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Optimum Nutrition Micronised Creatine review: the right compound, the minimum dose

Optimum Nutrition Micronised Creatine review: the right compound, the minimum dose

The best-selling creatine on Amazon UK, and one of the few supplements where the science is not the weak link. One ingredient, no filler, no invented mechanism. The argument is about the size of the scoop and what the listing declines to tell you.

Wellnesslife reviews · August 2026 · No affiliate links, no paid placement

8.0Very good
The best-selling creatine in Britain, and the one product in this series where the evidence is as strong as the sales — the right compound, properly micronised, nothing added. It is dosed to the legal minimum rather than the dose most trials used, and sold without the purity credentials cheaper rivals publish. Buy it, use a scoop and a half.
Formulation
9
Dosing vs evidence
7
Real-world record
9.2
Value
7
Practicality
8
Transparency
6
Why 8.0. One ingredient, properly micronised, no fillers, and the compound with the strongest evidence base in sports nutrition — 21,000 buyers at 4.6, with strength mentions running 41 to nil. Formulation is close to faultless. The marks come off on dose and disclosure: 3 g of creatine is the minimum the authorised claim requires rather than the 5 g most trials used, the pack gives no loading phase or bodyweight guidance, and the scoop is too small to measure 5 g in one go. No purity specification, Creapure licence or sport certification is stated either, which matters for anyone competing under anti-doping rules.
Per scoop
3.4 g creatine monohydrate — about 3.0 g of creatine itself
Ingredients
Creatine monohydrate. May contain milk, gluten, egg, soy, nuts and peanuts
Directions
One scoop in 240 ml of liquid, one serving a day — no loading phase given
Pack
317 g — 93 servings, about three months · also 187 g and 634 g
Price
Not shown on the listing as accessed — no featured offer available
Purity certification
None stated — no Creapure, no Informed Sport or Informed Choice
Made by
Optimum Nutrition · contact address Dublin, Ireland
Rating
4.6 from 21,495 Amazon ratings

What one scoop contains

The pack arithmetic is sound. A 317 g tub divided by a 3.4 g scoop gives 93 servings, exactly as claimed. That is more than most of this category manages.

The wording is not. The product description says each serving provides “3g of creatine monohydrate”, while the directions say the scoop is 3.4 g. Both figures are real; they describe different things.

3.4 g → 3.0 gCreatine monohydrate carries a water molecule, so 3.4 g of the powder contains about 3.0 g of creatine. The scoop is 3.4 g of monohydrate; the 3 g is the creatine inside it. Optimum Nutrition has the right number attached to the wrong noun — and 3 g of creatine happens to be the exact minimum the UK authorised performance claim requires.

That coincidence is worth sitting with. The dose is not a formulation decision arrived at from the literature. It is the smallest amount that lets the pack make its claim.

Three grams or five?

Three grams a day does work. It maintains raised muscle creatine stores, and the widely used maintenance formula of 0.03 g per kg of bodyweight puts a 100 kg lifter at almost exactly 3 g. Nobody following this pack is wasting their money.

But the bulk of the research did not use 3 g. Most strength and lean-mass trials settled on 5 g a day, often after a loading week at around 20 g, and 5 g is the figure the International Society of Sports Nutrition position stand centres on.

1.7 scoopsWhat it takes to reach 5 g of creatine from this tub, since 5 g of creatine means about 5.7 g of monohydrate. A reviewer in Germany, elsewhere on the same listing, arrived at the same place independently: he takes about 5 g daily and finds the scoop too small for one measure. At that rate the 317 g tub lasts 55 days, not 93.

The instruction “one serving per day” is the real shortfall. There is no loading option, no mention of bodyweight, and no distinction between a 55 kg beginner and a 95 kg powerlifter. Creatine is one of the few supplements where dose guidance is genuinely settled, and the pack gives none of it.

The evidence, for once, is strong

Most supplements have to be marked down for thin trials. This one does not. Creatine monohydrate is among the most heavily studied compounds in sports nutrition, with hundreds of randomised trials behind it, and the effects are consistent: improvements of roughly 5–15% in output during short, repeated, high-intensity work, and gains of about one to two kilograms of lean mass over a few weeks of training, some of it intracellular water.

