There is a rumour on the internet that says 60% of what you put on your skin gets absorbed into your bloodstream. Think about that for a moment. If it was true then when you swim in a pool 60% of all those chemicals would get absorbed into your body through your skin. Also, it would mean that anything you touch in your daily routine would end up to some extent inside your body. Does that sound right to you?
The skin is our primary barrier to the outside world. It works by preventing things from getting into our body and therefore our bloodstream. Remember that we still use injections to get medication into our body. Having said that, the outer layer of skin does have receptors that can filter outside molecules and allow certain ones into our body - think of the hormonal patches that are used as transdermal medication. Products that contain oestrogen and progesterone can be absorbed by the skin because they look like the hormones that are natural to body and so they do not trigger a systemic immune system response.
The reality is that almost none of your skincare products will make it to dermis layer, which is where you have blood vessels. There have been certain sunscreen factors that may enter the bloodstream through absorption but again they are the rare exceptions and not the norm.
So what about allergic reactions to various nut oils? As mentioned there are skin receptors in the outer layer (dermis) of your skin. The primary function of these receptors is to act like border agents. They check the molecules and decide whether to allow them in or not. Certain chemicals like the hormones mentioned above have particular shapes that are recognised by these receptors, which is how some of the oestrogen in your cream can be absorbed into your bloodstream.
Peanut oil, an ingredient in some skincare products, contains 13 known proteins that have been identified as allergens. These allergens cannot be recognised by the receptors and so will be considered foreign invaders. Once identified, this triggers an immune system response which can develop into a systemic immune system response. This is where the immune system overreacts to the harmless allergens it is encountering. In this instance, people who are severely allergic to tree nuts or a particular nut like peanut can all of a sudden exhibit a local (itchiness, redness, swelling) or systemic (Immune shock, anaphylactic reaction) response.
No matter how much the ingredients are refined for use in the cosmetic industry, not all of these proteins can be removed from the natural source. In most cases a sever reaction is limited to only a few people and the skin typically does a good job of keeping these foreign objects away from the skin's receptors.
In one study, the number of people who experience an allergic reaction to coconut oil was only a handful each year. Coconut is not even a nut. It is a fruit but it does contain allergens. Some of these allergens can cross react and over a period of time people with sever sensitivity to these particular allergens can start to show a reaction to them. Again, the reaction is coming from the skin's receptors which have triggered a systemic immune response. The compound is definitely kept out of the body but if sensitisation has occured over a period of time, it can still trigger the immune response and result in a reaction on the skin.
Most skincare companies go through the rigours of screening their ingredients to ensure they are of high quality, but it is up to the individual to identify the source of any sensitivity and then avoid all products that include the ingredients that trigger their personal allergic reaction.
This is one of the reasons that at BOA we believe in maintaining a simple skin care ritual. You don't need 10 different steps and products to look after your skin. Keep it simple and you can avoid many of the skin complications that can develop over time.