Side Effects of Octinoxate

Image by, courtesy of Robert S. Donovan

Octinoxate, or octyl methoxycinnamate, is a chemical used in the skin care industry in sunscreens. The substance can also be found in lip balms as well. Octinoxate is an ester, an organic compound that is a clear liquid insoluble in water and soluble in oil.

Esters are formed from a process involving an acid and alcohol, according to Skin MD Natural. According to the Environmental Working Group (EWG), octinoxate is "the most widely used sunscreen ingredient." Sunscreens are designed to filter ultraviolet light from the sun.

Ultraviolet Light

Ultraviolet A and B (UV-A, UV-B) light are what sunscreens were designed to block. The sun gives off ultraviolet-A and ultraviolet-B light, both of which can be harmful to us. Scientists believed for many years that UV-B was the more harmful of the the two rays, but both are dangerous according to, and the harmful effects of UV-A "may take longer to show up," says Health A to Z, Life Steps.

How Octinoxate Works

According to Skin MD Natural, octinoxate's primary function is in sunscreens "to absorb ultraviolet-B, (UV-B) light from the sun, protecting the skin from damage." The chemical acts like a shield for the skin.

Smart Skin Care says that "when exposed to sunlight, octyl methoxycinnamate is converted into a less UV absorbent form, which reduces its effectiveness." That is why sunscreens with octinoxate will have another sunscreen ingredient as well.

Side Effects

According to the EWG, octinoxate has been linked to "developmental and reproductive toxicity, a broad class of health effects that can range from infertility and reproductive organ cancers to birth defects and developmental delays for children." The problem is that the chemical is readily absorbed through the skin and can "produce oestrogen-like effects" on the body, says. That is why any product containing this chemical should not be used by women who are pregnant, or by children.

The chemical has also been linked to allergies and immune system damage by compromising the body's ability to fight disease, and in the healing process, according to the EWG.

According to a Norwegian study on mice cells using octinoxate, the chemical was found to be toxic to them. The level of octinoxate used on the mice in the study were at lower levels than found in sunscreens, according to

Using sunscreens can also produce acne, burning of the skin, rashes and dried or tightened skin, according to Health A to Z, Life Steps.


Octinoxate does not block UV-A light which has also been found to be harmful. When Octinoxate is exposed to sunlight, "it is converted into a less UV-B absorbent form, which reduces is [sic] effectiveness," according to Using another UV blocker called Tinosorb M can "partly prevent" the conversion to a less absorbent form, says.

Concerns and Warnings

According to EWG, octinoxate resists breakdown in the environment, and builds up in wildlife and human tissues "for years after exposure." In addition, this chemical affects our bodies at the cellular level, but how it does this is not well understood says EWG.

Octinoxate is prohibited from being used in cosmetics, and the concentration amount allowed in sunscreens is limited, according to EWG.

With this chemical being toxic to both environment, and life, it should not be used without fully understanding its risks.