Magnesium, RBC
Magnesium stored inside red blood cells, a more stable read on body magnesium than serum.
Consider this test if:
- Muscle cramps, twitching, palpitations, poor sleep, or persistent fatigue with no clear cause
- A normal serum magnesium but ongoing symptoms that suggest depletion
- Long-term use of diuretics, proton-pump inhibitors, or heavy alcohol intake
- Checking whether magnesium supplementation is actually restoring your stores
- HSA/FSA eligible
- Typical results in 2-4 days · Reviewed by a real clinician
- Drawn at a CLIA/CAP-accredited lab near you ·
Pre-test considerations
No fasting required. If you take magnesium supplements, note the dose and timing, since recent intake can raise the result; keep your routine consistent when comparing results over time.
Video consult with your Care Team
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What this test is for
RBC magnesium measures the magnesium held inside red blood cells, which reflects your longer-term magnesium status more reliably than a single serum reading. Magnesium drives hundreds of enzymatic reactions, including muscle and nerve function, heart rhythm, blood sugar regulation, and energy production. Low magnesium is linked to muscle cramps, twitching, fatigue, irritability, palpitations, poor sleep, and headaches, and is more common with heavy alcohol use, certain diuretics or proton-pump inhibitors, and poorly controlled diabetes. Because the body keeps blood magnesium in a tight range by pulling from tissue stores, serum magnesium can read normal while you are actually depleted, which is why this intracellular measure is useful when deficiency is suspected.
This is the red-blood-cell form; the separate serum or plasma magnesium test is the routine, faster screen and the right default for acute or general checks.
What to expect
- 1 Book instantly
Click, book, done. Choose a convenient lab location near you. Transparent, up-front pricing.
- 2 Quick lab visit
Testing to fit your busy schedule, usually 15 minutes or less. Walk-in and appointments available.
- 3 Typical results in 2-4 days
Your results post straight to your dashboard as soon as the lab completes them.
- 4 Expert guidance
Included with Mito membership. A clinician reviews your results and your personalized action plan follows, with clear next steps.
Everything your health needs,
in one membership
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Every test at our cost
Members pay our cost on every test, with lab fees passed straight through. The full receipt is itemized, never padded.
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Continuous tracking, all in one place
Upload past labs and watch your trends over time. Every marker and visit lives in one longitudinal record, so all your care stays together.
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Year-round clinician support
Text anytime and get clinician-reviewed answers. When you want to go deeper, 1:1 consultations are available at affordable rates.
All for $9/month
Order any test or consult without joining. For $9/month, members unlock member prices, trend tracking, and year-round clinician guidance.
Mito Membership
$9 /mo
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Without membership
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At-cost pricing on labs, scans, and more
Priority turnaround on your results
On-demand clinician consults when you need guidance
Personalized action plans across supplements, exercise, nutrition, and sleep
AI health coaching to help you act on your results
Year-round medical support, with in-chat clinician escalation
All your health records in one personal vault, with trends and biological age tracking
Early access to new diagnostics and product releases
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Frequently asked questions
View all FAQsHow does pricing work?
Every test shows the member price next to the standard non-member price, so you can see what membership saves you. The member price is our cost — covering the lab and what it takes to run the service — never a profit on the test itself; Mito makes its money on the $9 membership, not on marking up your tests. Membership is $9/mo, and you still pay the lab’s order fee. Prices are itemized before you pay, with no hidden fees.
Where do I get tested?
Choose a partner lab (Quest, Labcorp, or BioReference) at checkout. If your cart spans multiple tests, we consolidate the whole order onto a single lab so you only make one visit.
Is this eligible for HSA/FSA?
Yes. This test is HSA/FSA eligible, and you can pay with your HSA/FSA card at checkout.
When will I get my results?
Your results post to your dashboard once your lab completes them, then a clinician reviews them and your full analysis and personalized action plan (with clear next steps) follow. Turnaround varies by test: specialty assays and at-home kits take longer, and each test shows its expected turnaround before you buy.
Do I need a doctor’s order?
No. Mito provides the lab order for you, so you can book and get tested without a separate doctor visit.
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