VCVITAMINS/CHART

The Bottom Line

Yes, you can take vitamin K (K1, K2) and evening primrose oil (GLA) together — they do not interact and are safe to combine.

VERDICT

Vitamin K (K1, K2) and evening primrose oil (GLA) together are a safe combination with no significant interaction. Evening primrose oil provides the omega-6 fatty acid GLA, while vitamin K supports clotting and bone health, and they do not interfere with each other's absorption or function.

Safe to combine Strong evidence
01 / MECHANISM

How They Interact

Vitamin K is a fat-soluble vitamin that acts as a cofactor for enzymes involved in blood coagulation and bone metabolism. Evening primrose oil contains gamma-linolenic acid (GLA), an omega-6 fatty acid that is converted into anti-inflammatory prostaglandins. There is no known biological pathway where these two compounds interact. Both require dietary fat for optimal absorption, but they are absorbed through separate intestinal pathways and do not compete for transport. Although both are metabolized in the liver, they use different enzyme systems, so there are no clinically relevant cytochrome P450 interactions between vitamin K and GLA.

02 / BEST PRACTICES

How To Take Them

If you are taking both, the easiest way is to combine them in a single meal. Take vitamin K2 (MK-7) at 100 mcg and evening primrose oil at 500–1000 mg with breakfast or lunch that includes healthy fats like avocado, olive oil, or eggs. There is no need to space them apart. If you miss a dose, skip it and resume at your next scheduled time — never double up. For optimal absorption, ensure your meal has at least 10–15 grams of fat.

03 / FORM MATTERS

Form & Quality Differences

Vitamin K is available as phylloquinone (K1) from green leafy vegetables and menaquinones (K2, including MK-4 and MK-7) from animal foods and fermented products. MK-7 has a longer half-life and is often preferred for bone and cardiovascular health. Evening primrose oil is standardized to a specific GLA content, usually 8–10% GLA. These form differences do not change the fact that vitamin K and GLA do not interact, though MK-7 may produce more consistent blood levels than K1 when taken daily.

04 / COMMON STACKS

Where This Pair Shows Up

This specific pair is not a common commercial stack. Vitamin K is frequently included in bone health formulations alongside vitamin D3 and calcium, while evening primrose oil is often paired with omega-3 fish oil for skin and menstrual support.

Multivitamins Prenatals Performance Longevity
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Practical Tips

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Frequently Asked Questions

Who Should Be Careful If you take anticoagulants such as warfarin, keep your vitamin K intake consistent and have your INR monitored as usual. Evening primrose oil should be avoided in pregnancy, especially near term, due to possible uterine-stimulating effects. People with a history of seizures or taking phenothiazines should avoid GLA-containing supplements. These cautions are specific to each supplement, not to their combination.
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Sources & Further Reading

  1. NIH ODS NIH Office of Dietary Supplements — Vitamin K Fact Sheet
  2. NIH ODS NIH Office of Dietary Supplements — Evening Primrose Oil Fact Sheet
  3. Examine.com Examine.com — Vitamin K interaction page
  4. Examine.com Examine.com — Evening Primrose Oil interaction page

Reviewed by Caroline M. on April 26, 2026 for accuracy against the sources listed above. This page is educational and is not a substitute for professional medical advice.

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The matrix has 86 supplements and 7310 pairwise interactions. Click any cell to see the full breakdown.

Back To The Vitamins Chart All Vitamin K (K1, K2) Interactions All Evening Primrose Oil (GLA) Interactions