Comments

• EVchem Member

  August 2021

  I don't think it's a dumb question but I also don't have a great answer. Without major equipment I don't see how you would test which oils are staying on the surface vs being absorbed. I think if you are trying to target a specific time to absorb then make just one of these oils your base and then you could use the others to try and adjust the feel/absorption time. If you work with suppliers, IOI oleochemical had a presentation all about creating different textures from application to rub-in/ afterfeel with different chain length lipids and their technical team might be able to provide more clarity.
• Perry Administrator, Professional Chemist

  August 2021

  I agree it is not a dumb question. You would be surprised how many "dumb" questions don't actually have answers in cosmetic science.
  
  The first big challenge with your question is how to quantify the subjective measures of "rapid", "fast", "average" and "slow". If it is just subjective feel then you'll have a really hard time as most people will have different perceptions of what is fast or slow absorption. 
  
  The answer will of course depend on whether the components of one specific oil is more compatible with the other oils or with the lipophilic components of skin. That's hard to say.
  
  The only way to really get this answer is to use expensive equipment as @EVchem suggested.  However, you can get a relative answer by conducting your own experiment. Make a 50:50 mixture of the fastest absorbing and the slowest absorbing and measure absorption rate. From there, it will just be more experimenting with different ratios using different oils. 
  
  But there is no simple answer.
  

  Learn to formulate cosmetics
• RedCoast Member

  August 2021 edited August 2021

  I can give you some guidance on this, because your question does relate to perfume oils, which I make.
  

  Having a "quick absorption rate" is very much subjective. Some people think that having a dry after-feel means it's "quick", while others think that the oil having less shine after 10-30 minutes after application means it "absorbed quickly" even if they can feel a thick film. Furthermore, there are actual cultural differences over what "fast absorption" means, which can get confusing pretty quickly if you're trying to sell it in a different country.
  

  There is a tendency for certain fatty acids to have certain emollient properties/after-feel, but that's not universal. The fatty acid profile can vary (quite wildly, too) in natural oils due to growing conditions and subsequent processing. Ambient humidity and pre-existing skin conditions also effect consumer perception of emolliency.
  

  You may be interested to know that adding essential oils complicates the "absorption rates". Some terpenes in those oils act as penetration enhancers, while others make the EO or absolute in question tricky to heat and use. So, if you're thinking about using essential oils to add a "natural scent" to your product, beware that you will likely need to tweak your base oil.
  

  You will need a lab with the specific equipment to get an objective answer... but you can do experiments on your own for a "close enough" answer.

  You can compare/contrast your own oil blends against 100% caprylic/capric triglycerides, for example. You can also compare/contrast against 100% petrolatum (USP grade) for thickness, spreadability and shine. It wouldn't be a bad idea to pick a very lightweight emollient (like cyclopentasiloxane) if you want to compare/contrast against lighter emollients.