What Is Vitamin D?

Vitamin D is a fat-soluble vitamin crucial for calcium absorption, bone health, immune regulation, and hormone function. It acts more like a hormone than a traditional vitamin, influencing over 1,000 genes. The body synthesizes it through sunlight exposure, with smaller amounts obtained from food or supplements. Low vitamin D is common, especially in people with limited sun exposure, darker skin, or gut absorption issues.

Why You May Want to Improve It

Vitamin D deficiency is linked to fatigue, poor immune response, bone loss, depression, and chronic illness risk. Raising your levels can improve energy, support mood, and protect long-term health.

• Bone and Muscle Health: Supports calcium absorption and reduces risk of osteoporosis and fractures.

• Immune Function: Enhances response to pathogens and may reduce risk of respiratory infections.

• Mood and Energy: Deficiency is associated with low mood, fatigue, and seasonal affective symptoms.

• Hormone Balance: Plays a role in testosterone, estrogen, and thyroid hormone regulation.

How to Improve Vitamin D Naturally

Sunlight

• Midday Sun Exposure: Aim for 10–30 minutes of direct sun on face, arms, or legs at least 3x per week, depending on skin tone and location.

• No Sunscreen Initially: Allow short unblocked exposure; apply sunscreen after desired duration to avoid burns.

• Latitude Matters: People living further from the equator may need longer exposure or seasonal supplementation.

Diet

• Fatty Fish: Salmon, sardines, and mackerel are among the richest natural food sources of vitamin D.

• Egg Yolks and Liver: Contain modest amounts of vitamin D and support co-nutrients like choline.

• Fortified Foods: Plant milks, cereals, and dairy alternatives often have added vitamin D.

Supplements

• Vitamin D3: The most effective form—cholecalciferol—is best absorbed with fat-containing meals.

• Dose Based on Testing: Supplementation should be tailored to your levels (e.g., 1,000–5,000 IU/day for most adults with deficiency).

• Pair with Vitamin K2: Helps direct calcium to bones and away from arteries when supplementing with D3.

Medical Support

• Get Your Levels Tested: Blood test for 25-hydroxyvitamin D (25(OH)D) guides personalized dosing.

• Monitor Over Time: Recheck levels every 3–6 months when supplementing to avoid excess.

Normal Levels

Your ideal level depends on age, health status, and sun exposure. Work with your provider to interpret results.

When to See a Doctor

• Persistent fatigue or low mood

• Frequent illness or slow recovery

• Muscle weakness, bone pain, or fractures

• Autoimmune or inflammatory conditions

A MitoHealth micronutrient panel can assess your vitamin D and related nutrient levels to guide your wellness plan.

FAQs

Is vitamin D from sunlight better than supplements?

Sunlight triggers natural production and may have co-benefits (e.g., circadian rhythm), but supplements are effective when sun exposure is limited.

How long does it take to raise vitamin D levels?

With daily supplementation, levels can rise within 4–12 weeks. Individual response varies.

Can you get too much vitamin D?

Yes, especially from high-dose supplements. Symptoms of toxicity include nausea, weakness, and calcium imbalance. Stay within tested dosage ranges.

Is vitamin D3 better than D2?

Yes. D3 (cholecalciferol) is more bioavailable and effective at raising and maintaining levels.

What affects vitamin D absorption?

Fat intake, magnesium levels, gut health, and genetic factors may influence absorption and activation.