Androstenedione / Andro

Medically reviewed by Prof. Giorgi Pkhakadze, MD, MPH, PhD — GMJ Editorial Board

What is Androstenedione / Andro?

Androstenedione, commonly known as “andro,” is a steroid hormone naturally produced by the adrenal glands, ovaries, and testes. It serves as a precursor to both testosterone and estrogen in the body’s hormone synthesis pathway. In the late 1990s and early 2000s, androstenedione gained widespread attention as a dietary supplement marketed to athletes and bodybuilders for enhancing muscle mass and athletic performance.

The supplement became infamous when baseball player Mark McGwire admitted to using it during his record-breaking 1998 season. However, due to safety concerns and its classification as an anabolic steroid, androstenedione was banned by the FDA from dietary supplements in 2004 and is now classified as a controlled substance under the Anabolic Steroid Control Act of 2004.

Health benefits & uses

Athletic performance enhancement: Limited evidence
Despite marketing claims, scientific studies have failed to demonstrate that androstenedione supplementation effectively increases muscle mass, strength, or athletic performance in healthy individuals. Multiple controlled trials showed no significant improvements in lean body mass or strength compared to placebo groups.

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Testosterone enhancement: Limited evidence
While androstenedione is a testosterone precursor, research indicates that oral supplementation does not reliably increase testosterone levels in healthy adults. Some studies showed temporary, modest increases in testosterone, but these were inconsistent and often accompanied by unwanted increases in estrogen levels.

Medical applications: No established uses
Currently, there are no approved medical uses for androstenedione supplementation. The hormone plays important physiological roles in normal hormone production, but therapeutic supplementation has not been validated for any health conditions.

How it works

Androstenedione functions as an intermediate compound in steroid hormone biosynthesis. In the body, it can be converted to testosterone through the enzyme 17β-hydroxysteroid dehydrogenase or to estrone through the enzyme aromatase. The theory behind supplementation was that increasing androstenedione levels would drive more hormone conversion toward testosterone production, thereby enhancing muscle growth and athletic performance.

However, research revealed that oral androstenedione supplementation often leads to increased estrogen production rather than the desired testosterone boost. This occurs because the aromatase enzyme readily converts androstenedione to estrone, which can then be converted to estradiol, potentially causing feminizing effects in men.

Dosage

No safe or effective dosage established. Androstenedione is banned as a dietary supplement in the United States and many other countries. Historical studies used doses ranging from 50-300 mg daily, but these doses were associated with adverse effects without proven benefits. There is no recommended daily allowance (RDA) or upper limit (UL) established by health authorities, as it is not recognized as an essential nutrient.

Anyone considering hormone-related supplementation should consult with a qualified healthcare provider who can assess individual needs and recommend safe, legal alternatives if appropriate.

Food sources

Androstenedione is not naturally found in significant quantities in common foods. While trace amounts may be present in certain animal products, dietary intake from food sources is negligible and does not contribute meaningfully to the body’s androstenedione levels. The body produces sufficient amounts endogenously for normal physiological functions.

Safety & side effects

Androstenedione supplementation carries significant health risks, which contributed to its ban. Documented side effects include:

• Hormonal imbalances: Increased estrogen levels, particularly in men
• Cardiovascular risks: Decreased HDL (good) cholesterol, increased LDL (bad) cholesterol
• Masculinizing effects in women: Deepened voice, facial hair growth, male-pattern baldness
• Feminizing effects in men: Gynecomastia (breast tissue development)
• Liver stress: Potential hepatotoxicity with prolonged use
• Mood changes: Increased aggression, mood swings
• Acne and skin problems

Interactions

Androstenedione may interact with various medications and supplements, though comprehensive interaction data is limited due to its banned status. Potential interactions include:

• Blood thinners: May affect bleeding risk
• Diabetes medications: Could influence blood sugar control
• Liver medications: May compound hepatic stress
• Other hormone supplements: Risk of additive hormonal effects
• Insulin: May affect glucose metabolism

Who should be cautious

Given its banned status and safety profile, no one should use androstenedione supplements. However, those at particularly high risk if exposed include:

• Adolescents and young adults (risk of hormonal disruption during development)
• Women who are pregnant or breastfeeding
• Individuals with hormone-sensitive conditions (breast cancer, prostate cancer, endometriosis)
• People with liver disease or dysfunction
• Those with cardiovascular disease
• Competitive athletes subject to drug testing

Frequently asked questions

Is androstenedione legal to buy or use?

No, androstenedione is banned as a dietary supplement in the United States and classified as a controlled substance. It is also prohibited by most sports organizations worldwide. Possession and distribution may carry legal penalties.

Are there safer alternatives for testosterone support?

Yes, several legal and safer options exist, including maintaining a healthy lifestyle with adequate sleep, regular exercise, stress management, and proper nutrition. Vitamin D, zinc, and magnesium may support healthy testosterone levels when deficient. Always consult a healthcare provider for personalized advice.

Can androstenedione be detected in drug tests?

Yes, androstenedione and its metabolites can be detected in urine and blood tests for extended periods. Athletes who test positive may face serious consequences including disqualification and bans from competition.

What should I do if I have old androstenedione supplements?

Dispose of them safely through a medication take-back program or follow FDA guidelines for safe disposal. Do not use expired or banned substances, as they may pose serious health risks.

Why was androstenedione banned if it’s naturally produced by the body?

While androstenedione is naturally produced, supplemental doses far exceed normal physiological levels and can disrupt hormonal balance, leading to serious adverse effects. The ban was implemented to protect public health due to the lack of proven benefits and significant safety concerns.