Methylmalonic Acid (MMA)
A metabolite that accumulates when B12 is functionally insufficient inside cells.
The most sensitive and specific test for true B12 deficiency. Serum B12 can look 'normal' while you're functionally deficient — MMA reveals what's actually happening at the tissue level.
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🩸 Test your Methylmalonic Acid (MMA)
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Order this test — 10% off → Browse all 102 markers →What Methylmalonic Acid (MMA) is usually tested alongside
On its own, one marker is a data point. These panels include Methylmalonic Acid (MMA) plus the markers that make it interpretable — each names every test, why it is on the list, and loads the whole set into your cart in one click at 10% off.
includes this + 11 more markers — Persistently exhausted despite adequate sleep, and either haven't been tested or were told everything is normal.
includes this + 8 more markers — Persistent low mood, anxiety, irritability, or motivation that has quietly disappeared — especially if it doesn't match what's going on in your life.
What moves your Methylmalonic Acid (MMA)
5 supplements in the Vault have a documented effect on this marker, or are a reason to have measured it first:
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Would you feel it? Symptoms Methylmalonic Acid (MMA) helps explain
People rarely search for a marker — they search for how they feel. These are the complaints where this marker is worth checking, and whether it is a first-line test or a follow-up once the obvious causes are ruled out.
Why your Methylmalonic Acid (MMA) might be wrong
Most abnormal results are interference, not disease. These are the things that measurably move this specific marker — check them before you change anything. Each one says whether the number is wrong and should be repeated, badly timed and should be redrawn, or real with a cause worth explaining.
Supplementing before the draw normalises MMA quickly and hides the deficiency you were testing for. This is the most common way a real B12 problem gets missed — the test is run after treatment has already started.
Draw MMA BEFORE starting B12, not after. Once supplemented, the window has closed for months.
MMA is cleared renally, so impaired kidney function raises it independently of B12 status. That turns the test that was supposed to resolve an ambiguous B12 into a second ambiguous number.
Read MMA alongside creatinine or cystatin C. With reduced clearance, homocysteine becomes the more informative functional marker.
Raises MMA independently of B12 status, which is the main cause of a false-positive result.
Interpret against eGFR — a raised MMA in kidney disease is much weaker evidence of B12 deficiency.
Gut bacteria produce propionate, which raises MMA without B12 deficiency.
Consider SIBO if MMA is raised and B12 repletion doesn't lower it.
What Methylmalonic Acid (MMA) means in combination
A single marker tells you a little. Combinations tell you the story — these are the named patterns this marker takes part in, and what each one points at.
MMA rises when B12 is short at the tissue level regardless of what the serum number says. This is the test that settles the argument, and neurological damage from prolonged deficiency is not always reversible.
Treat it, do not re-argue the serum number. Methylcobalamin or hydroxocobalamin; injections if absorption is the problem. Look for the cause: metformin, PPIs, gastric surgery, coeliac, pernicious anaemia, plant-based diet.
What to test next
Markers rarely answer alone. These are the ones that put Methylmalonic Acid (MMA) in context — each with its own full breakdown.
Frequently asked questions
<0.40 µmol/L Ranges vary by laboratory and assay — always compare to the range printed on your own report.
Optimal ranges, root causes and the full correction protocol are available inside Coach Cam's Peptide Academy.
See the full breakdown inside the Academy.
See the full breakdown inside the Academy.
You can order Methylmalonic Acid (MMA) directly through Marek Diagnostics without a doctor's visit — drawn at any Quest Diagnostics location in the US. Code CAMERON applies 10% off automatically.