Safety evaluation of metal exposure from commonly used moisturizing and skin-lightening creams in Nigeria

- Skin-lightening creams contained higher concentrations of the studied metals than the moisturizing creams.
- Persons who use skin-lightening creams are potentially exposed to higher concentrations of metals.
- Chromium was found at concentrations that can induce allergenic contact dermatitis in pre-sensitized individuals.

The concentrations of ten metals (Cd, Pb, Ni, Cr, Cu, Co, Fe, Mn, Zn and Al) were measured in some commonly used moisturizing and skin-lightening creams in Nigeria with a view to providing information on the risk of exposure to metals from the use of these products. The metal concentrations in these products were measured by atomic absorption spectrometry after acid digestion of the samples. The measured concentrations of metals in the skin moisturizing creams ranged from <0.15 to 6.3 μg/g Cd, <0.02 to 17.5 μg/g Cu, 2.25 to 6.25 μg/g Cr, <0.25 to 124.3 μg/g Al, 0.2 to 7.3 μg/g Pb, <0.03 to 10.7 μg/g Ni, 17.3 to 372.0 μg/g Zn, <0.02 to 1.0 μg/g Co, 17.75 to 28.8 μg/g Mn, <0.1 to 89.8 μg/g Fe while the concentrations of metals in the skin-lightening products ranged from <0.15 to 16.5 μg/g Cd, <0.02 to 10.0 μg/g Cu, 4.25 to 8.0 μg/g Cr, <0.25 to 128.0 μg/g Al, 0.5 to 4.5 μg/g Pb, <0.03 to 1.65 μg/g Ni, 24.7 to 267.5 μg/g Zn, <0.02 to 2.5 μg/g for Co, 19.3 to 31.8 μg/g Mn, 9.5 to 211.63 μg/g Fe. In a significant number (>93%) of the samples investigated the concentrations of Pb, Cd, Ni and Co were below the specified limit, or the maximal limit for impurities in colour additives in cosmetics for external use. However, Cr was found at concentrations above the allergenic limit of 1 μg/g. The results also showed that skin-lightening creams contained higher concentrations of the studied metals than the moisturizing creams, except for Ni, which indicates that persons who uses skin-lightening creams in preference to moisturizing ones, are exposed to higher concentrations of metals.