Replacement of the hormone testosterone is the main treatment for Klinefelter syndrome. Other treatments vary depending on the symptoms and may include educational support for language and learning difficulties and counseling or social skills training for behavior problems.

Initial treatment

Treatment for Klinefelter syndrome usually starts when a boy is about 11 to 12 years old. It begins with measuring the amount of testosterone and other hormones in his blood. Many teenage boys with Klinefelter syndrome don't have low levels of testosterone.⁴ If a boy's testosterone level is low, he is given a man-made form of testosterone (Depo-Testosterone) on a regular basis. Testosterone can be given as an injection or through a skin patch or gel.

Testosterone:

• Increases body hair, mainly on the face (beard), under the arm (axillary), and in the genital area (pubic).
• Increases muscle development.
• Increases sex drive.
• Helps prevent osteoporosis.
• May prevent or shrink enlarged breasts.
• Provides better self-esteem by allowing the boy to "fit in" with his peers. This can result in more successful interpersonal relationships.

Side effects of testosterone replacement therapy are uncommon, but include worsening acne, overly rapid sexual development, and behavior problems (such as being overly aggressive). Careful monitoring is important to prevent these side effects.

Ongoing treatment

Ongoing treatment for Klinefelter syndrome may include:

• Help for language and learning difficulties. If language delays are identified in early childhood, educational assistance and speech therapy can be used to treat the problem. Children with learning difficulties can receive educational support through the school system.
• Testosterone replacement. This is given by injection or through a skin patch or gel. Testosterone replacement usually continues throughout the man's life but does not help infertility. For men who want to start a family, counseling and treatment at a fertility clinic are generally recommended.
• Regular medical checkups to monitor for development of other conditions, such as autoimmune diseases, behavior problems, or psychiatric disorders, such as depression. Professional counseling or medication may be needed.