Laminate flooring is intended to be cheap, readily disposable, and resilient against scuffs and scrapes. Against moisture, it is much more vulnerable due to the MDF core. The top layer is already sealed, but moisture will eventually work its way between the planks, and I don't believe there's any practical way to seal these gaps.
A good quality laminate glue and silicone caulk can help seal your laminate to help make it more resistant to moisture. How To Do It Right Glue the locking system of the planks to create a more water resistant connection, however do not glue your laminate to the subfloor as it needs to float.
Re: Sealing Seams In Laminate Tops You can purchase a kit of Seam Seal through the distributor. ie Formica, Arborite, etc. It's not cheap, but these fillers will match and fill any colour of top.
Designed to protect the core of click flooring from moisture and water damage It will prevent joint swelling and opening Suitable for use on all glueless flooring laminate and engineered wood floors
Sealing laminate joints in kitchen I'm fitting Hampton Bay laminate in my kitchen. The specs state it has "Wax-coated joints provide enhanced moisture protection" but I'd like to seal the joints a little better in the kitchen area where we will inevitably get spills, as well as seal the perimiter with silicone.
Pergo SimpleSolutions Sealant is an acrylic-based sealant designed to help protect your floor from damage in wet areas such as bathrooms, kitchens and laundry rooms. It is used to spot fill the expansion space around bathtubs, sinks, refrigerator water lines and dishwashers to protect against minor spills.