Vitamin D3 4000IU

Focus on the science behind immunity, bone strength, and mood balance

Vitamin D is one of the most vital nutrients for maintaining year-round health — yet it’s also one of the most commonly deficient. Studies show that over half of adults in the UK have suboptimal levels during winter, and many remain low even in summer due to indoor lifestyles or sunscreen use. YouNutri Vitamin D3 provides the same biologically active form your body produces from sunlight — at a strength proven to restore and maintain healthy levels safely and effectively.

🌞 The Sunshine Nutrient for Strong Bones & Immunity

Vitamin D3 (cholecalciferol) is the natural form of Vitamin D synthesised in the skin when exposed to UVB light. It plays a critical role in calcium and phosphorus absorption — minerals essential for bone and muscle health. Without enough Vitamin D, the body cannot properly utilise these nutrients, which can lead to fatigue, muscle weakness, or reduced bone density over time.Beyond skeletal health, Vitamin D is a key immune modulator. It helps regulate both innate and adaptive immune responses, supporting the body’s ability to defend against everyday infections and maintain balanced immune function throughout the year.

⚖️ Evidence-Based 4000 IU Dose — Effective Yet Safe

The 4000IU (100 µg) dosage in YouNutri Vitamin D3 is carefully calibrated to reflect the UK’s safe upper daily limit, as recognised by the NHS and European Food Safety Authority (EFSA). This level provides an optimal “repletion dose” — strong enough to restore healthy blood concentrations, yet safe for continuous daily use.Unlike megadoses or weekly capsules that cause peaks and troughs, YouNutri’s once-daily format supports consistent, steady levels for better long-term balance and absorption.

💪 Bone, Muscle & Mood Support

Vitamin D3 helps regulate calcium transport into bone tissue, ensuring proper mineralisation and strength. It also supports normal muscle contraction and coordination — helping reduce cramps or weakness associated with low D status.Emerging research links adequate Vitamin D levels with improved mood and cognitive well-being, likely due to its influence on serotonin production and brain receptor sensitivity. That’s why maintaining optimal levels is often associated with more stable energy and emotional balance, particularly during darker months.

❤️ Immune System Resilience

Vitamin D receptors are found on nearly every immune cell in the body, from macrophages to T-cells. By activating these receptors, Vitamin D3 helps regulate the immune response — enhancing pathogen defence while helping prevent overactivity that can cause inflammation or fatigue.Regular supplementation supports a balanced, responsive immune system throughout seasonal changes and periods of low sunlight.

🧩 Synergy with Magnesium and Vitamin K2

Vitamin D doesn’t work alone — it relies on other key nutrients to perform optimally.Magnesium is required for the enzymatic conversion of Vitamin D into its active form (calcitriol), meaning that low magnesium can reduce D3 effectiveness.Vitamin K2 complements D3 by directing absorbed calcium into bones and teeth rather than arteries or soft tissue.That’s why YouNutri recommends pairing this supplement with Magnesium Bisglycinate + Aquamin® or Vitamin D3 & K2 for a complete, synergistic approach to bone and cardiovascular health.

🧠 The Result — Stronger, Balanced, and Protected

By restoring natural Vitamin D levels, YouNutri Vitamin D3 helps you maintain:

• A resilient immune system year-round
• Strong, mineralised bones and teeth
• Normal muscle function and reduced fatigue
• Balanced mood and focus, even in winter
• Long-term vitality through consistent nutritional support

Manufactured in the UK under GMP standards, independently lab-tested, and formulated for vegetarian use, YouNutri Vitamin D3 delivers clinically relevant results — naturally and safely.