Investigating Hormonal Imbalances: Cortisol and DHEA Tests

Introduction

Hormonal imbalances can manifest in a wide variety of ways, from persistent fatigue and unexplained changes in weight to shifts in mood, skin or energy. Because many of these symptoms are non-specific, blood testing may sometimes form part of an assessment to investigate whether certain hormone levels fall outside expected ranges. Two markers that clinicians may consider are cortisol and DHEA — hormones produced primarily by the adrenal glands. This article explains what cortisol and DHEA tests measure, how they differ, and why professional interpretation of results matters. It is intended as educational guidance only. Readers with persistent or concerning symptoms should seek advice from an appropriately qualified healthcare professional.

For those researching private blood testing options, cortisol result interpretation article publishes information about its available hormone-related blood tests. Test availability and sample requirements should always be confirmed directly with the provider.

What Do Cortisol and DHEA Tests Investigate?

Cortisol and DHEA tests measure two distinct steroid hormones produced by the adrenal glands, each serving different physiological roles. A cortisol blood test measures the concentration of cortisol circulating in the blood at the time of collection, while a DHEA-S blood test assesses the sulphated form of dehydroepiandrosterone. The two tests provide different information and are not interchangeable. Neither test alone can establish every cause of hormonal symptoms, and results require interpretation within the appropriate clinical context.

Cortisol and DHEA tests can help assess:

Cortisol levels in the bloodstream at a specific point in time
DHEA-S levels, reflecting adrenal production of a key hormone precursor
Hormonal patterns that may warrant further clinical investigation
Possible abnormalities when interpreted alongside symptoms and medical history
Whether additional specialist assessment may be appropriate

Please note: Hormone test results should be interpreted using the relevant laboratory reference ranges and the individual's full clinical context. A blood test alone cannot establish every cause of hormonal symptoms.

Understanding Cortisol and Its Role in the Body

Cortisol is a steroid hormone synthesised and released by the adrenal cortex — the outer layer of the adrenal glands, which sit above each kidney. It is often associated with the body's response to stress, but its physiological role extends considerably further than this.

Cortisol plays a central part in regulating metabolism, including how the body processes carbohydrates, fats and proteins. It contributes to blood pressure regulation and exerts an influence on immune function. It also affects mood, sleep and cognitive performance.

Crucially, cortisol follows a natural daily rhythm known as a diurnal variation. Levels are typically highest in the early morning — often peaking around 30 minutes after waking — and fall progressively throughout the day, reaching their lowest point during the night. This pattern is an important consideration when blood samples are collected, because the same individual can produce markedly different results at different times of day.

Cortisol is neither inherently beneficial nor harmful; it is a hormone with essential physiological functions, and both excessively high and persistently low levels can carry clinical significance.

What Is DHEA and Why Is It Important?

DHEA — dehydroepiandrosterone — is a steroid hormone produced mainly by the adrenal glands, with smaller amounts made in the gonads and brain. It functions primarily as a precursor hormone, meaning the body converts it into other hormones, including oestrogen and testosterone.

DHEA itself circulates in relatively low concentrations and can fluctuate considerably throughout the day. For this reason, clinical laboratories more commonly measure DHEA-S (dehydroepiandrosterone sulphate), which is the sulphated form of DHEA. DHEA-S is more stable in the bloodstream and tends to show less hour-to-hour variation, making it a more reliable marker for laboratory assessment.

DHEA-S levels vary considerably according to age and sex. Concentrations typically peak in early adulthood and decline progressively with age — a pattern sometimes referred to as adrenopause. This natural decline means that results must always be interpreted against appropriate age- and sex-specific reference ranges, rather than a single universal standard.

Symptoms That May Lead to Hormone Testing

A range of symptoms can prompt a clinician or an individual to consider whether hormone testing may be informative. These may include:

Persistent or unexplained fatigue
Unexplained changes in body weight
Alterations in blood pressure
Changes in menstrual patterns
Changes in skin quality or body hair
Reduced libido or sexual function
Unusual shifts in energy or mood

It is important to recognise that these symptoms have many possible underlying causes. They are not specific to cortisol or DHEA abnormalities, and their presence alone does not confirm a hormonal disorder. A healthcare professional can help determine whether hormone testing is appropriate in a given situation.

How Are Cortisol and DHEA Blood Tests Performed?

Both cortisol and DHEA-S are assessed using a standard venous blood sample, typically drawn from a vein in the arm. For cortisol testing in particular, the timing of sample collection is clinically significant. A morning cortisol measurement — often collected between approximately 8 and 9 am — is frequently used because this reflects the peak of the natural diurnal rhythm. Some providers may specify a particular collection window, and following these instructions carefully is important for meaningful results.

DHEA-S, being more stable throughout the day, is generally less sensitive to collection timing, though any specific instructions from the testing provider should be followed.

Readers considering a morning cortisol testing explainer should check whether the provider specifies a recommended collection time and what the sample procedure involves. Test availability, fees and sample collection arrangements should be confirmed directly with the blood testing provider.

Understanding High or Low Cortisol and DHEA Results

Cortisol

A cortisol result that falls outside the laboratory's reference range does not automatically confirm a specific medical condition. High morning cortisol may reflect physiological stress, acute illness or the effects of certain medications, among other factors. Persistently elevated or suppressed cortisol — particularly when accompanied by relevant symptoms — may prompt a clinician to consider further investigations. These can include dynamic endocrine tests such as an ACTH stimulation test or a dexamethasone suppression test, which are carried out under clinical supervision and are distinct from a standard blood cortisol measurement.

