Cosmetics are products used to improve the appearance and function of the skin and hair.

Cosmeceuticals combine cosmetic and pharmaceutical uses and are commonly used in dermatology to improve skin tone, glow and have anti-aging benefits. The cosmetic industry is constantly growing and profitable with the average woman spending $15,000 on beauty products in her lifetime. The use of natural ingredients in cosmetics is becoming more popular due to their environmental friendliness, fewer side effects and safety.

Marine organisms, including seaweeds, are rich in bioactive compounds that can be used as functional ingredients for cosmetic applications because of their potential treatment of skin problems.
The skin is the largest organ in the human body, consisting of three main layers: epidermis, dermis and subcutaneous tissue. The epidermis, the outermost layer, contains keratinocytes, melanocytes and Langerhans cells. Keratinocytes produce keratin and make up the stratum corneum, the top layer of the epidermis.

Melanocytes produce melanin, the pigment that gives skin its color, and Langerhans cells prevent foreign materials from penetrating the skin. The dermis, the middle layer, contains collagen and elastin which provide structural support and elasticity to the skin. Hyaluronic acid is also present in the dermis and helps retain moisture. The subcutaneous tissue, the deepest layer, is made up of connective tissue and fat and loss of this tissue with age can lead to wrinkles and sagging skin.