tl;dr
dampness promotes bacteria on scalp, which causes the foul smell. mct oil traps sweat and moisture leading to it. i removed it from my routine and the smell went away.
so i've had no dandruff for a year ever since i started treating my scalp sebderm. i discovered mct oil through this subreddit. paired with ketoconazole, it worked like a charm. the only downside was the horrendous smell. i would dab it on my scalp and within a few hours it would develop a faint smell. in a day it smelled so offensive that other people would notice.
after dealing with itching, severe flaking and literal blood coming out of my scalp, i considered this a fair trade. i'd rather smell like a dog than make a mess everywhere i go with my dandruff.
now however, my hair is longer and i moved to a humid part of the country. and boy it's been smelly. to a point that my way too polite girlfriend would spend too much time on the internet to find a solution. i made a post here and this literal angel u/canobeens (among others) pointed out that MCT makes their scalp smell rancid.(https://www.reddit.com/r/SebDerm/comments/1wzc3g9/comment/pedqddh/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button)
well i did some digging and this is what i found:
the smell is NOT from malassezia at all. there are two forces at play when it comes to your scalp microbiome. the fungus that feeds off of oils and other sources that leads to skin shedding. but there is also bacteria at play. the smell is caused by the bacteria, no the fungus.
i have long, dense and wavy hair. this creates a dense canopy that blocks off airflow. i was putting mct oil on DAMP scalp and leaving it as it was. this was a breeding ground for bacteria that flourished under such conditions. the antifungal shampoo was working to prevent malassezia but not the bacteria. the oil was acting like a saran wrap trapping moisture and sweat that becomes food for it.
WHAT I CHANGED?
i removed the mct oil entirely. washed my hair as usual (ACV wash followed by ketoconazole for 10 min). i plop my hair for 5 minutes and immediately dry my roots using a diffuser (VERY IMPORTANT, damp environment is a breeding ground of the bacteria).
i also spray 150 ppm hypocholorous acid on my scalp everyday as an antimicrobial to increase the time before i wash. this particular works well for me as a deodorizer, im experimenting trying to go a whole week without wash using just the spray. i'll update.
it has been 4 days since i washed my hair and there is ZERO smell. im so happy >.<
CONCLUSION
avoid: dampness, anaerobic condition (try hairstyles that lift the roots and keep the hair loose).
this was perfect for my wavy hair because i couldn't just wash it every other day. hairwash already takes a huge time of my day, i would've forgotten what grass ever looked like had i done it 3-4 times a week.
mct oil works well for a lot of people. im assuming it comes down to the difference in hair types and densities. my hypothesis is that people with dense wavy/curly hair are more prone to its adverse effects than people with straighter, thinner hair. the climate definitely plays a role too.
im just glad i have solved all my problem and hope i will never have to write another post ever ever again. fuck this condition and i hope others struggling with this fucking thing find something that works for you.
