Are there any shower facilities at Dubai airport?

Answer from Dubai International Airport Customer Care:

Dubai International Airport Hotel:

Located at both Terminal 1 & 3 above gate no 117 & 217 respectively

The cost ( 45Dhs/14u$).

No pre-booking required.

The Shower rooms provided with Shampoo, Towels, Soap.

Terminal 3:

Located on the West side near to Gate no 201 & East side near to

Gate no 231.

Free Shower rooms

The Shower rooms are not provided with Shampoo, Towels, Soap.

There are also some showers in the First and Business class lounges.

Can't comment on the facilities though as I haven't used it. There are some reviews online - mostly 2 & 3 out of 5-star rating.