Powders usually contain ingredients that do one major thing: dry the hair of any oil or moisture to aid and expedite the placement or maintenance of dreadlocks. Powders may be especially helpful for novices who don’t have much experience with dreading hair as it can help expedite the process and encourage the hair to knot up easily in cases where the user’s technique might not quite be perfect or where the hair may be particularly greasy/slippery. (However, washing before starting the dreading process and using the right kind of shampoo will help eliminate this issue.)
For the sake of this article we will focus on the most popular, commercially available locking powder: DreadHeadHQ Lock Peppa. However, many commercially available locking powders do contain some or all of the main active ingredients which are: Zinc oxide, silicon dioxide, methyl salicylate, rosin, bentonite, and wintergreen.
Of those ingredients, methyl salicylate and silicon dioxide are those that are specifically cause for concern.
In topical applications on the skin, methyl salicylate can be irritating and cause scalp irritation, especially in sensitive individuals. In children less than 6 years of age, a teaspoon (5 mL) of oil of wintergreen has been implicated in several well-documented deaths. So you need to be extremely cautious if/when using locking powders around animals and children.
Silicon dioxide is really a technical, chemical name for sand. Depending on the particle size, it can build up in the lungs causing lesions know as silicosis. For the typical dreadhead who uses it only periodically for home maintenance this isn’t a big deal. However, for dreadlock professionals who may use it on a regular and frequent basis, this can be particularly worrisome. Additionally, its insoluble in water which means it may be difficult to wash out of the dreadlocks.
Now, this isn’t all to say that all locking powders are bad. There are plenty of alternatives to the ingredients listed above that can be used that are safe and non-toxic if you feel a locking powder is desirable or necessary.