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What is the Free Androgen Index?

The Free Androgen Index (FAI) is a calculation used to measure the amount of biologically active testosterone circulating in the body. Testosterone is an androgen hormone essential for various functions in both males and females. Unlike total testosterone, which includes bound and inactive hormones, the FAI focuses on the โ€œfreeโ€ testosterone that is unbound and available to tissues. This measure helps clinicians understand the bodyโ€™s hormone balance more accurately, particularly for conditions related to hormonal imbalance.

Why is the Free Androgen Index important?

Since FAI focuses on free testosterone, it is especially valuable for diagnosing and managing conditions such as polycystic ovary syndrome (PCOS), hirsutism, and other hormonal disorders. In women, an elevated FAI can signal increased androgen activity, often resulting in symptoms like irregular menstruation, excess facial or body hair, and acne. For men, the FAI can help evaluate issues like low libido, fatigue, and even infertility. By knowing the FAI, healthcare providers can assess the functional testosterone level and help develop a personalized treatment approach, as opposed to relying solely on total testosterone, which may not reflect active hormone levels.

How can I better understand my Free Androgen Index?

FAI is calculated by dividing the total testosterone level by sex hormone-binding globulin (SHBG) and then multiplying by 100 to obtain a percentage. Understanding FAI results requires considering age, gender, and other health factors.

The normal ranges for the Free Androgen Index are as follows:

  • Females:
    • Out of range: 0-0.4
    • In range: 0.4-8.4
    • Out of range: 8.4+
  • Males:
    • Out of range: 0-14.0
    • In range: 14.0 โ€“ 126.0
    • Out of range: 126+

For females, an elevated FAI would indicate high androgen levels, while a lower FAI may be seen with low androgen levels or increased SHBG, often due to oral contraceptives or liver conditions. For males, lower values might suggest hypogonadism, while higher values can reflect increased androgen production or lower SHBG levels.

How can I maintain optimal Free Androgen Index levels?

If you need to maintain or adjust your FAI, consider the following strategies [1]:

Dietary Changes: Foods high in healthy fats, such as avocados, nuts, and olive oil, can help support hormone production and increase FAI, while reducing processed sugar intake can help lower FAI.

Lifestyle Changes: Balanced physical activity and weight management can help to regulate hormone levels naturally.

Supplementation: Since zinc and vitamin D are necessary to produce testosterone, supplementing with these nutrients may help to increase your FAI. Consult your healthcare provider before starting any supplements or making major lifestyle changes.

Where can I learn more?

DISCLAIMER: IF YOU ARE CONCERNED WITH ANY OF YOUR RESULTS, PLEASE CONSULT WITH YOUR PHYSICIAN.

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