NutriStack
Chlorella and Vitamin K1, a caution.
Stacking a vitamin K1 supplement on top of chlorella meaningfully increases total vitamin K1 exposure. For most healthy people this is simply additive and unremarkable, but the combined load becomes clinically relevant for anyone whose vitamin K status is being deliberately managed (for example, people on warfarin or other vitamin K antagonists, or those undergoing INR monitoring), where the two sources together can blunt anticoagulation and destabilize INR more than either alone.
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
- Chlorella and Vitamin K1
- Pair type
- Caution
- Evidence (highest tier)
- Moderate
- Source citations
- 3 sources
- Stack Score effect
- −5 to your Stack Score (per scored caution row).
- Scope
- Supplement × Supplement
- Last verified
- May 30, 2026
Caution · Moderate evidence
Caution
What is happening. Stacking a vitamin K1 supplement on top of chlorella meaningfully increases total vitamin K1 exposure. For most healthy people this is simply additive and unremarkable, but the combined load becomes clinically relevant for anyone whose vitamin K status is being deliberately managed (for example, people on warfarin or other vitamin K antagonists, or those undergoing INR monitoring), where the two sources together can blunt anticoagulation and destabilize INR more than either alone.
Mechanism. Chlorella is one of the most concentrated whole-food sources of vitamin K1 (phylloquinone), the same constituent that drives its documented interaction with anticoagulants. Taking a vitamin K1 supplement alongside chlorella produces additive phylloquinone intake. Vitamin K1 is a cofactor for hepatic gamma-carboxylation of clotting factors II, VII, IX, and X, so the combined intake raises total functional vitamin K delivered to the coagulation cascade.
Recommendation. For healthy users with no clotting concerns, no special action is needed beyond awareness that chlorella already supplies substantial vitamin K1, so an additional K1 supplement may be redundant. Anyone on warfarin or another vitamin K antagonist should keep total vitamin K intake (chlorella plus any K1 supplement) consistent day to day rather than starting, stopping, or fluctuating doses, and should have INR checked after any change. Keep the daily chlorella dose stable (commonly 2 to 5 g) and discuss the combination with the prescribing clinician before adding supplemental K1.
Minimum separation. None required; consistency of total daily intake matters more than separation in time
Sources (3)
- Pharmacology and nutrition reviews documenting chlorella as a rich dietary source of vitamin K1 (phylloquinone)
- Case report and clinical literature on warfarin therapy and chlorella, describing reduced anticoagulant effect via vitamin K (Japanese clinical literature, 1990s)
- Standard texts on vitamin K1 as a cofactor for hepatic gamma-carboxylation of vitamin K-dependent clotting factors
Stack Score
How this pair moves the number.
Effect on the composite score
If both Chlorella and Vitamin K1 are in the same stack, this pair applies −5 to your Stack Score (per scored caution row).
The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.
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