Earth Rhythm

Mineral Sun Serum

A sugar based emulsifier that's especially great for low viscosity lotions or even sprays. It's effective in small amounts, only 1-1.5% is needed to form an emulsion. The resulting cream or lotion has great cosmetic properties with good spreadability and an enhanced soft skin feel. 

When it comes to sunscreen agents, Zinc Oxide is pretty much in a league of its own. It's a physical (or inorganic) sunscreen that has a lot in common with fellow inorganic sunscreen Titanium Dioxide (TiO2) but a couple of things make it superior even to TiO2.

If physical sunscreens don't tell you anything, go ahead and read about the basics here. Most of what we wrote about Titanium Dioxide is also true for Zinc Oxide so we will focus here on the differences. 

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A light emollient ester (C8-10 fatty acids connected to C12-18 fatty alcohols) that absorbs quickly and leaves a dry but silky finish on the skin. In terms of skin feel, it is similar to Dicaprylyl Carbonate, another commonly used light emollient. 

A plant based ingredient that helps water to mix with oil (aka W/O emulsifier).  It's especially good for soft to low-viscosity water-in-oil emulsions with non-greasy, pleasant skin feel like lip balms or thick body butters.

A liquid fatty acid created from oleic acid. It's claimed to have great odour, thermal and oxidation stability and is great for  the stabilization of pigments and mineral particles in oils and solvents. It's quite popular in foundations.

A clear, oil-soluble, "cosmetically-elegant" liquid that is the most commonly used chemical sunscreen. It absorbs UVB radiation (at wavelengths: 280-320 nm) with a peak protection at 310nm. 

It only protects against UVB and not UVA rays (the 320-400 nm range) – so always choose products that contain other sunscreens too. It is not very stable either, when exposed to sunlight, it kind of breaks down and loses its effectiveness (not instantly, but over time - it loses 10% of its SPF protection ability within 35 mins). To make it more stable it can be - and should be - combined with other sunscreen agents to give stable and broad-spectrum protection (the new generation sunscreen agent, Tinosorb S is a particularly good one for that).

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An oil-soluble chemical sunscreen agent that protects the skin from UVB (295-315 nm) with a peak protection at 306 nm. Homosalate is not a strong UV filter in and of itself (gives only SPF 4.3 protection at max. allowed 10% concentration) and it is not photostable (looses 10% of its SPF protection in 45 mins) so it always has to be combined with other sunscreens for proper protection. Its big advantage, though, is that it is a liquid and is excellent for dissolving other hard to solubilize powder sunscreen agents, like the famous Avobenzone.

Regarding Homosalate's safety profile, we do not have the best news. In-vitro (made in the labs) studies have shown that it might have some estrogenic activity. Do not panic, these studies were not conducted on real humans under real world conditions. Still, if you are a 'better safe than sorry' type, be careful when using Homosalate containing sunscreens long-term and full-body.

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There is definitely some craze going on for coconut oil both in the healthy eating space (often claimed to be the healthiest oil to cook with but this is a topic for another site) and in the skin and hair care space. 

We will talk here about the latter two and see why we might want to smear it all over ourselves. Chemically speaking, coconut oil has a unique fatty acid profile. Unlike many plant oils that mostly contain unsaturated fatty acids (fatty acids with double bonds and kinky structure such as linoleic or oleic), coconut oil is mostly saturated (fatty acids with single bonds only) and its most important fatty acid is Lauric Acid (about 50%).  Saturated fatty acids have a linear structure that can stack nice and tight and hence they are normally solid at room temperature. Coconut oil melts around 25 °C so it is solid in the tub but melts on contact with the skin. 

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The emollient plant oil that comes from almonds. Similar to other plant oils, it is loaded with skin-nourishing fatty acids (oleic acid - 55-86% and linoleic acid 7-35%) and contains several other skin goodies such as antioxidant vitamin E and vitamin B versions. 

It's a nice, basic oil that is often used due to its great smoothing, softening and moisturizing properties. It's also particularly good at treating dry brittle nails (source).

A big molecule from repeated subunits that is used to form gel-like textures and create a film on the skin. 

A very common ingredient that can be found in all cell membranes. In cosmetics it's quite the multi-tasker: it's an emollient and water-binding ingredient but it's also an emulsifier and can be used for stabilization purposes. It's also often used to create liposomes. 

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). 

A controversial preservative that has formaldehyde-releasing properties. It works great against bacteria and also has mild fungicide abilities. 

Cosmetic chemist, Colin wrote a great article about formaldehyde and DMDM Hydantoin.  He writes that formaldehyde is the perfect example of "the dose makes the poison" principle. It's a natural stuff that can also be found in fresh fruits and vegetables, and eating it in tiny amounts is totally ok. However, in larger amounts (according to Wikipedia 30 mL of a solution containing 37% formaldehyde) it's deadly. 

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This totally unpronounceable ingredient (let’s take a shortcut: MCI) is a super effective preservative with both antibacterial and antifungal effects that works at very low concentrations. 

The bad news with it though is that it can sensitize the skin easily (it’s a so-called non-fragrance allergen). It’s not permitted to be used alone, but only with its BFF, methylisothiazolinone (MI), another icky preservative. Together they have a broad spectrum antimicrobial effect but are permitted to be used only in rinse-off products (under 0.0015%).

As you may guess, if something is only recommended in products that you rinse off (cleansers and shampoos), then it’s probably not the best ingredient for the skin.

Methylisothiazolinone (MI) is a preservative that' super efficient against bacteria at surprisingly low concentrations. The problem with it though is that it can also sensitize and irritate the skin quite easily when it comes in leave-on formulas.

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It’s pretty much the current IT-preservative. It’s safe and gentle, but even more importantly, it’s not a feared-by-everyone-mostly-without-scientific-reason paraben.

It’s not something new: it was introduced around 1950 and today it can be used up to 1% worldwide. It can be found in nature - in green tea - but the version used in cosmetics is synthetic. 

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The emollient plant oil that comes from almonds. Similar to other plant oils, it is loaded with skin-nourishing fatty acids (oleic acid - 55-86% and linoleic acid 7-35%) and contains several other skin goodies such as antioxidant vitamin E and vitamin B versions. 

It's a nice, basic oil that is often used due to its great smoothing, softening and moisturizing properties. It's also particularly good at treating dry brittle nails (source).

It’s the most commonly used version of pure vitamin E in cosmetics. You can read all about the pure form here. This one is the so-called esterified version. 

According to famous dermatologist, Leslie Baumann while tocopheryl acetate is more stable and has a longer shelf life, it’s also more poorly absorbed by the skin and may not have the same awesome photoprotective effects as pure Vit E.