Squalane technically isn't an oil, which is why it is not in the oil guide. However it is super useful and super light. I know a few students who have replaced many DIY oils with this ingredients and have had really good results. It is also suitable fro Dandruff scalp types too, which makes it even more useful! ​ For Black Cumin Seed Oil and Marula Oil , what we are unsure about these ingredients, is how comedogenic/ irritating they could be for the scalp. This would then affect whether these ingredients can be used in products for the scalp, or should only be used for the strands! Although it would be ok to use these oils to replace most other oils in a DIY products, they may not hold the same benefits as some of the ingredients chosen for specific formulations.