Creatine, Teen Muscles, and Quietly Unhappy Kidneys. From your pediatrician who is now ordering way too many kidney labs on teenage boys.
Let’s talk about creatine—the white powder your teen swears is “totally safe” because “everyone on YouTube takes it.” Creatine has decent science behind it in adult athletes, at proper doses, under supervision. That is not the same thing as “your 15-year-old mixing mystery powder into a shaker bottle in his bathroom.” And while the internet is busy calling creatine “the most studied, safest supplement,” I’m over here ordering kidney function tests on high school boys who have gotten suspiciously more muscular in a short period of time—whether they admit to creatine or not—and I’m not loving what I’m seeing.
What Creatine Actually Is (Not Just “Protein Powder’s Cousin”)
Creatine is a compound your body already makes and stores in muscle. It helps with short bursts of high-intensity activity—think sprinting or heavy lifts. In adults, studies show: Small but real strength and performance boosts. Some increase in muscle mass. Generally no major kidney harm in healthy adults at recommended doses That’s the adult story. Your teenager is not an adult. His kidneys are not adult kidneys. His decision-making skills are definitely not adult.
What the Big Organizations Actually Say About Teens
This part doesn’t usually make it onto TikTok. The American Academy of Pediatrics and other pediatric/sports medicine groups do not recommend creatine for kids and teens. They’ve been consistently conservative about performance supplements. Children’s hospitals and pediatric sports programs routinely advise against creatine under 18 because we don’t have robust, long‑term safety data in adolescents. Translation: the people who actually see kids’ labs and long-term outcomes are not high-fiving creatine use in high school. Yes, there are newer reviews and position statements trying to carve out a “maybe okay under supervision for older teens” lane—but even those emphasize careful monitoring and high‑quality, tested products, not “whatever was cheapest online.”
My Clinic Reality: The Part the Labels Don’t Tell You
Now the uncomfortable part. From my experience, I am routinely ordering kidney function tests on teenage boys who come in noticeably more muscular over a short period—whether they openly admit to creatine supplementation or not. I don’t have time to chase every powder brand name; I have time to look at labs. And unfortunately, I am finding evidence of early kidney dysfunction in kids who should have pristine kidney numbers. Elevated creatinine. Abnormal kidney markers. Patterns that make me deeply uneasy for a population that is supposed to have decades of healthy kidney function ahead. This is not one weird case report; this is becoming a pattern.Is every single abnormal lab definitively caused only by creatine? Of course not. High‑protein diets, dehydration, other supplements, underlying medical issues—they all play a role. But here’s the important part: when the published literature says “we don’t really know long‑term effects in adolescents,” and I’m staring at lab work that looks worse than it should for a 16‑year‑old… I’m not inclined to shrug and say, “Well, the internet says it’s fine.”
The Problem Isn’t Just Creatine—It’s How Teens Actually Use It
In studies, creatine is: Pure, tested creatine monohydrate. Given at specified doses. Used in generally healthy subjects. Monitored over time.
In real life teen behavior, creatine is: Whatever powder was cheapest or most hyped online. Sometimes stacked with other supplements (pre‑workouts, stimulants, “bulk” mixes). Mixed with inconsistent hydration, weight‑cutting, or high‑protein diets. Used with exactly zero lab monitoring.
Supplement quality is a mess. Independent testing has repeatedly found: Mislabeling. Contamination with other substances. Variable creatine content. Occasional heavy metals or banned substances. So when a study says, “Creatine appears safe in healthy adolescents at recommended doses,” that is not the same as “whatever your teen bought from a random brand is safe, at whatever dose they decided on, with whatever else they’re doing to their body.”
“But Coach Said Everyone Is Taking It”
Surveys of high school athletes do not show “everyone” taking creatine. They show something like 5–15% depending on sport and region. “Everyone” is teen code for “some guys on varsity and my favorite influencer.” Also: The performance benefit is real but modest. Sleep, nutrition, and structured training get your kid most of the way there. It is entirely possible—boring, but possible—for your teen to build muscle without experimenting on his kidneys at 16.
The Kidney Piece: Why I’m Sounding an Alarm
The research reviews say something like this: In healthy adults, creatine at normal doses appears safe for kidneys. In people with underlying kidney risk, high doses, long use, or stacked with other stressors, there may be problems. Long‑term safety in adolescents is not established, full stop. As a pediatrician looking at early kidney changes in teens, I’m not interested in being the “trial period” for proving long‑term safety. This is not theoretical; this is me telling you I’m seeing labs I should not have to see in high school boys who are following supplement trends like they’re fashion.
What I Tell Parents, Bluntly.
Under 18? My default answer is no to creatine. Your teen’s growth, kidneys, hormones, and long-term health are not worth a modest performance bump. If you’re still considering it for an older teen, bare minimum: Talk to your pediatrician first. Use only third‑party tested products (NSF Certified for Sport, Informed‑Sport, USP Verified). No stacking with unknown pre‑workouts or “muscle blends.” Monitor kidney function and hydration seriously—this is not a toy. And if your teen “gets bigger fast” and suddenly looks like a different human in three months? That’s not just a “good job, buddy” moment. That’s a “we should probably check labs” moment.
Sources
Mayo Clinic. “Creatine.” 2026.
Goldberg K. “Are Creatine and Liquid IV Safe for Teen Athletes?” University Hospitals, 2023.
CHOC Children’s Health Hub. “Should teens use creatine?” 2022.
Kreider RB et al. “Common questions and misconceptions about creatine supplementation.” 2021.
Creatine supplementation in the pediatric and adolescent athlete. 2023.
“Creatine Supplementation in Children and Adolescents.” 2021.
“Effect of creatine supplementation on kidney function: a systematic review.” 2025.
“Effects of creatine supplementation on renal function.” 2004.
Parent-focused summary on AAP position and adolescent creatine data. 2026.
“Is Creatine Safe for Kids? What Parents Should Know.” 2026.