Testosterone is the hormone responsible for male characteristics, so it may be surprising to some people to know that women's bodies also produce what is classically known as the 'male' hormone. Why do women produce testosterone, and what does it do?
Women and Natural Testosterone
Most of us know the effects of testosterone in men, so it's probably quite obvious that women produce a lot less of this hormone than men do – on average, a man has a level of free (bioavailable) testosterone between 270-1100 ng/dl, whereas a woman has a much lower normal range, between 6-86 ng/dl.
Testosterone is produced by the ovaries and adrenal glands in women, and it performs a number of functions, including stimulation of blood cell production, maintaining bone strength, and stimulation of the libido. The majority of the testosterone produced by the ovaries is converted into oestradiol, the main female sex hormone, through a process known as aromatisation.
Testosterone and Polycystic Ovary Syndrome (PCOS)
Naturally high testosterone levels in women are most commonly associated with Polycystic Ovary Syndrome (PCOS). This condition is thought to effect up to 10% of women, and has symptoms such as irregular or heavy periods, infertility, acne, thinning hair or baldness, and hirsutism. Women with PCOS suffer from ovarian cysts and may find it difficult to become pregnant. These women are also prone to metabolic illness such at type 2 diabetes, obesity, and mood disorders.
High testosterone levels in woman may also be associated with other conditions, including adrenal hypoplasia, hypothyroidism, hyperprolactinemia, and some cancers of the reproductive system.
Testosterone for Women to build Muscle
There has been a fair amount of research looking into the female body's response to resistance training, including the effects on endogenous testosterone levels.
Most of the research that has been conducted has shown that testosterone levels sometimes rise slightly after exercise, but that in the long term, neither resistance training or weight training have been shown to greatly alter levels of testosterone in the body (1). In addition, research has shown that while there are may be other hormonal changes thought to be related to the stress of training, the amount of endogenous testosterone does not significantly differ between elite athletes and sedentary women (2). Women have been shown to be able to build muscle without high levels of testosterone (3), but it is very difficult for a woman on a strength training program to build the type of bulk that a man will with the same sort of training, due to lower endogenous testosterone levels.
This type of bulky muscle gain is however seen in women who abuse testosterone at greater than physiological doses.
Women and Testosterone for Weight Loss
There is quite a bit of anecdotal evidence for the idea that testosterone can assist weight loss. We know that our sex hormones influence the distribution of body fat, and preliminary research performed in men with low levels of testosterone shows that administration of this hormone can shift the kilos (4). But is this the answer for women?
A conscious effort to lose weight by a woman is generally associated with the desire to improve health or aesthetic appearance. The side effects caused by use of testosterone from an external source runs counter to both these aims, so it is not an appropriate aid to weight loss in women.
Women and Testosterone Side Effects
As discussed earlier, there are a number of symptoms associated with high androgen levels in a woman, and many of these include the development of more masculine characteristics. These can include thinning hair and male pattern baldness, hair growth on the face or body, oily skin and increased acne, increased sweating, hoarseness or deepening of the voice, decreased breast size, increased clitoris size, missed periods and infertility, aggression and mood changes. High doses of testosterone may also cause liver damage and abnormalities in the bones and blood cells. The magnitude of these side effects is positively associated with the level of free testosterone. This means side effects are more likely in women who abuse testosterone as a performance aid, just as men who abuse testosterone and other androgenic anabolic steroids are more likely to suffer side effects than men with naturally high levels of this hormone. Women are more likely to suffer noticeable side effects from the abuse of endogenous testosterone supplements than are men.
Women and Testosterone Supplements
Supplements designed to naturally raise testosterone levels in men are amongst the most popular safe and legal muscle building aids. Unfortunately many of the ingredients present in these supplements have not been trialled for their efficacy in women for fat loss or muscle building. There has, however, been promising research into popular testosterone booster Tribulus terrestris, showing that this is an effective libido enhancer in women (5), and other ingredients have also shown benefit, such as Epimedium or Horny Goat Weed, which has shown promise fighting tumour cells and osteoporosis (6), and Longifolia or Tongkat Ali has shown effectiveness in boosting mood, cognition and sexual function (7)
Because these supplements are non-hormonal, we do know that they are safe for use. We won't say 'be a man' and give it a go because that would be quite misleading, but we will say that many women have found non-conventional benefits from using a supplement of this type.
(1)Enea C, Boisseau N, Fargeas-Gluck MA, Diaz V, Dugué B. Circulating androgens in women: exercise-induced changes. Sports Med. 2011 Jan 1;41(1):1-15.
(2) Tegelman R, Johansson C, Hemmingsson P, Eklöf R, Carlström K, Pousette A. Endogenous anabolic and catabolic steroid hormones in male and female athletes during off season. Int J Sports Med. 1990 Apr;11(2):103-6.
(3) Kraemer WJ, Ratamess NA. Hormonal responses and adaptations to resistance exercise and training. Sports Med. 2005;35(4):339-61.
(4)Saad F, Haider A, Doros G, Traish A. Long-term treatment of hypogonadal men with testosterone produces substantial and sustainedweight loss. Obesity (Silver Spring). 2013 Oct;21(10):1975-81.
(5)Elham Akhtari, Firoozeh Raisi, Mansoor Keshavarz, Hamed Hosseini, Farnaz Sohrabvand, Soodabeh Bioos,Mohammad Kamalinejad, Ali Ghobadi. Tribulus terrestris for treatment of sexual dysfunction in women: randomized double-blind placebo - controlled study. Daru. 2014; 22(1): 40.
(6)Li C, Li Q, Mei Q, Lu T. Pharmacological effects and pharmacokinetic properties of icariin, the major bioactive component in Herba Epimedii. Life Sci. 2015 Apr 1;126:57-68.
(7) Shawn M Talbott, Julie A Talbott, Annie George, Mike Pugh. Effect of Tongkat Ali on stress hormones and psychological mood state in moderately stressed subjects. J Int Soc Sports Nutr. 2013; 10: 28.