal hyperplasia, or rarely an adrenal or ovarian tumor. High levels can cause symptoms such as hirsutism (excess facial or body hair), acne, irregular or absent menstrual periods, thinning scalp hair, and fertility problems. It is important to investigate the underlying cause with your healthcare provider, as treatment varies significantly depending on the diagnosis.
Is androstenedione the same as testosterone?
No, androstenedione is not the same as testosterone, but it is directly related. Androstenedione is a precursor — a building block — that the body converts into testosterone (a more potent androgen) and also into estrone (an estrogen). Think of androstenedione as an upstream hormone in the production chain. Measuring both androstenedione and testosterone together gives a more complete picture of a person's androgen status.
Can androstenedione levels fluctuate throughout the day or month?
Yes, androstenedione levels can vary. Like cortisol and other adrenal hormones, androstenedione tends to be higher in the morning and lower in the evening (diurnal variation). In women, levels also fluctuate across the menstrual cycle, typically peaking around mid-cycle (ovulation). For this reason, blood samples are often collected in the morning, and in women, the timing relative to the menstrual cycle is noted to ensure accurate interpretation.