Spermidine

Spermidine or spermidin or C7H19N3 is a natural component of our cells that is found in sperm, different fruits and vegetables, meat, and cheese. Spermidine is essential for healthy metabolism in humans. Two-thirds of the spermidine levels in humans are maintained through eating a healthy, balanced diet combined with certain bacteria in the digestive tract, the remaining third of the spermidine is produced by the body's own cells.

Spermidine is a polyamine found in almost all tissues in association with nucleic acids and is thought to help stabilize some membranes and nucleic acid structures. It is a precursor of spermine.

Theory
A balanced diet can help maintain high levels of spermidine, but spermidine of also sold as a dietary supplement.

Hair loss
Spermidine has been tested for a number of different uses, and there is evidence that it is effective for hair loss (alopecia), although almost all these studies have been co-authored by and funded by spermidine supplement producers.

Endothelial function improvements
Matsumoto et al. 2019 conducted a double-blinded placebo-controlled study of a yogurt containing Bifidobacterium animalis subsp. lactis (Bifal) and the amino acid arginine, concluding that this increased the production of putrescine, a spermidine precursor, which increased spermidine levels, resulting in improved a marker of endothelial function in healthy adults after 12 weeks. The Wirth-Scheibenbogen hypothesis of ME/CFS states that endothelial dysfunction is the cause of the symptoms of ME/CFS. Matsumoto's study also suggested that the yogurt is likely to prevent or reduce the risk of atherosclerosis, and found no self-reported changes in mental or physical health, and that the yogurt did not affect weight or vital signs, did not cause safety issues, and did not have a negative effect on blood parameters.

Animal experiments
Experiments on animals (rodents) provide evidence that higher polyamine intake inhibits the emergence of tumors (including cancer) in rodents, promote the growth of existing, and that spermidine has similar effects to caloric restriction - including causing increased anticancer immune-surveillance in mice (when spermidine or other polyamines are increased in the diet) - increasing life span and autophagy in worms, flies, yeast, and mice.

Cognitive dysfunction
Spermidine has shown promise for improving cognitive impairment in older adults with cognitive decline and in patients with dementia.

There are no clinical trials of spermidine published for ME/CFS, fibromyalgia or Long COVID so effectiveness, safety and side effects in these patients are unknown.

Risks and safety
A very large trial found an increased risk of stroke in healthy people taking spermidine supplement.

Costs and availability
Spermidine is expensive compared to other nutritional supplements.

Learn more

 * Spermidine - DrugBank
 * Spermidine, the new 'wonder supplement'? SADLY NOT! - Edzard Ernst, MD