Clenbuterol to Target DUX4 in FSHD

Inclusion Criteria: * Genetically confirmed diagnosis of FSHD type 1 or 2, or have a clinical diagnosis of FSHD type 1 with a first degree relative with confirmed mutation * between 18 and 75 years of age * with a clinical severity score between 0 and 10 * Able to walk 30ft without support of another person * Showing anti-gravity strength on at least one of the tibialis anterior muscles or having an MRI eligible muscle in the leg for needle biopsy * willing and able to provide informed consent * agree to follow the contraceptive requirement for duration of the study Exclusion Criteria: * Pregnant or planning to become pregnant during the conduct of the study * have a poorly controlled medical condition * Were involved in a study of an experimental agent within 3 months of enrollment * Are taking beta-blockers or anabolic agent or potassium wasting diuretics * Are taking or are planning to take a GLP-1 Agonist during trial * have any condition or contraindication which would interfere with testing or preclude use of beta-agonist * Are taking blood thinners or medications which make a needle muscle biopsy contra-indicated * Has contraindication to lactose such as galactosmia, lactase deficiency and glucose-galactose malabsorption. For those who are lactose intolerant, the PI will determine acceptability based on tolerance reaction to lactose * Are taking any medications or therapies with a contraindication to Clenbuterol