Causes of Hair Loss in Women – Part 1: Low Metabolism

Behind every healthy head of hair is healthy, functional metabolism.

Although our metabolic rate is somewhat “pre-programmed” by our genes, we can help boost it via our diet and lifestyle.

Many people suppress their metabolism through dieting, being overly stressed, working out too hard without replenishing calories, or not moving enough.

We’ll talk about that more, but first, let’s talk about what metabolism means.

It is the process by which your cells create energy for every single aspect of your life.

High-functioning metabolism means that your cells use oxygen efficiently, and turn the calories you eat into readily usable energy with which your whole body can build, heat, and repair itself.

It refers to all of the chemical reactions going on in your body, down to the cellular level. These reactions are put in motion by enzymes, and help you to grow, interact with your environment, and build, repair, and maintain your body (including your hair, skin, and nails).

A fully functional metabolism means there is excellent circulation to all parts of the body. It means that the enzymes that control hormone production, hair growth, digestion, and other important functions can work their best. And it means a healthy immune system.

Symptoms of Low Metabolism

Lowered metabolism means less heat and energy being created in the cells, resulting in a lower core body temperature and low heart beat (two of the best diagnostics for low metabolism), and poor circulation. When your core temperature is too low, the enzymes responsible for making hormones, and moving your digestive system won’t function as well.

Some symptoms of impaired metabolism are chronic constipation, lack of energy, low sex drive, infertility, high cholesterol, heart disease, getting up to pee at night, and trouble sleeping, and even cancer.[1]

Here is a great graphic that also illustrates how a person might find her or himself with low metabolism:

Many people who have low metabolism look and feel older than they are. Because when your cells aren’t getting the energy necessary to keep you warm and energized and well-circulated, you lose many “youthful” characteristics that signify bounteous good health.

A compromised metabolism means that your body must struggle to use every last calorie and nutrient in your body just to keep you alive and breathing. So there’s not a lot left to spare for growing your hair, skin, and nails.

Metabolism and Hormonal Balance

When metabolism is functional, your body is warm with plenty of energy to perform the essential functions of life, as well as the non-essential-yet-enjoyable ones. You have abundant energy to create reproductive hormones that make you ovulate.

Our bodies are stingy with their energy reserves during a time of starvation and stress. It would make sense that in a low metabolic state, energy is allocated away from reproduction and growth, in favor of self-preservation.

Even if you don’t want to get pregnant, or you have passed through menopause, hormonal balance is important for well-being. Healthy metabolism helps prevent against diabetes, hypothyroidism and obesity, and therefore it helps prevent against estrogen dominance and imbalances of the stress hormones that sap your energy for living.

Low Metabolism and Hypothyroidism

A low metabolism leads to hypothyroidism and hypothyroid symptoms. This can be because low metabolic rate leads to low body temperature – which has a direct effect on the enzymes that help thyroid hormones convert to their active form.

Since low metabolic rate affects our ovulation which leads to not enough progesterone to balance out estrogen, estrogen dominance can become a problem in the case of low metabolism. Excess estrogen can prevent thyroid from converting to its active form in the liver. Thus, a low metabolism can lead to sub-clinical hypothyroidism.

Symptoms of low metabolism and hypothyroidism can be very similar, because they are closely related. If you believe you are hypothyroid, you may consider trying to raise your metabolic rate as the first step to improving your thyroid function.

Once we feed ourselves with nutritious foods, get plenty of healthy movement, bask in warm healthy relationships, reduce our stress levels, get out in the sun, and seek joy in our daily lives, metabolism returns and our bodies should begin to heal.

When our metabolism returns, our body is at the right temperature for enzymes to convert thyroid hormones in all of our tissues. Thyroid symptoms start to disappear. We may find we need less medication as our health problems start fading. As male hormones and stress hormones level off, hair grows back where it should on the scalp and eyebrows, and our face and body become less hairy. And when thyroid rises alongside a healthy metabolism, we get our energy and our lives back.

To read more about thyroid problems and how they affect your hair, see Part 2 on Thyroid Hair Loss

Metabolism, Inflammation, and Immunity

When we have a low metabolic rate, everything about us seems to be slow and sluggish – except for the aging process, which seems to speed up.

Constipation is a common problem of low metabolism, because the chemical processes responsible for digestion and transit time are slowed. In the case of constipation, the bacteria that would normally be eliminated from the digestive tract build up. These bacteria can sometimes escape from the bowel out into the body, wreaking havoc and increasing inflammation.

Metabolism has a very important connection to our immune system, the study of which is called immunometabolism. A healthy metabolism is important for a healthy immune system, protecting against autoimmunity as it regulates the homeostasis of immune cells.[2]

Much of our immune system is based in our digestive tract, so a high metabolism, which keeps digestion moving, helps keep any autoimmunity at bay. We are more likely to get sick, remain chronically ill, and be prone to infections when our metabolism is low.

Overgrowth of yeasts such as Candida albicans and Malassezia globosa, which cause dandruff and folliculitis on the scalp, happen less when we have higher metabolism.

Pathogens that lead to chronic disease and inflammation cannot thrive in a person with a high metabolic rate because high body temperature and good circulation prevent those organisms from thriving and overpopulating.

(Crash Diets + Exercise) x Stress = Low Metabolism

Crash diets, excessive exercise, and stress are major causes of low metabolism. For many women, diets seem to be the primary culprit to low metabolic rate.

