sun_simple_2Doesn’t it seem like everyone’s Vitamin D deficient these days? Just a few years ago, very few people talked about Vitamin D at all–they just assumed that they were getting enough from the sun. Then all of a sudden a new lab test that measures Vitamin D levels comes out and nearly all types of healthcare professionals–conventional and holistic–are recommending that their clients take a Vitamin D supplement. That includes me!

Vitamin D deficiency contributes to several skin issues that clients hire me to help them overcome, and it also has a protective effect on the skin due to its antioxidant properties in addition to a whole slew of other benefits–so it’s definitely in my arsenal of recommendations.

At first the main questions were “How much should I take?” That varies. Or “What type should I take?” Vitamin D3–cholcalciferol. Or “Do I take it with food?” Yes–with a healthy fat. And then of course people wanted my recommendations for brands, drops vs pills vs liquids, and so on.

I recently had a conversation with a friend who recently visited a holistic chiropractor and Ayurvedic practitioner, and it was recommended that she not take any oral forms of Vitamin D at all. This practitioner solely recommended transdermal Vitamin D–meaning Vitamin D applied topically to the skin–preferably to an area of the body that has a decent amount of fat. The reasoning was that oral Vitamin D isn’t absorbed and can cause issues with the liver.

I’ve heard of transdermal medications and supplements before, so I wasn’t surprised to hear a recommendation for transdermal Vitamin D since many people have absorption issues.

Is transdermal Vitamin D really more effective than oral Vitamin D?

Vitamin_D_structureI decided to do some homework–especially since some formulators of transdermal Vitamin D are packaging it into facial skincare products and body care products like deodorants. I found some interesting information, but I also found some conflicting and rather vague information (shocker).

First of all, it’s important to note that Vitamin D is a fat soluble nutrient. It must be taken with a fat in order to have any chance at all at absorption (which is why skim milk should NEVER be marketed as a good source of Vitamin D, or calcium for that matter since calcium is also fat soluble). It’s only found in a few whole food sources, and it’s manufactured in the skin from contact with direct sunlight. So packaging Vitamin D in any form that’s NOT fat soluble in an oral product whether it’s a food or a supplement is just silly.

One particular study used a transdermal Vitamin D in an aloe vera-based gel. Aloe vera gel is water soluble. It’s a humectant which means it draws moisture from the environment and binds it into the skin, and it’s also an emollient, meaning it stays on the surface of the skin and forms a seal for protection.

My initial question regarding any transdermal (or topical) product at all is how much of the actual active ingredient will actually make it past the stratum corneum’s natural lipid barrier and other layers of the epidermis into the papillary dermis which contains the blood vessels. I immediately questioned why a researcher would put a lipophilic ingredient like Vitamin D3 into a hydrophilic vehicle like aloe, which does hydrate, but doesn’t fully penetrate into the skin. Most topical active skincare ingredients are either lipophilic or encapsulated with a lipid (like lecithin or another phospholipid) at the molecular level to give it a better chance of penetrating beyond the stratum corneum–especially since the stratum corneum is hard to penetrate. I found my answer in the discussion following the results of the study:

471px-Anatomy_of_the_skin“Although the stratum corneum is an efficient barrier, some chemical substances are able to penetrate it and to reach the underlying tissues and blood vessels. These successful substances have to be lipophilic and Vitamin D is fat-soluble which means it should be able to cross the skin barrier…the most ideal penetration enhancer discovered to date is undoubtedly water. Hydration of the stratum corneum has been shown to increase the penetration of both hydrophilic and hydrophobic drugs. In this study we used a composition of aromatic oils and glycerine as permeation enhancer, which worked without complications.” So even though the product was aloe-based, it also consisted of oils.

