Thread by @dr_sumit_sharma

Your B12 levels are 'normal.' But you're tired, foggy, and anxious.

Here's the truth: You might have functional B12 deficiency, and it's silently damaging your brain, nerves, and energy.

A Thread on why "Normal" B12 levels can still leave you deficient:

1. The "Normal" B12 Lie

Your doctor says your B12 is "normal" at 300 pg/mL. But you feel terrible.

• Lab "normal" range: 200-900 pg/mL
• Functional optimal range: 500-1000 pg/mL
• Neurological symptoms start: Below 400 pg/mL

The problem: Labs use ranges based on sick populations, not optimal health.

You can be "normal" and still be functionally deficient.

2. What Functional B12 Deficiency Really Means

Functional deficiency = Your B12 levels aren't low enough to cause anaemia, but they're too low for optimal brain and nerve function.

You're not crazy - you're functionally deficient.

Why this happens:

- Standard tests miss cellular B12 status
- Early deficiency affects brain before blood
- Stress and medications increase B12 needs
- B12 needs are individual (genetics, stress, age)

3. The Hidden Symptoms Nobody Connects to B12

Brain symptoms:

- Difficulty concentrating
- Anxiety and depression
- Mood swings and irritability
- Brain fog and memory issues

Physical symptoms:

- Balance problems
- Shortness of breath
- Tingling hands and feet
- Chronic fatigue despite sleep

These symptoms can persist for years with "normal" B12 levels.

4. Why Standard B12 Tests Are Useless

Serum B12 measures: B12 in your blood

What matters: B12 getting into your cells

Better tests to request:

- Homocysteine: Elevated in B12 deficiency
- Holotranscobalamin: "Active" B12 available to cells
- Methylmalonic acid (MMA): Rises when B12 is functionally low

If MMA is high or homocysteine is elevated, you're functionally B12 deficient regardless of serum B12.

5. The Absorption Problem

Absorption blockers:

- Alcohol consumption
- Metformin for diabetes
- Age (stomach acid decreases)
- Digestive issues (SIBO, Crohn's)
- Stomach acid medications (PPIs, H2 blockers)

40% of people can't absorb B12 properly, even with adequate intake.

The solution: Bypass the gut with sublingual or injectable B12.

6. The Methylation Connection

B12 is essential for methylation, your body's cellular repair system.

The MTHFR factor: 40% of people have genetic variants requiring methylated B12 (methylcobalamin), not regular B12.

When B12 is functionally low:

- DNA repair slows down
- Energy production decreases
- Neurotransmitter production drops
- Detoxification becomes impaired

7. Why Vegans Aren't the Only Ones at Risk

The shocking truth: Many meat-eaters are B12 deficient due to absorption problems, not intake issues.

High-risk groups:

- Anyone over 50 (stomach acid declines)
- People on acid-blocking medications
- Those with digestive issues
- Chronic stress sufferers
- Heavy alcohol users

8. The Right Form of B12 Matters

Cyanocobalamin: Cheap, synthetic form in most supplements
Methylcobalamin: The Active form your cells can use immediately
Adenosylcobalamin: Mitochondrial form for energy production

For functional deficiency: Use methylcobalamin or hydroxycobalamin, not cyanocobalamin.

Dosing: 1000-5000 mcg daily for therapeutic effect.

9. The Nerve Damage Timeline

B12 deficiency damages nerves progressively:

- Months 1-6: Fatigue, brain fog, mood changes
- Months 6-12: Tingling, numbness, balance issues
- Years 1-2: Permanent nerve damage if untreated

The critical point: Early symptoms are reversible.

Advanced nerve damage is permanent.

Don't wait for "severe" deficiency - optimise now!

10. The B12 Optimisation Protocol

Step 1: Get proper testing (MMA, homocysteine, B12)
Step 2: Use methylcobalamin 1000-5000 mcg daily
Step 3: Take sublingual or injectable form
Step 4: Add B6 and folate (work together)
Step 5: Retest in 8-12 weeks

Pro tip: If you feel better within days of high-dose B12, you were functionally deficient.

11. The Quick Self-Test

Try sublingual methylcobalamin (2000-5000 mcg) for 5 days.

If you feel dramatically better, you have found your answer.

If you're functionally deficient, you'll notice:

- Reduced anxiety
- Improved sleep quality
- Increased energy within 2-3 days
- Clearer thinking and a better mood

12. The Action Plan

1. Request advanced B12 testing (MMA, homocysteine)
2. Try therapeutic B12 (methylcobalamin 2000-5000 mcg)
3. Address absorption issues (stomach acid, medications)
4. Monitor symptoms and energy levels
5. Retest in 8-12 weeks to confirm improvement

Don't let "normal" lab ranges keep you feeling terrible when the solution might be a simple B12 optimisation.

Functional deficiency is more common than doctors realise.

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Share this with someone battling brain fog or fatigue, and stuck with “normal” labs. You might just save their health.:

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