Androstenedione Test

If you have unexplained acne, thinning hair, irregular periods, or have been told your testosterone is "borderline," your androstenedione level may hold the answer your standard labs missed. This hormone sits one step upstream of both testosterone and estrogen, so it can spike before either of those downstream hormones crosses a flagged range on a routine panel.

Androstenedione (delta-4-androstenedione) is made in two places: your adrenal glands (small glands above each kidney) and your gonads (ovaries in women, testes in men). Because it feeds into both the male and female hormone pathways, an abnormal level can reveal problems in either system, and it often catches hormone overproduction that testosterone or estrogen testing alone would miss.

What Androstenedione Tells You

Think of androstenedione as raw material. Your body converts it into testosterone (the primary androgen) and estrone (a form of estrogen). When the machinery that makes hormones is overactive, androstenedione is often the first number to rise, because it is the intermediate that accumulates when production is ramped up.

In a study of 129 women (86 with PCOS and 43 controls), serum androstenedione was a more sensitive indicator of androgen excess than testosterone alone, picking up androgen excess (hyperandrogenism) in women whose testosterone levels still appeared normal. Elevated androstenedione also predicted worse insulin sensitivity and a higher chance of blood sugar problems. A separate study of 846 women with PCOS found that women whose androstenedione was high relative to their free testosterone actually had a more favorable metabolic profile than women whose free testosterone was the dominant elevation, suggesting the pattern of androgen excess matters, not just the total amount.

Polycystic Ovary Syndrome

PCOS is the most common reason androstenedione is ordered. A 2024 diagnostic meta-analysis across 18 studies (about 2,850 women) found that androstenedione had a pooled sensitivity of about 75% and specificity of about 71% for detecting biochemical hyperandrogenism (lab-confirmed androgen excess) in PCOS, with an overall accuracy (area under the curve) of 0.80. Total testosterone and free testosterone performed slightly better (accuracy around 0.85 to 0.87), which is why international PCOS guidelines recommend testosterone as the first test to order.

Where androstenedione earns its spot is as a second-line marker: when testosterone comes back normal but clinical suspicion remains high, an elevated androstenedione can confirm androgen excess. A 2023 case-control study of 213 women found that androstenedione alone had the highest diagnostic accuracy among individual androgens, with about 82% sensitivity and 83% specificity for hyperandrogenic PCOS. A model combining testosterone, androstenedione, and the free testosterone index further improved diagnostic efficiency over any single marker.

Congenital Adrenal Hyperplasia

In congenital adrenal hyperplasia (CAH), a group of inherited conditions where the adrenal glands overproduce androgens, androstenedione is the primary marker doctors track to judge how well treatment is controlling hormone excess. Two landmark phase 3 randomized trials published in 2024 tested crinecerfont, a drug that blocks a brain signal driving adrenal overproduction, in both children (103 patients) and adults (182 patients) with classic CAH.

In the adult trial, baseline androstenedione averaged 620 ng/dL, well above the normal range. After four weeks, the crinecerfont group saw androstenedione fall by about 299 ng/dL while the placebo group actually increased by about 46 ng/dL. This allowed 63% of the crinecerfont group to reach a normal steroid dose (compared with 18% on placebo), reducing the long-term side effects of excess steroid medication like weight gain, bone loss, and blood sugar problems.

Breast Cancer Risk

Higher circulating androstenedione has been classified as having "convincing" evidence for increased breast cancer risk in postmenopausal women, according to a 2024 umbrella review that graded hundreds of non-genetic risk factors. A case-cohort analysis of 1,208 postmenopausal women from the Melbourne Collaborative Cohort Study found that each doubling of plasma androstenedione was associated with about a 20% higher risk of estrogen-receptor-positive breast cancer (risk ratio 1.20), even after adjusting for lifestyle and other hormones.

The connection makes biological sense through a well-understood mechanism: androstenedione is converted into estrone (a type of estrogen) by an enzyme called aromatase in fat tissue. A genetic study found that women who carry a variant in the HSD3B1 gene that increases androstenedione production had significantly higher circulating androstenedione and were enriched among estrogen-driven postmenopausal breast cancer cases compared with the general population (17.5% vs 9.6% genotype frequency, p = 0.008). This suggests the link between androstenedione and breast cancer is not just an association but may be causal.

Heart Disease Risk

A genetic association study of eight steroid hormones identified 15 gene regions that influence steroid hormone levels (including androstenedione), with key loci at CYP17A1 and CYP21A1. Using a technique called Mendelian randomization (which uses genetic variants as a natural experiment to test cause and effect), the researchers found a potential causal link between higher androstenedione and coronary artery disease risk. This is still early evidence, but it aligns with the broader finding that androgen excess tends to cluster with cardiovascular risk factors.

