Proponents and practitioners of various esoteric forms of spirituality and alternative medicine refer to a variety of claimed experiences and phenomena as being due to an energy or force that defies measurement or experimentation, and thus are distinct from uses of the term energy in science.

Claims related to energy therapies are most often anecdotal, rather than being based on repeatable empirical evidence, thus not following the scientific method.

There is no scientific evidence for the existence of such energy, and physics educators criticize the use of the term energy to describe ideas in esotericism and spirituality as unavoidably confusing.

The concept of esoteric energy has appeared in various cultures and spiritual traditions throughout history. Although interpretations differ, many traditions describe it as a vital force that animates living beings and permeates the cosmos. These ideas often overlap with religious, medical, and mystical frameworks, influencing practices ranging from healing to spiritual enlightenment.

In ancient civilizations, esoteric energy was frequently associated with breath, spirit, or divine power. The ancient Egyptians referred to ka, a vital essence that sustained life and represented a person’s spiritual double. In ancient Greece, the Stoics developed the concept of pneuma, a universal breath that pervades all existence, while Aristotle and Plato explored the idea of a world soul, or anima mundi, as the unifying force of nature. The Romans adopted similar notions through the term spiritus, which referred to both breath and an animating principle.

Many indigenous and shamanic traditions also describe energy in ways that influence their spiritual and healing practices. Native American belief systems frequently refer to a medicine energy that connects all living things, often associated with the guidance of spirit beings. Among the Yoruba, aṣẹ is regarded as a divine force that animates life and can be channeled through ritual and invocation. Similarly, in Polynesian traditions, mana is seen as a powerful spiritual energy that exists in people, objects, and the natural world.

Eastern traditions developed complex theories of energy as a subtle force flowing through the human body and the universe. In Taoist philosophy and Traditional Chinese Medicine, qi (气) was understood as a dynamic energy circulating through the body's meridians, influencing health and vitality. Eastern philosophy also includes the notion of "negative qi", typically understood as introducing negative moods like outright fear or more moderate expressions like social anxiety or awkwardness. Deflecting this negative qi through geomancy is a goal of feng shui.

The concept of qi also appears in the art of feng shui and Chinese martial arts. Practices such as acupuncture, tai chi, and qi gong were developed to regulate and cultivate this energy. The traditional explanation of acupuncture states that it works by manipulating the circulation of qi through a network of meridians. In tai chi, the ancient Chinese martial art, participants aim to concentrate and balance the body's qi, providing benefits to mental and physical health.