Uoga Uoga

Invisible Hero

So what the heck is a wax ester and why is that important anyway? Well, to understand what a wax ester is, you first have to know that oils are chemically triglycerides: one glycerin + three fatty acids attached to it. The fatty acids attached to the glycerin vary and thus we have many kinds of oils, but they are all triglycerides. Mother Nature created triglycerides to be easily hydrolyzed (be broken down to a glycerin + 3 fatty acid molecules) and oxidized (the fatty acid is broken down into small parts) - this happens basically when we eat fats or oils and our body generates energy from it.

Mother Nature also created wax esters but for a totally different purpose. Chemically, a wax ester is a fatty acid + a fatty alcohol, one long molecule. Wax esters are on the outer surface of several plant leaves to give them environmental protection. 25-30% of human sebum is also wax esters to give us people environmental protection. 

So being a wax ester results in a couple of unique properties: First, jojoba oil is extremely stable. Like crazy stable. Even if you heat it to 370 C (698 F) for 96 hours, it does not budge. (Many plant oils tend to go off pretty quickly). If you have some pure jojoba oil at home, you should be fine using it for years. 

Second, jojoba oil is the most similar to human sebum (both being wax esters), and the two are completely miscible. Acne.org has this not fully proven theory that thanks to this, jojoba might be able to "trick" the skin into thinking it has already produced enough sebum, so it might have "skin balancing" properties for oily skin.

Third, jojoba oil moisturizes the skin through a unique dual action: on the one hand, it mixes with sebum and forms a thin, non-greasy, semi-occlusive layer; on the other hand, it absorbs into the skin through pores and hair follicles then diffuses into the intercellular spaces of the outer layer of the skin to make it soft and supple.

On balance, the point is this: in contrast to real plant oils, wax esters were designed by Mother Nature to stay on the surface and form a protective, moisturizing barrier and jojoba oil being a wax ester is uniquely excellent at doing that.

As for skincare, argan oil is loaded with lots of skin goodies (but so are many other plant oils): it contains 80% nourishing and moisturizing unsaturated fatty acids, mainly oleic (38-50%), linoleic (28-38%) and palmitic (10-18%). It also contains a relatively large amount of antioxidant vitamin E (600-900 mg/kg, about twice as much as olive), small amounts of antioxidant phenols (including caffeic acid, ferulic acid, and epicatechin), as well as some rare sterols with soothing and anti-inflammatory properties. 

Thanks to all the above goodness in argan oil, it can greatly nourish and moisturize the skin and hair. It's also claimed to be able to neutralize collagen-damaging free radicals, help reduce scars, and revitalize and improve skin elasticity. You can even read that argan might help acne-prone skin, but being a high oleic oil, we would be careful with that. 

All in all, argan oil is a real goodie but we do not fully understand the special miracle status it enjoys.

Another advantage of squalane is that it is pretty much compatible with all skin types and skin conditions. It is excellent for acne-prone skin and safe to use even if you have fungi-related skin issues, like seborrhea or fungal acne.

The unsaturated (with double bonds) and hence less stable version of Squalane is Squalene, you can read about it here >> 

If you are into chemistry (if not, we understand, just skip this paragraph), the reason is that electrolytes (you know, the Na+ and Cl- ions) screen the electrostatic repulsion between the head groups of ionic surfactants and thus support the formation of long shaped micelles (instead of spherical ones) that entangle like spaghetti, and viola, a gel is formed. However, too much of it causes the phenomenon called "salting out", and the surfactant solution goes runny again. 

Other than that, salt also works as an emulsion stabilizer in water-in-oil emulsions, that is when water droplets are dispersed in the outer oil (or silicone) phase. And last but not least, when salt is right at the first spot of the ingredient list (and is not dissolved), the product is usually a body scrub where salt is the physical exfoliating agent. 

Our intro did get pretty big after all (sorry for that), so let's get to the point finally: sunflower oil - similar to other plant oils - is a great emollient that makes the skin smooth and nice and helps to keep it hydrated. It also protects the surface of the skin and enhances the damaged or irritated skin barrier. Leslie Bauman notes in Cosmetic Dermatology that one application of sunflower oil significantly speeds up the recovery of the skin barrier within an hour and sustains the results 5 hours after using it.

