Allies of Skin

Peptides Antioxidants Firming Daily Treatment

It's a really promising candidate (see below), but while reading all the goodness about it in a minute, do not forget that derivatives not only have to be absorbed into the skin but also have to be converted to pure vitamin C (ascorbic acid or AA) and the efficacy of the conversion is often unknown. In addition, vitamin C's three magic properties (antioxidant, collagen booster, skin brightener) are all properly proven in-vivo (on real people), but for the derivatives, it's mostly in-vitro studies or in the case of THDA, it's in-vitro and done by an ingredient supplier.

With this context in mind let's see what THDA might be able to do. First, it is stable (if pH < 5), easy to formulate, and a joy to work with for a cosmetic chemist.

Second, because it's oil-soluble, its skin penetration abilities seem to be great. So great in fact, that it surpasses the penetration of pure vitamin C threefold at the same concentration and it penetrates successfully into the deeper layers of the skin (that is usually important to do some anti-aging work). There is also in-vitro data showing that it converts to AA in the skin. 

Third, THDA seems to have all three magic abilities of pure vitamin C: it gives antioxidant protection from both UVB and UVA rays, it increases collagen synthesis (even more than AA) and it has a skin brightening effect by reducing melanogenesis by more than 80% in human melanoma cell cultures.

So this all sounds really great, but these are only in-vitro results at this point. We could find Tetrahexyldecyl Ascorbate mentioned only in one published in-vivo study that examined the anti-aging properties of a silicone formula containing 10% AA and 7% THDA. The authors theorized that the 10% AA is released slowly from the silicon delivery system and probably stays in the upper layer of the skin to give antioxidant benefits, while THDA penetrates more rapidly and deeply and gives some wrinkle-reducing benefits. The study was a small (10 patients), double-blind experiment, and the formula did show some measurable anti-aging results. However, it is hard to know how much pure vitamin C or THDA can be thanked.

Bottom line: a really promising, but not well-proven vitamin C derivative that can be worth a try especially if you like experimenting (but if you like the tried and true, pure vitamin C will be your best bet).

So Astaxanthin's main thing is being an antioxidant. You can take it as a supplement or slather it on your skin, it works both ways. A mouse skin study from 2012 found that a liposomal Astaxanthin formula prevented UV‐induced skin damage in multiple ways: UV-induced skin thickening, collagen reduction, and melanin formation were all hindered or prevented when the skin was pretreated with the Astaxanthin formula. 

Another study from 2012 examined the cosmetic benefits of Astaxanthin and found that combining oral supplementation (6mg/day) and topical application for 8 weeks in 30 volunteers showed improvements in skin wrinkle (crow’s feet), age spot size (cheek), elasticity (crow’s feet), skin texture (cheek) and moisture content of the skin (cheek).  If that would not be enough, a 2017 mouse study found our carotenoid molecule to be effective in speeding up wound healing.

Overall, Astaxanthin is an up and coming antioxidant nice to spot on any ingredient list. 

Second, still according to Estee Lauder research but now from 2012 the ingredient has anti-microbial and anti-inflammatory properties and holds promise in the treatment of acne and rosacea. For the former one 5% was needed to show effectiveness, but for reducing skin sensitivity already 1% showed results. 

The anti-acne effect is confirmed also by US manufacturer, Barnet, that says that Lactobacillus ferment is helpful in killing harmful bacteria and creating a healthy balanced microflora. Compared to well-known anti-acne and anti-inflammatory salicylic acid the probiotic worked faster at reducing the size and redness of acne lesions. 

It also goes by the trade name Leucidal Liquid SF and can serve in the formula as a natural preservative. 

Bottom line: It’s not the most proven ingredient (yet) but definitely a very promising one especially if you have sensitive skin, acne or rosacea.  

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.