Get your ACTN3 gene tested by the world leading fitness dna testing company : AnabolicGenes

ACTN3 gene is one of the most popular gene. It highly affects muscle fiber composition. Every human has the ACTN3 gene. But there are 3 types we as humans can have : XX, RR, or RX genotype. The ACTN3 gene is responsible for the production of alpha-actinin-3 -a molecular protein that is only found in fast twitch muscle fibers (IIA et IIX). Scientific researchs have found that if you have the XX group, you will have a deficiency in the alpha-actinin-3 protein. People with the XX genotype can’t produce ACTN3 protein, and may produce more ACTN2 protein which increases the endurance capabilities (Figure 1).

actn3 gene
Figure 1 : Genotype frequency (RR, RX, XX ) among athletes is shown

ACTN3 gene and performance

A scientific research had all the subjects perform an exercise using an isokinetic dynamometer, ( hi-tech knee machine that is able to measure force/power output). If the subjects with the RR genotype could generate more force and power than the XX one, then that would mean there’s a strong genetic evidence as to why some individuals can generate more power and strength

Who has the ACTN3 gene ?

The frequency of the XX groupe in the population varies across the globe – from 25% of the population in Asia, to <1% of the Bantu population. In the European population approximatively 18% of people have the XX alleles. Scientific researchs have shown that elite athletes in different sports ( endurance sports + power sports ) are more likely to have specific genotypes when compared to a control population – Figure 2. Sprint athletes had a lower frequency of the XX group. And no sprint Olympians were XX ! Sprint elite athletes had a higher frequency of the RR genotype and endurance athletes slightly higher frequency of the XX one. actn3 gene Figure 2 : Genotype frequency (RR, RX, XX ) among athletes is shown


The scientific studies concluded that the subjects with the RR genotype generated more force/power and had a higher proportion of fast twitch muscle fibers than the XX genotype. The big problem is : genetics is much more complexe than that and fiber type composition depends on lots of other gene variants and interactions. That’s why Anabolicgenes doesn’t only test ACTN3 gene. We test a full gene panel and study the interactions between all these genes ( ACTN, PPAR-alpha, ACE, PGC1-alpha, etc… ). More details here Get your ACTN3 gene and much more here 23andme raw data interpretation also available here