Effaclar Dual Action Acne Face Wash With 4% Benzoyl Peroxide
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La Roche-Posay Effaclar Dual Action Acne Face Wash With 4% Benzoyl PeroxideIngredients explained
The gold standard topical ingredient in treating acne. There is no miracle cure for acne (we do really wish for one, *sigh*), but Benzoyl Peroxide (BP) is probably the closest thing we have. But, as usual, big effects come with big side effects, so we think BP is best used as a last resort (at least, in the topical treatment field).
The good thing about BP is that it is amazingly effective against inflammatory-type acne. Not so much against blackheads or whiteheads, but against acne that is caused by the evil bacteria called Propionibacterium acnes (and that is most types of acne). Apart from being antibacterial, it is also anti-inflammatory, keratolytic and wound-healing, all of which are properties that make it so darn effective against spots.
Another big pro of BP is that there is no bacterial resistance to it, meaning if it works once it will continue to work. Antibiotics are also a common way to treat acne, but antibiotic-resistant P. acnes are increasing worldwide. BP will probably help you even if antibiotics have stopped working, and the two are also often combined for a more complex acne therapy. Btw, BP plays nice not only with antibiotics but also with retinoids.
The side-effects part? BP works its antibacterial magic by being a powerful oxidizing agent, meaning it is a pro-oxidant. As in the opposite of an antioxidant. BP literally generates evil ROS (reactive oxygen species) in the skin that kills P. acnes but also harms the surrounding skin cells. Ongoing BP-use ages your skin, which is why, we say, use it as a last resort. If you do use BP, please also use a good sunscreen and a good antioxidant serum to apologise to your skin (btw, these things are useful in any case). Use the BP treatment at night and the antioxidant serum in the morning so that they do not cancel each other out.
Another side effect of BP is that it can be very skin drying. BP is an example where more is not better. In fact, it is equally effective at concentrations of 2.5, 5.0 and 10%, but the higher the concentration the more irritating and drying side effects occur. So using BP at 2.5% percent is the ideal amount. Another side effect which is good to know is that BP can bleach bedsheets and clothes. Be careful with your expensive satin bedsheets.
Overall, Benzoyl Peroxide is a uniquely effective topical acne treatment, but it comes at a price. Use it as a last resort and for good measure (and with plenty of moisturizers, sunscreen, and antioxidant serum).
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.
- A natural moisturizer that’s also in our skin
- A super common, safe, effective and cheap molecule used for more than 50 years
- Not only a simple moisturizer but knows much more: keeps the skin lipids between our skin cells in a healthy (liquid crystal) state, protects against irritation, helps to restore barrier
- Effective from as low as 3% with even more benefits for dry skin at higher concentrations up to 20-40%
- High-glycerin moisturizers are awesome for treating severely dry skin
- It's a helper ingredient that improves the freeze-thaw stability of products
- It's also a solvent, humectant and to some extent a penetration enhancer
- It has a bad reputation among natural cosmetics advocates but cosmetic scientists and toxicology experts do not agree (read more in the geeky details section)
A thickening and foam-boasting co-surfactant with amphoteric structure meaning that its head contains both a positively and a negatively charged part (surfactants are most commonly anionic meaning their head has a negative charge). It's very mild and gentle, comes from coconut oil and is readily biodegradable.
A versatile and biodegradable cleansing agent with high cleaning power and strong foaming properties. Unfortunately, these two properties for a surfactant usually mean that it is harsh on the skin, which is the case here as well.
It's one of the most commonly used thickeners and emulsion stabilizers. If the product is too runny, a little xanthan gum will make it more gel-like. Used alone, it can make the formula sticky and it is a good team player so it is usually combined with other thickeners and so-called rheology modifiers (helper ingredients that adjust the flow and thus the feel of the formula). The typical use level of Xantha Gum is below 1%, it is usually in the 0.1-0.5% range.
Btw, Xanthan gum is all natural, a chain of sugar molecules (polysaccharide) produced from individual sugar molecules (glucose and sucrose) via fermentation. It’s approved by Ecocert and also used in the food industry (E415).
It's a very alkaline stuff that helps to set the pH of the cosmetic formula to be just right. It's similar to the more often used sodium hydroxide and pretty much the same of what we wrote there applies here too.
Sodium chloride is the fancy name of salt. Normal, everyday table salt.
