Can You Absorb Vitamin D Through Your Clothing?

October 31, 2025 •

4 min read

According to the Vitamin D Council, over one billion people worldwide have a vitamin D deficiency. This widespread issue leads many to question how effectively they can absorb vitamin D through their clothing.

Quick Summary

Clothing blocks the necessary UVB rays that trigger vitamin D synthesis in the skin. The level of blockage depends on the fabric's properties, like weave, material, and color. For adequate vitamin D production, direct skin exposure to sunlight is required, not exposure through clothing. Dietary intake and supplements are often necessary to compensate.

Key Points

Clothing is a UVB Barrier: For vitamin D synthesis to occur, direct UVB radiation must reach the skin; clothing acts as a physical barrier that blocks these rays.
Fabric Matters: The amount of UVB blockage is influenced by a fabric's properties, with dark, tightly woven materials offering the most protection.
Thin Clothes Offer Little Help: Even thin, light-colored clothing significantly reduces the amount of UVB that penetrates, making it an unreliable source for vitamin D production.
Studies Confirm the Link: Research has demonstrated that individuals wearing full-coverage or concealing clothing have a higher prevalence of vitamin D deficiency.
Alternative Sources Are Necessary: For adequate vitamin D levels, especially for those with limited sun exposure due to clothing, diet and supplementation are crucial.
Sun Protection is Important: While direct skin exposure is needed for vitamin D, protecting the skin from overexposure with appropriate clothing and sunscreen is vital for reducing skin cancer risk.
Dietary Fortification Helps: Many foods are fortified with vitamin D to help address potential deficiencies, though supplements are often needed for optimal intake.

The Science of Vitamin D Synthesis and Clothing

To understand whether you can absorb vitamin D through your clothing, it's crucial to know how vitamin D is produced naturally. The process begins when ultraviolet B (UVB) radiation from the sun penetrates the skin. On the skin's surface, a cholesterol precursor called 7-dehydrocholesterol absorbs the UVB radiation. This triggers a chemical reaction that converts the precursor into previtamin D3, which then thermally isomerizes into active vitamin D3.

Here's the key takeaway: This entire process depends on direct and unfiltered UVB ray contact with your skin. Clothing, much like sunscreen, acts as a physical barrier that prevents or significantly reduces the amount of UVB radiation reaching your skin's surface. The American Cancer Society explicitly states that if you can see light through a fabric, UV rays can get through, but tightly woven, dark, and dry fabrics offer far more protection.

How Fabric Characteristics Affect Sun Protection

Different types of clothing materials offer varying levels of protection against UVB rays. The effectiveness of a garment in blocking sunlight is measured by its Ultraviolet Protection Factor (UPF). A high UPF rating indicates that less UV radiation can pass through the fabric. Several factors contribute to a fabric's UPF rating:

Weave Density: Tightly woven or knitted fabrics, like denim or thick wool, offer superior protection because they have fewer and smaller openings for UV light to pass through. Conversely, a loosely woven fabric like a thin white cotton t-shirt offers very little protection and loses even more effectiveness when wet.
Fabric Content: The type of fiber matters. Synthetic materials such as polyester and nylon are generally more effective at blocking UV rays than natural fibers like unbleached cotton or rayon. Some fabrics are also treated with chemical UV absorbers or special dyes to enhance their protective properties.
Color: Darker or brighter colors absorb more UV rays than lighter, paler shades, which allows less radiation to penetrate the skin. A black shirt, for instance, provides better UV protection than a white one.
Fit: Tightly fitting clothes can stretch the fabric's fibers, opening up the weave and reducing its protective ability. Loose-fitting clothing is more effective at blocking UV rays.