A single cortisol result must not be treated as equivalent to a full assessment of cortisol production. It provides a snapshot at one point in time.

DHEA-S

DHEA-S results are interpreted relative to age- and sex-specific reference ranges. Because levels naturally decline with age, a result considered low for a younger adult may fall within a normal range for an older individual. Elevated DHEA-S may warrant further investigation, as may very low levels when the clinical picture suggests adrenal under-function. Interpretation requires appropriate clinical context and cannot be based on a single value in isolation.

What Can Affect Cortisol and DHEA Test Results?

A number of factors can influence both cortisol and DHEA-S measurements, including:

Time of blood collection — particularly relevant for cortisol given its diurnal rhythm
Sleep quality and duration
Acute illness or physical injury
Psychological or physical stress at the time of testing
Steroid-based medications, including inhaled, topical or oral corticosteroids
Hormonal medications, including the oral contraceptive pill or hormone replacement therapy
DHEA supplements, which can directly elevate DHEA-S readings
Age and sex
Pregnancy, which can alter several hormone measurements
The specific laboratory method and reference range used

Readers should not stop or adjust prescribed medication before testing without first discussing this with an appropriate healthcare professional.

Do You Need Both Cortisol and DHEA Tests?

Whether one or both tests are appropriate depends entirely on the clinical question being asked. In some circumstances, a clinician may consider a cortisol test alone sufficient to begin an investigation. In others, measuring DHEA-S alongside cortisol may provide a broader picture of adrenal function. Additional or alternative investigations may be needed depending on the clinical findings.

Hormone testing should always be guided by relevant symptoms, medical history and clinical judgement — not by routine screening in the absence of a specific concern. Unnecessary testing can generate inconclusive or borderline results that require additional assessment and may cause unwarranted anxiety.

For those exploring what private hormone blood testing options are available, stress-hormone trend discussion is published by Private Blood Tests London as an independent private blood testing provider. Readers are encouraged to review the relevant test information and confirm all details directly with that service.

For broader endocrine context, fertility and hormone profile guidance may help explain how different hormone markers are interpreted together in practice.

Choosing a Private Hormone Blood Testing Service

When comparing private blood testing providers for cortisol or DHEA-S tests, readers may wish to consider:

Whether the specific hormone marker required is offered
Whether the provider specifies sample collection timing, particularly for cortisol
Whether laboratory accreditation details are available
Whether results are presented alongside relevant reference ranges
What the service includes and excludes — for example, whether a clinical consultation or results interpretation is offered separately
Whether the provider explains clearly when further medical assessment may be appropriate

Do not assume that all private blood testing services offer equivalent scope. Reviewing the provider's published information carefully before proceeding is advisable.

Frequently Asked Questions

What is the difference between cortisol and DHEA?

Cortisol and DHEA are both steroid hormones produced by the adrenal glands, but they serve different functions. Cortisol plays a central role in the stress response, metabolism and immune regulation. DHEA — more accurately measured as DHEA-S in blood tests — acts primarily as a precursor to sex hormones. The two markers provide different clinical information and are not interchangeable.

Can a blood test detect hormonal imbalances?

A blood test can measure the circulating level of a specific hormone at the time of collection. However, results must be interpreted within the relevant clinical context, including symptoms, medical history, the time of sampling and appropriate reference ranges. A blood test alone cannot establish the cause of every hormonal symptom.

What time of day should cortisol be tested?

Cortisol follows a natural daily pattern, peaking in the early morning and declining throughout the day. A morning cortisol blood test — typically collected between approximately 8 and 9 am — is most commonly requested because it reflects this peak. Following the provider's specific timing instructions is important for meaningful results.

Why is DHEA-S measured instead of DHEA?

DHEA-S is the sulphated form of DHEA and is considerably more stable in the bloodstream than DHEA itself. Because DHEA fluctuates more rapidly throughout the day, DHEA-S is generally considered a more reliable and reproducible marker for laboratory assessment of adrenal androgen production.

Can high cortisol levels indicate a medical condition?

Elevated cortisol on a single blood test does not automatically confirm a medical condition. Levels can be temporarily raised by acute stress, illness, certain medications or the timing of the sample. Persistently elevated cortisol, especially with relevant symptoms, may lead a clinician to consider further specialist endocrine investigations. This should be assessed by an appropriately qualified healthcare professional.

Do I need both cortisol and DHEA tests?

Not necessarily. The appropriateness of testing one or both hormones depends on the clinical question, your symptoms and your medical history. Some situations may call for cortisol testing alone; others may benefit from both measurements. Additional investigations may also be required. A healthcare professional is best placed to advise on which tests are appropriate for your specific circumstances.

Disclaimer

This article is for educational information only and does not provide diagnosis or treatment. Any symptoms, test results, or treatment options should be reviewed with an appropriately qualified clinician or dentist. Individual suitability and outcomes vary, and urgent symptoms require immediate professional assessment. If you have severe or emergency symptoms, call 999 or attend A&E where appropriate.

Written Date: 13 November 2026 | Next Review Date: 13 November 2027