Article in English: Some people are born with freckles, but many others develop them over time as a result of sun exposure. They may fade during the winter, but they come back darker every summer if you don't take precautions to keep the sun's rays off of your skin.  Use plenty of SPF 30 or higher sunscreen on your face, neck, and body and reapply it every hour, or more often if you are swimming or sweating.  Wear a hat and other protective clothing. Sunscreen can only go so far to protect your skin from the sun. Having a layer of clothing over your skin is a much more effective way to prevent freckles from forming. Wear light, airy long-sleeved shirts and pants during the summer to keep cool and protect your skin at the same time. This nutrient helps to lighten freckles, so make sure you're getting plenty of it in your daily diet.  Citrus fruits, kiwis, spinach, and other leafy greens are all excellent sources of vitamin C.  Start your day with a burst of vitamin C with a fruit and vegetable smoothie. Add a kiwi, a nectarine, and a cup of raw spinach to your blender. Puree the produce with almond milk or another healthy base. Vitamin C supplements are another option you can choose to make sure you're getting enough. Take pure vitamin C or a multivitamin that contains it.

Summary in Vietnamese:
Bảo vệ cơ thể khỏi ánh nắng mặt trời. Bổ sung vitamin C.