Understanding how HTMA works


Inside a hair root (hair follicle), there are lots of different structures. These include:

  • Capillaries (the smallest type of blood vessels)

  • Nerve fibres

  • Lymphatic channels (for drainage of tissue fluids)

  • Connective tissues (fibrocytes & fibroblasts) that lay down the collagen / elastin matrix which supports the other tissues.

In our discussion here, the capillaries are of vital importance, because not only do they provide vital oxygen & nutrients to the hair root, but additionally they are the site of transfer of minerals & heavy metals into the growing root tip.   



In the diagram above, we see that various minerals and other molecules are floating around in the bloodstream. By filtration pressure, they pass through small holes in the capillaries called fenestrations (or little windows) into the adjacent extracellular / interstitial fluids. From there, they traverse the basement membrane of the dermal papilla and pass through the germinal matrix epithelium into adjacent hair root matrix cells. From there, as these cells mature, they become cortical hair cells, whose main job is to manufacture the keratin strands that compose ~ 90% of hair tissue. Within these strands, the minerals and metals become bonded to the keratin and thus remain locked into position for the life of that individual hair. That's why hair is such an excellent material for mineral & heavy metal analysis. 


A similar process occurs in fingernails & toenails, albeit that the quantities of minerals tend to differ as compared with hair tissue.


HTMA Ca, Mg, Na, K & Rb levels derive from the  exchange (flux) of mineral elements across the germinal matrix epithelium, and their subsequent passage across to adjacent hair matrix cells. Therefore, they don’t necessarily represent serum or cellular tissue levels, e.g. in bone or muscle tissue. HTMA iron levels do NOT necessarily reflect serum ferritin, but rather are the product of both % transferrin saturation and the density of transferrin receptors on the germinal matrix epithelium. Most other HTMA mineral levels seem to reflect tissue levels.

By contrast, heavy metal levels may or may not necessarily reflect levels in other tissues. (e.g. bone cadmium & lead). High cobalt levels may either reflect industrial exposure, low selenium levels or excessive Vit. B12 ingestion / supplementation. High boron levels usually reflect a high intake of fresh fruit, dried fruits, nuts & vegetables whilst low lithium levels are a commonly overlooked cause of anxiety and depression. Australian soils are typically low in iodine, selenium & lithium and high in sodium & boron.


Basic Principles of HTMA Analysis


Trace Elements Inc. classify all HTMA samples into one of 8 groups, namely Fast 1-4 and Slow 1-4.


Fast – Sympathetic dominant or Yang types

Slow – Parasympathetic dominant or Yin types


Roughly one third of Australians below age of 70 are fast metabolizers.


Most children and men < 60 years  are Fast 1,  whereas most adult women are Slow 1.


Ø Fast metabolizers have a Ca / P ratio less than or equal to 2.63.


Ø Slow metabolizers have a Ca / P ratio greater / equal to 2.64.


The 1 – 4 sub-classifications are based on both the Ca / K and Na / Mg ratios for any given individual.


Note:  Metabolic types can change over time. Biological changes that occur with changing dietary patterns, with pregnancy, with ageing and even life stresses all influence one's HTMA classification by altering key nutrient ratios (see below).

















As you can see from the chart, the Calcium / Potassium (Ca/K) ratio, representing Thyroid activity and the Sodium / Magnesium (Na/Mg) ratio representing Adrenocortical gland activity define the subtypes in each of the two main (Fast / Slow) categories. Note that the lower the Calcium / Potassium (Ca/K) ratio, the faster the thyroid gland will be working. This would normally be reflected in a lower TSH and higher fT3 & fT4 levels, thereby translating into higher cellular metabolic activity and tissue oxygen consumption.


The converse applies with Adrenal activity. Here we see that an increased Sodium / Magnesium (Na/Mg) ratio translates to higher blood pressure, increased Cortisol and Aldosterone production, together with sodium retention by the kidneys. These factors increase the flux of sodium across the germinal basement epithelium, leading to higher hair tissue sodium levels, usually at the expense of magnesium. By comparing these elements in hair with those excreted in a 24hr urine collection, we can gain real insight as to how the body is handling these essential nutrients.