it is because all the sweat comes down and makes your hair oily.
Whe you don't shower and its more then 2 days your nose will get really shiny from being too oily.
2 or three days depends on u. if ur hair gets all oily in the roots or dry and itchy after 2 days then wash it if it last for longer then keep it but remember styling products dry out ur hair so it will only look good for the first 2 days or so then ull c it changing.
Its unfortunate that in India there are very less oily hair shampoos however one of them that i use has changed my hair completely and it is Loreal pure Resource ,its a good shampoo basically a purifying shampoo.if u have excessive oily hair then use it after every 2 days else use it as a weekly treatment.iAlso its not a over the counter shampoo so you will get it from good shops and saloons.
Most sources recommend that people should wash their hair daily or every 2 days. This is usually because if hair is not washed this often it can begin to look oily or greasy.
If you eat any junk foods, your face will get oily, and oil clogs pores so that's why eating junk food is associated with acne... if you don't wash your hair for 1 or 2 days it'll get oily. Some people's hair just gets oily faster, or more oily depending on the shampoo they use. Sometimes if you put too much conditioner in, your hair will seem really oily. But the only thing I can think of that'll make it really oily ''all of a sudden'' is if you put oil in it yourself. Haha :) But I don't know how long you meant, so I hope I helped :)
sometimes hormones in your body tend to make your hair oily. and if you have a dry scalp that produces more oil which gets to your hair. try using a variety of different shampoos, and if you wash your hair every day try to wash every 2 days. do not use conditioner on your roots cause that will most likely cause it to get even worse. if you have extremely oily hair you can try using the vinegar treatment you just simply apply the vinegar ( or lemon juice for a better smell ) to your hair and let it sit for awhile. but be sure to not put it on your scalp. dont brush your hair as often because this can produce more oil. also buy a shampoo that says "For Oily Hair" do not buy one that says for Dry/Thick hair
Mine looked oily after 4 days, and smelled bad. also it will look really greasy and its bad for your hair so i would say.. START WASHING YOUR HAIR i wash mine like every day or 2
tie it up in a ponytail and its not as noticeable. if you leave your hair down then people can tell its greasy.
every 2 days
If you are wanting to use a styling product like gel or mousse you can right away. Just don't wash your hair for the recommended 2 or 3 days after.
2 DAYS
Straighten it Straighten it