The information provided here is not a replacement for a doctor. You shouldn't use it for the purpose of self-diagnosing or self-medicating but rather so you can have a more informed discussion with a professional TCM practitioner.
Weak legs can be the consequence of several so-called “patterns of disharmony” in Chinese Medicine.
Chinese Medicine sees the body as a system, not a sum of isolated parts. A "pattern" is when the system's harmony is disrupted, leading to symptoms or signs that something is wrong (like weak legs here). It is similar to the concept of disease in Western Medicine but not quite: a Western disease can often be explained by several Chinese patterns and vice-versa.
A pattern often manifests itself in a combination of symptoms that, at first glance, do not seem necessarily related to each others. For instance here weak legs is often associated with lower back pain, cold and weak knees and feeling of cold in the pattern “Kidney and Spleen Yang Deficiency”.
Once identified, patterns are treated using medicinal herbs, acupuncture, and other therapies. In the case of weak legs we’ve identified that a herbal formula called Li Zhong Wan can help treat the patterns behind the symptom.
In Chinese Medicine weak legs is a symptom for the pattern "Kidney and Spleen Yang Deficiency". Below is a small explanation for it with links for more details.
The Kidneys is a so-called "Zang" Organ. Learn more about the Kidneys in Chinese Medicine
Pulse type(s): Deep (Chen), Weak (Ruo)
Kidney and Spleen Yang Deficiency is often treated with Li Zhong Wan, a herbal formula made of 4 herbs (including Dried Ginger - Gan Jiang - as a key herb). Li Zhong Wan belongs to the category of "formulas that warm the middle and dispel cold", which might be why it is often recommended for this pattern. Its main action as a formula is: "Warms the Middle Burner".
Source date: 220 AD
Number of ingredients: 4 herbs
Key actions: Warms the Middle Burner. Strengthens the Spleen and Stomach.
Because it is a formula often recommended to treat the pattern 'Kidney and Spleen Yang Deficiency' of which weak legs is a symptom.
Its main actions are: Warms the Spleen and expels Cold. Restores collapse of Yang and expels Interior Cold. Warms the Lungs and assists expectoration of Cold Phlegm. Stops chronic bleeding caused by Cold.
Because it is a herb specifically indicated to treat weak legs as can be seen on Areca Peel's page.
Its main actions are: Assists in the downward movement of Qi and relieves Food Stagnation. Removes Stagnation of Water by draining downward.
Because it is a herb specifically indicated to treat weak legs as can be seen on Evodia Fruit's page.
Its main actions are: Warms the Spleen, expels Cold, relieves pain and helps the Liver. Directs Rebellious Qi downward
Because it is a herb specifically indicated to treat weak legs as can be seen on Phellodendron Bark's page.
Its main actions are: Expels Damp-Heat in the Lower Burner. Clears Kidney Yin Deficient Heat. Applied externally or toxic Fire, especially associated with Dampness.