You sleep a full eight hours and still wake up feeling like you have not slept. You open your health check report and there is not a single flagged value, yet you start wondering whether the problem is your own discipline, whether you simply are not going to bed early enough. This kind of "tiredness with no identifiable cause" is often not a question of willpower at all, but a few key hormones — cortisol, DHEA and insulin — quietly going off track. These markers are rarely part of a standard health check and need a targeted blood test to see, which is why so many people keep adjusting their habits and still feel exhausted.
What does high cortisol mean, and why do you still feel tired when the health check is normal?
Cortisol: the body's front-line stress hormone
Cortisol is the stress hormone secreted by the adrenal glands. Its job is to raise alertness and mobilize energy when the body faces stress. In the short term this is a protective mechanism, but under sustained pressure cortisol stays elevated and starts affecting metabolism, immunity and sleep quality. There is also the opposite scenario: after long-term stress has worn the system out, cortisol can swing low instead — which also produces fatigue, just with a different presentation. A single blood value makes it easy to read the situation the wrong way; it usually needs to be compared against DHEA to show whether the body is in "combat readiness" or "depletion".
DHEA: the adrenal "reserve" marker
If cortisol represents the body's stress response right now, DHEA represents the reserve left after carrying stress over the long term. DHEA is another key adrenal hormone, and even when cortisol sits inside the normal range, a low DHEA can indicate that the adrenals are already close to depletion. That is why so many people who are clearly "not ill" are nevertheless tired to the bone. Because cortisol and DHEA only mean something when read together, they are usually assessed alongside a full set of endocrine and metabolic markers. What does the Body Decode Core Panel cover? →
Blood sugar is more than fasting glucose — what are HbA1c and the HOMA indices?
Beyond adrenal hormones, glucose metabolism is another commonly overlooked piece of the fatigue picture. Many people only check whether fasting glucose is above the cut-off, but a "normal" fasting glucose does not rule out insulin resistance — which is why some people who eat modestly and have a normal body weight still feel too tired to get up.
HbA1c: your average blood sugar over the past three months
HbA1c reflects the proportion of red blood cells bound to glucose, giving you an average blood sugar picture over roughly three months. It shows a long-term trend far better than a one-off fasting glucose. The commonly used international reference sits at around 5.7% or below, but please interpret your result against the reference range printed on your own report — it can vary slightly between laboratories and methods.
HOMA-IR and HOMA-beta: resistance, or declining secretion?
Large swings in blood sugar, or blood sugar dipping overnight, prompt the body to release stress hormones in the middle of the night to compensate — one of the reasons many people wake at 3am. HOMA-IR is an index calculated from fasting glucose and insulin levels, used to assess the degree of insulin resistance. HOMA-beta assesses how well the pancreatic beta cells are secreting insulin. Only by reading the two together can you tell whether the problem is "the body responding poorly to insulin" or "the pancreas producing less of it" — and the next steps for those two situations are not the same.
| Marker | What it reflects |
|---|---|
| Cortisol | The intensity of your current stress response |
| DHEA | Adrenal reserve after long-term stress |
| HbA1c | Average blood sugar over the past three months |
| HOMA-IR | Degree of insulin resistance |
| HOMA-beta | Insulin secretion capacity of pancreatic beta cells |
Cortisol, DHEA, blood sugar, insulin and HbA1c each reflect a different facet of the endocrine and metabolic systems, and reading any one of them alone makes it easy to miss the full picture. The Body Decode Core Panel (136 markers) brings these markers together in a single report, so one blood draw shows you both your adrenal and your metabolic status.
See what the panel covers →Eat, supplement, move, sleep: where can you start today?
While you are waiting for blood results, there are four directions you can start working on in daily life to reduce unnecessary cortisol stimulation.
Eat: watch when you take caffeine and refined sugar
Both caffeine and refined sugar push cortisol up, keeping the body in a state of readiness and making blood sugar more volatile. Everyone's caffeine tolerance is different, so start by controlling the timing — avoiding it after midday, for example — and watch how that relates to your sleep quality that night. Find the range your own body can handle rather than applying a one-size-fits-all rule.
