Can You Get Vitamin D Through Swimwear? What You Need to Know
Cover More While Allowing Some Sunlight to Reach Your Skin
Vitamin D is important for maintaining healthy bones, teeth and muscles, and sunlight on the skin is one of the ways our bodies produce it.
Traditional swimwear creates a barrier between the sun and the covered areas of your body. Tan-through swimwear is different because its specially constructed fabric allows some ultraviolet light to pass through to the skin beneath.
However, tan-through swimwear should not be treated as a guaranteed source of vitamin D or as a reason to spend longer in direct sunlight.
Here is what the science—and current UK health guidance—can tell us.
New to Tan-Through Swimwear?
Start with our Ultimate Guide to Tan-Through Swimwear, where we explain how the fabric works, what results to expect and how to choose the right style for your holiday.
How Does the Body Produce Vitamin D?
The body can create vitamin D when sunlight reaches the skin.
UVB radiation is the part of sunlight involved in this process. When UVB reaches exposed skin, it begins a series of reactions that allow the body to produce vitamin D.
Vitamin D supports the regulation of calcium and phosphate, helping to maintain healthy bones, teeth and muscles.
Can You Get Vitamin D Through Ordinary Swimwear?
Traditional swimwear generally blocks much of the ultraviolet light that would otherwise reach the covered skin.
How much light passes through any material depends on factors including:
- The fabric construction
- Thickness
- Colour
- Stretch
- Fit
- Whether the material is wet or dry
Research examining ultraviolet transmission through clothing has found that fabric type, colour, fit and wetness can all affect how much vitamin-D-effective UV reaches the skin. Clothing can also significantly inhibit vitamin D production.
Therefore, you should not assume that your body is producing meaningful amounts of vitamin D through an ordinary bikini or swimsuit.
What About Tan-Through Swimwear?
Tan-through swimwear is specially designed to allow more ultraviolet light to pass through than conventional swimwear.
SWIMSARA fabric contains thousands of microscopic openings that allow some sunlight to reach the skin beneath the garment. This is the same principle that can help reduce the contrast between covered and exposed areas of skin.
Because vitamin D production requires UVB to reach the skin, it is reasonable that a fabric transmitting some UVB may permit some vitamin D production beneath it.
However, the precise amount will depend on:
- How much UVB the particular fabric transmits
- Your skin type
- The strength of the sunlight
- Where you are in the world
- The season and time of day
- How closely the garment sits against your skin
- How long the skin is exposed
Unless a finished garment has undergone specific clinical testing, it is not possible to promise how much vitamin D an individual will produce while wearing it.
Does SWIMSARA Guarantee Vitamin D Absorption?
No. SWIMSARA should not claim that wearing its swimwear will prevent vitamin D deficiency or provide a guaranteed amount of vitamin D.
Our fabric is designed to allow some sunlight to reach the covered skin, unlike conventional swimwear that creates a more complete barrier.
This makes sunlight transmission a genuine feature of the fabric. However, vitamin D levels are influenced by many personal, environmental and lifestyle factors, and swimwear is not a medical product.
The most accurate description is:
Innovative tan-through fabric designed to allow some sunlight to reach the skin beneath.
This is more responsible than promising increased vitamin D absorption.
Why Season and Location Matter
The strength of UVB varies throughout the year and between locations.
In the UK, most people can usually make vitamin D from sunlight during spring and summer. Between October and early March, the sun is generally too low in the sky for the body to produce sufficient vitamin D from sunlight alone.
This means that wearing tan-through swimwear in Britain during winter would not suddenly enable your body to produce vitamin D.
The strength of the sun at a summer holiday destination may be very different, but stronger sunlight also increases the risk of burning and skin damage.
Can You Get More Vitamin D by Staying in the Sun Longer?
You should not stay in direct sunlight for longer simply to increase your vitamin D levels.
More UV exposure does not automatically mean a healthier result. Prolonged or unprotected sun exposure increases the risk of:
- Sunburn
- Premature skin ageing
- Long-term skin damage
- Skin cancer
NHS guidance advises protecting your skin when spending longer periods outdoors and avoiding sunburn. Current clinical guidance also warns against sunbathing specifically to raise vitamin D levels.
Does Sunscreen Prevent Vitamin D Production?
In theory, sunscreen reduces the UVB reaching the skin and could therefore reduce vitamin D production.
In everyday use, however, studies have not consistently found that proper sunscreen use leads to vitamin D deficiency. One controlled holiday study found that sunscreen could protect against sunburn while still allowing vitamin D levels to increase.
