376591423_c0b3889fc6_oYou just started testosterone replacement.

You involuntarily hold your breath in anticipation as you wait for the chemical cavalry to come and rescue your waning energy, buttress your failing libido, and transform your body into something worthy of an underwear model.

Too bad it doesn’t exactly work that way. Testosterone can be an amazingly transformative drug in a variety of ways and while the transformations are quick, they’re not generally something you’re going to experience in an hour, a day, or even a week.

Some, like sexual effects, happen relatively quickly, gradually ramping up over the weeks. Others, like changes to muscle, bone, and waist size happen more gradually, starting a few months after therapy begins and finally leveling off after two or three years.

We know this from experience and through the studies that have been conducted to gauge how fast testosterone replacement therapy works. Unfortunately, most of these tests have been conducted only on men, but most doctors and scientists, including those at Optimal Health Medical Group, feel that the general results (except gender specific categories like erection and ejaculation quality and frequency) apply to women, too, even though the exact time frames may differ slightly.

Let’s take a look at some of the effects of testosterone replacement therapy and how long it takes for them to kick in:

Psychosocial Parameters

Most people don’t realize it, but common psychological problems like depression and anxiety might have their roots in low testosterone levels. Similarly, positive traits like sociability and “appropriate aggressiveness” might be tied to having higher testosterone levels. (Even though it sounds like something you might do in response to being cut off on the freeway, “appropriate aggressiveness” refers to asserting yourself or acting confidently when it’s called for. Lack of it might lead to missed opportunities in the workplace or matters of love.)

  • Anxiety Levels, Appropriate Aggression, Sociability, and Activation (stimulation of the cerebral cortex into a state of wakefulness, attention, and even creativity) All four of these parameters generally show significant improvement 3 weeks after starting testosterone replacement therapy. All areas generally continue to improve for about 9 weeks, plateauing about 3 months after beginning therapy.
  • Depression and listlessness — Both of these parameters decrease by week 6, but maximum benefits take longer.

Sexual Benefits

The sexual benefits of testosterone replacement therapy go far beyond merely increasing sex drive. Patients receiving testosterone report stronger and more frequent erections and ejaculations, in addition to a generally more satisfying overall sex life.

  • Number of Spontaneous Erections and Number of Ejaculations — Positive changes occur at about week 3 and increase to stable levels between weeks 19 and 21.
  • Number of Sexual Thoughts and Fantasies — These parameters start to increase noticeably by week 3, eventually doubling in number and stabilizing at that frequency.
  • Sexual Desire — Desire follows a similar tract as sexual thought and fantasies, eventually plateauing at about week 9.
  • Satisfaction With Sex Life — Satisfaction rose dramatically by the 3rd week and continued to rise through week 30 (when this particular study concluded).

Health Benefits

Testosterone Replacement Therapy is seemingly one of the best things you can do to improve your health, as the hormone plays a pivotal role in insulin sensitivity, bone density, and even cardiovascular health, among other things.

  • Insulin Sensitivity – Insulin can make you fat or it can make you lean and muscular. It all depends on whether you’re insulin sensitive or insulin resistant. Without optimal insulin sensitivity, a lot of the food you eat gets broken down and transported to fat for storage (as opposed to being transported to muscle). Testosterone, however, increases insulin sensitivity in just a few days, with effects becoming evident (less body fat) in 3 to 12 months, but often continuing for several years.
  • Inflammation – Inflammation plays a pivotal part in all kinds of human diseases and conditions (including heart disease), but testosterone generally helps reduce systemic inflammation in 3 to 12 weeks.
  • Bone Density – Men with low testosterone levels often have signs of osteoporosis, but testosterone can start to show positive effects on bone density after 6 months, continuing for at least 3 years. Furthermore, testosterone can also help women in this regard as it enhances the effects of estradiol therapy on bone density.
  • Blood Chemistry – Testosterone replacement therapy can decrease total cholesterol and LDL (“bad” cholesterol) without altering HDL (“good” cholesterol) levels. These beneficial effects start to appear after about 4 weeks and maximize within 6 to 12 months.

Positive Effects on Appearance

Testosterone can have dramatic effects on the way you look, particularly if you maintain a concurrent exercise program and make an effort to eat correctly.

  • Body Fat – Body fat in general may start to decrease in 1 or 2 months, but may take 1, 2, or 3 years to plateau.
  • Waist Size – Waist size should start to decrease within 1 to 2 months, possibly continuing for years. (One study of 255 men on testosterone replacement therapy reported that the men lost an average of 3.5 inches on their waist after 1 year.)
  • Increased Muscularity – Muscularity is highly dependent not just on having adequate testosterone levels, but also diet, exercise, and genomic (relating to an individual’s genes) factors. However, given the right conditions, muscularity can begin to improve in as little as a month, peak at approximately 12 months, and continue at a slower pace for some time.

An Intangible Benefit

 There’s one benefit that’s extremely difficult to quantify and it’s what you get when you bunch all of the positive attributes of testosterone replacement therapy into one great, big psychological, sexual, health, and cosmetic sandwich.

It’s what the French refer to as joie de vivre, or “joy of life,” and if you feel like you’re not getting your fair share of it, talk to one of the doctors at Optimal Health Medical Group to see if testosterone replacement therapy is right for you.


Jockenhovel, Minneman, et al, Timetable of effects of testosterone administration to hypogonadal men on variables of sex and mood, The Aging Male, December 2009 12(4): 113-118

Saad, et al, Onset of effects of testosterone treatment and time span until maximum effedts are achieved, European Journal of Endorcrinology, 2011 Nov; 165(5): 675-685