How Levels Change with Age

Androstenedione declines steadily across adult life. A cross-sectional study of 1,423 community-recruited women ages 18 to 75 found that androstenedione fell steeply from the early reproductive years, with the sharpest drop happening before age 40. The decline then flattened in later decades. Natural menopause itself had no independent effect on androstenedione levels when age was accounted for, meaning the fall is driven by aging, not by menopause specifically.

In men, the Massachusetts Male Aging Study (1,709 men ages 39 to 70) showed a similar age-related decline. A 2025 study of 1,104 women ages 40 to 65 confirmed this pattern and found that bilateral oophorectomy (surgical removal of both ovaries) lowered androgens further in older women, indicating that even the postmenopausal ovary continues producing androgens.

Reference Ranges

Androstenedione reference ranges depend heavily on the assay your lab uses. Immunoassays and mass spectrometry (a more precise technique often abbreviated LC-MS/MS) can give meaningfully different numbers for the same sample. The ranges below come from studies using the more accurate mass spectrometry method. They are orientation for understanding your result, not universal targets. Always compare your results within the same lab over time.

These ranges decline with age. In women, a study of 985 participants established age-specific ranges using quantile regression for each year of age from 20 to 80, because a level that is normal at 25 may be abnormally high at 55. If your lab reports only a single reference range for all adult women, you may want to compare your result against these age-stratified values for a more meaningful interpretation.

When Results Can Be Misleading

Androstenedione has a within-person variability (coefficient of variation) of about 20%, meaning that your level can naturally fluctuate by that much from one draw to the next even when nothing has changed. A single reading that is mildly above or below range may simply reflect this normal fluctuation.

• Time of day and menstrual cycle: Steroid hormones, including androstenedione, vary throughout the day and across the menstrual cycle. Morning draws (before 10 AM) in the early follicular phase (days 2 to 5 of the cycle) give the most reproducible results.
• Oral contraceptives: Combined oral contraceptive pills suppress androstenedione substantially, so testing while on the pill will yield falsely low results that do not reflect your underlying hormone production. Test after at least one full cycle off hormonal contraception.
• Glucocorticoid medications: Prednisone, dexamethasone, and similar drugs suppress the adrenal glands and can lower androstenedione without the drop reflecting actual improvement in an underlying condition like PCOS. If you are on these medications, your result may underestimate true adrenal androgen output.
• Assay method: Immunoassays can show an intermethod variability of up to 30% for androstenedione. If your result is borderline, ask whether your lab uses mass spectrometry, which is the gold standard for androgen measurement.

Tracking Your Trend

With 20% within-person variability, a single androstenedione result is a snapshot, not a verdict. The real value of this test comes from tracking it over time under consistent conditions: same time of day, same lab, same phase of menstrual cycle if applicable. Two to three readings taken under similar conditions give you a much more reliable picture of your true baseline.

If you are making a change, whether starting a medication, losing weight, or adjusting a supplement, retest in three to six months to see whether the number has moved. Annual monitoring makes sense if your level is stable and within range. If you are managing a condition like PCOS or CAH, your endocrinologist may want more frequent checks, sometimes every three months, to fine-tune treatment.

What to Do with an Abnormal Result

A high androstenedione, especially if confirmed on a repeat draw, should prompt a broader hormone workup. The most useful companion tests depend on your clinical picture.

• Suspected PCOS: Order total testosterone, free testosterone, SHBG (sex hormone binding globulin, a protein that carries sex hormones in the blood), and DHEA-S (dehydroepiandrosterone sulfate, an adrenal androgen). Fasting insulin and glucose help assess metabolic risk.
• Suspected adrenal source: 17-hydroxyprogesterone is the key companion test to rule out congenital adrenal hyperplasia. If markedly elevated, an ACTH stimulation test may follow.
• Postmenopausal women with high androstenedione: Consider an imaging study of the adrenal glands and ovaries, particularly if the elevation is sudden or severe, to rule out an androgen-producing tumor.
• Specialist referral: An endocrinologist is the right specialist for persistent androgen elevation. A reproductive endocrinologist is appropriate when PCOS and fertility are the primary concerns.

A low androstenedione in a young woman, especially alongside low testosterone and DHEA-S, may point toward premature ovarian insufficiency or adrenal insufficiency and warrants further evaluation of gonadal and adrenal function.