Seizing The Years with Dr. Susan Kleiner
Susan Kleiner’s story with creatine begins long before it was a household name. Back in 1993, she found herself reading the original research papers, not online, but via mailed letters, the slow dance of pre-internet scientific correspondence.
“I probably wrote Roger Harris a letter,” Susan recalls with a quiet laugh. “I said, I’m reading this. I understand the biochemistry. This seems profound. Is it as significant as it feels to me?”
Harris’s response was clear and pragmatic: start with athletes. Susan followed this direction and told me, “You can’t study healthy people and get statistical significance. But if you study extremes (like anabolic steroid-using bodybuilders), you get measurable results.”
At the time, Susan was one of the few dietitians immersed in strength and power sports nutrition, a niche overshadowed by the cardiovascular craze sweeping health circles. “When I first submitted my doctoral research in 1987, the American College of Sports Medicine said weightlifting wasn’t exercise. Bodybuilders weren’t athletes.” Her proposal was rejected by one group and celebrated by another: the American College of Nutrition awarded her a young investigator award and funding. That early push fueled a career that was as much about challenging norms as it was about science.
“It was an awkward time to be strength training,” she says. “But my personal mantra was keep going strong. I lived in a fourth-floor walk-up, and before lifting, I had to make multiple trips with grocery bags. Six months later, I could carry everything up at once. That practical progress was undeniable, and it felt amazing.”
Creatine quickly became her companion, a near-constant in a world where few women dared to take it seriously. “I was probably the only woman I knew taking creatine,” she admits. While there were on-and-off years, in the past decade, especially after being diagnosed with osteopenia, she has ramped up her intake (alongside a focused powerlifting regimen) to remarkable effect.
Her relationship with creatine deepened not just through personal experience, but through a decades-long dialogue with pioneers like Roger Harris, who once told her,
“Creatine’s application will be far bigger in medicine than athletics.” Susan agrees: “We still have a long way to go, but that vision is becoming clearer every day.”
Beyond the labs and papers, Susan paints a portrait of the early exercise physiology researchers as Renaissance people; scientists who were also artists, musicians, and explorers of the human experience. “I came in when they were still active, the ‘parents of the field.’ I’m incredibly grateful for those experiences.”
The roots of today’s creatine conversation run deep. When asked about the early research on mental health or bone density, Susan notes that these were not on the radar back then. “No, not at all. And the question of why we’re only now talking about women’s health and creatine… well, that’s another story entirely.”
Susan puts it simply: “It’s only now that we have data.” For decades, female athletes and fitness enthusiasts were navigating uncharted territory. As a sports nutritionist, Susan admits she was “just making it up” when working with female clients because the research simply didn’t exist.
“We finally understood that women metabolize carbohydrates during high-intensity exercise similarly to men,” she explains, “but the real breakthrough is how we study female biology in this context. We’ve made progress, thanks to a growing cadre of female scientists, but there’s still a mountain to climb.”
One of the most exciting frontiers? Creatine’s impact on women’s bone health, particularly in building peak bone density during those crucial late 20s to early 30s. The question is big: Can creatine push the needle beyond what we thought possible? If yes, the payoff is huge… more bone strength early on means more resilience decades later.
Susan’s own journey is a testament to this potential. After the COVID-19 pandemic disrupted her self-care routine, she found herself diagnosed with osteopenia at 64 years old. Rather than turning immediately to medication, she asked her doctor for a year to try a different approach.
“I increased my creatine intake to eight grams a day,” she says, “and started powerlifting three times a week with a trainer. I focused on sleep, nutrition, and all the anabolic signals my body needed.” The result? Within a year, DEXA scans showed new bone growth. Two years later, even more. By year three, Susan was no longer osteopenic.
“If I can do that in my mid-60s, what might younger women achieve?” she asks, underscoring that it’s never just one thing. “It’s the whole package but creatine matters. So why leave it out when women are doing everything else to support their health?”
More than muscle size, for Susan it’s about strength. Not just physical power, but the confidence, independence, and presence strength brings. “It changes how you interact with the world. Strength makes you stand taller. It’s about carrying groceries, taking a hike, or simply feeling strong in your own skin.”
And yet, creatine’s muscle-building reputation remains a barrier. “That association puts a lot of women off,” she says. “But bone and brain health? That message lands differently.” The challenge is shifting the narrative from ‘muscle bulk’ to strength, in every sense.
Susan’s insights challenge a longstanding cultural ideal that encourages women to be “as small as possible.” She reflects on how this negative messaging starts early, with girls absorbing their mothers’ dissatisfaction and dieting behaviors, reinforcing the idea that “a woman’s body doesn’t work very well, doesn’t look very good… there’s always something negative.” Yet Susan’s own experience was different.
