Home Cosmetic Science Talk Formulating Skin Comedogenic Rating is accurate or NOT

  • Comedogenic Rating is accurate or NOT

    Posted by dtdang on September 19, 2018 at 3:47 am

    I wonder that Comedogenic Rating is accurate?
    For example, babassu oil and coconut oil are very high saturated fatty acids, specially Lauric Acid. But babassu oil is Comedogenic of 1, but coconut is 4.

    anyone understands it, please help me understand. I appreciate all comments.

    thanks in advance

    dtdang replied 5 years, 6 months ago 7 Members · 32 Replies
  • 32 Replies
  • Sibech

    Member
    September 19, 2018 at 5:16 am

    They are desceiptive, but have been performed in rabbit ear canals, which are much more sensitive than human skin. In addition the “rating” of raw materials may vary by supplier or even by batch.

  • ngarayeva001

    Member
    September 19, 2018 at 11:20 am

    @Dtdang, this is so interesting! I compared coconut and babassu. They have very similar saturated fat composition. I have never worked with it. Is it an oil or butter? Should be solid with this amount of saturated fats.

  • dtdang

    Member
    September 19, 2018 at 11:34 am

    Thanks @ngarayeva001 & @Sibech
    both are oil and have antibacteria due to very high Lauric acid 

  • ngarayeva001

    Member
    September 19, 2018 at 11:37 am

    Babassu oil Coconut oil
    Acid Type Acid Type %
    Lauric

    Saturated

    50% Lauric saturated

    Saturated

    48%
    Myristic

    Saturated

    20% Myristic saturated

    Saturated

    16%
    Palmitic

    Saturated

    11% Palmitic saturated

    Saturated

    9.50%
    Stearic

    Saturated

    4% Caprylic saturated

    Saturated

    7%
    Total Saturated 85% Decanoic saturated

    Saturated

    8%
    Oleic Monosaturated 10% Total Saturated 89%
    Other Oleic

    monosaturated

    6.50%
    Other

    polysaturated

    5%
  • ngarayeva001

    Member
    September 19, 2018 at 11:42 am

    This is very interesting. If their saturated fatty acid profile is so similar, probably it has something to do with unsaturated fats? Because I agree that coconut oil is marked as “high” on all comedogenic scales. I can’t find detailed breakdown for babassu oil. @Dtdang, do you have more details?

  • dtdang

    Member
    September 19, 2018 at 1:04 pm

    @ngarayeva001
    Yes babassu oil had been researched by scientists in Brazil. It is reported in researchgate. 

  • dtdang

    Member
    September 19, 2018 at 1:08 pm
  • markbroussard

    Member
    September 19, 2018 at 1:09 pm

    @Dtdang:

    The simple answer to your question is “No” … Studies done several decades ago on rabbit ears and there is no correlation between the assigned comedogenicity value assigned an individual ingredient and the comedogenicity of the finished product.

    You would think that someone, somewhere would update the comedogenicity scales using human subjects.

    Now, if you are developing cosmetics for rabbit ears, yes, they are accurate.

  • microformulation

    Member
    September 19, 2018 at 1:10 pm
    @Dtdang I have seen that study presented at a conference. They did a small scale study on an animal model and never went any further with human studies. In fact, the presenter was asked about the properties as an anti-bacterial and the presenter stated, “We have not yet studied that” and stated that in no way were they saying that the oil has these activities in humans.
  • ngarayeva001

    Member
    September 19, 2018 at 1:56 pm

    Guys, is there any scientific approach to choosing oils? At the moment I am just following the “do big companies use this oil” approach. 

  • oldperry

    Member
    September 19, 2018 at 2:18 pm

    @ngarayeva001 - unless you are going to do the safety testing yourself, that’s probably a reasonable approach.

  • ngarayeva001

    Member
    September 19, 2018 at 2:19 pm

    Thank you @Perry. 

  • markbroussard

    Member
    September 19, 2018 at 4:32 pm

    @ngarayeva001

    It all depends on what you are trying to achieve:

    Certain oils are “dry” oils that absorb rapidly giving a better sensorial.

    Certain oils contribute a natural SPF so you would selectively use these oils for sunscreens.

    Other oils have a fatty acid profile that closely resembles human sebum.

    And, there is a finite universe of carrier oils that you can use, so pick your carrier oil combinations to best achieve your objectives.

  • ngarayeva001

    Member
    September 19, 2018 at 5:24 pm

    Is there any rule (such as higher/lower amount of linoleic acid) that can be used as a starting point when selecting oils for different skin types? I just have a feeling that suppliers’ recommendations are not supported by any researches. They even make claims like rosehip oil is a source of vitamin C, which is a complete nonsense because it’s water soluble.

  • Sibech

    Member
    September 19, 2018 at 7:08 pm

    Thank you @MarkBroussard & @Microformulation for being more eloquent on comedogenicity than I am in the wee hours of the morning.