For many of us who have dieted into adulthood, after the protective qualities of youth are diminished, the stress of calorie restriction and over-exercising create chronic energy deficits. If stress of any kind is already present, metabolism can decrease even faster.

As a result, our body adapts to that energy deficit and stress state by decreasing the metabolic rate further. This shuts down our ability to burn calories, and our pretty much abandons all non-essential functions (i.e., hair growth) in favor of the more essential functions. This is all in a deeply ingrained effort to ensure our survival during times of famine.

Starvation, fasting, and exercising for hours on end all stress a woman’s body. In his book, Diet Recovery 2, Matt Stone speaks about how endurance exercise causes adaptive changes such as a drop in metabolic rate and body temperature, lean muscle and bone wasting, and shrinking internal organs. This is basically so a person can keeping going longer on fewer calories. The body also drops production of progesterone and increases production of cortisol.

You don’t have to be lean in order to have a low metabolism though. Some women (including myself and others I know) have done the same metabolism-ruining things like stressing and massive dieting, but never lost much of the weight. And the little they do lose comes back with a vengeance, causing more stress, and more hair shedding.

If you believe low metabolism is part of the puzzle in your hair loss problem (it likely is), there are two easy ways to tell.

Your temperature: should be over 98 degrees F in the morning after you first wake up.
Your pulse rate: Should be at least 70 beats per minute at rest.

These standards are based on the work of physician Broda Barnes. If the above are not true for you, you may have a low metabolism.

If you think your low metabolism is due to over-dieting and stress, just remember that your body needs calories from protein to build hair and other tissue. You need natural saturated fats to make important hormones, and you need carbohydrates to create energy to support your body’s important processes.

The hormones and nutrients that help hair grow healthy are derived from proteins, fats, and carbohydrates.

If you don’t get enough of the right kinds of calories, your body thinks you’re starving and starts shutting down non-essential processes. Accessory functions, like hair growth, shut down as the result prolonged low-grade starvation. Body heat and energy aren’t made as efficiently.

Chris Kresser states, “Your body is genetically programmed to recognize low blood sugar as a threat to survival…when blood sugar levels drop below normal, your adrenal glands respond by secreting a hormone called cortisol..”[3]

Keeping blood sugar from falling too low (also from spiking too high with too much food) is a key to preventing a stressful famine state.

Chronically low blood sugar not only increases adrenal activity, it also taxes our liver, reducing its efficiency. Our liver can both store glucose and make it, according to the body’s needs. When you eat, your unused glucose will be stored in the liver as glycogen. And when you are fasting (between meals or during sleep), the liver turns that glycogen back into glucose by a process called glycogenolysis.

If glycogen stores are depleted from the liver in the case of chronic fasting or hypoglycemia, the liver will manufacture glucose from amino acids, fat byproducts, and waste in a process called gluconeogenesis.[4] This process requires the liver to work harder, leaving it less able to do its duty of clearing out excess estrogen, and converting the thyroid hormone T4 to its bio-active form, T3.

Protein, along with carbohydrate is of prime importance to healthy liver function, giving the enzymes in the liver the strength they need to convert thyroid hormones.[5] There is a correlation with malnutrition and advanced liver disease, as starvation causes poor liver function. And an impaired liver won’t process your food correctly, leaving you even more malnourished.[6]

It’s clear that the body does not like to be malnourished. And hair growth is one of the first things to go when a person is starved for calories or nutrients. If you have a history of heavy dieting, consider that as a possible cause of your hair loss.

Vitamin/Mineral Deficiency

Our bodies need a variety of micronutrients, which support the function of enzymes involved in metabolism. If we eat a healthy variety and amount of nutrient-dense foods, we can meet our micronutrient needs. But when we fill our diet with “empty” unnatural foods, deficiencies of trace elements and essential minerals can add up, and have a negative impact on metabolism and hair growth.

It is rare for a single nutrient deficiency to be so great that it is the sole cause of your hair loss, but denying minerals from our diet for too long will gradually affect the organs and glands that promote hair growth.

If you are supplementing with vitamins and minerals, it’s important to remember that “excessive intakes of nutritional supplements may actually cause hair loss and are not recommended in the absence of a proven deficiency.”[7]

Vitamin deficiencies are best handled by eating a diet rich in healthy foods, potentially with some added supplementation.


A high metabolic rate results from eating well with good nutrition, being well rested, and un-stressed.

This is very different from the high metabolic state found in healthy metabolism. When you are receiving abundant energy, you have enough to repair your body, grow luscious hair, and produce more energy to fuel you on every endeavor in life.


1. Diet Recovery 02. Matt Stone February 2013
2. The Crucial Connection Between Metabolism and the Immune System. Posted on May 7, 2013 by Greg Cherryholmes in Immunology with 0 Comments
3. Thyroid, Blood Sugar, and Metabolic Syndrome by Chris Kresser

Thyroid, Blood Sugar, and Metabolic Syndrome

5. An Interview With Dr. Raymond Peat A Renowned Nutritional Counselor Offers His Thoughts About Thyroid Disease by Mary Shomon
6. Prevalence and Mechanisms of Malnutrition in Patients With Advanced Liver Disease, and Nutrition Management Strategies Kally Cheung Samuel S. Lee Maitreyi Raman
7. Nutritional factors and hair loss D. H. Rushton Article first published online: 20 AUG 2002 DOI: 10.1046/j.1365-2230.2002.01076.x from: Clinical and Experimental Dermatology Volume 27, Issue 5, pages 396–404, July 2002

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