I had fully expected to like Ole Henriksen's potion, Express The Truth (it's a good name after all). It was not to be. The first 14 ingredients - mundane fillers that have a mild conditioning effect, some silicone and stabilizers -  left me cold. But what really got me shivering in my shoes, was the discovery that it contains sodium benzoate.

At first blush sodium benzoate looks fairly benign. It occurs naturally in some plants, such as cranberries. It is used as a preservative in food and cosmetic products and has a very low level of toxicity. Various tests have shown that it is not carcinogenic. But when sodium benzoate encounters vitamin C, it is transformed from friend to foe.

If you mix sodium benzoate with vitamin C (and it happens that there are two types of C in Express The Truth - calcium ascorbate and sodium ascorbyl phosphate), benzene can form. And benzene is carcinogenic. In the UK, a Food Standards Agency survey of benzene in soft drinks found high levels of it in four brands, which were removed from sale.

Even without getting mixed up with vitamin C, sodium benzoate might not be as friendly as it looks. A study conducted by Peter Piper, a professor at Sheffield University in the UK and an expert in molecular biology and biotechnology, found that sodium benzoate damages cells.

He tested benzoate on yeast cells and found the preservative spurred an increase in production of oxygen radicals, or free radicals. Benzoate appeared to attack cells' mitochondria, damaging their ability to prevent oxygen leaks that create free radicals. Yeast cells were used because of their similarity to human ones, but no research on humans has been done.

Piper was quoted in the British newspaper, Independent on Sunday, as saying: "These chemicals have the ability to cause severe damage to DNA in the mitochondria to the point that they totally inactivate it: they knock it out altogether.

"The mitochondria consumes the oxygen to give you energy and if you damage it - as happens in a number of diseased states - then the cell starts to malfunction very seriously. And there is a whole array of diseases that are now being tied to damage to this DNA - Parkinson's and quite a lot of neuro-degenerative diseases, but above all the whole process of aging."

Sodium benzoate is readily absorbed by the skin and so its presence in an anti-aging cream may, ironically, actually age you faster by, as Prof Piper, puts it "knocking out" your DNA.

Ingredients in Ole Henriksen's Express The Truth

Water, Caprylic/Capric Triglyceride, Glycerin, Triisostearyl Citrate, Ethyl Macadamiate, Stearic Acid, Stearyl Alcohol, Dimethicone, Cetearyl Alcohol, Polysorbate-60, Ceteareth-20, Sorbitol, Glycerine, Calcium Ascorbate, Aspalathus Linearis Leaf Extract, Polylysine, Sodium Hyaluronate, Zinc Gluconate, Copper Gluconate, Manganese Gluconate, Tocopheryl Acetate, Sodium Ascorbyl Phosphate, Aloe Barbadensis Leaf Juice, Chamomilla Recutita (Matricaria) Flower Extract, Simmondsia Chinensis (Jojoba) Seed Oil, Prunus Amygdalus Dulcis (Sweet Almond) Oil, Sodium PCA, Allantoin, Curcuma Longa (Tumeric) Root Extract, Limonene, Potassium Cetyl Phosphate, Carbomer, Glyceryl Laurate, Linalool, Sorbitan Stearate, Potassium Hydroxide, Benzyl Alcohol, Sodium Benzoate, Potassium Sorbate, Citral, Fragrance, Flavor.