Testosterone levels in women will change as they age and grow naturally, whether it be during the menstrual cycle, or during different periods of the day and so on. However, there are women who are naturally low on this sex hormone, and thus experience negative side effects to their quality of life directly due to this deficiency.
Having low testosterone levels actually will affect fertility, sex drive, energy levels, red blood cell synthesis, muscle mass and distribution of fat around your body.
While many believe that testosterone is purely a male only sex hormone, that is a misconception. Women have it too but of course, in smaller amounts to men and just enough to regulate adrenal glands, alongside the ovaries. 
What is testosterone in women?
Testosterone is a hormone needed for both men and women’s health. Within the male testicles, that is where testosterone is made. However, in women, it is primarily made within the ovaries, yet secreted in far smaller amounts overall, from the moment of puberty, until around the age of 30, where the levels dip slowly naturally. Menopause in women, obviously depletes any existing small amount further than ever before, making this one of the reasons as to why women are more prone to osteoporosis in older age, as this hormone is key for bone formation and maintenance around the body. 
What is testosterone’s key functions in women?
Women’s health needs testosterone too, that’s a fact. Of course, as with anything else in the world, if you have too much or too little of anything, it can lead to negative effects later on within life. According to the Journal of Clinical Endocrinology, this hormone is key for the neuroprotective function in women i.e. cognitive function.  In fact, due to menopause and the lessened testosterone production, this correlates to a higher chance of getting Alzheimer’s disease, as both estrogen and testosterone are imperative for brain function and the prevention of a larger development of Alzheimer’s plaques. Women in fact have a greater risk than men, to develop the disease (2 times more likely) and this is primarily linked to the lower testosterone in women, and how the biological damage to the brain begins more earlier and at a 30% increased rate more in women than men. 
The maintenance of the natural sex drive and general sexual desire depletes with age very normally, down to hormone regulation. While testosterone levels are primarily associated with males and their reproductive systems, women actually rely on this too, on the course of their fertility. This hormone is key to spur on our sexual desires as mammals, in addition to giving the energy levels a little boost to actually do the deed too! This idea has been relatively new to the world of science, after having been introduced by the research centre of the University of California. 
What are the normal testosterone levels in women?
The normal levels of testosterone in women will peak between the ages of 18-19, and ultimately begin to dip between the ages of 45 and 55, post menopause. At the heights of the female reproductive system, women who have normal levels of testosterone in their body will find that it can range from 15 and 70 ng/dL.
What are the causes of testosterone deficiency in the body?
The causes of low testosterone within the body is primarily due to function issues within the ovaries, adrenal glands and peripheral tissues.  The ovaries produce a majority of the testosterone within the body of a woman. Naturally the non-existence/decrease in these hormones due to pre-puberty and post menopause are normal, however there are some women that almost stop producing testosterone altogether both pre-puberty and post menopause. Meaning, they likely have a genetic malfunction within their body, that affects the precursor synthesis of testosterone and the enzymes needed to process and regulate the precursor compounds. 
Other factors for low testosterone levels within women include adrenal insufficiency and their inability to produce adequate amounts of the anabolic steroid testosterone. The adrenal glands are the secondary source towards supplying this vital female and male hormone. 
Hypopituitarism is another big factor to the causes and symptoms of low testosterone in women. Located in the brain, the pituitary gland is responsible for the release of multiple hormones including testosterone. This gland is key for metabolism as a whole, in addition to the menstrual cycle and fertility in women (regarding stimulation of the FSH and LH hormones for the ovaries). It is understandable, that should this gland be under-active, it can create havoc and imbalance within the female body. 
What are the symptoms and signs of low testosterone in women?
Sex drive – The key symptoms of low testosterone levels, as credited by many medical institutions is first and foremost, a low libido and sexual desire. Having low libido in the periods of high fertility within a woman’s lifetime i.e. 20-35, should be a key indicator and a symptom to be sought out for further opinions from a doctor and ultimately diagnosis.
Sexual desire disorder is more prevalently noticed in men, due to physical indicators in male anatomy. Female diagnosis is a little bit more difficult and requires a blood test to review regulations in women’s health.  This ties into infertility pretty well too as of course, testosterone production is a reflection for fertility in regard to the ovary and secretion of other fertility sex hormones such as LH and FSH. If there is a concern for low testosterone, there is a high chance other sexual hormones will be affected too.
Period irregularities – The absence of your period, and its irregular appearance, is another key factor in regard to testosterone insufficiency. Periods will fluctuate depending on the health and lifestyle changes that a woman goes through, yet a blood test can actually diagnose if a woman’s period changes/absence is directly due to missing sex hormones she needs. 
Mood and wellness – Other ways of noticing a possible issue to your testosterone levels, is through a woman’s general mood and wellbeing. Depression and mental health impacts are common to those that have testosterone problems, for if your hormones are not regulating as they should, the body will be out of sync. Everything from your sleeping schedule, to muscle soreness, skin irregularities, weight gain and lethargy can make women spiral into a place of depression and decreased satisfaction with themselves. Such lifestyle changes are not experiences that occur all at once, which is why it can sometimes be misdiagnosed often at first. 
