Vitamin D is one of the most essential nutrients for the human body. Yet, almost 70–80% of Indians are deficient, especially women, due to limited sun exposure, cultural clothing practices, hormonal changes, and higher nutritional demands during pregnancy and breastfeeding. Known as the “Sunshine Vitamin,” it supports bone health, immune function, mood, and hormone function. Unlike most vitamins, sun exposure (not just food) is the main source of vitamin D.
This leads to these questions:
-Is it possible to determine the optimal time of day to maximize our intake of vitamin D from sunlight?
-Is there a potential link between sunscreen, climate, skin color, and how much vitamin D we make?
This article will outline a simple and straightforward explanation of how the timing of your vitamin D absorption is important.
Why Timing Is So Important For Vitamin D Absorption?
Vitamin D is produced from exposure to ultraviolet (UVB) light from the sun, which converts cholesterol to vitamin D in the skin cells. However, UVB rays aren’t always available or have variable strength throughout the day.
The intensity of UVB rays varies by:
-the time of year
– your geographic location
– your skin type
– the amount of pollution in the air
Hence, it is important to know when to maximize your vitamin D production while at the same time reducing your risk for damage from overexposure.
The Most Effective Time to Absorb Vitamin D: Mid-Morning to Midday (10 AM – 2 PM)
Most dermatologists will agree that the most effective time to absorb vitamin D is between 10 AM and 2 PM.
At this time of day:
-UVB rays are at their highest intensity
-Your body will produce vitamin D most efficiently during this time period.
-You’ll need less exposure to the sun to receive your body’s vitamin D production compared with early morning and late afternoon.
-You’ll also have less risk of experiencing excessive UV exposure due to the shorter amount of time spent outside.
The majority of experts agree that solar noon (approximately 11:30 AM to 12:30 PM) is the best time to absorb vitamin D because UVB radiation is the strongest, and the sun is positioned directly above.
Why Is Midday Sunlight The Most Efficient One?
On average, a person with light to light-medium skin tone will absorb 3 times more vitamin D from sunlight between midday hours than they would receive from sunlight during early morning hours, and they will need only an average of 10 – 20 minutes of exposure at this time. And it reduces the chances of long exposure that leads to tanning
Exposure Time Based on Skin Tone
| Skin Tone | Ideal Sun Exposure (Midday) |
| Fair / Light | 10–12 minutes |
| Kelly or Olive skin color tones | 15–20 minutes |
| Dusky / Brown | 20–30 minutes |
| Dark/Deep Brown | 30–45 minutes |
Darker skin tones have more melanin in their bodies, which acts to absorb the UVB rays. Therefore, to receive the same amount of vitamin D production as light to medium skin tones, a person with a dark to very deep brown skin tone must remain outdoors for longer than the average individual.
Is Early Morning Sunlight Good for Vitamin D?
The early morning sunshine has been commonly believed to be one of the safest and healthiest for human beings.
In this regard, it is beneficial for the following:
-Mental well-being
-Circadian rhythm
-Walking in the morning
However, this is not a good source of vitamin D. Prior to the time of 9 am- 9:30 am, the amount of UVB rays in early sunlight is very low, particularly during the winter months. This means you can sunbathe for approximately 45 – 60 minutes, but not be able to produce the necessary amount of vitamin D.
Seasonal Impact on Vitamin D Absorption
-In winter, low UVB levels may require longer sun exposure or a vitamin D supplement.
-In summer, short sun exposure is usually sufficient, but avoid the risk of sunburn.
-During the rainy season, due to cloud cover blocking UVB, you can produce vitamin D, so make sure to sunbathe when the sky is clearer.
-On days of high air pollution, it blocks UVB and decreases the ability of one to produce vitamin D.
Does Sunblock/Sunscreen Affect Your Ability to Absorb Vitamin D?
Sunblock/Sunscreen can affect your ability to absorb vitamin D. Sunblock SPF 30 and above can block between 80% – 95% of the UVB rays from the sun.
Note: If you want to sunbathe to produce vitamin D, please expose your arms and legs to the sun for at least 10 -20 minutes without any sunblock and then apply sunscreen afterward.
Is a Vitamin D Supplement Necessary?
