Highlights
Key Ingredients
Skim through
| Ingredient name | what-it-does | irr., com. | ID-Rating |
|---|---|---|---|
| Houttuynia Cordata Extract | antioxidant, soothing | goodie | |
| Butylene Glycol | moisturizer/humectant, solvent | 0, 1 | |
| 1,2-Hexanediol | solvent | ||
| Sodium Lactate | buffering, moisturizer/humectant | goodie | |
| Water | solvent | ||
| Allantoin | soothing | 0, 0 | goodie |
| Glycolic Acid | exfoliant, buffering | superstar | |
| Panthenol | soothing, moisturizer/humectant | 0, 0 | goodie |
| Betaine Salicylate | exfoliant, antimicrobial/antibacterial | ||
| Ethylhexylglycerin | preservative | ||
| Sodium Hydroxide | buffering | ||
| Sodium Hyaluronate | skin-identical ingredient, moisturizer/humectant | 0, 0 | goodie |
SEOUL 4PM AHA BHA Heartleaf 92 TonerIngredients explained
Houttuynia cordata is a flowering plant native to Southeast Asia. It is eaten as a leaf vegetable, and also has a long history of use in traditional Chinese medicine, including as an attempted treatment for SARS (it didn’t really work). Regarding cosmetics, however, houttuynia cordata extract has a good bit of potential!
The main active components in the plant are these fancy chemicals called flavonoids. Houttuynia cordata specifically has a good amount of polyphenolic flavonoids, four common ones being quercetin, quercitrin, hyperoside, and rutin. All of these exhibit anti-inflammatory, antioxidant, and antibacterial properties. Quercitrin has also been shown to decrease damage from UVB rays, which is an added bonus. One thing to keep in mind, though, is that the flavonoid content of this extract can depend on if the extract is taken from the roots or the leaves, as well as if it’s a water extraction or an alcohol extraction.
Another thing Houttuynia cordata extract contains are polysaccharides, i.e. big molecules from various sugar units (in this case it is galacturonic acid (29.4%), galactose (24.0%), rhamnose (17.2%), arabinose (13.5%), glucuronic acid (6.8%), glucose (5.3%), xylose (2.1%) and mannose (1.8%) ). Polysaccharides and sugars in skincare are excellent humectants and skin hydrators, meaning they help the skin to hold onto water.
Last but not least, we also found an in-vitro (made in test tubes) study showing that houttuynia cordata extract had strong anti-allergic effects and could be helpful in treating skin allergies such as eczema (atopic dermatitis).
Butylene glycol, or let’s just call it BG, is a multi-tasking colorless, syrupy liquid. It’s a great pick for creating a nice feeling product.
BG’s main job is usually to be a solvent for the other ingredients. Other tasks include helping the product to absorb faster and deeper into the skin (penetration enhancer), making the product spread nicely over the skin (slip agent), and attracting water (humectant) into the skin.
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.
A really multi-functional helper ingredient that can do several things in a skincare product: it can bring a soft and pleasant feel to the formula, it can act as a humectant and emollient, it can be a solvent for some other ingredients (for example it can help to stabilize perfumes in watery products) and it can also help to disperse pigments more evenly in makeup products. And that is still not all: it can also boost the antimicrobial activity of preservatives.
The sodium salt of lactic acid. It's a great skin moisturizer and also used to regulate the pH value of the cosmetic formula. It's a natural ingredient approved by both ECOCERT and COSMOS.
Good old water, aka H2O. The most common skincare ingredient of all. You can usually find it right in the very first spot of the ingredient list, meaning it’s the biggest thing out of all the stuff that makes up the product.
It’s mainly a solvent for ingredients that do not like to dissolve in oils but rather in water.
Once inside the skin, it hydrates, but not from the outside - putting pure water on the skin (hello long baths!) is drying.
One more thing: the water used in cosmetics is purified and deionized (it means that almost all of the mineral ions inside it is removed). Like this, the products can stay more stable over time.
Super common soothing ingredient. It can be found naturally in the roots & leaves of the comfrey plant, but more often than not what's in the cosmetic products is produced synthetically.
It's not only soothing but it' also skin-softening and protecting and can promote wound healing.
