⏱ 3 Min Read

Think you might have PCOS? Test these 5 hormones

Written by
Eleni Stefanou

Medically reviewed by
Dr Dupe Burgess, BSc MBBS MRCP

Updated on
20 Nov 2023

If you've been reading up on PCOS and think there's a chance you have this common endocrine disorder, read on to find out which hormones to test.

5 facts before you get started

1. If you’re on birth control you'll usually need to come off it for three months before doing blood tests to ensure accurate results.

2. If you’re not on birth control and have irregular or no periods, your doctor can help you determine the best time to take a test.

3. In the table that follows, you’ll notice the term ‘normal range’. This shows the range of results observed in healthy people. These measurements vary from lab to lab. A doctor will be able to put your results into context based on your full medical history.

4. Your hormone levels should always be assessed in relationship to each other, along with other signs such as acne, weight gain, and period-related abnormalities. For example, if your LH is much higher than your FSH, this is a strong indicator of PCOS.

5. PCOS is a complex condition and not all cases will present with obvious markers. Make sure the healthcare professional assessing your results is familiar with the condition so that they don’t miss atypical presentations.

5 hormones to test if you suspect PCOS

Tap to expand and learn about each hormone

1. Follicle-Stimulating Hormone (FSH)

Function: Helps regulate the production of eggs.

Dysfunction: High levels can indicate PCOS or primary ovarian deficiency (when the ovaries stop functioning earlier than expected).

When to test: Between day 1-5 of your cycle.

Normal rage

  • Follicular phase: 3.5-12.5 IU/L

  • Ovulation: 4.7-21.5 IU/L

  • Luteal phase: 1.7-7.7 IU/L

  • Post-menopause: 25.8- IU/L

2. Sex Hormone-Binding Globulin (SHBG)

Function: Helps regulate testosterone and estrogen.

Dysfunction: High levels reduce your testosterone and estrogen. Low levels increase your testosterone and estrogen.

When to test: Whenever

Normal rage: 32.4-128 nmol/L

3. Thyroid Function Test (Free T4 and TSH)

Function: TSH and T4 help regulate your metabolism.

Dysfunction: If TSH is high and T4 is low, you may have an underactive thyroid (hypothyroidism). If TSH is low and T4 is high you may have an overactive thyroid (hyperthyroidism). An under or overactive thyroid can impact your weight, menstrual cycle, and energy levels.

When to test: Whenever

Normal rage: 

  • TSH: 0.27-4.20 mU/L

  • Free T4: 12.0-22.0 pmol/L

4. Free Testosterone

Function: Helps regulate testosterone and estrogen.

Dysfunction: High levels can disrupt ovulation which can lead to irregular or missed periods. Can also cause oily skin, acne, and excess hair growth.

When to test: Between day 14-21 of your cycle.

Normal rage: 0.29-1.67 nmol/L

5. Luteinising Hormone (LH)

Function: Triggers ovulation.

Dysfunction: High or low levels can cause irregular periods and trouble getting pregnant.

When to test: Between days 14-28 of your cycle.

Normal rage:

  • Follicular phase: 2.4-12.6 IU/L

  • Ovulation: 14-95.6 IU/L

  • Luteal phase: 1-11.4 IU/L

  • Postmenopause: 7.7-58.5 IU/L

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