Common Vitamin D Myths and Questions

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Making Vitamin D from sun exposure seems like a fairly simple thing, but when you start thinking about it a bit more in depth you realize that there are actually a lot of questions that might come up and some common Vitamin D myths that people may believe.

These myths and questions are ones that I've learned about over the past several years as I gradually learned more and more about the process of making Vitamin D from being outside in the sunshine and all of the different factors that can have an effect on our body's ability to produce Vitamin D.

And before we get into the myths and questions, I also need to state a quick disclaimer that I'm not a doctor or a medical professional, and the information in this article is just for educational purposes. Ok, now that that's out of the way, let's talk about some common myths and questions about making Vitamin D from sun exposure.

Jump to:

• Can You Make Vitamin D by Sitting Near a Sunny Window?
• Can You Make Vitamin D If It's Cloudy Outside?
• Can You Make Vitamin D Anytime the Sun Is Shining?
• Will Taking A Shower Wash Away Vitamin D?
• Can You Make Vitamin D With Clothing On?
• Do Body Lotions and Creams Affect Vitamin D Production?

Can You Make Vitamin D by Sitting Near a Sunny Window?

When you are sitting next to a sunny window or driving in a car and the sun is shining in through the window, it might seem like you are getting some Vitamin D, especially if you can feel the warmth of the sun and see the rays hitting your skin. But it turns out that most glass actually blocks the UVB rays that are needed for producing Vitamin D from the sun. According to the International Ultraviolet Association, regular glass will block basically all UVB rays (which means no Vitamin D). So, even though it might feel pleasant to feel the warmth of the sun through a window and see the bright light of the sunshine, you wouldn't be able to make any Vitamin D if there is window glass between you and the rays of the sun.

But what about getting Vitamin D through an open window with a screen or through an open car window? I think I remember hearing something on a video on the Quantum Conversations YouTube channel about how it might be possible to get Vitamin D through an open window as long as the sun's rays were actually touching your skin. I'm not 100 percent sure that this is where I heard that information (and if it is then I have no idea which video it was where I heard it because it was several months ago at this point). If I ever find the source of this information I will try to remember to give an update here, though.

So it might be possible to produce some Vitamin D by sitting close to a sunny window that is open where the sun is directly hitting your skin with no glass in between. Being fully outside is probably the better option if possible, but for those who aren't able to go outside for whatever reason then an open window with just a screen seems like it would be better than nothing at all if your goal is to make some Vitamin D from the sun.

Can You Make Vitamin D If It's Cloudy Outside?

I used to always think that it wasn't really possible to make Vitamin D if it was cloudy outside, but from what I've read the real answer to that question might be a bit more complicated than a simple yes and no. This article talks about some of the different factors that can affect our ability to produce Vitamin D during cloudy days, including how thick the cloud cover is, the time of day, your location, etc. (Note: I am not familiar with the supplements this article mentions, and I'm linking to the article only in reference to the information about cloud cover and Vitamin D and not endorsing or recommending these supplements since I have not tried them personally.)

A good way to see how cloud cover might affect Vitamin D production is to use an app like My Circadian App that has a Vitamin D timer where you can input information about how cloudy the sky is at the time you are trying to get some Vitamin D. The Vitamin D timer in My Circadian App will tell you approximately how long you would want to be out in the sun based on how cloudy or clear the sky is, the amount of clothing you are wearing, etc.

So, while it's not impossible to be able to make Vitamin D on a cloudy day, you would need to be outside for quite a bit longer than you would need to be if the sky were completely clear. And if there is a thick cloud cover then it's probably unlikely that you'd be able to make any significant amount of Vitamin D.

Can You Make Vitamin D Anytime the Sun Is Shining?

We know that cloudy days aren't the best for producing Vitamin D, but can we make Vitamin D anytime we are out in the sunshine? The short answer is, no, just because the sun is shining doesn't mean that it's possible to make Vitamin D from the sun.

There are actually a few different factors when it comes to our ability to make Vitamin D from sun exposure. Some of the biggest factors are the time of the year and the location where you live and also the time of day. According to some sources, the sun has to be at least 30 degrees above the horizon for UVB rays to be present which would allow us to make Vitamin D. (I've also seen mentions of 50 degrees above the horizon, but maybe that is for the most optimal Vitamin D production.) And I've also read that the UV index needs to be a 3 or above for Vitamin D production to occur. Unless you live near the equator, it's unlikely that this will be the case year round. Where I live in Massachusetts, for example, it isn't possible for me to make any Vitamin D from the sun at all during the winter months because the sun doesn't ever get high enough above the horizon for UVB rays to be present.

