Optimum Nutrition Micronised Creatine Powder review

Our take: the right ingredient, the right dose, a brand price

Creatine is the rare supplement where the honest review is mostly good news. The ingredient has decades of randomised trials behind it, the dose that works is known, and it is cheap to make. That leaves very little room for one creatine to be better than another — and it makes this a review about the label and the price rather than about whether the product works.

Optimum Nutrition Micronised Creatine Powder is, on its own panel, one ingredient: creatine monohydrate. Each serving gives 3.4 g of creatine monohydrate, which the panel states as 3.0 g of creatine. That 3 g figure matters, because it is exactly the daily intake the UK’s authorised creatine claim is conditioned on, and it is enough to fill muscle creatine stores over about four weeks without the loading phase gym folklore insists on.

Where it falls short is housekeeping. The brand’s own GB page describes a single serving in three different ways, and none of them is wrong enough to matter physiologically — but a one-ingredient product should not need a reader to reconcile its label. And at list price you are paying roughly double what a discounted own-brand monohydrate cost on the same day, for a powder that is chemically the same thing.

This is a desk review. We have read the brand’s published label, the pricing across UK retailers and the research on creatine monohydrate. We have not used this tub, tested its contents or run a trial. Where we say something about mixing or taste, we say whose claim it is.

What exactly are you buying?

The figures on this page were read from Optimum Nutrition’s GB product page on 28 September 2026. The unflavoured powder comes in three pack sizes: 187 g (55 servings), 317 g (93 servings) and 634 g (186 servings). The brand also sells Fruit Punch, Blue Raspberry and Orange versions in different pack weights; flavoured powders carry more than creatine, so if you want the product reviewed here, choose unflavoured.

The ingredient list is two words long: creatine monohydrate. The panel gives 3.4 g of creatine monohydrate per serving, equal to 3.0 g of creatine — the difference is the water molecule bound into the monohydrate form, which is about 12 per cent of its weight. Nothing else is added to the unflavoured version, so there is no sweetener, flavouring, anti-caking agent or proprietary blend to account for.

“Micronised” means the powder is milled to a finer particle size. The brand says this helps it mix and stay suspended in liquid. That is a plausible handling benefit, and it is only a handling benefit: we know of no evidence that micronised creatine is absorbed into muscle better, or works better, than standard creatine monohydrate. Treat it as a reason the drink may be less gritty, not as a reason it may be more effective.

One thing the page does not tell you is where the creatine comes from. Some brands name a specific manufacturer’s creatine on the tub; this page does not name any source. That is not evidence of a problem, and creatine monohydrate is a simple, well-characterised compound. It is simply a detail the label leaves out.

The label disagrees with itself on serving size

Read the brand’s GB page from top to bottom and a serving is described three ways. The headline bullets say “3g of creatine monohydrate per serving.” The nutrition panel says a serving is 3.6 g and contains 3.4 g of creatine monohydrate. And the pack arithmetic — 187 g divided by 55 servings, or 317 g divided by 93 — gives a serving of 3.4 g.

For a powder with one ingredient, a 3.6 g serving cannot contain only 3.4 g of that ingredient, so one of those numbers is wrong. The most likely reading is that a serving is 3.4 g of creatine monohydrate, which provides 3.0 g of creatine, and that the 3.6 g figure and the “3g of creatine monohydrate” bullet are drafting errors. That reading is ours; the brand has not confirmed it. The practical consequence is small — every version lands close to the 3 g of creatine that matters — but it is the reason this page loses marks for transparency.

The directions are also inconsistent. The panel says one level scoop in 240 ml of cold water; the suggested-use section says one rounded teaspoon in water or juice. A level scoop is the one to follow, because the pack arithmetic depends on it.

What 3 g of creatine can realistically do

The evidence is strong, and specific

Creatine monohydrate is one of the most studied supplements in sports nutrition. The International Society of Sports Nutrition’s 2017 position stand describes it as the most effective ergogenic nutritional supplement currently available for increasing high-intensity exercise capacity and lean body mass during training, and summarises a large body of research on both performance and safety.

The meta-analyses put numbers on that. A 2017 systematic review in Sports Medicine pooled 53 randomised, placebo-controlled studies — 563 people taking creatine and 575 controls — and found a consistent improvement in upper-body strength in exercises lasting under three minutes, including bench press. An earlier review by the same group reported the same pattern for lower-limb strength. The effect sizes are modest rather than dramatic: this is a reliable few per cent on top of training, not a replacement for it.

