In this blog, I have been reviewing products that we put on our skin, on the premise that what we put on our skin gets absorbed by the skin. In other words, toxic chemicals in shampoos, body washes, lotions, and creams do not just irritate the skin but end up in our blood stream. Thus, we have to be careful what we put on our skin. I sat down with Dr. Dan Cahill, MD to talk about that to see if my assumption is correct.
Dr. Cahill is a physician licensed to practice medicine in the State of Michigan, and is board certified by the American Board of Internal Medicine. He practices just outside of Ann Arbor, Michigan. Dr. Cahill attended the University of Notre Dame, and graduated from the Premedical Program. He was a member of the Honors Program at Notre Dame. Dr. Cahill attended medical school at Wayne State University in Detroit, Michigan and received his Medical Doctorate degree in 1992. Following medical school, Dr. Cahill did a four-year residency at St. Joseph’s Mercy Hospital in Ann Arbor, Michigan. Since his residency, he has worked in an outpatient primary care practice for the past seventeen years. I spoke with him by telephone, because I wanted to clarify my assumptions.
Irina: Dr. Cahill, is it true that substances we put on our skin get absorbed by the skin and go directly to our bloodstream?
Dr. Cahill: yes, that’s true. Let me give you some examples of how the skin’s ability to absorb is used in medicine. There are many medications that are available in transdermal or patch form. Examples include: female hormones, anti-hypertensives, nicotine and narcotics. Patches are applied to skin and the medication is absorbed into the epidermis, or surface skin, then the dermis where blood vessels are located. The medications’ effectiveness is based on a slower rate of absorption from the patch into the bloodstream. Patches are usually applied on a daily basis but may remain active for several days and up to a week or longer.
The specific chemical makeup of the adhesive used in transdermal patches varies from product to product. Due to these chemicals, there are potential side effects to the skin from any transdermal treatment unrelated to the active medication. These potential side effects include skin irritation, erythema (redness), depigmentation and atrophy (weakness). Patches must be applied directly to dry hairless skin and should be rotated to various areas of the body to limit potential problems.
Irina: It sounds like substances get absorbed more effectively through skin than through the digestive system. Is this true?
Dr. Cahill: It depends on the substance. For example, some women take female hormones via the skin. Oral pills need to pass through the digestive tract to get into the blood stream. Pills are taken once a day and the active ingredients get into the blood stream all at once. Transdermal hormones get absorbed into the skin, then into the blood stream steadily throughout the day. For some women the skin approach is more efficient.
Irina: A lot of manufacturers tell us that we should not be concerned with toxic chemicals in skin products, because there is very little of it used. Are they right?
Dr. Cahill: Again, it would depend on the substance in question and other factors. For a manufacturer to make that claim, there should be peer-reviewed studies as to each substance (and the doses) for which that claim is made. I would ask anyone who makes that claim for the literature upon which they are basing that statement. Without conclusive studies, we do not know and cannot say anything one way or the other.
Irina: What advice do you have for consumers of skin care products who want to limit their exposure to toxins?
Dr. Cahill: Be aware that toxins can be absorbed into the body through the skin. We simply do not know enough about all of the substances we are using in skin care and other products to be able to say one way or the other whether they are safe, and the amount that would be considered a safe dose. These products may be harmful or they may be harmless, but anyone who wants to minimize their exposure to potentially harmful products should pay close attention to the products they use on their skin and scalp.
Irina: Thank you, Dr. Cahill – this has really been eye-opening!
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