The Discovery
A French chemist named Chevreul isolated creatine from meat broth in 1832. Scientists spent the next century and a half confirming what he’d found: a compound your own liver, kidneys, and pancreas already manufacture, stored mostly in skeletal muscle, tied directly to short-burst energy production. None of that filled a single gym bag. What filled the gym bags was 1992 — when Roger Harris and colleagues published a study showing that oral creatine monohydrate could raise muscle creatine stores by roughly 20%. That was the fuse. By the late ’90s, every locker room had a tub of it.
Why It Works — The Short Version
Muscle cells burn ATP for energy and immediately need to regenerate it. Phosphocreatine is the fastest-available backup: it donates a phosphate group to rebuild ATP in seconds, no oxygen required. That system is what gets tapped during short, explosive efforts — a sprint, a max lift, a jump. Saturate the phosphocreatine pool beyond what diet alone provides, and you extend how long that fast-regeneration system can keep firing. That’s the entire mechanism. Everything else in this lab is downstream of that one fact.
The Purge
The supplement market of the late ’90s and early 2000s was a regulatory Wild West. A 1994 law classified supplements as food, not drugs — which meant almost nothing had to prove itself safe before hitting a shelf. Into that gap walked a wave of products that weren’t really nutrients at all. They were pharmaceutical-grade stimulant compounds sold as sports nutrition. One by one, the FDA caught up with them. Creatine is still standing. Here’s the split, and it isn’t luck.
× Pulled From Shelves
- Ephedra — a stimulant alkaloid; banned by the FDA in 2004 after being linked to cardiac events and deaths
- Androstenedione — a steroid precursor; reclassified as a controlled substance in 2004
- DMAA — an amphetamine-like stimulant; FDA warning letters and product seizures beginning 2013
- Original Hydroxycut formula — recalled in 2009 over liver-injury reports
✓ Still Standing
- Creatine monohydrate — a nutrient your own liver, kidneys, and pancreas already synthesize
- No controlled-substance status, ever
- No FDA warning letters directed at the compound itself
- Roughly 30 years of use with no documented link to kidney damage in healthy people
The Actual Mechanism — Not Luck
Every compound in the “pulled” column worked by forcing the body into a state it doesn’t normally reach — a stimulant surge, a hormone spike. Creatine works by topping off a pool the body already maintains. The supplement doesn’t introduce anything foreign; it saturates existing stores beyond what diet alone supplies. Nutrient versus drug isn’t a marketing distinction here — it’s the actual reason one category survived the purge and the other didn’t.
The Honest Caveat
“No documented harm in healthy people” is not the same claim as “safe for everyone in every circumstance.” People with pre-existing kidney disease, and anyone on medications that affect kidney function, should talk to a physician before adding any supplement — creatine included. Clean safety data in healthy populations is a real finding. It is not a substitute for your own doctor knowing your own labs.
The Body of Evidence
The meatheads didn’t know they were onto something bigger than a gym supplement. The same principle — more available energy at the cellular level — turns out to matter well outside the biceps. Click a domain to see where the research actually stands. Evidence strength varies a lot between these; that’s the honest part.
The Signal
A systematic review published in Brain Medicine, out of the University of Ottawa, pooled five randomized controlled trials of creatine for depression — 238 participants across South Korea, the United States, Brazil, Israel, and India. The finding isn’t a verdict. It’s a genuine, honestly-reported mixed signal, and the shape of the mix is the whole story.
What Actually Held Up
Two trials, both in women with major depressive disorder, showed a real effect. In one, 5 grams a day added to the antidepressant escitalopram outperformed the drug alone by a wide margin — a large effect size. Three other trials found nothing meaningful: one in adolescent girls, one in treatment-resistant depression, one in bipolar disorder. That 2-for-3 split isn’t noise the researchers are hiding — it’s the actual, reported result, and they said so plainly: the signal is real enough to justify bigger trials, but it isn’t yet something a clinician can promise will work.
The Safety Flag
Two patients with bipolar disorder developed hypomania or mania while taking creatine in these trials. This is not something to add casually to anyone’s regimen, and it is specifically not something to try without a psychiatrist’s knowledge if bipolar disorder is anywhere in the picture.
The Sex-Difference Wrinkle
Both successful trials studied women exclusively, and the leading theory is that women carry lower baseline creatine stores than men on average, which may make the brain more sensitive to energy-availability effects. It’s a theory, not a settled mechanism — but it’s consistent with everything else in this lab: the effect follows the energy math, not the muscle.
The Honest Handoff — Where the Real Clinicians Take Over
This lab is the front door. It reports what a 2026 systematic review actually found — nothing more, nothing less. If any of this feels personal, the next click is one of these:
· National Institute of Mental Health — Depression — vetted, current patient information.
· American Psychiatric Association — clinical guidelines, the ones a treating psychiatrist follows.
· A psychiatrist or primary care physician — the right person to weigh a supplement against an existing diagnosis, an existing medication, or a history of bipolar disorder. Not a lab. Not a review paper. A person who knows your chart.
· If you’re in crisis right now, in the US you can call or text 988 (Suicide & Crisis Lifeline) any time.
About This Lab
The Creatine Lab is section 4.7.8 in College VII — B.J. Medical Center (Dean Dr. Janet Chen), cross-listed to College XII — Community Health & Social Services (Dean Risa Hughes) for the depression-trial tab. The lab’s honored anchor is Dr. Rich Kreidler — the OPA echo of Richard Kreider, rendered with the same single-letter honoring transform used for Dr. Michael De Blakely in the Heart Lab. Sister labs in the Body cluster: The Tendon Lab, The Continuum, The Heart Lab.
Honest handoff: NIMH · APA · 988 Suicide & Crisis Lifeline. OPA is the front door. The clinicians are the room.