Saturday, August 18, 2012

Question: Are silicones healthy for our hair or skin?

Laura wrote in this postHi! I found ur blog just yesterday but i'm falling in love! My question is... are silicones really sure and healthy for our hair? This is what i know: silicones occludes skin pores and cuticular layer of our hair, and don't let him repair from the inside... isn't real? And, also, is a petrol product, right? Sorry for bad english -.- Hope you'll answer me :D Laura

Let's take a look at your question. What are we talking about when we talk about silicones? In general, we talk about dimethicone and cyclomethicone

Are silicones healthy for hair or skin? Let's take a look at some stuff about silicones before we make a decision about healthy or not healthy. 

What do silicones do for our hair and skin? Dimethicone is considered an occlusive ingredient, approved as same by the FDA. We use occlusive ingredients to prevent transepidermal water loss (TEWL) from our skin. (From Wikipedia: TEWL is defined as the measurement of the quantity of water that passes from inside a body through the epidermal layer - skin - to the surrounding atmosphere via diffusion and evaporation processes.) We want to trap in that water and prevent it from evaporating from our skin, and protect our skin from further damage while it repairs itself from physical assaults of the day. So dimethicone can create an occlusive barrier on our skin or hair, which is a good thing as it prevents loss of water from our skin and prevents water from entering our hair shaft. 

I don't know where the idea that our skin can't heal from the inside when the top layer is occluded might come from, but in fact, the skin has more opportunity to repair itself when it isn't losing water. Hydrated skin is healthy skin. Allantoin and cocoa butter are the other approved occlusive ingredients, and I can't imagine anyone saying those aren't good for your skin. I think it's said about silicones because they are synthetic ingredients.

As an aside, our skin doesn't need to "breathe", which is one of the reasons people don't like occlusive ingredients. Transepidermal water loss is kind of like breathing - water diffuses to the outside world from our skin - but we want to stop this from happening. So if someone likens an ingredient to being plastic wrap that won't let our skin breathe - a statement I saw recently - they don't really know what they are saying. Ignore them, and look for a more knowledgeable web site. 

If you have frizzy hair - like I do - having a silicone coat my hair shaft is a good thing because it means that water can't enter my hair strand and make it swell. When hair swells, it creates more friction with other hair strands, and friction is one of the main ways to damage your hair. If I can prevent my hair strand from swelling with moisture, I can prevent a lot of damage. 

Silicones aren't derived from petroleum - they're derived from sand. They can't be derived from petroleum because they are silicon and petroleum products are hydrocarbons, so they aren't even remotely related in chemistry terms. 

Are silicones healthy for us? Silicones appear to have many benefits for our skin and hair, so I think the short answer is "yes", they are just fine.

If you look at this study, they note: "Occlusion of the skin is a risk factor for development of irritant contact dermatitis. Occlusion may, however, have a positive effect on skin healing. No consensus on the effect of occlusion has been reached." In this study, the occlusive ingredient was nitrile glove material, so they really mean occlusion! The conclusion? "Occlusion of healthy skin did not significantly influence skin barrier function, ceramide profile or the ceramide/cholesterol ratio." In other words, healthy skin isn't hurt by occluding the skin with a glove like material. So it's unlikely that healthy skin is hurt by occluding the skin with silicones.

Related posts:
Skin chemistry section of the blog


Musicmom said...

Hi Susan,

Thank you for the myth-busting general know how awesome info. I read the plastic bag thing too and ... Anyway. Honestly I have not been able to find any defensible argument against using silicones on our skin/hair in terms of human health risks. I am sure we will continue the debate as we read more and more studies become available. I have come across one and only one compelling reason not to use them regarding their lack of biodegradability and their ability to accumulate in the tissues of other organisms. I care first about my health and then of course the health of my friends/humans and then after that other animals etc. but I think for one who is concerned about the environment this is the only defensible con I have read about the cones. What about you?

Melanie Klar said...

I was just researching silicone safety and I did not find any evidence that they are bioaccumulative. It is interesting. If you look on EWG's skin deep website it says it is Classified as expected to be toxic or harmful" and "expected to be environmentally toxic" and yet when you go to the sites they say they got their information from, and look up the studies yourself-they do not say that! They say it is safe. I guess EWG thinks people will just trust them and not check sources themselves but I did. All the studies and agency conclusions I have seen say it is safe. If you have any actual studies to support that please tell me!