Origin: This fruit natively belongs to South Asia and North Eastern India. 
Around 1000-1200 century, lemon was introduced in Spain and North America. It further found it's way Europe through Crusaders. In 1400 century, the cultivation of lemon was started.

Scientifically: Lemon tree is a small tree or spreading bush of the family Rutaceae. Lemon is an edible fruit. Lemon is used in cooking a lot of dishes and pastries. It is also used in making a lot of cocktails and mocktails. Lemons are rich in vitamin C and also contain B vitamins like thiamin, riboflavin, and niacin. 

The lemon plant is an evergreen tree or shrub which spreads about 3–6 metres (10–20 feet) high. The young leaves are oval in shape and have a red tint. When the leaves are fully developed they turn green.  In some lemon plant varieties, the branches are angular or have sharp thorns at the axis of the leaves. The flowers have a sweet fragrance and are in small clusters in the axils of the leaves. The flowers are of red, white and purple colour. The fruit is oval in shape and has hard outer rind or peel. The fruit consists of small which are ovoid and pointed and the pulp is acidic and juicy.

Lemons usually grow in cool, equable climate. The fruit is usually picked while still green and, after curing, may be kept three months or more in storage. Yellow fruits are already fully ripe and must be sold immediately.

Usage: Lemons are used for citric acid, citrate of lime, lemon oil, and pectin. Lemons are also used for flavouring agent, cleaning agent and are also used in making cosmetics. It is the most domestically and commercially used fruit. 

Lemon is very low-calorific fruit and is rich in antioxidant compounds. lemons help in improving skin quality promotes weight loss, improves digestion and also prevents cancer. lemon is great in treating constipation, dental problems, throat infections, fever, burns, respiratory disorders, and high blood pressure, while also benefiting your hair.
Lemon effectively combats free radicals and removes them completely from your body. Being a good source of vitamin C, this fruit also repairs the damaged skin cells and also reduces the appearance of fine lines, blemishes, and wrinkles.

Lemon also helps in fading of acne scars. Lemon if used topically, works in promoting hair growth. Lemon also controls the secretion of sebaceous glands.  

Below are some DIYs with Lemon for beautiful hair and skin:

 - Take a lemon, squeeze the juice and massage your scalp with the juice for 5 minutes and then leave it in for an additional. Then wash your hair with a shampoo and air dry. This promotes hair growth, cleans the oily scalp, and removes dandruff. 
 - Take 1 tablespoon lemon juice and 1 tablespoon coconut water.  Mix them together and massage the mixture into your scalp and leave it on for 20 minutes. Later, wash it out. This remedy helps in strengthening the hair roots. 
 - Take 2 tablespoons of olive oil, 1 tablespoon of castor oil, 4-5 drops of lemon essential oil. Mix all the ingredients together, massage the oil blend into your scalp for about 15 minutes. Leave the oil in your hair for an additional 30 minutes. Rinse after 30 minutes. 
 - Take 2 tablespoons of aloe vera pulp and mix 1 tablespoon of lemon juice to it. Apply this mixture to the roots and the hair length and leave for 45 minutes. Rinse later. This mask helps in making hair lustrous. 
 - Take 1 tablespoon of honey and a tablespoon of lemon, mix them together and apply on body and skin before taking a shower. Let it be on for 15 minutes and then rinse.