I recommend 고려은단 Vitamin C 1000.

I've been taking Korean Endan Vitamin C with my husband for several years. They say that after age 40, you should take a few supplements... I thought it wasn't really necessary if I eat well, but now that I'm over 40, I can feel my energy changing day by day, so I started taking them. Maybe because my body is cold, winter is even more tiring, so I'm diligently taking them. Since the ingredients are not from China, I trust them. It's sad to get a year older soon, but today I will diligently take my vitamins and try to stay strong.