Lead(II) acetate is a white crystalline substance made by treating litharge (lead(II) oxide, PbO) with acetic acid. Lead Acetate is also known as lead diacetate.
In low concentrations, Lead Acetate is used as a color additive in "progressive" hair dye products. These products are applied over a period of time to achieve a gradual coloring effect.
Lead Acetate has been used in the United States as a color additive in progressive hair dyes for over 40 years. It is specifically approved for hair dye use based on extensive scientific studies. In order to be approved for this use, a color additive petition was required by the Food and Drug Administration to establish safety. The safety data submitted in support of this petition included results from trials on humans using the products. In the trials, people using the product under controlled conditions of use were monitored for the amount of lead in their bloodstream. No significant increase in blood levels of lead was seen in the trial subjects indicating that the lead was not absorbed into the body through such use. These data allowed FDA to determine that safe conditions of use could be established, and a color additive regulation (Title 21 of the Code of Federal Regulations, section 73.2396) allowing the use of Lead Acetate in hair dyes was established. The regulation requires that the following caution statement appear on the product labels: "Caution: Contains Lead Acetate. For external use only. Keep this product out of children's reach. Do not use on cut or abraded scalp. If skin irritation develops, discontinue use. Do not use to color mustaches, eyelashes, eyebrows, or hair on parts of the body other than the scalp. Do not get in eyes. Follow instructions carefully and wash hands thoroughly after use." To ensure safe use of these products, it is important that consumers follow these directions carefully.
Lead Acetate is a progressive hair dye ingredient. This means that the product is applied over a period of time and, with each application, darkens the hair. The Lead Acetate ingredient is present at low levels so that the effect is gradual, building up to the desired amount of color. After the desired effect is achieved, additional maintenance applications are made to keep the hair colored. Lead Acetate coloring works very gradually so that a color change may not be apparent for several days. The actual effect will depend on the color of the hair when the applications start. Scattered gray may take longer whereas solid gray areas may change sooner. Lead Acetate combines with the protein in the hair, and the combination of these substances is a dark, almost black color. The color is very stable and will not diminish quickly, so that maintenance applications are only necessary about once a week. However, the color that is formed will gradually fade as the color combination is washed out or wears off.
Link to the FDA Regulation Listing Lead Acetate as Safe for Use in Coloring the Hair: http://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfcfr/CFRSearch.cfm?fr... Editorial About Lead Hazard: http://junksciencearchive.com/news/grecian-formula.html