Initial Posting: 4/8/2015    Last Update: 8/3/2017
Answer: Although these products both refer to the term "alkaline," they contain different ingredients and are promoted for different uses.
Alkaline booster drops typically contain "buffering" ingredients, such as calcium chloride and potassium bicarbonate, which are promoted to "decrease toxins," increase energy and improve overall health by reducing acidity in the body. However, they are unlikely to have much of an effect on blood levels of acidity, which are closely regulated in the body, and remain within a normal, narrow range --even after supplementation with these types of "buffering" ingredients. More about this "Alkalinizing Myth" can be found in the Review of Greens and Whole Foods Powders and Pills, as "greens" have also been promoted for "alkalization."
Also, be aware that foods and supplements can, temporarily, increase or decrease the acidity of your urine or saliva. This is important to know because some supplement companies and health food stores sell test strips so that you can measure the pH of your urine or saliva as "proof" that a supplement is "working," but these won't reflect blood pH.
Unlike "booster drops," Kre-Alkalyn is not promoted to reduce acidity in the body. Rather, it is a brand of creatine which has been alkalized for "stability and purity." Evidence for this product, which was tested by ConsumerLab.com in 2014, is discussed in the Review of Muscle Enhancers.