- It’s the most researched AHA with the most proven skin benefits
- It gently lifts off dead skin cells to reveal newer, fresher, smoother skin
- It can help skin’s own collagen production that results in firmer, younger skin
- It can fade brown spots caused by sun damage or PIH
- Choose a product where you know the concentration and pH value because these two greatly influence effectiveness
- Don’t forget to use your sunscreen (in any case but especially so next to an AHA product)
- Slight stinging or burning with a stronger AHA product is normal
- If your skin is very sensitive, rosacea prone choose rather a BHA or PHA product
An easy-to-formulate, commonly used, nice to have ingredient that’s also called pro-vitamin B5. As you might guess from the “pro” part, it’s a precursor to vitamin B5 (whose fancy name is pantothenic acid).
Its main job in skincare products is to moisturise the skin. It’s a humectant meaning that it can help the skin to attract water and then hold onto it. There is also research showing that panthenol can help our skin to produce more lovely lipids that are important for a strong and healthy skin barrier.
Another great thing about panthenol is that it has anti-inflammatory and skin protecting abilities. A study shows that it can reduce the irritation caused by less-nice other ingredients (e.g. fragrance, preservatives or chemical sunscreens) in the product.
Research also shows that it might be useful for wound healing as it promotes fibroblast (nice type of cells in our skin that produce skin-firming collagen) proliferation.
If that wasn’t enough panthenol is also useful in nail and hair care products. A study shows that a nail treatment liquide with 2% panthenol could effectively get into the nail and significantly increase the hydration of it.
As for the hair the hydration effect is also true there. Panthenol might make your hair softer, more elastic and helps to comb your hair more easily.
The combination of famous exfoliant, salicylic acid and gentle moisturizer, betaine. It counts as a mild exfoliant and natural moisturizer, skin smoothing agent.
You usually find this guy in K-Beauty products, as due to regulations, pure salicylic acid can be used only in tiny amounts in South-Korean formulations. A generally accepted ballpark number is that betaine salicylate is twice as gentle as salicylic acid, i.e. a 4% betaine salicylate product is similar to a 2% salicylic acid one.
If you have spotted ethylhexylglycerin on the ingredient list, most probably you will see there also the current IT-preservative, phenoxyethanol. They are good friends because ethylhexylglycerin can boost the effectiveness of phenoxyethanol (and other preservatives) and as an added bonus it feels nice on the skin too.
Also, it's an effective deodorant and a medium spreading emollient.
The unfancy name for it is lye. It’s a solid white stuff that’s very alkaline and used in small amounts to adjust the pH of the product and make it just right.
For example, in case of AHA or BHA exfoliants, the right pH is super-duper important, and pH adjusters like sodium hydroxide are needed.
BTW, lye is not something new. It was already used by ancient Egyptians to help oil and fat magically turn into something else. Can you guess what? Yes, it’s soap. It still often shows up in the ingredient list of soaps and other cleansers.
Sodium hydroxide in itself is a potent skin irritant, but once it's reacted (as it is usually in skin care products, like exfoliants) it is totally harmless.
It’s the - sodium form - cousin of the famous NMF, hyaluronic acid (HA). If HA does not tell you anything we have a super detailed, geeky explanation about it here. The TL; DR version of HA is that it's a huge polymer (big molecule from repeated subunits) found in the skin that acts as a sponge helping the skin to hold onto water, being plump and elastic. HA is famous for its crazy water holding capacity as it can bind up to 1000 times its own weight in water.
As far as skincare goes, sodium hyaluronate and hyaluronic acid are pretty much the same and the two names are used interchangeably. As cosmetic chemist kindofstephen writes on reddit "sodium hyaluronate disassociates into hyaluronic acid molecule and a sodium atom in solution".
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).
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| what‑it‑does | antioxidant | soothing |
| what‑it‑does | moisturizer/humectant | solvent |
| irritancy, com. | 0, 1 |
| what‑it‑does | solvent |
| what‑it‑does | buffering | moisturizer/humectant |
| what‑it‑does | solvent |
| what‑it‑does | soothing |
| irritancy, com. | 0, 0 |
| what‑it‑does | exfoliant | buffering |
| what‑it‑does | soothing | moisturizer/humectant |
| irritancy, com. | 0, 0 |
| what‑it‑does | exfoliant | antimicrobial/antibacterial |
| what‑it‑does | preservative |
| what‑it‑does | buffering |
| what‑it‑does | skin-identical ingredient | moisturizer/humectant |
| irritancy, com. | 0, 0 |