PARIS, April 27 -- Often associated with nail- and haircare, castor oil has many other virtues, notably for the skin, as well as for health. From acne to skin firmness, radiance and hydration, this miracle product is now a must-have in natural beauty routines.

If you thought you already knew all there is to know about castor oil, then it might be time to think again. This oil, whose use in cosmetics dates back to the 19th century, is beneficial for hair, beards and nails, but also for skin - and through all stages of life. So it's perhaps not surprising that this oil is finding quite a following on social networks.

Ideal for hair and nails

Castor oil is known to be a friend to dull, brittle and dry hair, as well as to soft nails. Howev...