LILY SADO

Milk+ Manuka Ultra Moisture Face Wash

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. 

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. 

It also occurs naturally in our body and is used as a food additive. As cosmetic chemist Colins writes it, "its safety really is beyond any doubt".

Though the studies are only in-vitro (made in the lab, not on real people), and it also has a high comedogenicity index, it might be worth a try if you are prone to inflamed acne (the type that's caused by P. acnes bacteria).

The saturated nature of coconut oil also means that it is a heavy-duty-oil ideal for dry skin types. A double-blind research confirmed that extra virgin coconut oil is as effective in treating xerosis (aka very dry skin) as mineral oil. Another study found that coconut oil is more effective than mineral oil in treating mild to moderate atopic dermatitis (aka eczema) in children.

So when it comes to dry skin, coconut oil is a goodie, no question there. The question is if it is good or bad for acne-prone skin. Its main fatty acid, Lauric Acid has some research showing that it is a promising ingredient against evil acne-causing bacteria, P. acnes but at the same time, both Lauric Acid and coconut oil have a very high comedogenic rating (4 out of 5). Though comedogenic ratings are not very reliable, anecdotal evidence (i.e. people commenting in forums) shows that people have mixed experiences. While some claim that it worked wonders on their acne others say that it gave them serious blackheads and zits. Try it at your own risk. 

As for hair care, coconut oil has pretty solid research showing that it can penetrate into the hair very well (better than mineral oil and sunflower oil) and it can prevent hair protein loss as well as combing damage.  If you have problems with damaged hair, split ends, coconut oil is worth trying as a pre- or/and post-wash treatment.  Labmuffin has an awesome blogpost explaining in more detail why coconut oil is good for your hair.

A couple of other things worth mentioning: coconut oil might help with wound healing (promising animal study), it has some antifungal activity (against dermatophytes that cause the thing known as ringworm) and it also works as an insect repellent against black flies. 

Overall, coconut oil is definitely a goodie for the hair and dry skin. If that warrants for the magic oil status it enjoys, we don't know. 

So what the heck is a wax ester and why is that important anyway? Well, to understand what a wax ester is, you first have to know that oils are chemically triglycerides: one glycerin + three fatty acids attached to it. The fatty acids attached to the glycerin vary and thus we have many kinds of oils, but they are all triglycerides. Mother Nature created triglycerides to be easily hydrolyzed (be broken down to a glycerin + 3 fatty acid molecules) and oxidized (the fatty acid is broken down into small parts) - this happens basically when we eat fats or oils and our body generates energy from it.

Mother Nature also created wax esters but for a totally different purpose. Chemically, a wax ester is a fatty acid + a fatty alcohol, one long molecule. Wax esters are on the outer surface of several plant leaves to give them environmental protection. 25-30% of human sebum is also wax esters to give us people environmental protection. 

So being a wax ester results in a couple of unique properties: First, jojoba oil is extremely stable. Like crazy stable. Even if you heat it to 370 C (698 F) for 96 hours, it does not budge. (Many plant oils tend to go off pretty quickly). If you have some pure jojoba oil at home, you should be fine using it for years. 

Second, jojoba oil is the most similar to human sebum (both being wax esters), and the two are completely miscible. Acne.org has this not fully proven theory that thanks to this, jojoba might be able to "trick" the skin into thinking it has already produced enough sebum, so it might have "skin balancing" properties for oily skin.

Third, jojoba oil moisturizes the skin through a unique dual action: on the one hand, it mixes with sebum and forms a thin, non-greasy, semi-occlusive layer; on the other hand, it absorbs into the skin through pores and hair follicles then diffuses into the intercellular spaces of the outer layer of the skin to make it soft and supple.

On balance, the point is this: in contrast to real plant oils, wax esters were designed by Mother Nature to stay on the surface and form a protective, moisturizing barrier and jojoba oil being a wax ester is uniquely excellent at doing that.

While tea tree oil is a pretty well established anti-acne ingredient, manuka has more of a "might be useful" status for problem skin. Its strong suit is treating fungal infections such as athlete's foot, nail bed infections or foot odor. Other than that, manuka can help to relax muscles (useful for treating muscle and joint pain) and also has some antioxidant activity.

retinyl palmitate --> retinol -- > retinaldehyde --> all-trans-retinoic acid

As we wrote in our lengthy retinol description the problem is that the conversion is not terribly effective. The evidence that RP is still an effective anti-aging ingredient is not very strong, in fact, it's weak. Dr. Leslie Baumann in her fantastic Cosmetic Dermatology book writes that RP is topically ineffective. 