Growing up in Cleveland before Title IX, she found strength and acceptance through modern dance… a physically demanding art that embraced strong bodies, unlike the restrictive ideals of ballet. This foundation, combined with her early professional work studying muscle function and training with female bodybuilders, led her to reject the notion that women should shrink or disappear. “That’s probably when everything shifted for me,” she says, recalling the powerful impact of training alongside a competitive female bodybuilder, which made her question the damaging messages imposed on women’s bodies.
Driven by these insights and a perspective on strength, Kleiner has focused her career on supporting female athletes and promoting evidence-based guidance tailored for women. She co-founded Vynnna, aiming to create a female-centric supplement brand, but quickly realized repackaging existing products wasn’t enough. In the early 2010s, she helped craft a viral manifesto for women’s strength, confronting the “pink it and shrink it” mentality that pressures women to diminish their power. Kleiner’s message is clear: it’s time to build up, not break down and start embracing creatine, strength training, and self-care as vital tools for women to thrive at every stage of life.
“It’s going to take a couple of generations,” she says, acknowledging the challenge of cultural change. Older women are cautious, often hesitant to fully embrace the physicality needed for true strength. Meanwhile, younger women may have broader access but still face societal pressures.
Our conversation then turned toward fertility, a deeply personal and emotional topic for millions of women. Susan advocates for more research and testing, especially before women undergo invasive and expensive hormone treatments. Kleiner emphasises how low creatine levels in the uterine lining might be an overlooked factor when it comes to fertility treatment. “If it’s even 1%, that’s a lot of people who could avoid physical, financial, and emotional hardship,” she stresses. Kleiner believes fertility research could be a key catalyst for shifting women’s creatine messaging, moving it beyond the bodybuilding stereotype to something profoundly human and emotional.
As we near the end of our video call, Susan spoke some simple words that stuck with me:
“Nobody has a body that doesn’t need creatine.” Whether you’re tiny in the womb or gracefully aging on your deathbed, every cell in your body requires creatine to function optimally. It’s a universal necessity, far beyond the confines of the gym or athletic performance.
This understanding reframes how we think about creatine, not just as a supplement for elite athletes, but as a vital nutrient for fertility, fetal development, brain health, and overall vitality. The benefits feel almost limitless and Susan is optimistic. She points to the groundbreaking research by fertility experts like Dr. Stacy Ellery in New Zealand, whose work dives deep into creatine’s role from conception to newborn development. Despite misconceptions and misinformation (including concerns around creatine during breastfeeding), the evidence base is growing steadily, debunking fears and highlighting benefits.
What makes Susan’s perspective particularly compelling is her emphasis on lifestyle as the essential companion to supplementation. Creatine alone is not a magic bullet. “It’s the lifestyle,” she says, it’s about nourishing your body with enough protein and energy, prioritizing sleep, lifting heavy weights (not just light movements), and finding joy and meaning in life. Her message is a clarion call to young women in their late 20s and early 30s: prioritize yourself unapologetically and build habits that nourish growth and resilience.
In a world obsessed with restriction and dieting over recent decades, Susan’s approach feels refreshingly abundant. Something I feel freed by hearing as a 33-year-old woman myself. Rather than focusing on what you can’t eat, she encourages embracing a mindset of nourishment and growth for your muscles, bones, brain, and cells that renew every moment. Supplement wisely, yes, but more importantly, build a foundation of strength, movement, and connection.
One of the more poetic moments of our conversation came when Susan described the power of nature in health and healing. Drawing from a fascinating study at a London hospital where patients exposed to forest imagery recovered faster than those facing urban scenes, she highlights the deep restorative benefits of the outdoors. For Susan, living in the Pacific Northwest has meant a lifetime of rain or shine adventures and has become a spiritual practice that keeps her grounded and strong.
Her final advice is both practical and inspiring: to truly thrive, you must be strong! Strong enough to engage with life fully and resilient enough to weather its challenges. Strength training isn’t just about aesthetics; it’s about longevity and mental clarity. Sleep isn’t a luxury; it’s a necessity. And most importantly, self-care isn’t optional at all; actually, it’s foundational.
As the wellness industry continues to expand and evolve, Susan's voice reminds us of what truly matters: the intersection of science, lifestyle, and self-respect. Creatine may have started in the athletic domain, but its story is just beginning. It shows the potential for a promising future where every woman, at every stage of life, can harness its benefits to live stronger, fuller, and more vibrant.
Thank you so much, Susan, for sharing your story with us!
If you would like to be featured or know someone who would be great to feature, please don’t hesitate to email rachael@jenerise.com 😊
We all rise together,
Rachael Jennings | Co-Founder + CBO, Jenerise