If (similar to us) you are in the weird habit of reading the label on your shower gel while taking a shower, you might have noticed that sodium chloride is almost always on the ingredient list. The reason for this is that salt acts as a fantastic thickener in cleansing formulas created with ionic cleansing agents (aka surfactants) such as Sodium Laureth Sulfate. A couple of percents (typically 1-3%) turns a runny surfactant solution into a nice gel texture.
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.
A little helper ingredient that is used to adjust the pH of the product. It also helps to keep products stay nice longer by neutralizing the metal ions in the formula (they usually come from water).
- A multi-functional skincare superstar with several proven benefits for the skin
- Great anti-aging, wrinkle smoothing ingredient used at 4-5% concentration
- Fades brown spots alone or in combination with amino sugar, acetyl glucosamine
- Increases ceramide synthesis that results in a stronger, healthier skin barrier and better skin hydration
- Can help to improve several skin conditions including acne, rosacea, and atopic dermatitis
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).
We don't have description for this ingredient yet.
Propanediol is a natural alternative for the often used and often bad-mouthed propylene glycol. It's produced sustainably from corn sugar and it's Ecocert approved.
It's quite a multi-tasker: can be used to improve skin moisturization, as a solvent, to boost preservative efficacy or to influence the sensory properties of the end formula.
We don't have description for this ingredient yet.
A big molecule created from repeated subunits (a polymer of acrylic acid) that magically converts a liquid into a nice gel formula. It usually has to be neutralized with a base (such as sodium hydroxide) for the thickening to occur and it creates viscous, clear gels that also feel nice and non-tacky on the skin. No wonder, it is a very popular and common ingredient. Typically used at 1% or less in most formulations.
An Ecocert-approved, natural preservative that counts as gentle and non-irritating to the skin. Usually, it comes to the formula as part of a preservative blend as it's not enough on its own.
A multi-functional, silky feeling helper ingredient that can do quite many things. It's used as an emulsion stabilizer, solvent and a broad spectrum antimicrobial. According to manufacturer info, it's also a moisturizer and helps to make the product feel great on the skin. It works synergistically with preservatives and helps to improve water-resistance of sunscreens.
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 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
A handy helper ingredient that helps products to remain nice and stable for a longer time. It does so by neutralizing the metal ions in the formula (that usually get into there from water) that would otherwise cause some not so nice changes.
A helper ingredient that helps to neutralize the metal ions in the formula (they usually come from water) so it stays nice longer. The special property of this particular ingredient is that it's more effective against more problematic ions, like Cu (copper) and Fe (iron) compared to less problematic ones like Ca (calcium) and Mg (magnesium).
Citric acid comes from citrus fruits and is an AHA. If these magic three letters don’t tell you anything, click here and read our detailed description on glycolic acid, the most famous AHA.
So citric acid is an exfoliant, that can - just like other AHAs - gently lift off the dead skin cells of your skin and make it more smooth and fresh.
There is also some research showing that citric acid with regular use (think three months and 20% concentration) can help sun-damaged skin, increase skin thickness and some nice hydrating things called glycosaminoglycans in the skin.
But according to a comparative study done in 1995, citric acid has less skin improving magic properties than glycolic or lactic acid. Probably that’s why citric acid is usually not used as an exfoliant but more as a helper ingredient in small amounts to adjust the pH of a formulation.
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| what‑it‑does | anti-acne |
| what‑it‑does | solvent |
| what‑it‑does | skin-identical ingredient | moisturizer/humectant |
| irritancy, com. | 0, 0 |
| what‑it‑does | moisturizer/humectant | solvent |
| irritancy, com. | 0, 0 |
| what‑it‑does | surfactant/cleansing | viscosity controlling |
| what‑it‑does | surfactant/cleansing |
| what‑it‑does | viscosity controlling |
| what‑it‑does | buffering |
| what‑it‑does | viscosity controlling |
| what‑it‑does | chelating | buffering |
| what‑it‑does | cell-communicating ingredient | skin brightening | anti-acne | moisturizer/humectant |
| what‑it‑does | skin-identical ingredient | moisturizer/humectant |
| irritancy, com. | 0, 0 |
| what‑it‑does | exfoliant |
| what‑it‑does | solvent | moisturizer/humectant |
| what‑it‑does | surfactant/cleansing | emulsifying |
| what‑it‑does | viscosity controlling |
| irritancy, com. | 0, 1 |
| what‑it‑does | preservative |
| what‑it‑does | solvent | moisturizer/humectant |
| what‑it‑does | buffering |
| what‑it‑does | exfoliant | buffering |
| what‑it‑does | chelating |
| what‑it‑does | chelating |
| what‑it‑does | buffering |