What causes an elevated testosterone level?
On the other hand, there are cases where things can be quite the opposite and women will have an elevated testosterone, which can affect the physical appearance/ attributes of women. Just as low testosterone can be diagnosed by a doctor, so can elevated testosterone. Symptoms of high testosterone in women include, balding or excess body hair, deepening of the voice, an enlarged clitoris, increased muscle composition and a decreased breast size.  The causes of such changes are summarised below.
Hirsutism – Hirsutism is when women have a high growth rate of unwanted hair within particular regions of the body such as the face, chest and back. This is primarily caused when a woman has an imbalance of the androgen hormone levels. In addition, this often runs genetically, meaning usually it is mirrored within siblings and paternal linkage. 
Polycystic Ovary Syndrome – Again, this is another hormonal irregularity that is caused by a surplus of androgen hormones within the body. Women who have PCOS will suffer from periods that are prolonged or too short, alongside the signs of hirsutism too. Polycystic ovaries can be categorised by enlarged ovaries too, which can cause multiple complications when it comes to the topic of fertility, such as unwanted miscarriages, diabetes, obesity, breast cancer and cancer of the womb. 
What are the remedies and treatments for low testosterone hormone levels?
Women should consider testosterone treatment when they suffer from the symptoms and disorders listed above, particularly with period irregularities and physical changes such as increased growing facial hair etc. A doctor will always begin with a physical exam that involves blood work and internal scanning of the uterus. From there, if the female patient has the quantitative proof for the need of testosterone replacement in the body, treatment is often decided upon.
Treatment will often entail estrogen therapy in the form of replacement drugs. Yet there sometimes can be issues with dosage and malabsorption, meaning women would not get the full effect of their dosage. However, this problem is subjective from woman to woman. Other solutions include testosterone injections, via a series of testosterone therapy sessions with a doctor. 
Some testosterone health specialists also recommend the use of a topical gel or patch applications, however this is categorised by health systems such as the NHS, as testosterone products associated with testosterone therapy. With testosterone therapy, it can improve the dysfunction of hormonal regulation within women, yet before integrating the testosterone replacement, women will need to make sure that their estrogen levels are sufficient beforehand. Therefore, estrogen therapy is usually the go-to at the beginning. 
Does testosterone make females gain weight?
Testosterone levels that are lower than the expected in women (below 15 ng/dL) will lead to weight gain , as it is an imperative hormone in the regulation of metabolism, muscle retention and minimisation of fat storage within the body. When testosterone levels are low, and there is an adrenal insufficiency, women will also have an increased water retention mass, alongside high levels of cortisol due to the stress occurring within the body. This can cause havoc to the other key hormones responsible for fertility, such as progesterone and estrogen.  Progesterone is a precursor, like testosterone for the adrenal hormones, meaning it can be lowered for its efficacy if testosterone is not to the sufficient levels needed. This can then ultimately lead to estrogen becoming the dominant hormone, which can lead to an increased weight gain via insulin resistance metabolic stress. 
Natural remedies to increase testosterone levels
Natural remedies to boost testosterone within the body have been actively sought across the world due to the aggressive side effects that wish to be avoided in testosterone replacement therapy strategies. Herbs like Malaysian Ginseng, Ashwagandha and pine bark extract have been clinically proven to enhance androgen hormones that can help men overcome the hormonal issues that come with lower testosterone.  Unfortunately, studies in women are still yet to be explored to clarify the differentiation of remedies between the sexes, nevertheless researchers are hopeful to progress these findings forward to get the full approval from boards such as the FDA. 
Is it safe for females to take testosterone?
When women begin testosterone treatment, there is the chance of associated side effects which can cause discomfort and mood changes. The most common side effects of testosterone therapy include acne, breast enlargement and tenderness, a surplus of red blood cells, and swelling of the genitals. This is why doctors always have preferences for natural interventions like sex therapy, lifestyle changes such as sleep management, intuitive diet changes, and DHEA supplements that can be bought over the counter. 
Doctors in the NHS will always prefer to seek alternative products to therapy and injections for females, as currently many FDA approvals are only available for men and many clinics have managed to side step this issue by personalising the therapy towards women at a lower dosage.
Usually to ensure that testosterone replacement is done so correctly, women will be put on a course for a 6 months basis, to monitor changes over the progressive period of time. Should the testosterone products not be effective, alternative options should be explored.
Women should not take any androgens or direct testosterone therapies, when they are pregnant or breastfeeding, as the medications can be passed on to cause harm to the child. Therefore, whenever females wish to take testosterone as treatment, they must ensure to seek advice for medical information from a specialist. Tests are imperative to prove that testosterone is required, as well as a safety measure to avoid any compromise of medications that are being taken by the female, alongside seeking treatment. 
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