I find myself wondering when I do my deep conditionings if the hour long soaks really make a difference. Hair isn’t an indefinite mass and doesn’t have endless spongy properties, so at some point I will assume that hair has absorbed all it possible can from a treatment
As a personal observation for my hair, I don’t notice any difference in how my hair feels or reacts if I leave the conditioner for two hours instead of one. However, this doesn’t mean that there isn’t a difference in how my hair benefits from the conditioning
When it comes to treating your hair right, a lot of things have an effect you will probably never notice. You won’t know if you shed extra 5 hairs, you won’t know if you prevented some mechanical damage from an elastic, or break 5 hairs less, you don’t have a microscope ready to check all hundred thousands individual hairs and compare, etc
Maybe an extra hour of conditioning once a week makes the difference in whether I can reach floor length or not in 5 years. But I will never know! And that is the frustrating, unfair truth when it comes to a lot of hair care
My instinctive reaction is that 2 hours of conditioning must be better than one; at least unless it causes build-up or any other reaction I am able to notice. But maybe that isn’t the case. Maybe my hair already absorbed what it could from today’s conditioner after 30 minutes? Maybe I’m keeping my scalp wet and the follicles carrying the treatment-weight with no extra benefit?
My theory is that there is a maximum penetrability for any treatment. Of course this will depend on the ingredients in the treatment: Most cones will coat the strands and not penetrate. Protein has large molecules that make it hard to penetrate the hair strand especially for us coarsies that has an extra layer in the hair strand compared to other hair types. Coconut oil penetrates deeper than other oil types. Jojoba oil coats the hair strand and barely penetrates it. Henna molecules bind itself to keratin inside the hair strand. There are more examples than this, but this was just on top of my head
For now my conclusion is to do my deep conditionings as long as I have time for or my neck and head can stand it. The weight does add up: Wet hair, one full bottle of conditioner, woollen hats and an optional heat pack. It gets heavy!