Can pores close? Are essential oils anti-inflammatory? And an investigation of cited science

Ask a Skin Care Biologist

Ask a Skin Care Biologist is a weekly Bioluminescence post where OUMERE's CEO and CSO, Wendy Ouriel, M.S., answers your skin care questions. Wendy is a cellular biologist with expertise in cellular aging, extracellular matrix biology and the biology of skin care.

Thank you for all of your questions! I am thrilled to have the opportunity to explore the science of skin care together, to better develop our understanding of proper skin care, and to do some myth busting along the way. Keep the questions coming!

Question: Can anything be done about large pores?

-Lori S.

To answer this question, I first need to come out and say it: pores don’t open and close. It is a biological impossibility. In order for anything in the body to open and close, a muscle contraction must occur, and pores sit atop the skin, far away from the influence or control of muscular movement. The only muscle that influences the skin is the Arrector pili muscle, which is attached to the hair follicle in mammals, and upon contraction causes goosebumps.

The muscle sits below the skin, and has no ability to contract pores.

Steam, creams, toners, or anything that isn’t your hands stretching your face like this:

Is not going to open or close your pores. And doing anything to tighten the skin in such a way is going to lead to pre-mature sagging and wrinkles.

So, can anything be done about large pores? Yes. You can shrink pore size by making new skin, and the new skin makes new, smaller pores. You can make new skin with chemical exfoliation, which gets rid of the top layer of dead skin, stimulating stem cells that sit in the stratum basale to make new skin cells.

Furthermore, chemical exfoliation regulates oils levels, which reduces the size of the oil glands, and reduces inflammation from rapid keratinization, further shrinking the pores.

Another important aspect is preventing pores from getting larger. Pores increase in size when they are clogged: think of a deflated balloon and then filling it with water or air: it expands. And then if you empty the balloon, the balloon is somewhat stretched out and cannot regain its initial, smaller size. The same happens with your pores. To prevent pores from stretching from being clogged, and staying large after clearing the clog, be sure to use non-comedogenic skin care and to cleanse every evening to remove dirt and excess oil.

I am also aware that laser-resurfacing treatments exist to shrink pores, however, this is a temporary fix because it does not create new skin or address the issues of enlarge sebum gland size, rapid keratinization, or enlargement from clogged pores.

If you just have proper skin care, and perform it daily, you will see pores shrink over time and the result will last in the long-term.

Question: There are a few brands in "green beauty" that are challenging the science or theory that pure essential oils used in the right proportions are unsafe/damaging to the skin. They are claiming this is a fear-mongering marketing tactic. Just recently [REDACTED] put out a blog post about this very topic. What are your thoughts?

-Lauren S.

Just a note, I will redact names of companies, blogs, etc. for AASKB posts. Feel free to mention them in your questions sent to so I can do my background research, but I will leave out any identifying information when it comes time to publish.

From what I know as a cellular biologist, I understand that there are no health benefits to essential oils.

Essential oils contain no compounds that can be incorporated by the body for health because essential oils have no nutritional value both for the plant that produces them and for the organism that uses them.

Essential oils contain: No vitamins, minerals, fatty acids, carbohydrates or proteins. That is not a marketing gimmick. It is just biology.

Essential oils only contain terpenes, which are cytotoxic.

If you put essential oil on your skin, your skin will begin to die at the cellular level.

I have 10 years of education, training and experience in reading and writing biological research papers. I read through the scientific literature cited in the [REDACTED] blog posts and the studies cited are not credible sources.

Here is the study cited by the blogger as support that essential oils are anti-inflammatory:

Han, X., & Parker, T. L. (2017). Lemongrass (Cymbopogon flexuosus) essential oil demonstrated anti-inflammatory effect in pre-inflamed human dermal fibroblasts. Biochimie Open, 4, 107-111.

This is not a good scientific study.

