Creatine

The mechanism of action: ATP and Phosphocreatine

To understand the role of Creatine, it is necessary to start with ATP (adenosine triphosphate)-the main energy transport molecule in cells. During high-intensity physical exertion, ATP is broken down into ADP releasing the energy needed for muscle contraction. However, ATP reserves in muscle are limited and are depleted within seconds.

This is where Phosphocreatine comes in: through the reaction catalyzed by the enzyme creatine kinase (CK), Phosphocreatine gives up its phosphate group to ADP, rapidly regenerating ATP and allowing the muscle to prolong high-intensity activity. Increasing muscle Creatine stores through supplementation means increasing the system’s ability to regenerate ATP-with direct effects on strength, explosive power, and endurance to repeated exertion.

An additional documented effect concerns the lactacid anaerobic phase: increased availability of Phosphocreatine helps buffer lactic acid accumulation during prolonged exertion, improving fatigue tolerance.

The clinical evidence: over 500 studies in 30 years

Creatine is one of the most studied functional ingredients in the history of sports nutrition. The contexts in which the evidence is strongest include:

• Short, High-Intensity Exertions — weightlifting, sprinting, jumping and intermittent sports show the most obvious improvements: 5-15% increases in strength and explosive power documented in randomized controlled trials.
• Muscle Mass and Body Recomposition — Creatine supplementation, combined with resistance training, supports the increase of lean mass through multiple mechanisms: increase of muscle cell volume, stimulation of protein synthesis, and reduction of protein breakdown.
• Post-exercise Recovery — reduction of muscle damage markers (CPK, LDH) and acceleration of recovery between close training sessions.
• Cognitive Function — Emerging evidence documents positive effects on working memory, processing speed, and resistance to mental fatigue, particularly under conditions of cognitive stress, sleep deprivation, and in vegan populations with reduced brain Creatine stores.
• Elderly Population — supporting the maintenance of muscle mass and cognitive function with advancing age, a context in which endogenous Creatine synthesis tends to decline.

The forms available for formulation

There are many forms of Creatine on the market, but comparing scientific evidence provides clear guidance:

• Creatine Monohydrate — the gold standard. The most studied form, with decades of clinical research to support it. No alternative form has demonstrated superiority in efficacy, safety or absorption at the same equivalent dose. Available in powder, Capsules and tablets. Micronized version – with reduced particle size – improves water solubility and gastric tolerance without altering the efficacy profile.
• Creatine Hydrochloride (HCl) — hydrochloric acid-bound form with better water solubility. It is marketed with the promise of lower effective doses, but comparative evidence does not confirm clinical superiority over Monohydrate.
• Creatine Malate — related to malic acid, an intermediate of the Krebs cycle. Association theoretically favorable for energy metabolism, but without conclusive comparative clinical studies.
• Buffered Creatine (Kre-Alkalyn) — proposed as more stable in gastric acid environment. Independent studies show no real differences from Monohydrate in either performance or absorption.
• Creatine Ethyl Ester — has been shown to be inferior to Monohydrate in effectiveness: it degrades more rapidly to creatinine and is less bioavailable. Virtually disappeared from the market.

The recommended formulation choice in the literature is Creatine Monohydrate, preferably micronized to improve palatability in powder and stick pack formats. Advanced formulations frequently combine it with Magnesium-which supports cellular energy metabolism-and Essential Amino Acids to optimize the effect on protein synthesis in the context of muscle recovery.

Recruitment protocols

Two main approaches are documented in the scientific literature:

• Loading — 20 g/day divided into 4 intakes for 5-7 days, followed by a maintenance phase of 3-5 g/day. Allows muscle reserves to be saturated rapidly, but may cause gastrointestinal upset in some individuals.
• Direct Maintenance — 3-5 g/day from start, without loading phase. Requires about 3-4 weeks to saturate muscle reserves. Better gastric tolerability, preferred for prolonged supplementation cycles.

Contextual intake with carbohydrates or a protein source improves muscle uptake of Creatine through insulin stimulation. Timing with respect to training (pre or post) does not appear to be decisive in the available evidence, whereas the consistency of daily intake is the most relevant factor for saturation and maintenance of reserves.

The approved EFSA claim

EFSA has approved a specific health claim for Creatine under EC Regulation 1924/2006:

• Creatine increases physical performance in subsequent high-intensity sprints

The claim is applicable with a daily intake of 3 g of Creatine. It is one of the few approved claims in sports nutrition — accurate in scope (repeated high-intensity sprints) and effective dose. It does not include endurance activities, for which the evidence has not reached the level necessary for approval.

Security and false myths

Creatine is surrounded by some recurring concerns that the scientific literature has largely dismissed. The most prevalent relate to the kidneys: the increase in urinary creatinine observed during supplementation is not a sign of kidney damage — it is the normal excretion metabolite of Creatine. Short and long-term clinical studies in healthy subjects show no adverse effects on kidney function. The only documented contraindication is in persons with preexisting chronic kidney disease, for whom medical evaluation is necessary.

Similarly, the association between Creatine and hair loss is not supported by replicable evidence: it comes from a single study with significant methodological limitations, never confirmed by subsequent research.

Creatine is contraindicated in the presence of diagnosed chronic kidney disease. People being treated with nephrotoxic drugs or with pre-existing medical conditions should consult their physician before beginning supplementation.

Always remember that it is important to consult a health care professional before starting any new supplement or treatment.