Evidence desk · Supplement
Creatine monohydrate
The verdict
The strongest "yes" on this desk. Creatine monohydrate has hundreds of randomized trials behind it, a reassuring safety record, and — the rare part — most of the research is independent, not industry-funded, because it's a cheap, off-patent commodity no one gets rich selling. It reliably adds strength, power, and lean mass when paired with resistance training. 5 g/day of plain monohydrate, forever.
The fancy forms are a waste of money, loading is optional, the kidney scare is a misread lab value rather than real damage, and on a cut the only catch is a pound or two of water weight you shouldn't mistake for stalled fat loss.
Before you read on
Collagen had better-than-average evidence and still earned a shaky verdict, because the encouraging studies traced back to the people selling it. Creatine is the cheapest supplement here and nobody's getting rich on it. Quick: which way should that push your confidence in the research — and why is that the opposite of the collagen story?
The claims, sorted
Creatine is sold for a widening list of things. They don't share a verdict, so separate the bedrock from the frontier before judging any single study.
| Claim | Best evidence | Holds up? |
|---|---|---|
| Strength & power with training | Hundreds of RCTs, multiple meta-analyses | Yes — bedrock |
| Lean mass (incl. preserving it on a cut) | Consistent RCT evidence | Yes |
| Safe long-term in healthy people | Trials up to 5+ years; ISSN review | Yes |
| Cognition / brain (sleep-deprived, older, vegetarian) | Small RCTs & reviews, mixed | Promising, unsettled |
| Damages kidneys | No evidence of harm in healthy people | No — a myth |
| Causes hair loss | One 2009 study, never replicated | Not shown |
Why the evidence is unusually clean
This is the collagen case run in reverse, and it's worth sitting with because it sharpens the whole toolkit. With collagen, the trials that found benefits were mostly funded by collagen companies — so you discount them. Creatine monohydrate has been generic for decades; it costs pennies a serving and no patent protects it. There's almost no marketing money to bend the literature, and yet it's the most-studied sports supplement in existence — academic labs kept testing it for thirty years, and it kept working.
That's the tell to learn: heavy evidence plus no one with a financial reason to manufacture it. When the funding filter has nothing to subtract, a positive result means more. Creatine clears that bar; almost nothing else on the desk does.
You don't need to "load"
Your muscles hold a creatine reservoir, and the benefit comes from keeping it near full. There are two ways to fill it, and they reach the same place:
- Loading: ~20 g/day (split into 4 doses) for 5–7 days, then 3–5 g/day to maintain. Saturates in about a week — useful only if you want the effect fast.
- Just maintenance: 3–5 g/day from day one. Saturates in roughly 3–4 weeks with no loading phase, no extra cost, and less of the early GI upset some people get from big doses.
Same plateau either way. Unless you have a meet or a deadline, skip loading and let the daily dose get you there.
Buy the boring one
Creatine monohydrate is the form every trial used and the one that works. The pricier options — hydrochloride (HCl), buffered "Kre-Alkalyn," ethyl ester, liquid creatine — are marketed as better-absorbed or gentler, but none has beaten plain monohydrate in head-to-head trials, and some are simply worse. This is a marketing-versus-evidence split: the premium forms exist to create a patentable, higher-margin product out of a commodity. Pay for monohydrate (a third-party-tested or Creapure-labeled tub is a fine tiebreaker) and ignore the rest.
The two scares, defused
Kidneys. The worry comes from a real lab observation that's been misread for decades. Creatine is metabolized to creatinine — the very waste product labs measure to estimate kidney function. Supplementing predictably nudges serum creatinine up, which can make an eGFR estimate look slightly worse, but that's a bookkeeping artifact, not kidney injury. In people with healthy kidneys, trials out past five years show no damage. The one practical consequence is on your lab panel — covered below.
Hair loss. Traces to a single 2009 study in college rugby players that found higher DHT (a hormone linked to male-pattern balding) during loading. It measured a hormone, not actual hair, and no study since has replicated even that. It's a weak, isolated signal — not nothing, but nowhere near established. If you're predisposed and anxious about it, that's a personal risk call, not a settled fact.
