Frequently asked questions
This is what our customers ask us about the most. For more information, try our help centre.
What is Vitamin D?
Vitamin D is a fat-soluble vitamin essential for bone health, immune function, and muscle strength. It helps the body absorb calcium and supports overall well-being.
How much vitamin D do I need a day?
Adults need 10 micrograms (400 IU) of vitamin D daily, as recommended by the NHS. However, Dr Thom, Head Of Clinical Services at Forth, suggests that if your results show low vitamin D levels, a higher dose may be needed to rebalance your levels.
The healthy range used by our labs is 50-200 nmol/L, but a level above 75 nmol/L is optimal. We reviewed thousands of blood test results from Forth customers and found that around 50% of adult men and women in the UK have low vitamin D levels.
What is vitamin D good for?
Vitamin D supports bone health, immune function, muscle strength, and mental well-being. It also plays a role in reducing inflammation and supporting cardiovascular health.
Do I need to take vitamin D supplements?
If you have low vitamin D levels or limited sun exposure, supplements can help maintain optimal levels, especially during winter months. A blood test can confirm whether supplements would benefit you.
How long does it take to recover from vitamin D deficiency?
Recovery depends on the severity of the deficiency. With supplements and sun exposure, levels typically improve within weeks to months, but long-term maintenance is key.
Does vitamin D help with mental health?
Yes. Vitamin D is linked to mood regulation, and low levels have been associated with depression and seasonal affective disorder (SAD). Optimising levels may improve mental well-being.
What other biomarkers should I check with vitamin D?
Vitamin D works closely with calcium and magnesium. Checking these alongside vitamin D provides a fuller picture of bone and metabolic health. You can personalise this test to include these markers, giving you a more complete view of your nutritional health. Alternatively, our Nutricheck test checks 14 biomarkers, helping you to check for and manage vitamin deficiencies.
What foods contain vitamin D?
Vitamin D is found in oily fish (salmon, mackerel), fortified foods (cereals, dairy alternatives), egg yolks, and mushrooms. However, diet alone often isn’t enough to maintain healthy levels of vitamin D.
What causes vitamin D deficiency?
Lack of sunlight, poor diet, darker skin tones, age, and certain health conditions can lead to vitamin D deficiency. Winter months increase the risk in the UK.
How soon will the test arrive?
Your test kit is dispatched the same day if ordered before midday (Mon-Fri). It should arrive within 1-2 working days via tracked delivery.
How secure is my data?
We use industry-leading encryption to protect your personal information. Your results are private, confidential, and only accessible through your secure online account.
Can I have someone take my blood for me?
Yes. we offer the option for a trained healthcare professional to visit your home and collect your blood sample from your vein, or you can visit one of our many clinics nationwide.
When will I get my results?
Your results will be available within 2–5 days after your sample reaches our lab. You’ll receive a notification when they’re ready in your secure account.