And the list of reasons why this is not a good study to promote essential oils in a positive light:

1. The researchers tested Lemon grass essential oil on neonatal Human Dermal Fibroblasts- Unless your face is made up of newborn foreskin sitting in a petri dish, the results of a skin care study conducted on foreskin in a dish are not going to be relevant to you. The composition of foreskin compared to the skin on your face right now is completely different, and therefore results obtained on foreskin are not indicative of the results you will personally experience. Furthermore, the results of in vitro studies are not a strong indication of what you will experience because cells behave differently in a petri dish than in the body.

2. The skin cells were artificially inflamed, and inflammation will go away on its own. The researchers did not do anything to maintain inflammation of the cells during the course of the study, so it is likely that the inflammatory response ceased with the passage of time, and not by the use of the essential oils.

3. The researchers diluted Lemon grass in DMSO. DMSO (dimethyl sulfide) is a highly effective solvent that is also used for dermal delivery of medication and is a known anti-inflammatory agent. The inflammatory biomarkers that were allegedly inhibited are known to be inhibited by DMSO as well. Therefore we have absolutely no way of knowing if it was the DMSO or the lemongrass that was acting as an anti-inflammatory agent. However, since DMSO’s anti-inflammatory effects have been substantiated time and time again, I am wagering that it was the DMSO that was the real anti-inflammatory agent in this study

4. The Journal for which this paper was published has a very low impact score (3.112), meaning that the average paper in the journal is only used and cited by 3 other studies. Impact factor is an important metric because it lets you determine how often the studies published in a journal are used by other researchers as a basis and for background for their studies. If a journal churns out great studies, more people will use those studies in their research, and the score goes up. A red flag is that this journal publishes a lot of papers, almost 300 a year, (Nature publishes about 80-100 per year) and has a low impact score, which says to me that the journal is just a publication factory that publishes any study sent to them with little to no peer review.

The lack of credibility or impact of the journal is seen clearly: only one other scientific study has used the findings of this present study. Having only one citation would be understandable if we are talking about research on something very obscure, such as the mating habits of a certain genus of cave-dwelling insect when the tides are highest during a full moon in April (you get my point). But for something as popular as essential oils in skin care, there is only one reason why a study would not be cited by other research: it is bogus.

5. Also in this same study, the researchers note the cytotoxicity of lemongrass oil, and how it becomes toxic to fibroblasts at a concentration of 0.0037%, which is why they used a essential oil concentration of 0.0012% for their research.

So if we were to humor the authors, and say yes, lemongrass does have an anti-inflammatory response, the problem is that there is no skin care in existence that uses such a low concentration of essential oil. So, in a real-world application of these findings you are reaping the cytotoxic rather than anti-inflammatory effects of essential oil.

A careful reading of this article would tell anyone that essential oils are not inflammatory, essential oils are cytotoxic. However, if you just read the abstract or, even worse, the title, and call it a day, you would never come to that understanding.

Another article that is cited:

Mostafa, D. M., Kassem, A. A., Asfour, M. H., Al Okbi, S. Y., Mohamed, D. A., & Hamed, T. E. S. (2015). Transdermal cumin essential oil nanoemulsions with potent antioxidant and hepatoprotective activities: in-vitro and in-vivo evaluation. Journal of Molecular Liquids, 212, 6-15.

Is worth the read. I have academic credentials, so I can read the entire study. If you were to go to the link in the blog post that cited it:

You will find that it is behind a paywall, which means you can read the title, the abstract and nothing more. This is where things get interesting. If you were to just read the title of the paper or the abstract, you would assume that the cumin essential oil exhibits anti-oxidant activity because the authors are misleading in their title and summary.

If you read the study, you will find that cumin essential oil does not have anti-oxidant activity, it is the oleic acid added to the essential oil that exhibited free-radical scavenging ability. Cumin essential oil just enhanced the delivery of the oleic acid because it broke the skin cell down, allowing for permeation. The authors even admit in the study that cumin essential oil on its own does not exhibit free radical scavenging ability until it is mixed with other compounds, which means it is the other compounds that are acting as anti-oxidants.

The takeaway from this investigation is to consider the source. If you read a blog and the author is citing scientific research, ask yourself, do they understand the research they are citing?

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