Effects of Increased Testosterone on Physical Performance in Women

Effects of Increased Testosterone on Physical Performance in Women

Written by Ben Bunting: BA, PGCert. (Sport & Exercise Nutrition) // British Army Physical Training Instructor // S&C Coach.


Men tend to possess a 10-12 percent athletic advantage over women, often attributable to testosterone levels; however, other factors may also play a part in this difference.

Researchers have recently shown that an increase in testosterone can significantly enhance young physically active women's ability to run longer, according to research published in the British Journal of Sports Medicine.

Testosterone can also increase muscle mass and leanness even with short duration administration of this hormone.

Increased Lean Muscle Mass

testosterone dramatically boosts young female athletes' abilities to run longer and build more muscle, according to a new study published in the British Journal of Sports Medicine. For the first time ever, an artificially increased level of testosterone was given and then tested against physical performance measures; further, this research sheds light on how hormonal differences between genders might influence athletic ability.

Testosterone is an essential part of the anabolic system that aids muscle building, but women produce it at far lower levels than men. Puberty sees levels peak before starting their steady decline again as adults enter puberty.

Hypogonadism or low testosterone usually affects men but women can also suffer from it - low levels have been linked with decreased muscle mass, decreased libido, and an increase in fat deposits.

High levels of testosterone have long been associated with virilization, or the development of male physical characteristics like muscle bulk and facial hair.

Women suffering from the rare inborn condition known as hyperandrogenism may have testosterone levels comparable to that found in men. Two-time Olympic 800 meter champion Caster Semenya has this form of hyperandrogenism.

At the core of their study, researchers gave 48 non-elite female athletes cream containing testosterone or placebo for 10 weeks.

After this time period was up, they measured how fast their muscles absorbed leucine as a precursor for protein synthesis.

Testosterone significantly increased muscle protein synthesis by 27% when compared with placebo; additionally, this treatment increased running times and endurance by significantly improving muscle performance.

Researchers hypothesize that testosterone's endurance-increasing benefits stem from increasing the number of cells within muscles which absorb oxygen, ultimately aiding the heart in pumping blood efficiently around the body.

Testosterone has been demonstrated to increase bone density and decrease the rate of bone resorption, contributing to males having greater bone mass than females, though other factors such as nutrition, exercise and genetics likely play an even larger part.

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Improved Aerobic Running Time

Testosterone stimulates red blood cell production, increasing your oxygen-carrying capacity and enabling you to exercise at higher intensities for longer.

Low levels of this hormone have been linked with reduced exercise performance and heart disease risk. Increasing testosterone is therefore vital in improving health and fitness.

According to one study involving 48 physically active healthy women receiving testosterone therapy had significantly improved aerobic running performance as a result. In addition, increasing testosterone may increase muscle mass so as to burn off more fat efficiently.

At puberty, testosterone levels increase 20-fold among males compared to those seen in females, leading to at least 15-times higher concentrations circulating than seen among women.

Through natural selection-driven processes and secondary characteristics that distinguish males such as greater body size and strength that measurably differ between genders. These differences lead to gender segregation of most competitions.

However, some women produce very high levels of testosterone for biological reasons. Such conditions include polycystic ovary syndrome (PCOS), which may disrupt menstruation cycles and lead to infertility. Intersex individuals (those who possess both male and female genitalia and have internal testicular tissue); some intersex individuals experience signs of virilization such as increased body hair growth or deepening voices.

Testosterone increases muscle size and bone density while improving cardiovascular health by decreasing triglyceride and cholesterol levels.

Furthermore, this hormone has a profound impact on mood - inducing positive emotions such as friendliness while decreasing feelings of aggression or irritation.

Studies on men have largely demonstrated the athletic benefits of testosterone; it remains less certain whether women can realize similar gains.

Some researchers even suggest that gender-specific differences could be an evolutionary adaptation meant to differentiate males and females. No definitive answers can be provided until more studies have been conducted to demonstrate the effects of testosterone supplementation in healthy women athletes.

The International Association of Athletics Federations recently mandated that transgender and intersex athletes with naturally high testosterone levels must take medication to lower these levels before competing in female category events ranging from 400 meters to one mile distances.

Increased Lower Limb Lean Muscle Mass

Testosterone increases muscle mass by expanding lower limb muscles like quadriceps, hamstrings and calves.

As a result, legs become stronger and more powerful for endurance events like running or cycling. This may also aid performance at endurance sports events like running or cycling. 

Testosterone plays an essential role in the formation of skeletal muscle in children, so it comes as no surprise that higher testosterone levels are linked with more muscular bodies in women.

Testosterone also aids fat metabolism; thus increasing your levels can help prevent excess weight gain while keeping metabolic rates healthy when combined with a diet rich in proteins but low in calories.

Studies have demonstrated that higher testosterone levels increase leg muscle mass in healthy young women.

A randomized controlled trial concluded that increasing this hormone significantly enhanced female athletic performance. By increasing it to similar levels of their mle counterparts it improved their mile time, maximum speed and vertical jump performance as well as training intensity

Increased Endurance

Hirschberg et al published results of one of the first randomized controlled trials that investigated how increasing testosterone could affect healthy women, showing that those whose exogenous testosterone levels were raised significantly improved their endurance tasks like running a mile and climbing stairs for 30 minutes.

In this 10-week study, 48 healthy 18- to 35-year-old women were randomly assigned either testosterone cream or placebo for 10 weeks, and in comparison with the placebo their circulating levels increased from 0.9 nmol/L to 4.3 nmol/L; researchers measured improvements in endurance performance (how far a treadmill could run before becoming exhausted), leg strength and lean body mass.

The team examined changes to mitochondria present in skeletal muscles as well as how efficiently enzyme complex IV-subunit 2 and complex V of mitochondria (which produce energy) worked, suggesting that improvements seen may be tied to testosterone-induced phosphorylation of these proteins.

Testosterone production occurs naturally by women's ovaries; however, in some cases it can be increased through disease or medication to significantly higher levels than desired.

This condition is known as polycystic ovary syndrome or PCOS and it may result in irregular periods, infertility, larger than usual breasts (gynecomastia), increased hair growth on face chest or abdomen and a deeper voice


A rise in the male hormone testosterone boosts young, physically active women's ability to run faster and for longer. That's the finding from one of only a few studies so far that have tested whether elevated levels of testosterone can improve athletic performance in women.

Researchers at the University of Oregon provided 48 physically active premenopausal women either testosterone cream or inactive cream to apply on their skin for 10 weeks, then measured their endurance on a treadmill, leg power during stationary cycling, muscle strength via squat jumps, standing vertical jumps and tests of knee strength.

Researchers noted a +4% increase in lower limb lean muscle mass in participants who used testosterone cream, along with small but noticeable improvements in isometric knee extension strength and bench press strength as measured through this research study.

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