Ok so I really don't do sensationalist headlines, please blame this one on Alice (fab blog) who sent this email with this title to me :).
Alice says, 'I started doing some digging about mineral oil and I keep coming up with evidence that mineral oil isn't that bad for skin. In fact I keep finding that it's actually a "good" ingredient. The Beauty Brains cite it as a perfectly fine ingredient (here) and explain the benefits of it in skin care.
Basically, my questions are: Is mineral oil actually bad for hair, even though cosmetic grade mineral oil is ok for skin? If so where is the scientific proof of it? Is it possible that mineral oil is fine for some hair types and a death sentence for others, like silicones?'
Mineral oil is a cosmetic beauty standard. It is used because it is actually colourless and odourless (are you surprised?) and it mixes wonderfully with other ingredients to create a smooth product. Top beauty lines and drug store brands use it routinely for this reason.
It has been villified on many sites because it is often regarded as non-natural and a product of the petroleum industry. In my opinion it is natural because it is simply a product of filtering (or distilling to be more accurate) a naturally occurring oil.
The beauty brains post is very informative (click the link Alice provided!). Specifically for hair, mineral oil is useful for
1. Preventing the hair fibre from swelling too much when placed in water (see this post).
2. Preventing moisture entry in humid conditions (see this post)
3. Preventing UV damage to hair by forming a 'protective' layer which stops breakdown of the amino acids in the hair (Journal of the Society of Cosmetic Chemists, pg 109-122, 1993).
The sticking point (pun intended) of mineral oil is simply that, it sticks to the outside of the hair. It does not penetrate the hair like coconut oil does. Therefore, it is perhaps not the most beneficial oil that could be used on hair.
I definitely also agree that some hair can handle mineral oil better than others. Factors that could affect this include
1. How often you wash your hair with shampoo (more washing less build up)
2. How far up is mineral oil on the ingredient list on the product (top 5 listing means more mineral oil than if it appears in the bottom 5)
3. How often do you use the product with mineral oil (daily use probably means more accumulation than weekly or fortnightly use).
Avoiding mineral entirely for whatever reason is not bad, however using pseudo science to justify this is the problem.