Creatine Supplements: Evidence-Based Guide for Nutrition Professionals

Miguel Ramirez

Graduado en Nutrición Humana y Dietética, Universidad de Valencia. Certificación ISAK nivel 1, The International Society for the Advancement of Kinanthropometry.

Creatine is one of the most scientifically supported sports supplements available. However, recommending creatine supplements in professional practice requires going beyond generic advice.
Nutrition professionals need to understand how creatine works, its practical applications for strength, power, muscle mass, recovery, and cognitive performance, as well as the appropriate dosage protocols, safety considerations, and possible limitations. This makes it possible to provide evidence-based recommendations and adapt supplementation to each client’s individual circumstances.

In this guide, we examine what the current scientific literature says about creatine supplements and how nutrition professionals can apply that evidence in practice.

What Is Creatine and Why Is It Still Relevant in Nutrition?

• Physiological definition of creatine: Creatine is a compound made from three amino acids: arginine, methionine, and glycine. It occurs naturally in the body, with approximately 95% stored in skeletal muscle, although it is also found in the brain. It is synthesized in the kidneys, pancreas, and liver. Creatine can also be obtained from animal-based foods, but only in relatively small amounts.
• Role in energy metabolism: Creatine is involved in the phosphagen system, also known as the ATP-PC system. Phosphocreatine donates a phosphate group to ADP to rapidly regenerate ATP, the cell’s primary source of energy. This helps maintain maximum power output during high-intensity efforts lasting approximately 6 to 10 seconds.
• Why creatine is one of the most researched supplements: Creatine can act through several physiological pathways and has potential applications in both sports and clinical nutrition. Scientific interest in creatine supplements increased significantly after the 1996 Olympic Games, sometimes referred to as the “Creatine Games.” Creatine is also considered one of the safest and most extensively studied sports supplements.

Current Scientific Evidence on Creatine Supplements

• Short- and long-term safety: Creatine supplementation has demonstrated a strong safety profile. Research has examined high doses over periods longer than one year, and intakes of up to 30 grams per day for five years have been reported as safe and well tolerated in healthy individuals across different age groups.
• Position of scientific organizations: Leading institutions such as the Australian Institute of Sport classify creatine as a Group A supplement, the highest evidence category for sports supplements.
• Common myths vs. scientific evidence:
  • Myth: Creatine causes fluid retention and weight gain.
    Evidence: Creatine can increase water retention, but this occurs primarily inside the muscle cells rather than under the skin. This intracellular hydration is considered a positive physiological mechanism.
    https://pubmed.ncbi.nlm.nih.gov/32916658/
    
  • Myth: Creatine damages the kidneys.
    Evidence: Creatine supplements have not been shown to cause kidney or liver damage in healthy individuals.
    https://pubmed.ncbi.nlm.nih.gov/41199218/
    
  • Myth: Creatine causes hair loss.
    Evidence: There is currently insufficient evidence to conclude that creatine supplementation causes hair loss.
    https://pubmed.ncbi.nlm.nih.gov/40265319/

Effects of Creatine Supplements on Athletic Performance

• Strength and power: Creatine provides additional rapidly available energy during periods of maximum power or intensity, helping athletes maintain performance and resist fatigue.
• High-intensity sports: Creatine supplements may be particularly useful in sports that rely heavily on rapid energy production, including strength training, interval training, jumping activities, weightlifting, and CrossFit. In CrossFit, creatine may also help support glycogen resynthesis between consecutive workouts or WODs. It can also benefit intermittent sports such as soccer.
• Transfer to real-world performance: Creatine may help athletes sprint more effectively, complete an additional repetition, maintain power output, and reduce overall fatigue.

Creatine Supplements and Body Composition

• Muscle mass: Creatine supplementation may support protein synthesis and muscle hypertrophy. Proposed mechanisms include reducing myostatin activity, improving interactions with IGF-1, limiting oxidative stress, and activating satellite cells, which play an important role in muscle repair and regeneration. Creatine may also help preserve muscle mass during fat-loss phases.
• Intracellular water retention: Creatine draws water into muscle cells, improving cellular hydration. This is considered a beneficial effect that may support both athletic performance and anabolic processes.
• Clinical and aesthetic implications: This increase in intracellular water may cause a small increase in scale weight. However, this additional weight is not body fat and does not represent subcutaneous bloating. The response can also vary between individuals.

Creatine Supplement Use in Non-Athletic Populations

• Older adults: When combined with resistance training and an appropriate diet, creatine supplements may help prevent or slow sarcopenia, the age-related loss of muscle mass.
• Bone health and physical function: Creatine may indirectly support bone health by improving resistance-training performance. A greater ability to lift heavier loads efficiently increases the mechanical tension placed on the skeleton during exercise. This stimulus can support the formation of new bone tissue.
• Emerging clinical applications: Creatine is also being studied in several clinical contexts. It may help support glucose uptake in people with type 2 diabetes (https://pubmed.ncbi.nlm.nih.gov/34931982/), complement the treatment of major depressive disorder when used alongside selective serotonin reuptake inhibitors (https://pubmed.ncbi.nlm.nih.gov/39553021/), help manage liver fat (https://pubmed.ncbi.nlm.nih.gov/36220368/), potentially influence tumor growth in certain experimental studies (https://pubmed.ncbi.nlm.nih.gov/37662917/) , and support intestinal barrier function in conditions such as colitis (https://pubmed.ncbi.nlm.nih.gov/28137860/) .
  These applications remain context dependent, and creatine supplements should not replace appropriate medical treatment.