And even during the summer months, the best time for Vitamin D production is usually closer to the middle part of the day. Early in the morning and late in the afternoon the sun angle isn't usually high enough for there to be UVB rays present (for most locations anyways. There could be some exceptions.)

If you're not sure how many degrees above the horizon the sun get where you live, the website Time and Date allows to you search for the city where you live and find out information about the sunrise and sunset, and the information you would be looking for is the section where it mentions the altitude of the sun. You would want the altitude to be at least 30. Or, if you have a smart phone, the app My Circadian App is my favorite way to keep track of this because the angle of the sun is given right on the app along with the UV index, and you can see right on the app what time of the day is the window where UVB light will be present in the sky.

Here are a couple of sources with more information about different factors that can affect Vitamin D production from the sun:

• Vitamin D Availability
• How to Safety and Effectively Make Vitamin D from Sunshine

Will Taking A Shower Wash Away Vitamin D?

Several years ago I had read something about how taking a shower soon after sunlight exposure could wash away some of the Vitamin D before your body had a chance to synthesize it, so for years I would try to time my sunlight exposure to be after I had taken a shower. But then recently I saw this Instagram post by Sarah Kleiner Wellness that give some more detailed explanations about why that isn't true and that Vitamin D is actually made in deeper layers of the epidermis rather than on the surface of the skin, so taking a shower won't wash away the Vitamin D.

This seems to be one of the more controversial questions about Vitamin D because there is a lot of conflicting information online about this topic. But knowing that Vitamin D is made in deeper layers of the skin rather than on the surface makes it seem more reasonable to me to believe that it isn't something that you can simply wash off with soap and water.

Can You Make Vitamin D With Clothing On?

I talked about this question in a little more depth in my article about how people in the 1800s could have gotten enough Vitamin D without modern supplements, but I'll summarize some key points here. From what I've read, it sounds like it's possible for some UVB rays to go through certain types of clothing (especially clothing made from natural fibers, clothing that is loosely woven, and clothing that is lighter colored). Clothing that is made from synthetic fibers, clothing with tightly woven fabric, and darker colored clothing is the type of clothing that is the most likely to block UVB rays. This article talks about how well different types of clothes block UV rays, but you could also turn that information around to the opposite viewpoint to see what types of clothing let UV rays through instead.

So, it might be possible to make some Vitamin D from being in the sun if you were wearing light-colored, natural fiber clothing, but you would probably need to be out in the sun for a significant amount of time for that to happen. If your goal is to produce Vitamin D from sun exposure than having some skin exposure (like with a short sleeved shirt and/or shorts, etc.) is probably best.

Do Body Lotions and Creams Affect Vitamin D Production?

First of all, by lotions and creams I'm talking about regular body lotions and not sunscreen specifically. Sunscreen is designed to block UVB rays, so that means that sunscreen will block Vitamin D production, too. But what about regular moisturizing lotions that people wear everyday?

Some lotions will block UVB rays more than others will. In general, natural, simple-ingredient oils will allow your skin to absorb more UVB rays (as well as other beneficial aspects of natural sunlight such as infrared light, etc.) This article from Sarah Kleiner Wellness gives a detailed break-down of several different types of lotions and oils and what effect they have on the skin's ability to absorb light from the sun if you want to see if the type of moisturizer you usually use will allow you to make Vitamin D well. I was glad to see that tallow is listed as one that isn't a problem for Vitamin D production because tallow is what I typically use as an old-fashioned lotion substitute.

So its possible that your body lotion might hinder your body's ability to made Vitamin D from the sun, but if you stick with lotions, creams, and body butters made from natural ingredients you will have a better chance of your skin being able to absorb the UVB rays from the sun and make Vitamin D.

Did I forget about any other common myths or questions about Vitamin D? If you think of any I forgot feel free to let me know down in the comments section below!

(Lori Elliott is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.)

The information in this post is not to be taken as medical advice and is not intended to diagnose or treat any disease.