What Is Creatine?

What Is Creatine?

By: Krista Hoose

Even though at UFit we do not sell or recommend dietary supplements, our trainers are often asked about the purpose of certain supplements that are marketed toward athletes. Rather than our clients resort to Dr. Google for answers, we thought it was time to answer some of these questions based on what research is out there. As always, please consult your doctor or a medical professional prior to taking any dietary supplements, and please be aware that under law, dietary supplements are not required to have FDA approval. Their claims are not tested by the FDA for efficacy or safety. Dietary supplements are required to follow good manufacturing practices (GMP) to ensure their quality, strength, purity, and identity, and to follow guidelines for their manufacturing, packaging, and labelling. Even with this requirement, because of the large number of products out there and due to the lack of analytical methods for all types of products, quality and safety still varies, especially in products marketed toward body-building (Bailey, 2020).

What is creatine and how does it work in the body?

Creatine is a naturally-occurring amino acid that is made by two amino acids, glycine and arginine, primarily in the kidneys and liver. The body is also supplied with creatine from red meat and fish in the diet. Most of the creatine found in the body is stored in skeletal muscle and small amounts in the brain and the testes. About two-thirds of the creatine found in skeletal muscle is bound to a phosphate group, forming phosphocreatine. For muscles to contract, they must use ATP for energy. In short, what phosphocreatine does is provide a phosphate group to form ATP for energy, which is a quicker reaction that can be used before the body taps into anaerobic metabolism (Kreider et al., 2017). This is important during short-duration, high-intensity exercise, where energy comes predominantly from phosphocreatine and anaerobic metabolism (Hall & Trojian, 2013). Also, creatine causes water to enter muscle cells via osmosis which might cause cellular swelling (Chilibeck et al., 2017). Some evidence suggests this might activate protein synthesis, while other sources say there is no evidence that protein synthesis is activated (Chilibeck et al., 2017 and Hall & Trojian, 2013).

What are the proposed benefits of creatine for exercise enhancement?

Creatine supplementation is proposed to enhance muscular strength and improve performance during high-intensity, short-duration exercise (Hall & Trojian, 2013). Kreider et al. (2017) suggest the following potential benefits of creatine used to enhance exercise performance, stamina, and recovery:

• Increased single and repetitive sprint performance
• Increased work performed during sets of maximal effort muscle contractions
• Increased muscle mass and strength adaptations during training
• Enhanced glycogen synthesis
• Increased anaerobic threshold
• Possible enhancement of aerobic capacity via greater shuttling of ATP from mitochondria
• Increased work capacity
• Enhanced recovery
• And greater training tolerance (Table 1).

These proposed mechanisms would improve training quality, allowing an athlete to delay muscle fatigue and allowing for greater strength and muscle mass gains or gains in performance. According to Kreider et al. (2017), “Creatine supplementation has primarily been recommended as an ergogenic aid for power/strength athletes to help them optimize training adaptations or athletes who need to sprint intermittently and recover during competition…”. Evidence is mixed in regards to the effectiveness of supplementation in athletes of various sports. The International Society of Sports Nutrition (ISSN) concludes that creatine monohydrate is the most effective nutritional supplement to increase high-intensity exercise capacity and lean muscle mass during training in athletes. Most studies have been conducted on men, and some evidence suggests women may not see as much benefit (Kreider et al., 2017).

Are there side effects to creatine when used for exercise purposes?

Evidence is mixed on the safety of creatine supplementation. One source refuted claims to side effects, while several sources cited potential side effects. The following are potential side effects of creatine supplementation for exercise enhancement proposed by at least one source: weight gain, bloating, dehydration, digestive issues, compartment syndrome, muscle cramps, rhabdomyolysis, kidney stones, kidney damage, and liver damage (Mawer, 2019). Some sources went on to explain that these may be anecdotally unsubstantiated claims or case reports. Creatine does cause at least an initial gain in weight because it causes water to osmotically flow into muscle cells. Longer-term weight gain could be due to gains in muscle mass. Dehydration and difficulty regulating body temperature could occur due to the water shift, but some studies reported no issues. Some of these side effects were reported in individuals taking multiple supplements and/or inappropriate doses of creatine as well (Mawer, 2019). As always, it is important to pay attention to appropriate dosing, including the dose and duration of any loading doses and maintenance doses.

Two metabolites of creatine are known to be cytotoxic to the kidney, causing concern about potential harm especially with long-term use and high loading doses. Because of reports of kidney and liver dysfunction, caution is advised in those with preexisting or a history of kidney or liver problems (Mawer, 2019).

Bottom Line

The bottom line is that there is mixed evidence regarding the safety and efficacy of creatine supplementation to enhance exercise. There is more literature supporting that it may be effective in athletes looking to enhance speed or to achieve muscle gains in resistance training. According to the ISSN, “Creatine monohydrate is the most effective ergogenic nutritional supplement currently available to athletes with the intent of increasing high-intensity exercise capacity and lean body mass during training…. There is no compelling scientific evidence that the short- or long-term use of creatine monohydrate (up to 30 g/day for 5 years) has any detrimental effects on otherwise healthy individuals or among clinical populations who may benefit from creatine supplementation” (Kreider et al., 2017, para. 35). It might be unsafe for those with preexisting or a history of kidney or liver problems; caution is advised in these populations. The long-term effects of creatine’s metabolites on the kidney is unknown (Mawer, 2019). Again, always consult a doctor or medical professional before taking any dietary supplements. The purpose of this article is for educational purposes only, not to propose an opinion or a recommendation. Please direct any further questions to a doctor or other medical professional.