Before I start, I want to clarify that there is nothing wrong with using a cosmetic product that contains Vitamin E. I am specifically debunking the idea that you should be putting Vitamin E on scar tissue. Additionally, although post-inflammatory hyperpigmentation is colloquially referred to as "acne scarring", it is not actually a scar and there is no evidence that putting Vitamin E on hyperpigmentation is anything put benign.
What Are We Talking About?
So, what the hell is Vitamin E, anyways? In general, vitamins are organic compounds that the human body requires. (This contrasts with minerals, like calcium or potassium, which may also be required, but are inorganic.) Vitamin E is the name for eight different fat-soluble compounds, four of which are tocopherols and four of which are tocotrienols.
Image Source: http://en.wikipedia.org/wiki/File:Tocopherol,_alpha-.svg
When Vitamin E is added to topical cosmetics, it is usually in the form of tocopherol acetate. (Tocopheryl linoleate and tocopheryl nicotinate are also used cosmetically.) A wide variety of skincare companies make products featuring Vitamin E, including the Body Shop and Malin + Goetz, where it is typically touted as an antioxidant.
Secondly, what is a scar? I've written about scar tissue in more depth here, but a quick-as-a-motherfucker review: A scar is the fibrous tissue that your body may produce post-injury.
Why Do People Think Vitamin E On Scar Tissue is a Good Idea?
According to Baumann and Spencer (1999), "Since the discovery that vitamin E is the major lipid soluble antioxidant in skin, this substance has been tried for the treatment of almost every type of skin lesion imaginable." In other words, part of the craze is just because it's there. And, like, antioxidants and stuff.
However, as with many home remedies, there is some scientific reasoning behind the remedy.
Most notably, in vitro evidence shows that Vitamin E inhibits fibroblasts and keratocytes in both humans and rabbits. In particular, Vitamin E increases the levels of a cytokine called basic fibroblast growth factor (bFGF), which inhibits collagen production, an important part of scar formation. 'Bingo bango!' thought home remedy advocates. 'Vitamin E equals less collagen scar formation!'
Image Source: http://crm.nih.gov/stemcell_types/ESC_iPSC/images/fibroblast_D2.jpg
And that would seem true, if we didn't have any other evidence.
In vitro experiments, or "test tube experiments", which take place when you isolate a cell or tissue culture from the organism at hand. They are awesome because they let us look a lots of tiny parts individually without getting distracted by a bunch of irrelevant stuff. It's simple and an essential part of biological science.
But here's the thing: being able to predict the levels of bFGF in a petri dish don't always mean a crapload when what we really want is to extrapolate and talk about a big, honking, on-a-living-body scar. That's why in vivo evidence on an actual set of humans is so important when determining the efficacy of cosmetics ingredients.
Why Is This Actually a Terrible Choice?
We do, in fact, have that in vivo evidence.
Vitamin E, when applied topically to scar tissue, does not improve scar healing. Indeed, it actually results in a pretty worrisome number of minor but troublesome side-effects.
Jenkins and colleagues (1986) tracked 159 burn victims for one year. Participants were randomly assigned to be treated using a Vitamin E cream, a topical steroid cream, or a base cream containing nothing of note. The researchers assessed range of motion, scar thickness, change in graft size, and ultimate cosmetic appearance of the scar. They found no effects of either the topical steroid or the Vitamin E on any of their assessed factors and concluded that neither treatment was effective at reducing scar formation. What's more, 20% of those receiving the Vitamin E treatment reported some form of adverse side effects as a result of the application.
A later double-blind study by Baumann and Spencer (1999) had similar results. Skin cancer patients who had undergone surgery to remove their lesions were given two ointments labeled A and B, one of which contained Aquaphor, a traditional emollient, and one of which contained Aquaphor mixed with vitamin E. Scars were then randomly divided into part A and B. Participants were instructed to put Ointment A on part A of the scar and the Ointment B on part B of the scar twice daily for 4 weeks. Scar appearance was independently assessed by the patient, the physician, and a trained investigator. Instead of finding a beneficial effect of the Vitamin E on scar tissue, researchers concluded that "the application of topical vitamin E may actually be detrimental to the cosmetic appearance of a scar." Furthermore, 33% of the participants developed contact dermatitis, a form of skin inflammation, as a result of the Vitamin E exposure.
|Image Source: http://healthpsych.psy.vanderbilt.edu/2010/VitamineE_files/image002.png|
If the Evidence Isn't There, Why Does This Rumor Keep Showing Up?
In my opinion, part of the reason this home remedy refuses to die is because people cannot run a double-blind experiment on themselves... but scars do fade, no matter what you put on them. If someone hears about Vitamin E, uses it, and ends up with a faded a scar, even if it had nothing to do with the Vitamin E, they might continue to recommend it.
This is one of the reasons it is so important to check out what the scientific literature says on an ingredient, rather than relying on user testimonials.