The Effect of Clothing on Vitamin D Levels

Numerous studies have shown a direct link between covering the body with clothing and lower vitamin D levels, especially in women from regions with high year-round sun exposure. This confirms that even in sunny climates, limited skin exposure due to clothing can lead to vitamin D deficiency. Research conducted on women in Kuwait, where sun exposure is plentiful, found that those wearing more concealing clothing had higher rates of vitamin D deficiency. This was also supported by a study in Turkey that concluded clothing style is a significant factor affecting vitamin D status in young women.

Can any UVB get through? The thin fabric myth

While some anecdotal evidence might suggest that very thin clothing allows enough sunlight for vitamin D production, scientific evidence contradicts this. A lightweight, white t-shirt, for example, may only have a UPF of around 7, meaning a significant amount of UVB rays are still blocked. When wet, this protection level drops even further to a UPF of just 3. For efficient vitamin D synthesis, the skin requires a sufficient quantity of direct UVB exposure, something even thin clothing prevents.

Dietary Sources and Supplementation

For those who primarily wear clothing that covers their skin, relying on food sources and supplements is the most reliable way to ensure adequate vitamin D intake. A few foods naturally contain vitamin D, such as fatty fish, eggs, and certain fortified dairy products. However, the amounts found in food are often not enough to meet daily requirements, making supplementation a common and effective strategy. It is always recommended to consult a healthcare provider for proper dosage guidance.


Feature	Full Body Concealing Clothing	Minimal Clothing Exposure
Vitamin D Synthesis	Significantly reduced or blocked	Facilitated and effective during peak hours
Primary Source of Vitamin D	Relies on diet and supplements	Sun exposure can be the primary source
Risk of Deficiency	Higher risk, especially in sunny climates with cultural coverings	Lower risk, assuming regular and sensible sun exposure
Required Intake Strategy	Must actively seek dietary sources or supplements	Can often meet needs through natural sun exposure
Effect on Skin Health	Reduces risk of UV skin damage and cancer	Increases risk of UV skin damage and cancer if overexposed

Conclusion: The Final Verdict on Vitamin D and Clothing

Ultimately, the answer to whether you can absorb vitamin D through your clothing is a definitive 'no' in any significant amount. For the body to synthesize vitamin D, the skin must be directly exposed to UVB rays. Clothing acts as a barrier, with the level of blockage determined by the fabric's weave, material, color, and fit. Relying on sun exposure through clothes is not a reliable method for maintaining healthy vitamin D levels and can contribute to deficiency, even in areas with abundant sunshine. For those who must wear concealing clothing for cultural or other reasons, or who live in higher latitudes, dietary intake and supplementation are the most effective ways to ensure proper vitamin D levels. For adequate intake, it is vital to balance safe, direct skin exposure with other sources or a proper supplement regimen recommended by a health professional. You can find more information on vitamin D at the NIH's Office of Dietary Supplements.

Frequently Asked Questions

No, UVB rays do not effectively penetrate clothing to a degree that would stimulate significant vitamin D production. The process requires direct, unfiltered contact with the skin.

For fair to medium skin tones, experts often suggest 10–30 minutes of midday sun exposure to the face, arms, and legs a few times per week. Those with darker skin need more exposure time.

Yes, all clothing blocks some UVB rays, including light-colored items. While lighter colors are less effective barriers than dark colors, they still prevent the direct contact required for proper vitamin D synthesis.

Yes, wet clothing offers even less UV protection than dry fabric. For example, a wet white t-shirt's UPF drops significantly, meaning it allows more UV rays to pass through, but still not enough for adequate vitamin D production.

No, you cannot get vitamin D from sunlight through a window. Window glass blocks the UVB rays necessary for vitamin D synthesis, so only UVA rays, which do not produce vitamin D, pass through.

If you wear clothing that covers your skin, you should focus on dietary sources like fatty fish, eggs, and fortified foods, as well as take vitamin D supplements, as recommended by a healthcare provider.

For many, especially those with limited sun exposure due to clothing, climate, or indoor lifestyle, supplements are necessary to maintain adequate vitamin D levels. The body stores some vitamin D from summer exposure, but this may not be enough for year-round needs.