Vitamin B12 (Methylcobalamin) vs Casein Protein

Vitamin vs Protein · evidence-backed comparison

Quick take
  • Casein Protein has the broader effect profile across the 9 effect categories.
  • Vitamin B12 (Methylcobalamin) is cheaper per serving ($0.12 vs $0.95).
  • Vitamin B12 (Methylcobalamin) has higher bioavailability (better absorption).

Side-by-side traits

TraitVitamin B12 (Methylcobalamin)Casein Protein
Category
VitaminProtein
Active compound
MethylcobalaminCasein micelles
Form available
Tablet, Capsule, LiquidPowder
Source
microbialanimal
Typical dose
500–1000 mcg daily25–40 g per serving
Dose range
500–1000 mcg25–40 g
Loading protocol
Best taken with
sublingual or with foodwater or milk
Best time of day
morningevening
Bioavailability
How efficiently the body absorbs and utilizes the compound.
Very High (5/5)High (4/5)
Onset time
Cumulative: 2–8 weeksSlow: 4–7 hour drip-feed of amino acids
Half-life
~6 days~5 hours
Evidence level
Quality and quantity of human research.
Strong (multiple RCTs / meta-analyses)Strong (multiple RCTs / meta-analyses)
Overall effect
Subjective effect magnitude.
Low (2/5)Moderate (3/5)
Muscle / strength
Very Low (1/5)High (4/5)
Physical energy
High (4/5)Low (2/5)
Focus / cognition
Moderate (3/5)Very Low (1/5)
Mood / stress
Moderate (3/5)Low (2/5)
Sleep quality
Very Low (1/5)Moderate (3/5)
Immunity
Low (2/5)Moderate (3/5)
Recovery
Post-exercise recovery support.
Low (2/5)High (4/5)
Longevity / healthspan
Moderate (3/5)Moderate (3/5)
Safety rating
5 = exceptionally well-tolerated; 1 = significant risk profile.
Very High (5/5)Very High (5/5)
Price per serving
Approximate USD per typical daily dose.
$0.12$0.95
Vegan friendly
YesNo
Gluten free
YesYes
3rd-party tested
YesYes

About Vitamin B12 (Methylcobalamin)

Active 'methylated' form of B12 that bypasses MTHFR variants. Essential for vegans, the elderly, and metformin/PPI users.

Active compound: Methylcobalamin
Forms: Tablet, Capsule, Liquid
Onset: Cumulative: 2–8 weeks
energyvegan-essentialMTHFRmethylation

About Casein Protein

Slow-digesting milk protein that drip-feeds amino acids for hours. Best taken before bed to support overnight muscle protein synthesis.

Active compound: Casein micelles
Forms: Powder
Onset: Slow: 4–7 hour drip-feed of amino acids
muscleanti-catabolicovernightsatiety

Vitamin B12 (Methylcobalamin) safety

Common side effects:

  • Generally none

Avoid if:

  • Leber's optic atrophy

Drug interactions:

  • Metformin (depletes)
  • PPIs (reduces absorption)

Casein Protein safety

Common side effects:

  • Bloating
  • Gas (lactose)

Avoid if:

  • Milk allergy
  • Casein sensitivity

Drug interactions:

  • Levodopa

Common uses

  • Vegan supplementation
  • Energy
  • Cognitive function
  • Anemia

Stacks well with: Methylfolate (5-MTHF), Betaine Anhydrous

Common uses

  • Overnight recovery
  • Satiety
  • Anti-catabolic

Stacks well with: Zinc

Medical disclaimer

SupplementDuel is for educational purposes only and is not medical advice. Consult a physician before starting, stopping, or combining supplements — especially if you are pregnant, breastfeeding, take prescription medication, or have a chronic condition.