Over the past few weeks, I have credited jojoba oil with the improvements in my skin. It’s softer, smoother, and seems to be more tolerant of products that once irritated it (such as Retin-A .025%). In the process of trying to learn why this may be, I’ve encountered a lot of claims about jojoba oil: it’s anti-aging, it helps heal wounds, it has a smaller molecular size which makes it better absorbed by skin, it heals UV damage, and on and on.

While preparing this post, I went unusually deep. I dug through Google Scholar and sorted through several PDFs, trying to figure out what exactly was so magical about this little oil. It’s recommended everywhere and holds a fair amount of shelf space in natural health food stores like Whole Foods, Sprouts, and Trader Joe’s, and even appears in the acne.org routine.

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All About Jojoba Oil

Jojoba oil is produced from the seed of the Jojoba plant, a shrub native to Arizona, southern California, and northwestern Mexico. While frequently called “jojoba oil” due to it’s appearance as a liquidy oil, it is more appropriately described as a wax due to it’s composition, which also accounts for it’s high shelf-life and resistance to high temperatures.

It is also thought to be very similar to our skin’s natural oil, and is even suggested as an ingredient in synthetic lipids when testing how things will interact with human sebum.¹ Some feel like this similarity to our own natural oil can “trick” the skin and help balance it’s own sebum production, though I was unable to find any scientific literature to back up this claim.

Like all oils, jojoba oil is also frequently described and recommended as an occlusive. From HowThingsWork:

“‘Jojoba oil is rich in natural fats that mimic those in the outer layer of the skin,’ explains Joshua Zeichner, M.D., director of cosmetic and clinical research at Mount Sinai Medical Center in New York City. ‘This means it can help the skin retain moisture and heal itself.'”

To learn more, I dug into a study about the TEWL (trans-epidermal water loss) of several oils and popular occlusives, namely jojoba, soybean, almond, avocado, paraffin, as well as petrolatum (control). The study noted that TEWL measurements have become “an important, non-invasive tool in dermatology and cosmetology and is generally associated as a device for the monitoring of changes in the barrier function of the stratum corneum. In intact skin, TEWL values are rather low, as impaired skin provides increased values leading to decreasing value when the barrier recovers.”²

To test the effects on TEWL, two types of measurements were taken on six healthy volunteers, aged between 25-50. Volunteers were instructed to not utilize skincare at least 24 hours before, and not to bathe or shower up to 4 hours prior to the beginning of the measurements. TEWL measurements were taken before and thirty minutes after application as well as after the remaining oil had been wiped off. In vivo (meaning measured on a living being), laser scanning microscopy (LSM) revealed that substance penetration appeared to be limited to the uppermost two layers of corneocytes, meaning that no substance penetrated deeper than the stratum corneum (SC). Surprisingly, soybean and almond oil had the deepest penetration into the SC, down into its third layer, while jojoba, avocado, and paraffin was only detected on the skin’s surface and in lipids around the first few corneocyte layers. Petrolatum, the control, was also not vicisble in upper corneocyte layers. In short, despite quite different oil chemistry, the penetration of the tested vegetable oils vs paraffin oil was comparable.²

TEWL was also measured before the substances were applied as well as after substance application. The results showed that TEWL decreased markedly in all cases, except for jojoba oil.

While this study was very small (only six people), this may be why some people do not find jojoba oil very “moisturizing.”

Jojoba oil is also pretty well-tolerated, which may be due to it’s similarities to human sebum, but it may also be due to it’s composition of only 5-15% oleic acid³, a fatty acid that has garnered a reputation for causing acne, specifically due to it’s ability to increase the growth of P. acnes.⁵ In animal models, oleic acid “and it’s peroxides were able to induce fairly large comedones and there was good correlation between the lipid peroxide levels and the size of the comedones.”⁴ While this does not necessarily speak with absolute certainty to how oleic acid functions in humans, it shouldn’t be discounted and is worth further research.

I’ve also seen two particular studies used to inform whether jojoba has anti-inflammatory and anti-microbial effects. Specifically, one study in rats showed it to be anti-inflammatory by decreasing prostagladin E2 (PGE2) levels, while another (unspecified whether it was animal or human) “demonstrated that exposure of bacteria for 24h to [a jojoba/tea trea mixture] containing an antimicrobial leads to a loss of their culturability.”⁵ While the former may hold merit worth further exploration, as with the oleic acid experiment I noted above, it should be noted that in the latter study, the components in the mixture was not disclosed, and that tea tree was included – a substance that has shown to be as effective (over time) in killing P. acnes as benzoyl peroxide.⁶

An in vitro study (meaning a test taken outside a living organism, such as a tube or culture disc) also showed that jojoba “notably accelerates the wound closure of both keratinocytes and fibroblasts” in scratch wound experiments (“Cells are grown to confluence and a thin “wound” introduced by scratching with a pipette tip”⁷). This study suggests that jojoba could be used in the treatment of wounds in clinical settings, but I could not find any in vivo studies to give certainty to this.

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All Tied Together

While I didn’t figure out why this oil has been so magical for me, I do think jojoba is a special oil in it’s unique composition, which makes it worth checking out if you are acne-prone or sensitive.

If buying, look for gold, cold-pressed jojoba, which means that it was extracted mechanically and no extra heat was applied during extraction. This helps the oil retain it’s original properties. Unrefined, cold-pressed jojoba oil should have a very, very faint scent and be gold (but translucent) in color. If your jojoba oil is colorless, it may be refined – a process of bleaching and deodorizing an oil and adding preservatives.

I also suggest buying from a trusted retailer. All oils may vary from retailer to retailer, and from harvest to harvest, as they are collected from a natural source. I purchased my jojoba oil from Trader Joe’s, which while it does not advertise itself as “cold-pressed,” was confirmed to be cold-pressed by a representative for the company.

It should also be noted that it is not a very good occlusive ingredient (like… at all) and is better as an addition to your moisturizer if you need some “slip” or as a stand-alone emollient, filling in the “cracks” of the skin to make it smoother and softer. This lack of occlusivity should also serve in not preventing ingredients on top of it from being absorbed by the skin, such as Retin-A. In fact, it may be an excellent buffering ingredient for this reason.

The only real note is that if you use jojoba oil during the day, beneath sunscreen, make sure to blot your skin of additional oil before applying sunscreen. While sunscreen does not need to be “absorbed” by the skin to be effective (a common myth), it does need to form a film, which can require drying down or settling on the skin. Too much “slip” on the skin, in the form of oil, can prevent this from occurring and render your sunscreen less effective.

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Sources

1. Human synthetic sebum formulation and stability under conditions of use and storage
2. Cosmetic Oils in comparison: penetration and occlusion of paraffin oil and vegetable oils
3. Jojoba Oil Specifications
4. Google Books – Acne: Diagnosis and Management
5. Dermatologia e Venereologia – Warning: Graphic Images
6. Herbal Therapy in Dermatology
7. Scratch-wound assay