Well, yes, your friend is right. Vaseline can help you reduce the dark circles under your eyes. And it will not hurt your eyes when you apply it on your eyes. Generally speaking, Vaseline contains vitamin E and C, which can be helpful in reducing the dark circles. So in my opinion, you can just apply some Vaseline on your eyes. And just repeat it in several days. After that, it may relieve your dark circles under your eyes. Also, you should know that Vaseline can also be good for black eyes, and eye bags. So people with these eye problems can use Vaseline too. By the way, lemon juice, olive oil can be good for dark circles too. Anyway, just have a try.