Creatine Supplementation Protocols

• Standard dosage: A daily maintenance dose of 0.1 grams per kilogram of body weight may be used. Creatine monohydrate is the preferred form because it is the most extensively researched. Products carrying the Creapure® quality seal may provide additional manufacturing and purity assurance.
• Loading phase and when it may make sense: A typical loading phase involves taking 20 grams per day, divided into four servings, for one week. However, a loading phase is not necessary because creatine works through gradual accumulation. Its main purpose is to reach muscle creatine saturation more quickly, which is not especially relevant for most clients.
• Timing and adherence: The exact time of day is not particularly important. A creatine supplement can be taken in the morning, afternoon, or evening. Taking it after training may offer a very small advantage by supporting glycogen recovery, but consistency is more important than timing. Creatine can be mixed with water and does not need to be taken with foods that cause a significant insulin response.
• Duration of use: From a health perspective, healthy individuals do not generally need to cycle creatine or schedule breaks from supplementation.

Creatine Supplements and Kidney Function: What Does the Evidence Say?

• Healthy individuals: Creatine supplementation has not been shown to cause liver or kidney damage in healthy people.
• Cases requiring additional caution: Extra caution is necessary when a client has a pre-existing kidney condition, such as chronic kidney disease, kidney failure, or a solitary kidney, or when they are taking nephrotoxic medications. In these circumstances, creatine supplements should only be considered under the supervision of a physician or nephrologist.
• Correct interpretation of laboratory results: Creatine supplementation may increase blood creatinine levels. This can be a normal consequence of creatine metabolism and does not automatically indicate impaired kidney function or kidney damage. Supplement use should therefore be considered when interpreting laboratory results.

Common Mistakes When Recommending Creatine Supplements

• Unjustified concerns: Assuming that creatine damages overall health, causes fat gain due to fluid retention, or leads to hair loss.
• Unnecessarily complex protocols: Believing that creatine must be cycled, that a loading phase is mandatory, or that insulin spikes must be deliberately created for creatine to be absorbed.
• Lack of personalization: Failing to consider differences in individual response. Approximately 20% to 30% of people may experience a smaller response to supplementation. Creatine may also be particularly relevant for people following vegetarian or vegan diets, as their dietary creatine intake and baseline muscle creatine stores may be lower.

How INDYA Helps Professionals Track Creatine Supplementation

• Supplement tracking: INDYA’s professional nutrition software allows practitioners to plan the specific brand, format, dosage, and timing of the creatine supplement they recommend. Clients can see exactly when and how much creatine they should take within their daily nutrition plan.
  
• Connection with performance and body composition: Nutrition professionals can record when creatine supplementation was introduced and compare that date with future client assessments, feedback, performance data, and weight-tracking charts. This makes it easier to evaluate how the supplement may be affecting performance and body composition.
  
• Long-term monitoring: Once creatine has been added, it can remain included in future nutrition plans unless the professional decides to remove or adjust it. This streamlines the creation of new plans while maintaining an established supplementation protocol.
  
• Improved adherence to the protocol: When clients can see their creatine supplement included in their daily plan, they are more likely to remember to take it than when the instructions have only been shared through a chat message.

When to Recommend Creatine Supplements in Nutrition Practice

• Professional Criteria

Consider recommending creatine: When a client wants to improve their health or athletic performance, has established nutritional habits, and is interested in supplementation.

Do not prioritize creatine yet: When a client wants to improve their health or performance but still has inconsistent eating schedules, poor dietary habits, or an inadequate nutritional foundation. These fundamentals should be addressed before supplements are prioritized.

• Athletic vs. Clinical Contexts

Athletic contexts: Creatine supplements are particularly relevant for explosive and high-intensity sports, including team sports, racket sports, CrossFit, sprinting, and Olympic weightlifting.

Clinical contexts: Creatine may be considered as part of a broader strategy to support muscle-mass maintenance, bone health, strength, and physical function.

Creatine may also be useful for athletes in other disciplines because of its potential benefits for health, recovery, and repeated high-intensity performance.

• Communicating With the Client

Reviewing the supplements a client is already taking before beginning their nutrition plan is a good opportunity to assess whether creatine should be introduced immediately or at a later stage.
A client who has previously taken supplements or is currently using several products may already be comfortable with supplementation and interested in adding creatine. By contrast, when a client has never taken supplements or has only used them occasionally, it may be more appropriate to establish their nutritional habits first and introduce creatine later in the process.