A lot of people ask the question: Do relaxers have an expiration date? You can do a search on Google and it will turn up a large number of websites telling you no they don’t, but contrary to popular belief, just like most all products, yes they do!
One thing you should be aware of is that all manufacturers are different, and when purchasing products for home use you should ALWAYS follow the manufacturers instructions before application. If you have questions regarding any of the products, contacting the manufacturer directly is your best course of action. By law, manufacturers are required to keep samples of products they distribute. All products are coded with a number on each product; this tells the manufacturer exactly when the product was manufactured. The practice of coding and keeping samples is extremely important in cases where a product may not specify a specific expiration date.
Dr. Ali Syed, president and master chemist of Avlon Industries wrote an article in 1993 detailing the shelf life of many salon products. The article also answered the question as to whether using expired products are harmful.
Shelf Life: 1 to 1.5 years (Sodium Hydroxide)
2 years (Guanidine Hydroxide)
Of the most widely used relaxers, those formulated with sodium hydroxide are the most challenging to formulate. An improperly formulated relaxer can have a shelf life of six months or less. Well developed formulas will work effective for up to a year and a half.
Guanidine hydroxide relaxers are a little easier to stabilize from a product development standpoint, and can be effectively used for up to two years. (If the creme portion of the relaxer system seems a bit dry on the upper surface, do not assume that the product is beyond ‘” shelf life. This is characteristic of relaxers in this category, which contain
Shelf Life: 6 to 12 months Curl Boosters
6 to 12 months Rearrangers
1 year Neutralizers
What if a Product is Used Past its Shelf Life?
At best, a product that is beyond its shelf life will not perform as effectively as it did initially. Product application may be impaired and the way it reacts to the hair may very well be hindered. At worst, the product could cause harm to a client. In the case of an unstable or separated sodium hydroxide relaxer, the result will either be ineffective straightening or extreme causticity. This is because once a relaxer separates, the oils rise to the top and the water, containing most of the sodium hydroxide, descends to the bottom of the jar. When the stylist applies the upper portion of the mixture, the hair will be treated with the most impotent part of the relaxer. When the lower portions in the jar are used, the relaxer is much too strong and will likely damage the hair and bum the scalp. Stylists must not think that merely mixing the contents of a separated relaxer will again stabilize the formula because it won’t. Relaxers must be blended at a temperature of 80 C under scientifically-controlled conditions in order to get a stable mixture.
Another instance in which a client may actually be harmed by the use of product, which is beyond its shelf life, is when bacterial growth has occurred. Should a contaminated product, wherein the preservative system has broken down, be inadvertently rinsed into a client’s eyes, severe infection and/or impairment may result.[mashshare]