In a few weeks, Dermalogica is launching a new range of skin brightening products called ChromaWhite. I don't know too much about it except that the active ingredient is ferula foetida, but that is enough to intrigue me.

Ferula foetida is more commonly known as asafoetida. The root is used to make a particularly acrid and vile tasting powder that is used ubiquitously but sparingly in Indian cooking. I learned the sparing part the hard way when I ruined an entire meal by using a mere half-teaspoon of the stuff ("more diaper stew anyone?" asked one of my guests). The resin can be used for medicinal purposes, although you would already have had to have lost the will to live before allowing anyone to minister it to you.

As a skin whitener/brightener that will fade age spots, it is, on the other hand, benign and effective. Dermalogica doesn't seem to have made a breakthrough in discovering it because I have now found it in a number of potions. But I'll come back to that. In the meantime, how does it work?

Tyrosinase is the essential enzyme in the formation of melanin by converting DOPA to DOPAquinone. Therefore, reducing its activity is a principal method of improving skin tone and the one most commonly claimed for ingredients in current production for skin lightening.

The main constituents of asafoetida are high levels of ferulic acid esters, complex carbohydrates, sulphur compounds and terpenes. Terpenes are hydrocarbons that form the resin you get in plants like pine trees. Vitamin A - and we know that works on the hyperpigmentation front - is a terpene.

Just 0.52% of the dried asafoetida resin inhibits tyrosinase activity by 50%. In vitro tests showed that a 2% concentration of asafoetida extract reduced tyrosinase by 99.6%. Another test on 10 people showed that a 2% asafoetida worked better than hydroquinone. This is good news because hydroquinone can be severely irritating.

Some products that contain asfoetida:

Biotica Spot Whitening Serum ($29) also has other age spot zappers including licorice, kojic acid and papaya.

Bliss Sleeping Liver Spot Peel ($52) only has asafoetida as an active, so you'll need to be a believer.

Solange Fade Away Lightening Serum ($48.50) also has licorice, but I wasn't too enamored by the look of this one.

Saphoros Pigment Balancing Complex ($39,95) has lactic and glycolic acids, arbutin and licorice, as well as asafoetida.