Why creatine supplementation isn't unnatural but rather optimal

The human body synthesizes approximately 1 gram of creatine per day.An additional 1–2 grams may be obtained from dietary sources—primarily red meat and fish—provided intake is sufficient. However, the body appears to function optimally with a total daily intake of 3–5 grams, highlighting a substantial gap between typical intake and optimal levels.

One might wonder why the body does not simply produce more if higher levels are beneficial. The answer lies in a biological bottleneck: creatine is synthesized from the amino acids arginine, glycine, and methionine, and the synthesis process consumes around 40–50% of the body’s methylation capacity. This methylation is also required for essential processes such as the synthesis of dopamine, serotonin, melatonin, adrenaline, immune cell production, and DNA repair. As a result, even with abundant amino acid intake, endogenous creatine production is capped at around 1 gram per day.

Although supplemental creatine is sometimes considered "unnatural" or "excessive," this perception is not supported by the evidence.Research from the 1970s found that natural muscle creatine levels ranged from 102 to 146 mmol/kg. In the 1990s, supplementation studies demonstrated that creatine intake increased muscle levels to 140–160 mmol/kg, near the upper limit of the natural physiological range (PMID: 8828669). Muscles continue absorbing creatine until they reach the saturation point, suggesting that these higher levels are not only tolerable but preferential for cellular function.

Creatine’s primary role is to support the phosphocreatine system, which helps regenerate ATP—the body's energy currency—across all tissues. While 90–95% of creatine is stored in skeletal muscle, the remaining 5–10% is found in other tissues including the brain, retina, inner ear, digestive system, skin, and sperm cells. For example, sperm cells contain creatine concentrations similar to that of heart muscle, and supplementation has been linked to higher sperm counts and improved fertility outcomes (PMID: 35276945).

In athletic performance, creatine consistently shows 10–20% improvements in high-intensity exercise. And there is growing interest in its cognitive benefits. Studies indicate 5–15% improvements in memory and cognitive tasks, with enhanced clarity and recall. Notably, a single large dose of creatine (about 10 grams) has been shown to improve cognitive performance during sleep deprivation (source: Andrew Huberman and others).

Two common supplementation strategies exist:

Both approaches effectively saturate muscle stores over time. Regardless of method, the core insight remains: most individuals have suboptimal creatine levels, even with adequate dietary intake, due to built-in physiological limitations.

Creatine is inexpensive, well-studied, and remarkably safe for long-term use.It is one of the few supplements with consistent evidence supporting its benefits across muscular, neurological, reproductive, and cognitive domains.

Source: Paul Saladino newsletter