Just found out that if I change light on my face, hair stayed exactly the same.
I just have some black planes above my character to block the light.
The face take the shadow but not the hair.
Why does my lighting does not affect the hair ?
Worked! Thank you!
Up ! Anymore help for the reddish eyelashes problem and wrong reflection on hair ? 
(only with r.HairStrands.SkyLighting.IntegrationType 1)
I’d try increase the melanin of the hair material instead.
The only fix I have found that worked, finally, was to go into the Metahuman parent hair material graph (M_hair_v4 in my case), and make sure your SetMaterialAttributes output node is connected to the shader listed in the Feature Level Switch that you are actually using in your preview device profile in the project editor settings. I am on a Mac using SM6 and after connecting the node to SM6 all hair problems are gone. Default is ES3_1
I had this same issue, and what fixed it for me was to select all of my grooms together (hair, brows, etc.) and, under “Groom”, set “Use Cards” to true (checked). Hope this helps others!
Worked Thanks
So none of these methods worked for me. I did however find that it was the directional light causing issues. Specifically the source soft angle. Reducing this fixed the problem for me
Hi @The_Distiller, have you ever experienced issues with noise in hair and weird flickering caused by a backlight, like this one? I increased the light sample to 32, and I’m also using some CVRS, including the one from Epic staff here. However, it still doesn’t solve the problem. I’m wondering why this happens. Do you have any ideas? Thanks!!
In UE5.6, in the assembled metahuman blueprint, I set num LODs, Forced LODs, and Min LOD all to 0 and it seems to have improved the issue. But, of course, this means that the engine is using the highest quality MH LOD, which results in less optimization.
This was the solution for me.
using 5.5, I added those two commands to my DefaultEngine.ini and problem solved!
Thanks for sharing
Off all those option in the forum that I tried, this one works the best, can’t say if its perfect, but not looking bad anymore, mix it with the roughness value if need some tweaks and you’ll be set and done
this issue still exists in out of the box 5.7. with the default environment lighting setup you get glowing or super reflective metahuman grooms. none of the above worked for me - the only way i’ve found to fix it is to increase the melanin to .95-1.0 for every material for each groom in the scene. not ideal and not sure how to fix once we’re out of previs stage. may have to skip environment lighting altogether and use massive spotlights/directionals or something? this has been an issue with metahumans since introduction - how have we not receive official guidance from the metahuman team?
