Thorne Research

Price: Undecyn®
Size: 100 capsules
Undecylenic acid occurs naturally on the surface of skin where it seems to have an anti-yeast and anti-candida effect. It is:

  1. A Fatty Acid (10-undecenoic acid)
  2. A naturally product that occurs in sweat (skin)
    Undecylenic acid is our favorite product for yeast infections.
  3. Produced commercially by a vacuum distillation of castor bean oil
  4. An antifungal, as are most fatty acids

One study showed undecylenic acid to be 6 times more powerful than caprylic acid in Candida infections.1


This formula contains betaine HCl for acidification and to promote digestion and detoxification. Also, Bentonite clay is in the formula to aid in absorption of endotoxins and help heal the gut lining. This formula contains grapefruit seed extract, which is probably of little benefit (see our article on grapefruit seed extracts).

In total, we believe this product is effective in yeast infections and aids in establishing normal gut microflora.

1. Peck SM, Rosenfeld H. The effects of hydrogen ion concentration, fatty acids and vitamin C on the growth of fungi. J Invest Dermatol 1938;1:237-265.


    • 1 /4 capsule for each 10 lbs body weight twice daily up to a maximum of 3 capsules twice daily


    • 1/4 capsule daily with food


    • Add to soft foods
    • Sprinkle lightly on food twice daily
    • If giving orally, 1/32 capsule for each 200 grams body weight twice daily

    Ingredients Three Capsules Contain:

    • Bentonite Clay 450 mg.
    • Betaine Hydrochloride* 450 mg.
    • Calcium Undecylenate** 450 mg

    Other Ingredients: High and low viscosity hydroxypropyl methylcellulose and MagnesiumCitrateLaurate (Time-Sorb), Hypromellose (derived from cellulose) capsule, Leucine, Silicon Dioxide. *Betaine Hydrochloride derived from a non-plant source. **Calcium Undecylenate complexed with Time-Sorb, a time-release matrix.