You should not avoid sunscreen in an attempt to increase vitamin D.
Use broad-spectrum sunscreen on exposed skin and combine it with shade, suitable clothing and responsible sun exposure.
Who May Be at Greater Risk of Vitamin D Deficiency?
Some people are more likely to have low vitamin D levels, including those who:
- Spend very little time outdoors
- Cover most of their skin when outside
- Have darker skin
- Live in places with limited winter sunlight
- Are housebound or live in a care home
- Have been advised by a healthcare professional that they are at risk
UK health guidance recommends that everyone consider taking a daily 10-microgram vitamin D supplement during autumn and winter. Some higher-risk groups may be advised to take one throughout the year.
Speak to a pharmacist, GP or other qualified healthcare professional when concerned about your vitamin D levels.
Why Choose Tan-Through Swimwear?
Vitamin D should not be the primary reason for purchasing tan-through swimwear.
The more established benefits of SWIMSARA’s fabric include:
- Allowing some sunlight to reach covered skin
- Helping to create a more even-looking tan over time
- Offering more coverage than very minimal swimwear
- Lightweight comfort in warm weather
- Quick-drying performance
- Soft, flexible fabric
- Flattering bikinis and swimsuits
- Bold, confidence-boosting prints
It offers women a way to cover more of their bodies without wearing the dense, slow-drying fabric found in many conventional swimsuits.
Featured Tan-Through Styles
Long-Sleeve Tan-Through Top
Designed for women who prefer more coverage across their arms and upper body while still allowing some sunlight to pass through the fabric.
The Fitted Swimsuit
A flattering one-piece combining elegant coverage with lightweight tan-through fabric.
Sol Halter Bikini
A versatile halter neck bikini offering adjustable support and a confident, timeless fit.
Frequently Asked Questions
Can you get vitamin D through swimwear?
Traditional swimwear generally limits how much UVB reaches covered skin. Tan-through fabric allows more ultraviolet light to pass through, but the amount of vitamin D your body might produce cannot be guaranteed.
Does tan-through fabric allow UVB through?
Tan-through fabric is designed to transmit some ultraviolet light. The precise level depends on the particular fabric and garment construction.
Does SWIMSARA guarantee vitamin D absorption?
No. SWIMSARA is not a medical product and cannot guarantee increased vitamin D levels or prevent vitamin D deficiency.
Can tan-through swimwear replace a vitamin D supplement?
No. Follow NHS guidance or advice from your healthcare professional regarding supplements.
Should I avoid sunscreen to make more vitamin D?
No. Do not compromise sun protection in an attempt to increase vitamin D production.
Can I stay in the sun longer while wearing tan-through swimwear?
No. Tan-through fabric should not be used as a reason to extend your time in direct sunlight.
Can you make vitamin D from sunlight during the UK winter?
Generally, the UK sun does not contain enough UVB between October and early March for the body to produce sufficient vitamin D.
Does darker skin affect vitamin D production?
People with darker skin may require more sunlight to produce the same amount of vitamin D as someone with lighter skin, but everyone should avoid burning and follow sun-safety guidance.
Is sunlight the only source of vitamin D?
No. Vitamin D can also come from certain foods and supplements.
Should I have my vitamin D level tested?
Speak to a healthcare professional if you are concerned about a deficiency or believe you may be in a higher-risk group.
To learn more please see below;
- Ultimate Guide to Tan-Through Swimwear
- How Does Tan-Through Fabric Work?
- Does Tan-Through Swimwear Really Work?
- Can You Wear Sunscreen Under Tan-Through Swimwear?
- Is Tan-Through Swimwear See Through?
- What kind of fabric can you tan through?
- Long-Sleeve Swimwear Collection
Enjoy Innovative Coverage Without the Overpromises
Your body produces vitamin D when suitable UVB reaches your skin, and most traditional swimwear limits the light reaching covered areas.
SWIMSARA’s specially constructed fabric is designed to let some sunlight pass through while giving you the confidence and coverage of beautifully flattering swimwear. However, it should never be relied upon as a treatment for vitamin D deficiency or used as a reason to spend longer in direct sunlight.
Choose SWIMSARA for its lightweight comfort, flattering fits and ability to support a more even-looking tan—not as a replacement for responsible sun protection or professional health advice.
Ready to experience the difference?
Shop SWIMSARA’s best-selling tan-through swimwear collection.
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