The literature didn’t list what type of emulsifier they used–but that could be an issue, since some emulsifiers and other functional ingredients might end up interfering with product penetration in the final end product. This is a big concern, because typically the skin only absorbs up to 66% of what’s applied topically in the best case scenario of the skin being fully hydrated prior to application. I would think that these factors would make it difficult to consistently gauge how much of the actual nutrient is being absorbed (and that’s assuming the nutrient is kept intact and doesn’t degrade before having the chance to penetrate at all).

What about the liver connection?

Topical absorption issues out of the way, what about absorption of Vitamin D3 when taken internally? Just like with a topical product, an internal dietary supplement must be formulated in a way that makes the active nutrients recognizable and usable by the human body. This might seem like a no-brainer, but the majority of supplements on the market are mostly fillers and contain low quality and insufficient amounts of the actual nutrient.

The other factor in whether someone’s body can absorb a nutrient has a great deal to do with the condition of their digestive and immune systems. If someone has chronic or inflammatory digestive issues, it’s likely that their digestive systems need strengthening or healing–and until that happens, it’s likely that they’re not absorbing most nutrients. Digestion is key here–if food (and even supplements) aren’t properly digested, then the nutrients can’t be absorbed. The under digested foods begin to rot in the small and large intestines, which creates an overly acidic, toxic environment that breeds and feeds bacteria, viruses, and yeast. These toxins accumulate and get stored in fat cells, and also overload the liver, colon, and kidneys. If someone’s body is already in this compromised condition, then it’s likely they’re absorbing very little of anything beneficial.

Non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is rising in prevalence, and is attributed to Vitamin D deficiency. Other causes of NAFLD are obesity, diabetes, and insulin resistance to name a few. It’s very hard for the body to eliminate fat (as many are aware), so if someone already has NAFLD the concern with taking Vitamin D orally wouldn’t be with adding more fat to the liver as much as the risk of hypercalcemia–where the Vitamin D produces excessive amounts of calcium in the liver and the blood–where it doesn’t belong. This is known as “free calcium,” which tends to accumulate where it isn’t wanted, as plaque in the arteries, on the teeth, and as calciferous tumors anywhere else in the body. Keep in mind though, that one would have to take copious amounts of Vitamin D3 for this to happen–a minimum of 40,000 iu per day for several months.

Bypassing the liver, where oral Vitamin D is metabolized, as well as the kidneys, where it’s activated prevents this from happening since the nutrient would be absorbed directly into the bloodstream via the skin.

So what’s the bottom line here?

I think Vitamin D is important. I also think that however you WILL take it is the best way to take it, because no supplement is effective if you don’t actually take it. Some people like taking pills, others prefer liquids, and others do best with creams. I think that you have to know you’re getting a properly formulated product–and unfortunately you can’t depend on healthcare providers to understand formulation when they choose which products to recommend or retail. I’d recommend doing your homework and read the manufacturer’s website–and don’t be afraid to ask about the delivery system of the nutrient within the product. Ask to see clinical trials demonstrating absorption rates and efficacy. High quality supplement companies should be able to produce this information.

If you’re someone with digestive, known absorption, and/or immune issues, it’s likely that a transdermal option would be better for you. However, if you’re someone without conditions like NAFLD, diabetes, obesity, or other issues; and you eat whole, healthy foods and detoxify your body on a regular basis, then a high quality oral Vitamin D supplement will likely be fine for you.

When in doubt, ask your healthcare provider which is best for you–but if they give you a product to take, do your homework on that product to make sure it’s top quality whether it’s oral or transdermal Vitamin D.

*Image 2 credit “Vitamin D structure” by Nwanneka123 – Own work. Licensed under Creative Commons Attribution-Share Alike 3.0 via Wikimedia Commons – Image 3 credit Wong, D.J. and Chang, H.Y. Skin tissue engineering (March 31, 2009), StemBook, ed. The Stem Cell Research Community, StemBook, doi/10.3824/stembook.1.44.1, [CC-BY-3.0 (], via Wikimedia Commons Image 4 credit Nephron (Own work) [CC-BY-SA-3.0 ( or GFDL (], via Wikimedia Commons

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