Supplement: only with data behind it
Vitamin C, vitamin B5 (pantothenic acid) and magnesium are heavily consumed while the adrenals synthesize cortisol and DHEA, and they deplete faster under long-term stress. That said, these are safest taken with blood data to back them up, rather than buying from a list — confirming which one is genuinely low is what makes supplementing meaningful, and it avoids overdoing it or going in the wrong direction.
Move: avoid intense exercise close to bedtime
Regular moderate-intensity exercise during the day helps stabilize both blood sugar and cortisol, but prolonged high-intensity training adds to the adrenal load and makes fatigue harder to shake. Schedule moderate aerobic or resistance work during the day, avoid vigorous exercise within three hours of bed, and keep anything in the evening to light stretching — then notice whether you can genuinely wind down before sleep.
Sleep: a wind-down routine tells the brain it is safe to switch off
The point of a bedtime routine is not the ritual itself but letting the brain know it can relax and sleep now. A fixed wake-up time matters more than a fixed bedtime, and staying away from screens and work messages before bed removes sources of stimulation that keep cortisol elevated. These adjustments take a little time before you feel the difference, so there is no need to get it perfect at the first attempt.
The questions people ask most about cortisol, DHEA and insulin
What are the symptoms of high cortisol?
Common presentations of chronically elevated cortisol include fatigue, weight gain around the waist and abdomen, poorer sleep quality, and a tendency to feel tense or irritable. These symptoms can also have other causes, so the actual picture needs to be assessed alongside blood values rather than judged from symptoms alone.
Can I supplement DHEA on my own?
DHEA is a hormone precursor. Before taking it, we suggest finding out your own level through a blood test and discussing with a qualified professional whether supplementation is needed and at what dose. Buying a supplement without data to support it is not advisable.
Is insulin resistance the same as diabetes?
Insulin resistance is not diabetes. It is a state in which the body responds less well to insulin and has to secrete more of it to keep blood sugar stable, and it is an early-stage presentation of many metabolic problems. For the actual interpretation, please go by the reference values printed on your test report.
Do I need to fast for a cortisol and DHEA blood test?
Sampling requirements differ between tests, and cortisol in particular can be affected by the time of day the blood is taken. For the actual timing and fasting requirements, please follow the instructions from your testing provider or healthcare professional.
Does the Body Decode Core Panel include cortisol, DHEA, glucose and insulin?
The Body Decode Core Panel (136 markers) covers a range of endocrine and metabolic markers, including cortisol, DHEA and glucose metabolism values. There is no need to add these on separately.
What commonly causes high cortisol?
Sustained high pressure, insufficient sleep and large swings in blood sugar are all common reasons cortisol stays elevated. Work stress, overtraining and long-term under-eating can push it up through the same mechanism. The actual cause varies from person to person, so we suggest assessing it alongside blood values rather than judging from lifestyle alone.
What should I watch in my diet if cortisol is high?
Both caffeine and refined sugar push cortisol up, so pay attention to timing — avoiding caffeine after midday, for example. Eating at regular times and getting enough protein also helps stabilize blood sugar and reduce extra cortisol stimulation. The actual dietary direction is still best assessed by a professional based on your own test data.
Which specialist should I see if I suspect high cortisol?
Cortisol abnormalities usually fall under endocrinology, and if other systemic symptoms are present as well, more than one specialty may need to be involved. Functional medicine testing can serve as a supporting tool for clarifying the state of multiple body systems. For the actual specialty to see, we suggest discussing your symptoms and blood results with a healthcare professional.
Before you feel tired again, get the full picture of what is going on
If you often find yourself "not ill but exhausted", rather than guessing one marker at a time, it is worth seeing your current endocrine and metabolic status in one go.
The Body Decode Core Panel covers 136 markers, including cortisol, DHEA and glucose metabolism values, and comes with a professional report consultation.