    @ngarayeva001 A lot of recommendations given by suppliers is given in good faith, but if they do not specialise with the industry, but retail the raw materials, it is likely they are subject to the same misinformation as most consumers are.
    @MarkBroussard could you cite a source on the “natural SPF”, arguably some unsaponifiables could contribute, but I am sceptical of any significant degree of SPF from oils.
    I do subscribe to the notion that some oils may better distribute, give a better coating due to spreadability and percieved absorption (I would, for example, feel better applying recommended amounts of sunscreen predominant in light and “dry” oils, than something that feels heavy and fatty).

  • microformulation

    Member
    September 19, 2018 at 8:25 pm
    Comodenicity is one of those concepts which is taken as gospel initially as people begin Formulating. I believe that this arises since many “crafter sites” will post these numbers as if they are absolute and correct. As you progress and learn more, you see the issues with these numbers and the market applications, you will use these numbers as a rough guide, not an absolute measure.
    I would avoid going down the Oil “SPF” rabbit hole. The SPF levels assigned are low and if you read, it is based on 100% of that oil. So, for example, an oil might have an SPF of 3, but that is not directly assignable. Lastly, this approach is not approved by the FDA. I would step back carefully and evaluate any claims as such.
    Some oils are lighter and have different properties. It will become a matter of experience with the materials OR if your marketing does not limit your material selection, step up to the Emollients and Silicones and do it right!
  • Sibech

    Member
    September 19, 2018 at 8:56 pm
    @Microformulation I completely agree.
    In 1976 Fulton et al. published the article “Non-comedogenic cosmetics” which laid out the most commonly cited ratings.
    In 84 another article was published by Fulton, which Belassi mentioned in another thread. (https://chemistscorner.com/cosmeticsciencetalk/discussion/4798/all-d-c-dyes-comodegenic)
    The newer article concludes
    Some of our results with other ingredients are not exactly identical to those reported in I976. As there are many sources and grades of cosmetic ingredients and also a possibility for individual variation among rabbits, a variation in results is certainly possible. Examples are cetyl alcohol and polyethylene glycol 300. In our original studies, the cetyl alcohol was found to be noncomedogenic, but on repeat, it was comedogenic. The reverse was true of polyethylene glycol 300. It was comedogenic in our first studies, but the present source was noncomedogenic.
    Mills et al. described a human model for assessing comedogenic substances
    and more recently Draelos addressed a re-evaluation of comedogenicity using a modified version of the test Kligman performed. (https://www.sciencedirect.com/science/article/pii/S0190962205046001)
    Unfortunately, there is little chance this information passively diffuse out to crafting/DIY sites that are misinforming people.
  • ngarayeva001

    Member
    September 19, 2018 at 9:02 pm

    @Microformulation I agree that it’s a matter of experience. I bought a lot of exotic oils (like cherry kernel, peach kernel, grapeseed, anything that sounded cool) when started formulating. I don’t know why but people just love fancy oils. Then I moved to the ‘classics’: jojoba, squalane, shea etc. I started exploring emollients recently (hydrogenated polyisobutene). I hope it means that I am evolutionating :)

  • dtdang

    Member
    September 20, 2018 at 2:42 am

    Thanks all for your inputs into this topic.

  • MJL

    Member
    September 21, 2018 at 11:12 pm

    Is there any rule (such as higher/lower amount of linoleic acid) that can be used as a starting point when selecting oils for different skin types? I just have a feeling that suppliers’ recommendations are not supported by any researches. They even make claims like rosehip oil is a source of vitamin C, which is a complete nonsense because it’s water soluble.

    The higher the linoleic acid, the “dryer” the oil will feel and it will sink in faster. The higher the oleic acid, the more “rich” the oil will feel and it will take longer to sink in. 

    Oils higher in linoleic acid are often the best tolerated oils for those with oily and/or acneic/acne-prone skin types.

  • dtdang

    Member
    September 22, 2018 at 2:00 am

    @ngarayeva001, the research indicated that oleic acid is more than linoleic acid in the skin causing acne. 
    I believe that we need to select the oils based on comedogenic, density, and the most important fatty acids: omega-3, 6, 7, and 9….

  • ngarayeva001

    Member
    September 22, 2018 at 6:44 am

    @Dtdang and @MJL thank you both!

  • dtdang

    Member
    September 22, 2018 at 1:38 pm

    @ngarayeva001
    Oleic acid can be made from our body. But, Linoleic acid cannot be made from body, just from our food or skincare products. 

  • ngarayeva001

    Member
    September 22, 2018 at 7:43 pm

    Thank you ? 

  • Sibech

    Member
    September 23, 2018 at 8:13 am
    @Dtdang Frankly we don’t need it in skincare products, it often has a nice dry feeling - but you can’t satisfy nutritional needs topically.
    The issue with using unsaturated fatty acids (and other fats with a high iodine value) is a general lack of oxidative stability.
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