Onion extract is formed by breaking down the flesh of an onion. The resulting substance appears in some types of skin medications and lotions to treat and reduce the appearance of acne and scars. Creating onion extract is simple and economical, and doing so at home allows you to use the quantity you prefer. Check with your dermatologist before applying onion extract to your skin.

The items needed to make onion extract are likely already on hand in your home. You will need a cutting board and sharp knife to prepare the onion. Liquid dish soap, water, ice, a thermometer, coffee filters, distilled water, sodium chloride, also known as table salt, and two beakers or other containers that hold at least 8.5 ounces are additional pieces of equipment needed. Gathering all your materials in one place prior to beginning the process of making onion extract makes it quicker and more efficient.

Mix 3 grams of salt with about 1/3 ounce of liquid dish soap. Dice the onion into small pieces of uniform size and place them in one of the beakers. Pour the salt-soap mixture over the onions and stir. Place the beaker in a water bath at 140 degrees Fahrenheit for 15 minutes. Transfer the beaker to an ice water bath for five minutes and stir often. Pour the onion mixture into a blender and blend on high for five seconds. Place a coffee filter over the opening of the second beaker and pour the onion mixture into it. The foam should stay on the coffee filter while the onion extract flows into the beaker.

Onion extract is an ingredient in many skin care products. If these items seem to improve your acne or fade a scar, onion extract may be the reason. Try adding onion extract to your regular lotion or apply it directly to the problem areas. Always use onion extract, alone or in a topical product, under the supervision of your dermatologist.

If you have sensitive skin, straight onion extract may result in a reaction. This is called contact dermatitis and symptoms include a rash, itchy skin, blisters, cracks and pain. If these symptoms appear after using onion extract or a product that contains it, stop use and contact your dermatologist. Some research indicates that onion extract is beneficial for acne and scars because it has anti-inflammatory and antimicrobial properties. However, Leslie S. Baumann, director of cosmetic dermatology at the University of Miami, cautions that the studies were small and more research is needed to prove that onion extract cures or treats skin conditions.