The frontier: brain, not just muscle
The newest claims are about cognition — creatine helps fuel the brain too, and supplementation may help when the brain is stressed: sleep deprivation, aging, or low dietary intake (vegetarians, who start with smaller stores, tend to respond most). Some small trials are encouraging, including single large doses under sleep deprivation. But the results are mixed, doses vary wildly, and this is nowhere near the strength evidence. File it as a plausible bonus, not a reason to take it — the muscle case already justifies the 5 g on its own.
By phase
General reasoning — the same logic anyone on a GLP-1 fat-loss arc would apply. Unusually, creatine earns a "keep" in every phase; only the headline reason shifts. Your specific call is in the For you section below.
Phase 1 · Aggressive cut (Zepbound)
High value. The defining risk of a GLP-1 cut is losing muscle along with fat; creatine helps you hold strength and lean mass while in a deficit, which is exactly the job. One thing to expect, not fear: it pulls water into muscle cells, so the scale jumps ~1–2 lb in the first weeks and then sits higher. That's intracellular water, not fat — don't let it spook your weekly weigh-in or trip your >1.75 lb/wk logic in the wrong direction.
Phase 2 · Building muscle
Its home turf. Paired with progressive resistance training, this is where creatine's strength-and-hypertrophy evidence is strongest. If you ever run the optional Build phase, creatine stays in at the same 5 g — no change needed.
Phase 3 · Maintenance
Still worth it, and now the brain angle is the bonus reason rather than the muscle one. Cheap, safe, and the reservoir only stays full if you keep topping it up — so there's no natural "stop" point. Keep the daily 5 g.
For you
From your Life OS (Food & nutrition, Physique roadmap, Dashboard). You're not deciding whether to start — you already take 5 g/day in the morning shake. This is the right call and the strongest-evidence item in your whole stack, so the entry is less "should I?" and more "here's what to keep an eye on."
My call — keep it; it's your best-supported lever
Creatine is doing real work in your Phase 1 plan: 170 g protein + resistance training + creatine is the lean-mass defense triad on a Zepbound cut, and creatine is the only supplement in that group with bedrock evidence. Stay at 5 g monohydrate, daily, no loading. It costs almost nothing and there's no reason to ever cycle off.
Two personal notes. (1) Your labs. You track biomarkers closely, and creatine mildly raises serum creatinine — which can make your estimated eGFR read a touch low. It's an artifact of the supplement, not your kidneys. Two ways to keep it honest: tell whoever orders the labs that you supplement creatine, and if kidney function is ever genuinely in question, ask for cystatin C (an eGFR marker creatine doesn't perturb). (2) The water weight. The early ~1–2 lb bump is intracellular water and a sign it's working — read your cut trend over weeks, not the day creatine shows up on the scale.
Profile used: 41, 5′9″, 188 → ~157 lb target at ~1 lb/wk, Phase 1 cut on Zepbound, 170 g/day protein + resistance training, biomarker-tracking (incl. eGFR/creatinine on the panel), already taking 5 g creatine in the AM shake. Tell me if any of that moves and I'll update.
Recall check
- Why does creatine's lack of marketing money make its evidence more trustworthy, not less?
- Loading vs. just taking 5 g/day — what's the only thing that differs, and what's identical?
- A friend says "creatine wrecks your kidneys — my doctor saw it on a lab." What's actually going on, and what test settles it?
- You're on a cut and the scale jumps 2 lb the week you start creatine. Fat gain or not — and how do you know?
Explain it back
In one sentence: why is creatine the easiest "yes" on the desk while collagen, with similar-looking evidence, isn't?
Check it yourself
This verdict is just the toolkit applied. Re-derive it with the evidence ladder, publication bias & funding (the inverse of the collagen case), and is it strong enough to act? — then see where it lands in the protocol.
Sources · ISSN position stand: safety & efficacy of creatine (Kreider et al., 2017) · Common questions & misconceptions about creatine (Antonio et al., 2021) · Effects of creatine on cognition: systematic review (Avgerinos et al., 2018). Evidence summaries, not medical advice — confirm anything that touches your medication or labs with your prescriber.