Creatine is one of the most researched supplements - and the evidence for its performance benefits is robust. It helps you train harder, recover faster, and build more muscle. Everyone can benefit from taking creatine, but the size of the benefit isn't the same for everyone. Your genetics play a meaningful role in how well your body responds to creatine supplementation, which means understanding your DNA could be the difference between a modest result and a significant one.

If you're already tracking macros, monitoring HRV, and fine-tuning your training, creatine might be the one supplement worth optimising at the genetic level.

What is creatine, and what does it do?

Creatine is a naturally occurring compound synthesised in the body from amino acids. Around 95% of your body's creatine is stored in skeletal muscle, where it exists primarily as phosphocreatine - a rapidly available energy substrate.

During short-duration, high-intensity efforts (a heavy squat, a sprint, an explosive plyometric) your muscles burn through energy faster than your body can produce it aerobically. Phosphocreatine acts as an emergency fuel reserve, extending your capacity to sustain peak output before fatigue sets in.

What are the proven benefits of creatine supplementation?

Supplementing with creatine monohydrate increases your muscles' phosphocreatine stores, allowing you to train at a higher intensity for longer.

Higher training intensity leads to superior muscle adaptation - meta-analyses consistently show that creatine users gain more lean mass than placebo groups when resistance training is matched. Even for those focused on fat loss, creatine supports retention and growth of lean tissue while fat is lost - a more favourable body composition outcome than cardio alone. Beyond aesthetics, research also points to creatine's role in improving blood glucose regulation and reducing markers associated with cardiovascular risk.

Why doesn't creatine work the same for everyone?

Despite the strong average effect, the benefits of creatine aren’t evenly distributed. Some individuals see significantly greater improvements in strength and power than others following the same supplementation protocol. For years, differences in response were attributed to diet (vegetarians tend to have lower baseline muscle creatine and often respond more strongly) or training status. But genetics is an increasingly recognised factor.

The gene MYLK1 - myosin light chain kinase 1 - encodes an enzyme central to muscle contraction. It plays a key role in regulating how muscle fibres contract and generate force. Research indicates that individuals carrying one or two copies of the A variant of this gene show significantly greater improvements in strength and power when supplementing with creatine monohydrate compared to those without it. Your genetic profile could determine whether creatine delivers a marginal improvement or a substantial performance gain.

Should you still take creatine if you don't know your genotype?

You can - creatine remains one of the safest, most cost-effective supplements available. But if you're serious about maximising your return on supplementation, knowing your MYLK1 variant allows you to set realistic expectations. It's a principle that runs through personalised health more broadly: two people can follow the same protocol and get meaningfully different results. Your DNA helps explain why.

FAQs

What's the best form of creatine to take?

Creatine monohydrate is the most studied and cost-effective form. Despite marketing claims for alternatives like creatine HCl or buffered creatine, no form has been shown to be meaningfully superior in peer-reviewed research.

How much should I take per day?

This depends on your genetics. If you carry at least one copy of the A variant of MYLK1, you’re an enhanced responder, so a loading phase is recommended and particularly effective. 20g per day for 5-7 days, split into four 5g doses, then drop to a standard maintenance dose. 

If you don’t carry a copy of the A variant, a straightforward daily dose of 3-5g of creatine monohydrate can be beneficial. You may not see the same enhanced response, but evidence still supports meaningful improvements in strength and muscular power from consistent supplementation.

Does creatine cause bloating?

Creatine draws water into muscle cells, which is part of how it works. Any initial weight gain on the scale reflects increased intramuscular water, not fat. Subcutaneous bloating is not a typical outcome.

Will creatine help with endurance sports?

Creatine's primary benefit is in high-intensity, short-duration efforts. For pure steady-state endurance, the benefit is limited, though athletes combining interval training or resistance work with endurance sport can still see value.

What is a creatine non-responder?

An estimated 25 - 30% of users see little increase in muscle creatine levels after supplementation. Baseline creatine levels (influenced by diet and genetics) and variants like MYLK1 appear to be key factors.

How can a DNA test tell me more about my creatine response?

A FitnessGenes DNA test analyses variants, including MYLK1, that influence your physiological response to supplementation and training. Rather than experimenting blindly, you can understand whether creatine is likely to be a high-impact supplement for your specific genetic profile.

References

Lanhers C, et al. (2017). Creatine Supplementation and Upper Limb Strength Performance. Sports Medicine, 47(1), 163–173.

Forbes SC, et al. (2021). Meta-Analysis Examining the Importance of Creatine Ingestion Strategies on Lean Tissue Mass and Strength in Older Adults. Nutrients, 13(6), 1912.

Gualano B, et al. (2011). Creatine supplementation in type 2 diabetic patients. Medicine & Science in Sports & Exercise, 43(5), 770-778.

Ginevičienė V, et al. (2014). Association between MYLK gene polymorphism and athletic performance in Lithuanian basketball players. Medicina, 50(2), 100-105.

Mattos, D, et al. (2023). Individual Responses to Creatine Supplementation on Muscular Power is Modulated by Gene Polymorphisms in Military Recruits. Journal of Science in Sport and Exercise, 5, 70-76.

Syrotuik, D, et al. (2004). Acute creatine monohydrate supplementation: a descriptive physiological profile of responders vs. nonresponders. Journal of strength and conditioning research, 18(3), 610–617.