Yin Deficiency in TCM: signs and meaning

Yin and yang in short

In TCM, yin stands for what is cool, moist, quiet and restful, like night. Yang stands for what is warm, dry, active and moving, like day. Each depends on the other, and in a balanced state they keep each other in check.

When yin runs low, yang is not too strong in itself, but it is no longer held back. The tradition calls the warmth that results empty heat [虚热], to set it apart from the full heat of a pattern where heat itself is in excess.

Signs TCM associates with Yin Deficiency

No one shows every sign, and each of them can have other explanations. TCM looks at how they fit together:

• Feeling warm or flushed in the afternoon or evening
• Warm palms and soles, together with a restless feeling in the chest, which the tradition calls five-centre heat [五心烦热]
• Sweating at night
• A dry mouth and throat, often worse at night, and thirst for small sips
• Light or restless sleep
• Dry skin, dry eyes or dry stools

On the tongue and in the pulse

The classic tongue is red, often on the thin side, with little or no coating, and sometimes with fine cracks. The pulse is described as thin and rapid. You can read more about what each of these means in our guide to tongue diagnosis.

Which organ it is tied to

Practitioners usually name the organ system where the shortage shows most. The organ changes which signs stand out:

• Kidney Yin Deficiency [肾阴虚]. Seen in TCM as the root of yin in the whole body, linked with a sore lower back, ringing in the ears and night sweats.
• Lung Yin Deficiency [肺阴虚]. Linked with a dry cough with little phlegm and a dry throat.
• Liver Yin Deficiency [肝阴虚]. Linked with dry eyes, dizziness and numbness in the limbs.
• Heart Yin Deficiency [心阴虚]. Linked with restless sleep, palpitations and a feeling of unease.
• Stomach Yin Deficiency [胃阴虚]. Linked with thirst, a dry mouth and a tongue with a peeled coating.

A pattern or a constitution

TCM separates a pattern that shows right now from a constitution, which is the body's long term tendency. A Yin Deficiency Constitution [阴虚质] describes someone who leans towards this picture for years, often slim, warm and dry by nature. A pattern can come and go, while a constitution changes slowly.

How TCM thinking explains it

Classical TCM thinking describes yin as something that is used up by long periods of overwork, working late, too little sleep and lasting stress. Long illness, ageing, and a lot of hot, spicy food or alcohol are named as well.

Yin Deficiency in TCM dietetics

TCM sorts foods by their nature, from cold through neutral to hot. For this pattern the tradition favours foods it classes as cooling and moistening, such as pear, cucumber, mung beans, tofu, black sesame and soups. It is cautious with foods it classes as hot and drying, such as chilli, lamb, alcohol and coffee.

Yin Deficiency and Yang Deficiency

The two are often confused, because both are a shortage. Yin Deficiency leans towards warmth and dryness: feeling warm, night sweats, a red tongue with little coating. Yang Deficiency [阳虚] leans towards cold: cold hands and feet, a wish for warm drinks, and a pale, swollen, moist tongue.

A traditional reading, not a diagnosis

Yin Deficiency is a name from a traditional framework for describing what is observed. It is not a medical diagnosis. Night sweats, a fever that keeps coming back or weight loss you cannot explain should always be checked by your doctor.