It's also loaded with fatty acids (mostly linoleic (50-74%)  and oleic (14-35%)). The unrefined version (be sure to use that on your skin!) is especially high in linoleic acid that is great even for acne-prone skin. Its comedogen index is 0, meaning that it's pretty much an all skin-type oil. 

Truth be told, there are many great plant oils and sunflower oil is definitely one of them.

A well-known thing about Caffeine is that it improves the microcirculation of the blood vessels. Though conventional wisdom and anecdotal evidence says that this property is helpful for dark under-eye circles and puffy eyes, we have to mention that the double-blind research we have found about a 3% caffeine gel concluded that "the overall efficacy of the selected caffeine gel in reducing puffy eyes was not significantly different from that of its gel base."  But you know, the proof is in the pudding.

Another thing Caffeine is used for in body care products is its anti-cellulite effects. In theory, it can speed up the lipolysis process (the "fat burning"  by our cells) and stimulate the draining lymph system that might lead to the improvement of cellulite. But here again, the evidence that it actually makes a measurable, let alone visible,  improvement on actual human beings is limited (we could find only some animal skin studies or caffeine being combined with other actives). 

Last, but not least, we have to write about caffeine and hair growth. The theory is that it can inhibit the activity of the 5-α-reductase enzyme that plays an important role in hair loss and allows a renewed growth phase of the hair. We have found some recent and promising research to back this up. A 2017 study compared a 0.2% caffeine liquid with a 5% Minoxidil  (an FDA approved active to treat baldness) solution and found that  "a caffeine-based topical liquid should be considered as not inferior to minoxidil 5% solution in men with androgenetic alopecia", or English translation means that the caffeine liquid was pretty much as good as the FDA-approved Minoxidil stuff. Not bad!

Overall, we think that caffeine is a very versatile and biologically active ingredient. Even though some of its effects are more hyped up than backed up, it is still a nice to have on many ingredient lists. 

What's the problem?

Firstly, it's stability is only similar to that of pure ascorbic acid (AA), which means it is not really stable. A great study in the Journal of Cosmetic Dermatology compared a bunch of vitamin C derivatives and this derivative was the only one where the study said in terms of stability that it's "similar to AA". Not really that good.

Second, a study that examined the skin absorption of vitamin C found that ascorbyl palmitate did not increase the skin levels of AA. This does not mean that ascorbyl palmitate cannot penetrate the skin (because it can, it's oil soluble and the skin likes to absorb oil soluble things) but this means that it's questionable if ascorbyl palmitate can be converted into pure Vit C in the skin. Even if it can be converted, the palmitate part of the molecule is more than the half of it, so the efficacy will not be good and we have never seen a serum that contains a decent (and proudly disclosed) amount of AP.  We are highly skeptical what effect a tiny amount of AP has in a formula.

Third, another study that wanted to examine the antioxidant properties of AP was surprised to find that even though AP does have nice antioxidant properties; following UVB radiation (the same one that comes from the sun) it also promotes lipid peroxidation and cytotoxicity. It was only an in-vitro study meaning that it was done on cell cultures and not on real people, but still, this also does not support the use of AP too much. 

The only good thing we can write about Ascorbyl Palmitate is that there is an in-vitro (made in the lab, not on real people) study showing that it might be able to boost collagen production.

Regarding the skin-brightening properties of pure vitamin C, this is another magic property AP does not have, or at least there is no data, not even in-vitro, about it.

Overall, Ascorbyl Palmitate is our least favorite vitamin C derivative. It is there in lots of products in tiny amounts (honestly, we do not really understand why), however, we do not know about any vitamin C serum featuring AP in high amounts. That is probably no coincidence. If you are into vitamin C, you can take a look at more promising derivatives here. 

In spite of this, if you search for "hyaluronic acid vs sodium hyaluronate" you will find on multiple places that sodium hyaluronate is smaller and can penetrate the skin better. Chemically, this is definitely not true, as the two forms are almost the same, both are polymers and the subunits can be repeated in both forms as much as you like. (We also checked Prospector for sodium hyaluronate versions actually used in cosmetic products and found that the most common molecular weight was 1.5-1.8 million Da that absolutely counts as high molecular weight).

What seems to be a true difference, though, is that the salt form is more stable, easier to formulate and cheaper so it pops up more often on the ingredient lists. 

If you wanna become a real HA-and-the-skin expert you can read way more about the topic at hyaluronic acid (including penetration-questions, differences between high and low molecular weight versions and a bunch of references to scientific literature).