The mechanism explains why the benefit is narrow. Creatine tops up the phosphocreatine store muscles use to regenerate energy in the first seconds of hard effort. That helps with repeated sprints, heavy sets and anything with short, maximal bursts. It does little for steady endurance work, and it does not build muscle on its own — it lets you do slightly more work in training, and the training does the rest.

Why 3 g a day is enough — and loading is optional

The classic dosing study was run at Nottingham. Hultman and colleagues gave 31 men creatine in different patterns and found that 20 g a day for six days raised muscle creatine by about 20 per cent — and that 3 g a day for 28 days produced a similar 20 per cent rise, just more gradually. Their conclusion was that 3 g a day is, in the long term, likely to be as effective as the higher dose.

That is the whole case for this product’s single daily serving, and the brand’s own suggested-use text says the same thing: 3 g daily for 28 days to raise muscle stores. Loading with 20 g a day for a week gets you there faster, uses up a 317 g tub in about three weeks, and is more likely to upset your stomach. For most people there is no reason to hurry.

What the GB label is allowed to say

Under the Great Britain nutrition and health claims register, creatine has an authorised claim: it increases physical performance in successive bursts of short-term, high-intensity exercise. The claim may only be used on a food that provides 3 g of creatine a day. This product’s panel states 3.0 g per serving at one serving a day, so it meets that condition exactly, and the claim on the page is the authorised wording.

Anything the marketing says beyond that — faster absorption, better mixing, being the UK’s number one — is a statement about the product or its sales, not an assessed health claim. The “UK’s #1” line is footnoted on the brand’s page to retail sales data, which is a measure of popularity rather than of quality.

Third-party testing: what the brand does and does not claim

This matters mainly if you compete under anti-doping rules. Optimum Nutrition’s customer-service page on Informed Sport states that all of its powders and supplements are made at its Glanbia Performance Nutrition facility in Middlesbrough, and that the site is Informed-Sport registered — a certification covering manufacturing controls, inspections and facility swabbing.

The same page then names the specific products that are Informed Sport registered: Gold Standard 100% Whey England Rugby, Gold Standard 100% Plant and the Optimum Bar. Micronised Creatine is not on that list, and the GB product page makes no batch-testing claim for it. The page directs athletes who need batch-tested products to a separate custom LGC batch-tested range.

So the position is the same one we set out in our Gold Standard whey review: a registered British manufacturing site is a real quality signal for an ordinary buyer, and it is not a certificate for the tub in your hand. If you are drug-tested, strict liability applies, and you should buy a product whose batch you can look up in the certifier’s database. We did not search the Informed Sport database for this product, so we are reporting only what the brand itself states.

Price: the ingredient is cheap, so the maths decides it

On 28 September 2026 the brand’s GB store listed the unflavoured powder at £14.00 for 187 g, £22.00 for 317 g and £40.00 for 634 g. The page also advertised 25% off the 317 g tub until 4 October 2026, which would bring it to £16.50; we saw the offer on the product page but did not take it through checkout, so confirm it is applied before paying.

Because every serving is the same 3.4 g of the same ingredient, the fairest comparison is price per 100 g of creatine monohydrate. At the brand’s list prices that is £7.49 for the 187 g pack, £6.94 for the 317 g and £6.31 for the 634 g. With the 25% offer, the 317 g drops to about £5.21 — the cheapest way to buy it on the day we looked. Per serving, those work out at roughly 25p, 24p, 22p and 18p.

Retailers were not consistently cheaper. A UK price comparison on the same date listed the 317 g tub at £19.75 on OnBuy, £21.99 at Very, £22.51 on Amazon, £23.99 at BikeInn and £27.41 on eBay. The cheapest of those, at about £6.23 per 100 g, still sits above the brand’s own offer price, and the dearest charges over £5 more than the brand’s list price for the same tub.

The comparison that decides this purchase is plain creatine. On the same day Myprotein listed its unflavoured Impact Creatine at £15.99 for 500 g and 147 servings, discounted from £29.99. That is £3.20 per 100 g on offer — about half what Optimum Nutrition costs at list price — or £6.00 per 100 g at its undiscounted price, which is close to Optimum Nutrition’s. In other words, the gap between the two brands is mostly the gap between a discount and no discount. Whichever tub you buy, buy it when it is on offer.

Two practical traps. A flavoured creatine is heavier per serving and contains other ingredients, so compare it by grams of creatine, not grams of powder. And a bigger tub only saves money if you will finish it: at one serving a day, the 634 g pack lasts about six months.

Who should skip it, and what to watch for

The brand’s own label says the product is not suitable for anyone under 18. It also carries a may-contain warning for traces of milk, soy, gluten, egg, nuts and peanuts, because of the factory it is made in. For most people that is irrelevant; for someone with a severe allergy to any of those, it is a reason to look for a creatine made on a dedicated line.

