Nikun Co.

Acne And Acne Scar Serum

It’s an ingredient whose safety hasn’t been questioned so far by anyone (at least not that we know about). BG is approved by Ecocert and is also used enthusiastically in natural products. BTW, it’s also a food additive. 

Regarding research, we could find two studies where Potassium Azeloyl Diglycinate's name popped up. One study examined the management of rosacea and the other one researched the treatment of melasma. Both were successful (we mean people showed improvement :)) but our Azelaic acid derivative was combined with other actives so it's hard to know what to attribute to this guy only. 

Overall, a promising multi-function active that's worth checking out if you have pigmentation-prone, acne-prone or rosacea-prone skin.

The complication, however, is that different extracts and distillates can be made from different parts of the plant (bark, twigs, and leaves are typically used) and different extraction methods from different parts produce different results. So if you see only Witch Hazel Extract or Witch Hazel Water on the ingredient list, it's a bit hard to know what you're actually getting but we will try to summarize the possibilities to give an idea.

The main biologically active components in Witch Hazel are hamamelitannin (a potent astringent and antioxidant), catechins (anti-inflammatory and antioxidant) and gallic acid (antibacterial). The bark extract contains by far the most hamamelitannin and it has the most gallic acid and catechins. The twigs contain fewer catechins, less gallic acid, and much less hamamelitannin (4.77% vs 0.18%). The leaves contain hardly any tannins (0.04%) or catechins and contain a medium amount of gallic acid (compared to the bark and twigs).

Witch Hazel also contains tiny amounts of the essential oil and fragrance component eugenol, but the amount is so small that it's probably not significant for the skin.

Apart from the differences in active components in different parts of the Witch Hazel bush, the extraction methods also vary. Witch Hazel Distillate contains 14% added alcohol according to the USP specifications  and alcohol is, at best drying, and at worst skin-damaging. Luckily, there are also alcohol-free distillates, so if you prefer no alcohol check the ingredient list carefully. Witch Hazel Extracts can also be made in different ways: browsing Ulprospector, we could find hydroglycolic, hydroalcoholic and glicerine/water based extracts.

Well-known skin care expert, Paula Begoun rates witch hazel as poor and says,  "depending on the form of witch hazel, you’re exposing your skin either to a sensitizing amount of alcohol or to tannins, or both." This might be the case if you are dealing with an alcoholic witch hazel bark water or extract, but looking at CosIng (the official INCI name listing of the EU), witch hazel bark water or witch hazel bark extract are not listed ingredients. Bark and leaf or bark and twig or all three are used together to create extracts, so the chance that there is too much hamamelitannin in the final cosmetic ingredient seems small. Also alcohol-free extracts and distillates exist; actually, the majority seem to be alcohol-free nowadays. So all in all, we think "Hamamelis Virginiana Extract" on the ingredient list is nothing to worry about.

We even found a German study that compared the efficacy of Hamamelis ointment to panthenol ointment for soothing the skin in children (from 27 days to 11 years old). They observed 309 children and concluded that both ointments were similarly effective but the one with Hamamelis was even better tolerated (98.2% vs. 92.3% tolerated well the ointments in the two groups).

All in all, Witch Hazel Extract is a sloppy INCI name (btw, not in the CosIng listing), and you do not really know what you're getting. Most probably though, you are getting a goody with nice astringent, soothing, antibacterial, and even antioxidant properties.

As for scientific proof that snail slime does something for the skin, we did find a couple of studies to go by. A Spanish radiation oncologist, Rafael Abad Iglesias MD discovered for the first time that snail mucin can be used to treat radiation dermatitis (skin irritation caused by radiotherapy, a form of cancer treatment). He did a clinical study with 100 patients and reported a "statistically significant clinical improvement in erythema, itching and burning pain" in the group treated with snail slime. 

A 2007 study examined the molecular basis for the great regeneration properties of the ingredient. It found that snail slime (SS) indeed does a bunch of positive things that could be the reason for its great repair abilities. First, it has serious antioxidant properties thanks to two great antioxidant enzymes, superoxide dismutase and glutathione s-transferase. Second, SS induces fibroblast proliferation, that's particularly important during wound healing. Third SS was also found to downregulate MMP, an evil enzyme that's out there to destroy skin-firming collagen. These properties add up to give SS not only wound healing and regenerative properties but also serious anti-aging potential. 

Regarding anti-aging, a 2013 study in the Journal of Drugs in Dermatology examined the effect of SS on photoaged skin. The 14-week, double-blind, 25 participant study found that "there was a significant degree of improvement in fines lines", though the participants did not report a significant difference in the quality of their skin.

All in all, we think that snail slime definitely deserves the skin goodie status it already enjoys in the K-beauty space. If you have no problem with somewhat strange, yucky things or animal derived ingredients in your products, it's worth a try.