Vitamin patches, also called wellness or supplement patches, contain tiny amounts of vitamins, minerals such as iron and magnesium, and other compounds like caffeine and ginger extract. But can any of the health claims about them stick, or are they merely a Band-Aid solution?
Can vitamins actually get through the skin?
Very few medicines are available as patches, says Nial Wheate, a professor of pharmaceutical chemistry at Macquarie University. “There’s a reason we don’t have paracetamol and aspirin patches.”
The key issue is that the skin is a very effective protective barrier: the structure of its outermost layer, the stratum corneum, blocks water, bacteria and most drugs from getting through. “It doesn’t mean the right medicines can’t be delivered that way,” Wheate says. “The things that do get through the skin tend to be what we call lipophilic” – fat soluble. For this reason, skin patches are often used to deliver opioid medications, hormone replacement therapy and nicotine, which are all lipophilic.
For example, the advantage of a nicotine skin patch for smoking cessation, Wheate says, is that it gives a slow, sustained release “where you’re continuously releasing that drug into the bloodstream”, as opposed to an oral tablet which leads to a higher initial spike of the drug and more rapid clearance from the body.
However, he says: “One of the big fundamental problems of vitamin patches is that most vitamins are water soluble. What doesn’t get through the skin? Stuff that’s water soluble.”
Microdosing and the placebo effect
Some wellness patches market themselves as bypassing the “unwanted side effects” of oral supplements – constipation is a commonly reported side effect of iron tablets, for example. But iron, and other vitamins and minerals commonly used in patches, such as vitamin B12 and magnesium – cannot properly cross the skin barrier.
And if any amount does make it through the skin, “the other issue is the amount of drug you can load into a patch is very, very small,” Wheate points out. “So what you get is microdosing of any of those vitamins.” “The biggest effect [wearers] would get is a placebo effect.”
One patch available in Australia, marketed for immunity, for example, contains 1mg of vitamin C. The clinical signs of scurvy, by comparison, appear when daily vitamin C intake drops below 7 to 8mg.
More ‘bang for your buck’ in the fruit and veg section
The average person can get their recommended intake of vitamins (such as vitamin C and vitamin B12) and minerals (elements such as iron, zinc and iodine) from diet alone, without the need for supplements – in oral or patch form. “There’s definitely cases when people need [supplemental] vitamins and minerals,” says Clare Collins, professor of nutrition and dietetics at the University of Newcastle. This includes people with specific deficiencies, such as those with low iron or vegans who are at higher risk of vitamin B12 deficiency. Pregnant women, too, have a higher nutritional requirement for folate, iodine and vitamin D.
“The nutrients that are more likely to be absorbed [through the skin] are ones that dissolve in fat,” Collins says. “But they don’t necessarily go all the way into your bloodstream, which is why [vitamin patches] are not that effective.”
There have been few studies in humans into how well fat-soluble vitamins – vitamins A, D, E and K – are absorbed into the skin, Collins says. One small 2019 study looked at the effect of multivitamin patches in patients after gastric bypass surgery for weight loss, who are at higher risk of nutrient deficiencies. Patch users, it found, were “more likely to have vitamin D deficiency and lower serum concentration of various vitamins and minerals” than patients taking oral supplements.
“The patches were not able to replace oral supplements and that’s a very specific group where food intakes are markedly reduced,” Collins says. “In the current day, that would still apply to bariatric surgery, but that would also apply to people taking GLP-1 [weight-loss drugs].”
Given the lack of evidence for their effect, Collins suggests people save the money they would otherwise expend on vitamin patches and “spend it in the fruit and veg section … you’ll get more bang for your buck”.
Unlike patches, Collins says fresh fruit and vegetables will also provide a variety of phytonutrients – plant-based chemicals that occur naturally in foods – which have numerous benefits including antioxidant and anti-inflammatory properties. “You get the nutrients that improve your insulin sensitivity, and all the range of fibres that promote bowel health and promote a diverse microbiome.”
For people considering a vitamin supplement or a patch, Collins suggests “having a think about what the underlying issues are”. “If you’re just feeling run-down, then go and get yourself a check-up with your GP.”
