肌酸：不只是运动补剂（全面指南）

Creatine is a naturally occurring compound found in muscle tissue, where it serves as a rapid energy reserve. The body produces about 1-2g daily, and additional creatine comes from meat and fish. Supplementation increases muscle creatine stores by 20-40%:

• Energy production: Creatine donates a phosphate group to regenerate ATP (the cellular energy currency) during short, high-intensity activities. This is why it primarily enhances performance in activities lasting 5-30 seconds.
• Muscle growth: Beyond energy, creatine increases cell hydration (drawing water into muscle cells), which may stimulate protein synthesis and reduce protein breakdown. A 2022 meta-analysis in the Journal of the International Society of Sports Nutrition confirmed 1-2 kg increase in lean mass over 4-12 weeks.
• Brain function: The brain uses 20% of the body's energy and relies heavily on the creatine-phosphocreatine system. A 2018 study in Experimental Gerontology found creatine supplementation improved short-term memory and reasoning in older adults.

Creatine monohydrate is the gold standard — it is the form used in over 95% of clinical research. Other forms (creatine HCl, buffered creatine, creatine ethyl ester) are more expensive but have not demonstrated superior results. Check your creatine product's purity with WAYJET's Food Package Analyzer.

Creatine's benefits extend far beyond bodybuilders:

• Athletes and exercisers: Most direct benefit for strength training and high-intensity sports. Increases maximal strength by 5-10% and power output by 5-15%.
• Older adults: A 2021 meta-analysis in Medicine & Science in Sports & Exercise found creatine combined with resistance training improved lean mass and functional capacity in adults over 50 more than training alone. May help combat sarcopenia (age-related muscle loss).
• Vegetarians and vegans: Creatine is found almost exclusively in meat and fish. Vegetarians typically have 20-30% lower muscle creatine stores and may experience more pronounced benefits from supplementation, including cognitive improvements.
• People with depression: A 2020 study in the Journal of Affective Disorders found creatine augmentation improved antidepressant response in women with major depression.
• Traumatic brain injury: Preliminary research suggests creatine may be neuroprotective after TBI, though more studies are needed.

Women benefit equally from creatine supplementation for strength and body composition, despite common misconceptions. Creatine does not cause "bulkiness" in women — the 1-2 kg weight increase is primarily intracellular water, not fat.

The optimal creatine protocol is straightforward:

• Loading phase (optional): 20g daily (split into 4 doses of 5g) for 5-7 days. Saturates muscles fastest but may cause temporary GI discomfort and water retention.
• Maintenance dose: 3-5g daily, indefinitely. If skipping the loading phase, muscles reach full saturation in approximately 3-4 weeks.
• Timing: Any time of day is acceptable. Some evidence suggests post-workout may be slightly superior for muscle uptake, but the difference is minimal.
• With carbohydrates: Co-ingestion with carbohydrates (30-50g) or protein enhances creatine uptake into muscle via insulin-mediated transport.

Safety myths debunked:

• "Creatine damages kidneys": Multiple systematic reviews (including a 2018 review of 12 years of data) found no adverse effects on kidney function in healthy individuals. Those with pre-existing kidney disease should consult their doctor.
• "Creatine causes dehydration": Creatine actually increases total body water. A 2021 meta-analysis found no evidence of increased dehydration or cramping.
• "Creatine causes hair loss": Based on a single 2009 study showing increased DHT in rugby players. No subsequent studies have replicated this finding. The connection remains unproven.