Add-on · Minerals
A red cell magnesium test measures magnesium inside your red blood cells rather than in the fluid around them. Less than 1% of your body's magnesium is in the blood, and the serum level is held steady, so it can stay normal while stores run low. You can add red cell magnesium to TrueVitals Ultimate for £59, alongside the serum magnesium Ultimate already includes.
Add-ons are tested on the same blood draw as your panel and reported inside your clinician-reviewed report, read alongside your other 140 results. They are not sold on their own.
Pay in instalments with Klarna or Clearpay at checkout. Want it with Advanced instead? Email support@truevitals.co.uk and we will set it up.
Magnesium is involved in hundreds of enzyme reactions, including energy production, muscle and nerve function and heart rhythm. Most of it sits in bone and inside cells. The body keeps the serum level within a narrow band by drawing on those stores, so a normal serum magnesium does not rule out a shortfall.
Red cells live about four months, so red cell magnesium reflects a longer window. It is not a perfect measure of total body magnesium, and the NHS normally uses serum, so we report both side by side.
Ultimate includes serum magnesium, calcium, PTH, potassium, kidney function, HbA1c and fasting insulin. Reading red cell magnesium with those shows whether a low result has an obvious driver and whether it is affecting other minerals.
| Option | Includes it | Price | What else you get |
|---|---|---|---|
| Ultimate + red cell magnesium | Yes | £458 incl. clinic draw (home visit £487) | Read alongside serum magnesium, calcium, PTH, potassium, kidney function and HbA1c. Clinician-reviewed report. |
| TrueVitals Ultimate, Advanced or Signature | Serum only | From £319 | Serum magnesium is included in all three panels. |
| NHS GP | Serum, if indicated | Free | Serum magnesium, usually when symptoms or medicines suggest a problem. |
TrueVitals prices checked 5 November 2026. Every TrueVitals report is clinician-reviewed. Pay in instalments with Klarna or Clearpay. Book a draw at one of 103 partner clinics, or add a home visit.
When to get help: a racing or irregular heartbeat, fainting or muscle spasms you cannot control need urgent medical review, not a blood test panel.
A private panel is a good way to get a baseline, understand a result in context and track it over time. It does not replace your GP for symptoms, and anything that needs follow-up is flagged in plain words in your report.
Red cell magnesium on its own rarely tells the whole story. In TrueVitals panels it is reported with these related markers:
Yes, serum magnesium is included in Ultimate, Advanced and Signature. Red cell magnesium is an add-on for £59.
It reflects magnesium inside cells over a longer period, so it can pick up a shortfall that serum misses. Neither is a perfect measure of total body magnesium, which is why we report both together.
Keep taking them as normal unless you want to know your level without them. Tell us what you take in the lifestyle quiz so your report can account for it.
Usually diet first (leafy greens, nuts, seeds, beans, whole grains), then a supplement if needed, and a review of any medicines that cause losses. Retest after about three months.
Yes. Email support@truevitals.co.uk and we will set up an order with more than one add-on.
Some specialist add-ons are sent on to a reference laboratory. Your main report arrives within 4 working days, and if an add-on result comes back later it is added to your report automatically and we let you know.
How this page was written: by James Smillie, founder of TrueVitals, reviewed by the TrueVitals clinical review team, using NHS and laboratory reference sources. Ranges are typical values; your report uses your lab's own ranges. TrueVitals sells the panels named on this page, so we have stated plainly what this test cannot do. Last updated 5 November 2026.
Ultimate + red cell magnesium: £458 including the clinic draw, or £487 with a home visit. Clinician-reviewed report.
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