What's more, the anti-aging effectiveness is not the only questionable thing about RP. It also exibits questionable behaviour in the presence of UV light and was the center of a debate between the non-profit group, EWG (whose intentions are no doubt good, but its credibility is often questioned by scientists) and a group of scientists and dermatologists lead by Steven Q. Wang, MD,  director of dermatologic surgery at Memorial-Sloan Kettering Cancer Centre. 

Dr. Leslie Baumann wrote a great review of the debate and summarized the research available about retinyl palmitate here.  It seems that there is a study showing RP being photo protective against UVB rays but there is also a study showing RP causing DNA damage and cytotoxicity in association with UVA. 

We think that the truth lies somewhere in the middle, and we agree with Dr. Baumann's conclusion: "sufficient evidence to establish a causal link between RP and skin cancer has not been produced. Nor, I’m afraid, are there any good reasons to recommend the use of RP". We would add especially during the day!

Bottom line: If you wanna get serious about retinoids, RP is not your ingredient (retinol or tretinoin is!). However, if you use a product that you like and it also contains RP, there is no reason to throw it away. If possible use it at night, just to be on the safe side.

Regarding skincare and tea tree oil, its most well-known effect is probably being a well established anti-acne ingredient. Multiple studies confirm that TTO is effective against the evil acne-causing bacteria called P. acnes and the effectiveness of 5% TTO gel is comparable to the gold standard anti-acne treatment, 5% Benzoyl Peroxide lotion. You need to be a bit more patient with TTO, though, as its effects come slower but also with fewer side effects.

Regarding TTO and sensitive skin, we say that you should be careful. Even if your skin is not sensitive you should never put undiluted TTO on your skin. Luckily, it contains only very small amounts of the common allergens (such as limonene), but irritant and allergic reactions still happen, especially by oxidation products that occur in older or not properly stored oil.  So if you have some pure TTO at home, know that storage matters, keep it in a cool, dry, dark place and use it up in a reasonable amount of time.

Overall, we do not often give a goodie status to essential oils, but we feel that TTO's unique antibacterial and anti-acne properties with its minimal allergen content warrant an exception. If your skin is acne-prone, TTO is something to experiment with.

Anyway, it doesn't matter if it reflects or absorbs, Titanium Dioxide is a pretty awesome sunscreen agent for two main reasons: it gives a nice broad spectrum coverage and it's highly stable. Its protection is very good between 290 - 350 nm (UVB and UVA II range), and less good at 350-400 nm (UVA I) range. Regular sized Titanium Dioxide also has a great safety profile, it's non-irritating and is pretty much free from any health concerns (like estrogenic effect worries with some chemical filters).

The disadvantage of Titanium Dioxide is that it's not cosmetically elegant, meaning it's a white, "unspreadable" mess. Sunscreens containing Titanium Dioxide are often hard to spread on the skin and they leave a disturbing whitish tint. The cosmetic industry is, of course, really trying to solve this problem and the best solution so far is using nanoparticles. The itsy-bitsy Nano-sized particles improve both spreadability and reduce the whitish tint a lot, but unfortunately, it also introduces new health concerns. 

The main concern with nanoparticles is that they are so tiny that they are absorbed into the skin more than we want them (ideally sunscreen should remain on the surface of the skin). Once absorbed they might form unwanted complexes with proteins and they might promote the formation of evil free radicals. But do not panic, these are concerns under investigation. A 2009 review article about the safety of nanoparticles summarizes this, "to date, in-vivo and in-vitro studies have not demonstrated percutaneous penetration of nanosized particles in titanium dioxide and zinc oxide sunscreens". The English translation is, so far it looks like sunscreens with nanoparticles do stay on the surface of the skin where they should be.  

All in all, Titanium Dioxide is a famous sunscreen agent and for good reason, it gives broad spectrum UV protection (best at UVB and UVA II), it's highly stable, and it has a good safety profile. It's definitely one of the best UV-filter agents we have today, especially in the US where new-generation Tinosorb filters are not (yet) approved. 

Also, if your skin is sensitive, fragrance is again not your best friend. It’s the number one cause of contact allergy to cosmetics. It’s definitely a smart thing to avoid with sensitive skin (and fragrance of any type - natural is just as allergic as synthetic, if not worse!).