Definition & Overview

A subcutaneous hormone pellet implantation is a medical procedure used for prolonged and consistent supplementation of oestrogen and/or testosterone as part of a hormone replacement treatment. It offers a hassle-free alternative to using pills, creams, and hormone patches.

Who Should Undergo and Expected Results

The procedure is for patients who require hormone replacement therapy as a treatment for an existing medical condition or to replace the hormones that the body is no longer able to produce usually due to ageing. These include patients who require estradiol or testosterone therapy.

Estradiol is a form of oestrogen, which is the female sex hormone that is produced by the ovaries. Oestrogen replacement therapy can help menopausal and post-menopausal women deal with the symptoms of their condition including vaginal dryness, hot flashes, vaginal burning, and irritability. Oestrogen therapy can also help prevent osteoporosis as well as resolve issues linked with ovarian failure resulting in abnormally low levels of naturally produced oestrogen in the body. Estradiol replacement therapy is also sometimes used as part of cancer treatment.

Testosterone, on the other hand, is the primary male hormone produced by the testicles. It is responsible for the development of a male’s sexual characteristics. Testosterone replacement therapy is often performed on patients suffering from erectile dysfunction.

Subcutaneous hormone pellet implantation can also help reduce the symptoms of hormonal imbalances, such as:

  • Depression
  • Restless leg syndrome
  • Decreased sex drive
  • Vaginal dryness
  • Memory loss
  • Painful intercourse
  • Palpitations
  • Irregular menstrual periods
  • Irritability
  • Painful joints
  • Loss of muscle mass
  • Lack of self-esteem

Studies show that this method is highly efficient in producing the needed amount of hormones, which tend to decline as a person ages, especially in cases wherein prolonged administration is required. The procedure is more convenient when compared to using pills or creams as it automatically triggers the release of the correct amounts of estradiol and/or testosterone at the correct times.

How is the Procedure Performed?

A subcutaneous hormone pellet implantation is a minor surgical procedure performed under local anaesthesia. A small incision is made through the skin where the hormone pellet is inserted. Hormone pellets are similar in size to a grain of rice, so they are completely unnoticeable once placed.

Since an incision is made through the skin, the surgery will leave a wound, which usually takes 5 to 7 days to heal completely.

Possible Risks and Complications

A subcutaneous hormone pellet implantation is not free from any risks. Estradiol therapy can cause:

  • Increased risk of uterine cancer
  • Vaginal bleeding
  • Birth defects (in pregnant women)

Testosterone therapy, on the other hand, can cause the following side effects:

  • Sleep apnoea
  • Blood clots

It is also associated with an increased risk of:

  • Prostate cancer
  • Benign prostatic hypertrophy
  • Congestive heart failure

Hormone therapy, in general, can cause the following side effects especially among patients who have diabetes, hypertension, and high cholesterol levels and those who smoke and are overweight:

  • Blood clots
  • High blood pressure
  • Stroke
  • Heart attack

Despite these, the use of subcutaneous hormone pellets helps reduce the common problems associated with the use of pill-based or topical hormone therapies, such as overdosage or missed pills.


  • Snyder P, Bhasin S, Cunningham G, Matsumoto A, et al. “Effects of testosterone treatment in older men.” The New England Journal of Medicine. 2016; 374:611-624.

  • Rhoden EL, Morgentaler A. “Risks of testosterone replacement therapy and recommendations for monitoring.” The New England Journal of Medicine. 2004; 350:482-492.

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