4000IU Vitamin D3 + K2

Vitamin D is essential for bone strength, immune defense, mood balance, and muscle function. It helps your body absorb calcium and phosphorus, making it vital for bone density and overall skeletal health. Many people also take Vitamin D to support immune resilience and reduce seasonal fatigue.

Yes. Vitamin D3 4000IU is the established safe upper limit for daily Vitamin D3 intake in healthy adults. This dosage is often recommended for people with low Vitamin D levels or limited sun exposure. If you find the 4000IU strength too high, you can opt to take them once every 2-3 days instead of daily. This approach can be effective because both Vitamin D3 and K2 are fat-soluble, meaning they can be stored in the body's fat tissues and liver for future use. We would recommend consulting a doctor before consuming other products also containing Vitamin D3.

Vitamin D3 supports calcium absorption, but without Vitamin K2, that calcium may deposit in soft tissues like arteries instead of bones. Adding Vitamin K2 helps direct calcium into your bones and teeth, supporting strong skeletal health and reducing the risk of arterial calcification. This combination is considered more effective for bone and heart health than Vitamin D3 alone.

Common signs of low Vitamin D include:

• Fatigue or low energy
• Frequent colds or infections
• Bone or muscle pain
• Mood changes, including low mood or irritability
• Slow wound healing

You may be at higher risk if you:

• Live in areas with limited sunlight (especially in winter)
• Spend little time outdoors
• Are over 50 years old
• Follow a strict vegan diet

In these cases, supplementation with Vitamin D is often recommended. Most people notice improvements in energy and mood within a few weeks after taking our Vitamin D3, but it may take 2–3 months of consistent use to restore Vitamin D levels to an optimal range. Regular blood tests can help track your progress.

Improve VO2max:

Brzezianski et al - 2022 - Correlation between the positive effect of vitamin D supplementation and physical performance in young male soccer players. https://pubmed.ncbi.nlm.nih.gov/35564532/ 

Jastrzebska et al - 2018 - Can supplementation of vitamin D improve aerobic capacity in well trained youth soccer players? https://pubmed.ncbi.nlm.nih.gov/29599860/ 

Strength gains:

Rockwell et al - 2021 - Effects of seasonal vitamin D3 supplementation on strength, power, and body composition in college swimmers. https://pubmed.ncbi.nlm.nih.gov/32023539/ 

Bone health: 

Lewis et al - 2013 - The effects of season-long vitaminD supplementation on collegiate swimmers and divers. https://pubmed.ncbi.nlm.nih.gov/23475128/ 

van Ballegooijen et al - 2017 - The synergistic interplay between vitamins D and K for bone and cardiovascular health: a narrative review. https://pmc.ncbi.nlm.nih.gov/articles/PMC5613455/