NutriStack
Vitamin B12 and Vitamin C, timing-sensitive.
High-dose vitamin C (>500mg) may destroy vitamin B12 when taken simultaneously. The acidic environment created by high-dose ascorbic acid can convert cyanocobalamin to inactive analogues.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
Same shape as the other 1,729 pairs in the public database.
From the interaction database
What the row says.
Every entry follows the same shape: what is happening, the mechanism, the recommendation, and the primary literature.
At a glance
- Substances
- Vitamin B12 and Vitamin C
- Pair type
- Timing Sensitive
- Evidence (highest tier)
- Moderate
- Source citations
- 2 sources
- Stack Score effect
- −5 to your Stack Score (per scored timing-sensitive row).
- Scope
- Supplement × Supplement
- Last verified
- May 30, 2026
Timing Sensitive · Moderate evidence
Timing Sensitive
What is happening. High-dose vitamin C (>500mg) may destroy vitamin B12 when taken simultaneously. The acidic environment created by high-dose ascorbic acid can convert cyanocobalamin to inactive analogues.
Mechanism. Ascorbic acid at high concentrations can reduce the cobalt center of cyanocobalamin, converting it to inactive analogues. Methylcobalamin may be less susceptible than cyanocobalamin.
Recommendation. Separate high-dose vitamin C and B12 supplements by at least 2 hours. Low-dose vitamin C (<200mg) is fine to take with B12.
Minimum separation. 120
Sources (2)
- Herbert V, Jacob E. Destruction of vitamin B12 by ascorbic acid. JAMA. 1974;230(2):241-242. PMID 4479032
- Bayu P, Wibisono JJ. Vitamin C and E antioxidant supplementation may significantly reduce pain symptoms in endometriosis: A systematic review and meta-analysis of randomized controlled trials.. PLoS One. 2024. PMID 38820340
Stack Score
How this pair moves the number.
Effect on the composite score
If both Vitamin B12 and Vitamin C are in the same stack, this pair applies −5 to your Stack Score (per scored timing-sensitive row).
The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.
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