Muscle tension from Acetylcholine

Muscle tension can be described as the experience of extended partial contractions or over-shortening of muscles throughout the body, producing persistent stiffness, tightness, and low-level aching. Unlike the voluntary contraction of muscles during physical exertion, this tension occurs involuntarily and can be difficult or impossible to consciously release. It most commonly affects the jaw, neck, shoulders, back, and legs, though it can manifest in virtually any muscle group.

At lower intensities, muscle tension may present as a mild tightness or stiffness in certain areas of the body that is noticeable but not particularly distressing. The individual might find themselves unconsciously clenching their jaw, hunching their shoulders, or experiencing a subtle feeling of rigidity in their limbs. These sensations can often be temporarily relieved through stretching, massage, or changes in position, though they tend to return shortly after.

At higher intensities, the tension can become genuinely uncomfortable or even painful. Muscles may feel as though they are locked in a state of sustained contraction, producing persistent aching, cramping, and soreness. The jaw clenching associated with this effect, known as bruxism, can be particularly pronounced and may lead to tooth grinding and jaw soreness. In severe cases, the tension may be accompanied by muscle spasms or twitching, and the discomfort can significantly detract from an otherwise positive experience.

This effect is most commonly induced under the influence of moderate to heavy dosages of stimulating psychedelic compounds such as LSD, 2C-E, DOC, and AMT. It is also frequently associated with stimulant compounds like MDMA and amphetamines, particularly at higher dosages. Some GABAergic depressants such as GHB and phenibut can paradoxically produce muscle tension as well, particularly during the offset or withdrawal phase.

Muscle tension is often accompanied by other coinciding effects such as stimulation, teeth grinding, restless legs, and vasoconstriction. Magnesium supplementation is widely reported by users to help mitigate this effect, though its efficacy varies between individuals. Staying hydrated, stretching, and applying warm compresses to affected areas are also commonly cited harm reduction practices for managing substance-induced muscle tension.