The sun is the most effective source of vitamin D; however, many people do not get enough vitamin D. These people include:
-Working professionals who are mainly in the office.
-Individuals with dark to very dark skin tones.
-Individuals with a vitamin D deficiency during the winter months.
-Women who are 30 years of age or older.
-Individuals who are considered obese.
-People living in urbanized, polluted cities.
Most Sun-Responsive Body Areas for Vitamin D Absorption
The greatest areas to exhibit sunshine through skin and therefore obtain the most Vitamin D are:
-Arms
-Legs
-Back
-Abdomen
Suggested Way To Expose Skin For Maximum Vitamin D Synthesis:
-Best time: 10 a.m. – 2 p.m. – Peaks Between 11 a.m. – 12:30 p.m.
-Length: 10 minutes – 30 minutes, depending on the skin tone
-Best season: Summer > Monsoon > Winter
-Best to do: 3 – 4 times a week
Key Findings
- While the midday sun is the most effective time to get the best amount of vitamin D from the sun, UVB rays are the strongest in terms of quantity and strength (if/when the sun is directly overhead).
- When the sun is rising and/or lowering (i.e., early morning), which has almost no amount of UVB rays, they are good for mood but not good for vitamin D intake.
- Skin tone will determine the amount of time (the length of time that you can expose your skin to UVB rays); darker skin will need more time to obtain vitamin D.
- Clouds, pollution, and winter significantly decrease the amount of UVB rays that reach the ground (and therefore reach the skin).
- Sunscreen is a barrier for UVB rays; if you apply it to your arms/legs before you expose your skin for the purpose of obtaining vitamin D, you are reducing the amount of vitamin D you can obtain from UVB rays.
- Vitamin D is important to the immune system, bone health, hormone regulation, and energy level (etc.)
Gentle Reminder
Sunlight is the best natural source of vitamin D. Expose larger skin areas (arms, legs, back) between 10 AM and 2 PM for 10-30 minutes, adjusting for skin tone and weather. If necessary, consider vitamin D supplements after consulting a doctor or healthcare professional. Strive for a balance between sufficient UVB exposure for vitamin D synthesis and protecting your skin from overexposure.
FAQs
Q. What is the best time to get vitamin D naturally?
The best time for natural vitamin D production is during the hours of 10 AM – 2 PM, with solar noon being the most productive time to generate vitamin D (approximately 12 PM).
Q. Can early morning sunlight give vitamin D?
Early morning sunlight cannot generate vitamin D because the UVB rays are too weak during that time.
Q. How much sunlight do I need daily?
The amount of daily sunshine needed for each person can vary from 10 minutes to 30 minutes, depending on location and skin tone.
Q.Should I apply sunscreen while getting vitamin D?
It is advised to leave your arms and legs without sunscreen for a short duration—about 10–20 minutes—when getting sunlight for Vitamin D. However, avoid longer exposure, as going without sunscreen for too long increases the risk of sunburn and skin damage.
Q. Can I get enough vitamin D in winter?
Vitamin D production is more difficult in the winter months because of the lack of UVB rays. Therefore, winter months may require increased exposure time or supplementation to get the same amount of Vitamin D.
Q. Does pollution affect vitamin D absorption?
The air we breathe does affect vitamin D. When there are high levels of pollution in the air, the pollution intercepts the UVB rays and inhibits our body’s ability to create Vitamin D from natural sunlight.
Q. Can vitamin D deficiency cause fatigue?
Yes, a deficiency in vitamin D will result in an individual becoming fatigued. Additionally, low levels of vitamin D can also contribute to an individual developing a weaker immune system, mood swings, and muscle weakness.
Q. Is food alone enough to meet daily vitamin D needs?
Food alone will not provide the recommended daily value of vitamin D. Even if an individual eats a sufficient amount of vitamin D-rich foods, their dietary intake of vitamin D only accounts for approximately 10%-15% of the required daily intake of vitamin D. To obtain the full daily requirement of vitamin D, individuals will need to rely on sunlight exposure or vitamin D supplementation.
Recommended Reads
(The article is written by Deepa Sarkar, Medical Writer, and reviewed by Monalisa Deka, Deputy Manager, Clinical Health & Content, Medical Affairs)