One highly rated shower sealant is the GE Silicone II 10.1-oz. Clear Kitchen and Bath Caulk. This product receives a majority of 5- and 4-star reviews, notes Home Depot.
The GE Silicone II 10.1-oz. Clear Kitchen and Bath Caulk adheres to a wide variety of surfaces. One of the benefits of using this product is that it can be exposed to water in as little as 30 minutes after sealing.
Other highly rated shower sealants include the Momentive Performance Materials GE284 2.8-Ounce Silicone II Premium Waterproof Kitchen and Bath Squeeze Tube, according to Amazon, and Unibond Speed Seal Shower & Bathroom White Sealant, on DIY.com.