The mystery of the human body is vast and profound. Traditional Chinese medicine (TCM) believes that as finger and toenails are connected to the viscera through the meridians, monitoring their condition can help to interpret health signals of the body, and provide an early response to and relief of physical illnesses. 

Jonathan Liu, a TCM practitioner and a professor of traditional Chinese medicine at Georgian College, Canada, explained the secrets behind nail observation in the “Health 1+1” program.

In TCM, it’s believed that nails are the extension of sinews, and are the part of the sinews that extend furthest to the outside. Sinews in Chinese medicine include fascia, ligaments, muscles, and tendons and are governed by the liver. 

Therefore, the condition of the sinews can reflect the physiological function of the liver, and vice versa—problems with the liver system are often manifested in the nails.

The junction of the 12 meridians of the human body also convenes at the fingertips and the toes. For example, the big toe is the junction of the spleen, stomach, and liver meridians, and the thumb is where the lung and the large intestine meridians meet. 

Therefore, by examining the color, texture, and degree of cleavage of the nails, we can decipher, to a certain extent, the physical condition of the body as a whole.

Long ago TCM discovered that the body has a “meridian” system, with 12 main meridians corresponding to the 12 viscera, which circulate further to the hands, feet, head, and face, transporting “qi” and “blood” to the whole body. 

Qi and blood are interdependent, flow throughout the whole body, nourish various tissues and organs, and maintain the vital activities of the body. When there is a problem with one of the viscera, all the acupuncture points on the corresponding meridian path will experience discomfort.

Nail Color

Liu said that normal nails should appear light red and shiny. If the nails have any of the following six unusual colors, it means that there are corresponding physical problems.

  1. Pale
    Paleness more likely occurs in patients with a deficiency of qi and blood, or with anemia.
  2. Red
    Red reflects excessive red blood cells, manifested as headache, dizziness, or suffering from high blood pressure, and heart disease.
  3. Black
    The nails are hypoxic and may have poor localized small circulation, small artery blockage, or excessive fatigue and obesity.
  4. Yellow
    Yellow nails occur mostly in patients with liver and gallbladder diseases, such as jaundice, or are caused by cigarette tar.
  5. Blue
    Blue nails are a reflection of insufficient blood circulation and local blood stasis.
  6. Green
    Green nails reflect a pseudomonas aeruginosa infection, which is relatively rare.

Nail Texture

Liu pointed out that the seven patterns on the nails can also reveal the health status of the body.

  1. White spots
    White spots mean that the nails have suffered trauma, and the person suffers from allergies with zinc deficiency. In adults, it is a likely indication of liver disease, intestinal disease or diarrhea.
  2. Black lines and plaques
    Black lines indicate poor local blood circulation—a possible cause of kidney failure, which may result in the accumulation of toxins in the body, manifested as darkening of the skin or nails, especially in uremic patients. Black lines may indicate endocrine or menstrual disorders or severe menstrual cramps in women
  3. Beau’s line
    This means that the nails are sunken and have horizontal lines at the front, an indication that you may suffer from certain serious diseases, such as tumors, autoimmune diseases, and long-term chronic diseases. In addition, people facing severe stress, or severe zinc deficiency will also present as such.
  4. Horizontal stripes
    These are likely to occur in those who are overworked and stressed.
  5. Vertical stripes
    Those with chronic neurasthenia, staying up late, and suffering from insomnia will have more longitudinal nail lines, and may also present with chronic organ disease.
  6. Brittle nails
    The nails may be prone to breakage due to chronic iron deficiency, thyroid problems, or impaired kidney function, as well as poor blood circulation that prevents the blood from providing sufficient oxygen and nutrients to the nails.
  7. Broken nails
    Excessive drinking can cause liver damage, which can cause nails to break.

Nail Shape

Liu also said that in addition to the texture and color, observing the shape of the nails can reveal health issues.

  1. Eagle beak shape
    An indication of stasis in local blood circulation, manifested as stagnation of liver qi caused by stress, cardiovascular disease, or diabetes.
  2. Spoon-shaped (nail curled up)
    Sppon-shaped nails are mainly caused by insufficient yang qi, usually accompanied by insomnia.
  3. Nails too small
    Those who have small nails may have delayed development and it is considered blood deficiency in Chinese medicine.

Half-moon Marks on Nails

 Half-moon marks on the nails can also provide a glimpse into one’s health. Liu said that the half-moon mark on the nail is usually no more than one-third of the nail. If the half-moon mark is too small or too large, it indicates an unhealthy condition.

  1. The half-moon mark is too large (more than one-third of the nail)
    TCM believes that this is a deficiency of qi and blood, which may cause symptoms such as headache, dizziness, and high blood pressure; or a deficiency of kidney qi, which may cause inability to become pregnant in women, and infertility in men.
  2. The half-moon marks turned black or blue
    Normal half-moon marks should be white. If they turn black or blue, it may be a reflection of chronic pain, severe hyperlipidemia, arteriosclerosis, and similar conditions.
  3. No half-moon marks
    Liu said that eight out of the 10 nails of an average person should have half-moon marks, though it is normal for baby fingernails to have none. If all the nails do not have half-moon marks, the person is considered, in TCM, to have a cold body, which consumes a lot of Yang energy and is prone to serious illnesses.

Chinese medicine believes that people’s constitutions are different, and the two common constitutions are cold and hot. People with a cold constitution are more affected by wintry weather, more likely to have cold hands and feet, and their tongues are usually enlarged with a white coating People with a hot constitution are more affected by heat, prone to dry mouth, constipation, and red tongue. 

Moreover, Chinese medicine has discovered that all phenomena in nature have corresponding characteristics of “yin” and “yang.” For example, earth and sky, cold and heat. The two energies of yin and yang are interdependent. If yin and yang are balanced, people will be healthy and energetic, and things will be well coordinated and stable.

As for the reasons why some do not have half-moon marks on the nails, Liu shared his observations from his practice over the years and believes that it is mostly caused by modern-day lifestyle habits.

  1. Excessive desire
    Being too competitive at work and having too strong a sexual desire will likely harm the body and damage vitality.
  2. Eating too much cold food
    Cold food will transmit chilly air to the lower abdomen, which can cause symptoms such as stomach pain and menstrual cramps. TCM believes that food has different attributes of being cold, cool, or warm. Eating too much cold and cool food for a prolonged period can deplete the body’s yang qi causing loss of energy.
  3. Being easily excited
    When emotionally excited, energy and yang qi will be consumed.

As for ways to solve the problem of  “no half-moon marks,” Liu suggested one keep a peaceful and calm mind and try to avoid eating cold food. In addition, one can apply pressure and moxibustion on the Zusanli and Shenque acupoints.

Amber Yang worked as a marketing manager for natural skin care products for years and as a health and beauty reporter and editor for ten years. She is also the host and producer of the YouTube programs “Amber Running Green” and “Amber Health Interview.”

Harry McKenny

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