r/HaircareScience 17d ago

Discussion What is the science behind the LOC/LCO method?

As in: the leave-in/oil/cream method that I've seen recommended for over a decade.

I understand that leave-ins are important for protecting the strands throughout the day and that oils and creams lessen friction and tangling in ppls hair but why is it recommended for the method that one does all three and why in that order?

I was thinking, will just a formulated leave-in plus one type of oil work the same?

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u/sudosussudio 17d ago

LOC's origins are from the Natural Hair community. Some science books mention it like Fundamentals of Ethnic Hair by Crystal Aguh and Ginette A. Okoye

> “L.O.C.” method in natural black hair care forums and websites which stands for ‘liquid, oil, cream’ as some have noticed added benefit by following oil application with thick butters or creams that do not contain water as primary ingredients. Instead, these butters contain more conditioning agents and act similar to emollients. Occlusive moisturizers such as petrolatum and mineral oil are particularly effective at preventing water loss in the skin and are often found in ethnic hair care products as well [20]. Products containing these ingredients can also be used after oils but may leave the hair feeling excessively greasy or limp”

It is a method of conditioning, and there are unlikely to be any studies on it at this time. Results likely vary a lot based on the products used. And it's too heavy for straight, wavy, and looser curls.

It's likely as effective as any other method of conditioning, though folk wisdom about sealing in moisture turn out to be mostly untrue (works for skin, but not hair, see Trefor Evan's chapter on Absorption in Practical Modern Hair Science). And oils in many cases are not the best conditioners, especially for very damaged hair that has been stripped of its outer fatty layer - oils don't cling to that well. Cationic conditioners are a better choice for damaged hair since they are capable of clinging to (and smoothing/protecting) damaged hair. Lab Muffin discusses it in this video/post.

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u/julyruby_t 17d ago

Thanks! on page 363 of the Evan writing it was mentioned that there was a study where locks of hair with different water content was presented to ppl and they were asked to say which one felt like it had the most moisture; my question is it known from that study or others like it how many types of hair they were presenting?

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u/sudosussudio 17d ago

Unknown because it’s published in conference proceedings that haven’t been posted online, but you could email Evans and ask. I’d be curious to know if you get a reply.

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u/julyruby_t 16d ago

wait good idea... I could only find his linkedin page so far but i'll keep it in mind. unfortunate that I can't search the primary german(?) source

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u/Specific_Ocelot_4132 Quality Contributor 17d ago

The traditional explanation: water based products first to moisturize the hair, oil based products on top to seal it in. (At least for LCO—not sure about LOC.)

Some problems with this explanation:

  1. Hair products don’t affect the water content of hair that much. The water content of hair is generally about the same as the water content of the surrounding air.
  2. Even if you could manipulate the water content of your hair in a lasting way, you wouldn’t want to. Water makes hair swell, lifting the cuticle, making it more prone to damage.
  3. Oil doesn’t form an impenetrable layer on hair so it’s not going to seal anything in.

Some possible alternative explanations (just semi educated guesses):

  1. This method tends to be recommended for hair types that benefit from a lot of product. Maybe by using 3 products instead of 1 or 2, you’re more likely to use enough product, but you’d get similar results using a generous quantity of 1 product.
  2. For whatever reason maybe products sit better/get more even distribution if you apply water based products first? Perhaps because your hair is wettest when you start styling it, and by the time you apply the 2nd and 3rd products it’s slightly drier?
  3. Maybe order doesn’t matter—have you tried applying products in the wrong order? Were the results different?

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u/julyruby_t 17d ago

Interesting, thanks! in point 2 when you say water makes the hair more prone to damage, does that mean mechanical damage or all damage in general including sun/heat?

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u/Specific_Ocelot_4132 Quality Contributor 16d ago

Mainly mechanical, not sure about the other two.

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u/Ji66leGiggles 4d ago

What works for my 4c is water, butter, oils and then I redo it after 4 days with the same method and I wash my hair every two weeks. If I don’t do this my hair turns brittle, horrible and sheds a lot. I honestly feel like black hair is like a damn plant. You gotta be so careful with it otherwise it dies on you lol