HA is distributed widely throughout the human body in the connective, epithelial and neural tissues, and contributes significantly to cell proliferation and migration. For example, a 150-pound person has about 15 grams of HA in his body, one-third of which is degraded and synthesized every day.
HA is also a major component of synovial fluid (a transparent, viscous lubricating fluid secreted by membranes such as the bursa or tendon sheath).
HA has a role in the body’s wound-repair process. It can both promote an inflammatory response and moderate the response by stabilizing the granulation tissue matrix, and provides an open hydrated matrix that facilitates cell migration. In the normal epidermis, HA is a free radical scavenger and helps keratinocyte proliferation. Animal tests were done to reduce the HA content in the dermis which resulted in a decrease in skin elasticity. Impaired local inflammatory response and impaired tissue repair were observed.
Diminishes with Age
At a young age, the human body is very rich with HA, which is why young people have firm, well-hydrated skin that heals quickly. However, the quantity of HA declines dramatically with age, which makes skin susceptible to wrinkles, dehydration and infection. Reducing the size of the molecule for better penetration is of great importance.
Commercially-produced HA is isolated from animal sources within the synovial fluid, umbilical cord, skin and rooster comb, or from bacteria through a fermentation process or direct isolation. The bioactivity of the HA fragments depends on its molecular weight. The smaller the size, the better the penetration.
HA has many medical applications including eye surgery, treating osteoarthritis of the knee, and dry, scaly skin caused by eczema; but, of course, we are more interested in its cosmetic industry uses. It is a collagen alternative to fill wrinkles and fine lines. In 2003, the FDA approved HA injections for this purpose. HA injections temporarily smooth wrinkles by adding volume under the skin with effects typically lasting for six months. Another bacterial HA injectable filler is used for lip augmentation, reduction of folds and wrinkles, and removal of scars. These effects are also temporary. Low molecular weight HA is used as effective humectant, antioxidant and stimulating agent for collagen synthesis and cell proliferation and is believed to be a factor in fighting the aging process.
The following formula illustrates its use in an “age defying” cream. Kemira Specialty provides the HA.
Glyceryl stearate (and)
|Cetearyl alcohol (and) ceteareth-20||3.0|
|Jojoba esters (and) tocopherol||5.5|
|Macadamia seed oil (and) tocopherol||1.0|
Water (and) hydrolyzed
algin (and) Chlorella vulgaris
extract (and) sea water
|Hyaluronic acid (1%)||2.0|
|Jojoba wax PEG-120 esters||3.0|
Hydrolyzed jojoba esters
(and) water (aqua)
Procedure: With constant stirring, heat A to 75°C. Heat water in B to 75°C and add other ingredient. Add C to B and mix until uniform. Slowly add A to BC. Mix D and add to ABC. Cool to room temperature rapidly. Properties: pH: 5.2-5.5. Viscosity: over 175,000 cps.
Harvey M. Fishman
Harvey Fishman has a consulting firm in Wanaque, NJ, specializing in cosmetic formulations and new product ideas, offering tested finished products. He has more than 30 years of experience and has been director of research at Bonat, Nestlé LeMur and Turner Hall. He welcomes descriptive literature from suppliers and bench chemists and others in the field.