How much sun do I need?

This depends on latitude, season, skin type, and time of day. For lighter skin, 10–30 minutes of midday sun on exposed skin several times a week may suffice in summer; darker skin needs more. In winter or at high latitudes, supplementation is usually necessary. Track your vitamin D monthly to confirm your approach is working.

How much sun do I need?

This depends on latitude, season, skin type, and time of day. For lighter skin, 10–30 minutes of midday sun on exposed skin several times a week may suffice in summer; darker skin needs more. In winter or at high latitudes, supplementation is usually necessary. Track your vitamin D monthly to confirm your approach is working.

Home Biomarkers Metabolic EfficiencyVitamin D (25-OH)

Nutrients & Organ Health

Vitamin D (25-OH)

Q: What's the difference between deficiency and insufficiency?

Deficiency is generally defined as below 20 ng/mL; insufficiency is 20–30 ng/mL. Many functional and preventive medicine practitioners target 40–60 ng/mL for optimal immune, bone, and metabolic function. Your target is personal — track your trend and discuss with your clinician.

The sunshine vitamin — essential for immune function, bone health, and mood, and remarkably commonly deficient.

Optimal target40–60 ng/mL (deficiency < 20, insufficiency 20–30)

Start Testing — $79/Month View Metabolic Efficiency Panel

What it measures

Vitamin D (measured as 25-hydroxyvitamin D) is the storage form of vitamin D your body produces when skin is exposed to sunlight and obtains from certain foods and supplements. It functions more like a hormone than a vitamin, regulating hundreds of genes involved in immune function, bone mineralization, inflammation, and mood.

Deficiency is extremely common — especially in winter, at higher latitudes, with darker skin, and with indoor lifestyles — and is linked to immune dysfunction, low mood, poor bone health, and metabolic issues.

Why it matters

Essential for immune function and infection resilience.
Required for calcium absorption and bone mineral density.
Low vitamin D is linked to depression and seasonal affective disorder.
Supports metabolic health and insulin sensitivity.
Deficiency is remarkably common and often undiagnosed.

What affects your levels

Sun exposure and latitude

Skin pigmentation (darker skin needs more sun)

Season (lower in winter)

Sunscreen use and indoor lifestyle

Body fat (vitamin D is sequestered in fat)

Supplementation

How VitalDrop tracks it

Monthly tracking reveals seasonal dips and supplement response.
Confirms whether your supplement dose is achieving optimal levels.
Catches deficiency before it manifests as symptoms.

Related biomarkers

Ferritin

Frequently asked questions

Deficiency is generally defined as below 20 ng/mL; insufficiency is 20–30 ng/mL. Many functional and preventive medicine practitioners target 40–60 ng/mL for optimal immune, bone, and metabolic function. Your target is personal — track your trend and discuss with your clinician.

References & sources

01.

Vitamin D Deficiency and Health Outcomes. Endocrine Society / The Lancet Diabetes & Endocrinology, 2020.

02.

Vitamin D and Immune Function. Nature Reviews Immunology, 2019.

Medically reviewed by

Reviewed by Dr. Hassan Nasser

Medical Director — www.detroitfacemd.com

Board-certified facial plastic & reconstructive surgeon; clinical reviewer for VitalDrop laboratory insights. Verified at www.detroitfacemd.com

CLIA-certified laboratories

COLA-accredited processing

Physician-reviewed results

HIPAA-compliant & encrypted

Track Vitamin D (25-OH) monthly

Get lab-accurate results, trend graphs, and physician review — all from a single at-home capillary blood test.

Start Testing — $79/Month

Medical disclaimer: This content is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. VitalDrop provides laboratory test results and educational insights for wellness tracking. Always consult a qualified healthcare provider regarding abnormal or concerning results. Results and AI-assisted summaries are not a medical diagnosis.