Feeling low or anxious? A blood test can help rule out physical causes
Low mood and anxiety are complex, and most of the time the right support involves talking therapies, lifestyle changes, or your GP — a blood test is not a mental health diagnosis and doesn't replace that care. But several physical, biochemical issues can contribute to or worsen low mood and anxiety, and they're straightforward to check for.
An underactive thyroid, low vitamin D or B12, and imbalances in stress hormones like cortisol can all affect how you feel day to day. Ruling these in or out with a blood test can be a useful, practical first step alongside — not instead of — appropriate mental health support.
If your low mood or anxiety is severe, persistent, or affecting your daily life, please speak to your GP first; a blood test is a helpful complement to that conversation, not a substitute for it.
Common blood-testable causes
Underactive thyroid
Hypothyroidism is a well-recognised, treatable contributor to low mood, brain fog and fatigue. A thyroid panel checks TSH, FT4, FT3 and thyroid antibodies.
Check with Thyroid Profile →Low vitamin D or B12
Both are common in the UK and are linked to low mood, poor concentration and fatigue. They're simple to correct with the right dose once a deficiency is confirmed.
Check with TATT (Tired All The Time) →Stress hormone imbalance
Cortisol and DHEA-sulphate sit at the centre of your body's stress response; sustained highs or lows can affect mood, sleep and energy.
Check with Stress Panel →Hormonal changes
Shifting hormones around perimenopause, menopause or with low testosterone can affect mood alongside physical symptoms.
Check with Hormone Profile (Female) →Panels worth considering
Thyroid Profile
Your thyroid controls your energy, weight and mood. This panel checks all four key thyroid markers — much more thorough than a standard NHS TSH-only test.
Stress Panel
This focused panel measures two hormones — cortisol and DHEA-sulphate — that sit at the centre of your body's stress response.
TATT (Tired All The Time)
Our number-one panel for people who are constantly exhausted. Checks all the common culprits in one blood draw — thyroid, iron, B12, vitamin D and inflammation.
Common questions
Can a blood test diagnose depression or anxiety? +
No. Blood tests can't diagnose a mental health condition. They can help identify or rule out physical contributors — such as thyroid problems, vitamin deficiencies or hormonal imbalance — which is useful alongside proper mental health support, not instead of it.
Should I see my GP as well as booking a blood test? +
Yes, especially if your mood or anxiety is severe, persistent or affecting daily life. A blood test is a helpful complementary step; your GP (or NHS 111/999 in an emergency) is the right route for assessment and mental health support.
What if my results come back normal? +
A normal result rules out the physical causes checked in the panel — it doesn't mean nothing is wrong, and it's still worth discussing how you're feeling with your GP or a mental health professional.
Get a clear, clinician-reviewed answer
Same-week appointments. No GP referral. Prompt results, reviewed by a clinician.
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