Creatine is a compound your body builds from three amino acids: glycine, arginine, and methionine. Its chemical name is methylguanidoacetic acid. Whether you’re looking at creatine as a molecule in your body or as a white powder in a supplement tub, the answer to “what’s in it” comes down to these building blocks and, in the case of supplements, a small number of additional ingredients that affect how the product behaves on a shelf.
The Molecule Itself
Creatine is not a protein, a steroid, or a synthetic drug. It’s a naturally occurring compound classified as a non-protein amino acid. Your liver, kidneys, and pancreas produce it by combining glycine and arginine (both semi-essential amino acids) with methionine (an essential amino acid you get from food). Your brain and testes can also synthesize small amounts.
A 70-kilogram (about 154-pound) adult needs roughly 2 grams of creatine per day, split between what the body makes internally and what comes from food. Over 95% of the body’s total creatine is stored in skeletal muscle. A dedicated transporter protein on cell membranes shuttles creatine into muscle, heart, brain, and kidney cells using sodium and chloride to pull it across.
Creatine in Food
If you eat meat or fish, you already consume creatine. The richest sources are herring (6.5 to 10 grams per kilogram of raw fish), yellowtail (5 grams per kilogram), and salmon (4 grams per kilogram). Tuna ranges from 2.7 to 6.5 grams per kilogram, and cod sits around 3 to 4.4 grams. Shrimp is on the low end at about 0.7 grams per kilogram.
To put that in perspective, you’d need to eat roughly half a kilogram (about a pound) of salmon to get the same 2 grams found in half a teaspoon of supplement powder. That math is why most people who want performance or recovery benefits turn to the supplement form.
How Supplement Creatine Is Made
The creatine in your supplement tub isn’t extracted from meat. It’s synthesized in a chemical reactor. The standard industrial process combines two precursors: sarcosinate (a salt derived from sarcosine, a naturally occurring amino acid) and cyanamide. These are mixed in water at temperatures between 50 and 100 degrees Celsius for two to five hours. The solid creatine that forms is then separated out, washed, recrystallized for purity, and dried into the familiar white powder.
This reaction also produces small amounts of byproducts. The two most notable are creatinine (formed when creatine folds in on itself) and dicyandiamide, which comes from cyanamide molecules bonding together. A third potential contaminant, dihydrotriazine, can form depending on the raw materials used. Reputable manufacturers control for all three. The German-made Creapure brand, for example, holds creatinine below 100 milligrams per kilogram of product, dicyandiamide below 50 milligrams per kilogram, and dihydrotriazine below 3 milligrams per kilogram.
What’s in the Most Common Form
Creatine monohydrate is by far the most widely sold and researched form. “Monohydrate” simply means each creatine molecule is paired with one water molecule. That’s it. Pure creatine monohydrate is creatine plus water at the molecular level, and nothing else. The Creapure brand, used in most clinical research, tests at 99.9% purity.
Creatine hydrochloride (HCl) is the next most common form. Here, the creatine molecule is bonded to hydrochloric acid instead of water, which changes its solubility. Creatine HCl dissolves about 38 times more readily in water than monohydrate and contains roughly 78% creatine by molecular weight (the rest is the hydrochloride portion). Despite marketing claims, research has not shown HCl to be more effective than monohydrate at equivalent doses.
Other Ingredients in Commercial Products
If you buy unflavored creatine monohydrate from a reputable brand, the ingredient list is often just one item: creatine monohydrate. Some products add silicon dioxide as an anti-caking agent to keep the powder from clumping. By regulation, silicon dioxide can’t exceed 2% of the product’s total weight.
Flavored versions are a different story. These typically add sweeteners (sucralose, stevia, or acesulfame potassium), citric acid for tartness, natural or artificial flavors, and sometimes coloring agents. Some blended products include additional ingredients like electrolytes, B vitamins, or other amino acids. If you want pure creatine and nothing else, unflavored monohydrate is the straightforward choice.
Purity Varies Between Brands
Not all creatine powders are created equal. An analysis of creatine products sold on Amazon found that only 8% advertised third-party certification for purity or banned substances from recognized bodies like NSF International, Informed Sport, or the Banned Substances Control Group. That means the vast majority of products on the market rely on the manufacturer’s own quality claims without independent verification.
The practical takeaway: if purity matters to you (and it should, especially if you’re a tested athlete), look for products that either use Creapure as their raw material or carry a third-party testing seal. These certifications confirm the product contains what the label says and stays below safe thresholds for manufacturing byproducts like dicyandiamide and dihydrotriazine.