For healthy adults, creatine monohydrate has one of the better safety records in the supplement aisle. The ISSN’s 2021 review of common questions and misconceptions concluded that the research does not support the claims that creatine harms healthy kidneys, causes dehydration or cramping, or leads to hair loss. The hair-loss worry traces to a single 2009 study of 20 rugby players that found a rise in the hormone DHT after a loading phase; it did not measure hair loss and has not been replicated. It is reasonable to know about, and not a reason to expect your hair to fall out.

Two practical points are worth holding on to. Creatine often adds a kilogram or so of body weight in the first weeks, mainly water drawn into muscle; that is expected and not fat. And creatine raises blood creatinine, a marker doctors use to estimate kidney function, so a routine blood test can look worse than your kidneys actually are. If you have a blood test booked, tell the doctor you take it.

Anyone with kidney disease, anyone taking medicines that affect the kidneys, and anyone pregnant or breastfeeding should talk to their GP or pharmacist before starting. Food supplements sold in Great Britain are not approved by a regulator for safety or effectiveness before sale, so the label is the manufacturer’s responsibility rather than a regulator’s endorsement.

Optimum Nutrition, plain creatine, or none?

The closest comparison is any unflavoured creatine monohydrate from a reputable seller, such as Myprotein’s Impact Creatine. The ingredient is the same compound at the same dose, so the differences are pack size, price, mixability and testing claims. We have not written a full review of any other creatine yet, so we name these for price comparison only; do not read this as a recommendation of one over the other.

Some creatines advertise a named branded source of creatine monohydrate and cost considerably more. That can be a reasonable choice if traceability matters to you, but it is a claim about supply chain rather than about a better result: the trials were run on creatine monohydrate, not on a brand of it.

Newer forms — creatine HCl, buffered creatine, creatine ethyl ester — are usually more expensive and have far less research behind them. The ISSN position stand treats monohydrate as the reference form. If a product claims its form works better at a smaller dose, ask to see the trial.

And the last option is none at all. Creatine helps with short, intense, repeated efforts. If your training is mostly walking, running or steady cardio, the benefit is small. If you do lift, sprint or play a stop-start sport, creatine is one of the few supplements with a solid case — and the case is for creatine, not for any particular tub.

Best alternatives

The ones we have fully reviewed are linked. The others we name for comparison only: we have not reviewed them in full, so do not read their inclusion as a recommendation.

• Myprotein Impact Creatine (not yet reviewed) — the cheapest mainstream unflavoured monohydrate on the day we looked: £15.99 for 500 g on offer, or £3.20 per 100 g, against £6.31 to £7.49 for Optimum Nutrition at list price. Same compound, same dose.
• Bulk Creatine Monohydrate (not yet reviewed) — a price comparison site listed the unflavoured 500 g pack from £12.99, about £2.60 per 100 g. Bulk also sells a Creapure-branded version for buyers who want a named source, at a higher price.
• Optimum Nutrition Serious Mass (reviewed) — only if you also need a lot of extra calories: each serving includes 3 g of creatine alongside about 1,250 kcal. For anyone who just wants creatine, it is the wrong tool.
• A batch-tested creatine — if you compete under anti-doping rules, the best alternative is whichever monohydrate you can look up by batch in a certifier’s database, whatever the brand.

Sources and shopping: our UK buying checklist

Before you order, confirm four things: that you have chosen the unflavoured version, the pack size, the final delivered price, and the seller. On marketplaces, check that the seller is the brand or an authorised retailer — counterfeit sports nutrition is a documented problem, and a verifiable seller is the simplest protection. Then divide the price by the pack weight and multiply by 100 to get the cost per 100 g, and compare it with a plain monohydrate on the same day.

When the tub arrives, check that the seal is intact, that the label is in English with a GB or EU address for the responsible business, and that the batch code and best-before date are legible. Use a level scoop, once a day, and give it four weeks before judging whether it is doing anything. If you compete, do not rely on the site-level registration described above: use a batch-tested product you can look up.

Our commercial link for Optimum Nutrition in the UK is our UK Optimum Nutrition link. It earns us a commission at no extra cost to you, and it has no influence on the score above — which is a 7.4, held back by a label that contradicts itself and a list price that a plain creatine undercuts, not by any doubt about the ingredient.

The fair summary is this. Optimum Nutrition Micronised Creatine is creatine monohydrate at the dose the evidence supports, from a long-established manufacturer. It will do what creatine does. Whether it is the one to buy comes down to what 100 g costs on the day you look — and on the day we looked, the answer was only yes when it was on offer.