Don’t be put off by all the syllables in octadecenedioic acid. Or the fact that you’ve never heard of it. It is a very interesting skincare ingredient that can treat hyperpigmentation while being completely non-toxic. For the tongue-tied, it also goes by the friendlier names of dioic or Mediatone.
Octadecenedioic acid came about because scientists were looking for a higher efficacy alternative to azelaic acid, a well known active used for acne, rosacea and hyperpigmentation. Azelaic acid is found in grains, barley and rye. It is commonly used due to its low cost, despite the fact that side effects can include stinging, burning, itching, tingling, drying, or flaking of the skin – likely due to the high concentrations required (up to 20%) in order to treat acne, for example.
Octadecenedioic acid is derived from sunflower seeds and is structurally similar to azelaic acid. One of the things that makes it such a potentially interesting cosmetic active is its ability to lighten the skin, fading dark spots and hyperpigmentation. A study on over 70 women over 12 weeks claimed it reduced hyperpigmentation “significantly” (source). Another study compared twice-daily application of 1% dioic acid to 2% hydroquinone cream in 96 Mexican female subjects with melasma. Both agents demonstrated equal efficacy in reducing melasma by over 40% after 12 weeks of treatment. However, dioic doesn’t have the controversial associations with carcinogencity that hydroquinone does.
Unlike most other skin lighteners, octadecenedioic doesn’t work direct inhibition of tyrosinase. Curious about this scientists set about finding out how it does actually work and discovered that it is very good at binding to peroxisome proliferator-activated receptor (PPAR) - unlike azelaic acid (source). As a result, it can promote differentiation of keratinocytes, the primary cells in the epidermis.
Octadecenedioic acid was 50-fold more active than azelaic acid at inhibiting the growth of propionibacterium acne (source). It also also said to be a treatment for rosacea, but I haven’t been able to find research to back this up.
Mediatone is a form of dioic that is made by Sederma. It has been formulated to brighten and balance skin tone and supports even skin pigmentation. It acts all along the melanin pathway and can regulate melanin production by up to 51%, it also counteracts stress-induced pigmentation and melanin transfer to the keratinocytes.
Octadecenedioic acid/Mediatone is in MitoQ Cellular Radiance Protecting Serum and MitoQ Crystal Brightening & Skin Correcting Serum.