For the lucky few, such as Hollywood greats Raquel Welch, 60, Sophia Loren, 66, and Robert Redford, 64, the chemical balance appears just right to help retain their youthful looks.

• 对少数幸运的人来说，例如好莱坞的巨星60岁的拉克尔·韦尔奇，66岁的索菲娅·罗兰和64岁的罗伯特·雷德富，他们体内相关元素的均衡性正好让他们能青春永驻。