Creatine monohydrate: the most studied supplement there is, and the lab result it ruins

Almost everything about creatine is settled, which is rare enough to be worth saying plainly. The part worth a page is the one nobody mentions: it changes a routine blood result in a way that gets misread as kidney damage.

What it does, and what the evidence actually supports

Established clinical use Creatine is stored in muscle as phosphocreatine, which donates a phosphate to regenerate ATP during short, maximal efforts. Supplementation raises muscle phosphocreatine stores by roughly twenty per cent, and the downstream effect — improved performance in repeated high-intensity efforts, and greater training adaptation over time — is among the best-replicated findings in sports science. Several hundred trials, decades of use, consistent direction.

Off-label or community practice The newer claims are less settled but not baseless. Cognitive effects appear in trials under conditions of stress — sleep deprivation, hypoxia, mental fatigue — more consistently than in rested healthy people. Effects in vegetarians, who start with lower stores, tend to be larger across the board. Preservation of lean mass during a caloric deficit has reasonable support. None of these are on the same footing as the performance data, and describing them as if they were is the usual overreach.

Loading is optional. Twenty grams a day for a week saturates muscle faster; three to five grams a day gets to the same saturation in three or four weeks with far less gastrointestinal upset. The app’s own rows say exactly that.

The creatinine problem

Established clinical use Creatine degrades to creatinine at a steady rate, and serum creatinine is what laboratories use to estimate kidney function. Supplementing creatine therefore raises serum creatinine and lowers a calculated eGFR — without anything having happened to the kidney. The rise is real; the interpretation is wrong.

This is not a curiosity. It is one of the more common ways a healthy person gets referred for renal workup, and it is entirely avoidable by telling whoever ordered the test. The app puts it on the monitoring note for this compound specifically, and it is the single most useful thing on this page: if you supplement creatine, say so before a metabolic panel, and say it again if anyone raises an eGFR with you. Cystatin C is a kidney marker that creatine does not disturb, and it is the usual way to settle the question if it arises.

The kidney concern itself — that creatine harms renal function — has been examined repeatedly in people with healthy kidneys and has not been found. Existing kidney disease is a different conversation and one for the clinician managing it.

The rest of the practical detail

The initial weight gain is intramuscular water, not fat and not subcutaneous fluid, and it arrives in the first week or two. Anyone tracking body composition through a scale will see it and misread it, which is worth knowing in advance rather than discovering.

Monohydrate is the form with the evidence. The alternatives — hydrochloride, ethyl ester, buffered preparations — are sold on solubility or absorption claims and none has demonstrated superiority on an outcome. Paying more for one is paying for marketing. Since these are supplements rather than drugs, content varies with the manufacturer; this site names no brand and no testing service.

Non-responders exist — people whose muscle stores are already near saturated from diet get little further benefit — and that is a real phenomenon rather than an excuse. Anyone with kidney disease, or on medication that affects renal function, should be having this conversation with their clinician rather than treating it as a consumer-goods decision.

The dosing rows the app records

Off-label or community practice Reproduced from the app’s reference so you can see what it holds, not as a recommendation. Which row applies to a particular person, if any, is a clinical decision this page does not make — and rows describing supraphysiological or post-cycle use are filtered out before this table is built, so what you see here is a subset.

What the app monitors alongside it

The panel below is the app’s own monitoring note for Creatine Monohydrate, verbatim. None of the analytes it names has a page here yet.

Drawbacks and risks the app records

From the app’s own entry, and unusually mild: for a compound this well studied, the drawback list is mostly about measurement artefacts and expectations.

• Water retention initially (intramuscular, not subcutaneous)
• GI discomfort with loading phase — skip and dose daily instead
• Creatine non-responders exist (10-30% of population)
• Caffeine may blunt effects slightly
• Weight increase from water retention can be misleading on scale
• Quality varies — stick to pure creatine monohydrate

Questions people actually ask

Does creatine damage the kidneys?

Not in people with healthy kidneys — that has been looked at repeatedly. What it does is raise serum creatinine, which is the marker used to estimate kidney function, so it makes a healthy kidney look impaired on paper. Existing kidney disease is a separate conversation.

Do I need to load?

No. Loading saturates muscle in about a week rather than three or four, at the cost of more gastrointestinal upset. The endpoint is identical.

Is any form better than monohydrate?

No form has demonstrated superiority on an outcome. Monohydrate has the evidence and is the cheapest, which is an unusual combination.

What do I tell the lab?

That you supplement creatine, before the draw. If an eGFR has already come back low, cystatin C is a kidney marker creatine does not affect and is the usual way to settle it.

Where the load-bearing numbers come from

Named rather than linked. Publisher URLs move, and a citation that resolves to a 404 two years from now is worse than one you can search for by name — every entry below is findable from the title and year alone.