How Hormones and Diet Shape Creatine Needs in Women

In the first part of this interview, sports nutrition expert Susan Kleiner, PhD, RD, FACN, CNS-E, FISSN, Founder of High-Performance Nutrition LLC, reviews major gaps in creatine research for women. She highlights the failure to control for menstrual cycles, women’s lower baseline creatine stores, the impact of vegetarian and vegan diets, and emerging evidence on strength and performance responses compared with men. Dr. Kleiner also addresses common consumer misconceptions and brand claims.

Partial transcript:

Sebastian Krawiec: Obviously, creatine is a popular ingredient in sports nutrition as it relates to muscle strength and exercise performance, for example. Do these benefits look any different for women compared to men? I know there has been in the past some misconceptions about the use of creatine in women. Wonder if you could elaborate on that some more.

Susan Kleiner: We get so excited when we've got one study, so it's big news. Compared to the volume, the body of evidence that we have on men and males, for females, it's a very narrow slice of data, and so outcomes are not as firm, right? There's several layers of important evidence.

One is, women start out with apparently lower levels of creatine proportional to men. We're smaller, we have less muscle, we're going to have less circulating and stored creatine, but it is proportionately less, that even considering our smaller sizes, we have less creatine typically on board. And that seems to be attributed to less creatine consumption, lower creatine ingredient containing foods in our diets naturally. And so what has been shown is that we can see better stores with with very small increases in creatine intake because we have so little to begin with. So to get to the levels where we know physical performance outcomes change, we do see, especially, well across the board in vegans. Now, there are more females in studies that are vegan, vegetarian, typically than there are males when we are targeting athletic populations, and so that kind of, it doesn't jumble the mix.

It's documented that the lowest creatine stores are in people who don't consume meat or animal protein products, because that's the major source of creatine in our diets.

Next is our women who take in less, and so when we supplement them with creatine, they definitely get a strength and power enhancement outcome. It's a little foggier when it comes to cardiovascular performance or endurance performance, kind of as it is with males as well. It's not a universal response that everybody gets better.