The authorised UK claim — increased physical performance in successive bursts of short-term, high-intensity exercise — is one of the few sports-nutrition claims that reflects what the trials actually showed rather than a stretch from them.

Two honest limits. Around a fifth to a third of people respond little, because their muscle stores are already near saturation; vegetarians, whose baseline is lower, tend to respond most. And the cognitive benefits now widely promoted rest on far weaker evidence than the performance ones, mostly in sleep-deprived or low-intake groups.

On safety, one reviewer here warns that overdosing “may result in renal failure”. That is worth correcting. Creatine has been studied in healthy adults for up to five years without evidence of kidney damage. It does raise serum creatinine, because creatine breaks down into creatinine, and that can make a routine blood test look alarming without anything being wrong. Anyone with existing kidney disease is a different case and should ask a doctor.

What the listing doesn’t say

A one-line ingredient list is inherently transparent. There is no blend to hide behind and no percentage to misread. What is missing sits alongside it.

No purity specification is given. Creatine monohydrate can carry manufacturing impurities such as creatinine and dicyandiamide, which is why some brands publish a specification or license Creapure. Nothing of the kind appears here, and no third-party testing is mentioned at all. Two competing products listed on the same page — one Creapure, one Informed Choice certified — do state theirs. For a tested athlete that gap is decisive.

The allergen line deserves a mention too: a single-ingredient powder that may contain milk, gluten, egg, soy, nuts and peanuts is a shared-facility declaration, and someone with coeliac disease or a nut allergy would reasonably not expect it here.

Finally, the safety warning excludes anyone with a pre-existing medical condition or taking any medication. Read literally that rules out a large share of adults, including anyone on a statin. Blanket wording of that breadth protects the manufacturer and tells the buyer nothing useful.

What buyers report

Ten full-length reviews read in full: the eight most recent from the United Kingdom, all verified purchases, plus the two most recent from other Amazon stores. Overall 4.6 from 21,495 ratings — 80% five-star, 3% one-star.

Unflavoured — mixes into anything
7/10
Noticeable strength or performance gain
6/10
Dissolves cleanly, no clumps
5/10
Good value for the quantity
4/10
No stomach problems
3/10
Only works with daily consistency
2/10
Some grit or residue if under-mixed
1/10

Amazon’s topic breakdown, from a much larger sample, contains one figure that stands out.

41 to 0Positive against negative mentions of muscle strength. Mixability runs 76 to 4. Nothing in the breakdown is majority negative; the weakest attribute is digestive comfort at 22 negative out of 65. Reviews still cannot prove a supplement works — but here the trial evidence happens to point the same way they do.
Reviews establish reliably that the powder is tasteless, mixes well, comes with a usable scoop and lasts a long time. They cannot establish the strength gains, however unanimous: nobody is comparing themselves against a placebo, and creatine is taken by people who are also training. The difference here is that properly controlled trials reached the same conclusion independently. The digestive complaints are real and dose-related rather than product-specific — taking it with food and enough water is the standard fix.

Verdict

  • Works
  • One ingredient, no fillers, no proprietary blend
  • 93 servings from 317 g — the arithmetic checks out
  • Micronised: mixability 76 mentions to 4
  • Unflavoured, so it goes into anything
  • The compound with the strongest evidence in sports nutrition
  • Three pack sizes; scoop included
  • Doesn’t
  • “3 g of creatine monohydrate” is the wrong noun for the right number
  • 3 g is the claim minimum, not the 5 g most trials used
  • No loading phase or bodyweight guidance given
  • No purity specification, Creapure or sport certification
  • Rivals on the same page publish theirs
  • May contain six allergens despite one ingredient
  • Safety warning excludes anyone on any medication
  • Scoop is too small to measure 5 g in one go

Worth it if you want plain creatine monohydrate from a large brand, you mix it into a shake anyway, and you are willing to use a scoop and a half rather than the one the pack suggests.

Skip it if you compete under anti-doping rules and need a certified batch; if you want a published purity specification; if you have coeliac disease or a nut allergy; or if you can buy an identical single-ingredient powder cheaper, which on this evidence you often can.

Check with a pharmacist if you have kidney disease or reduced kidney function, take nephrotoxic medication or diuretics, are pregnant or breastfeeding, or are under 18 — the pack excludes all of these.

How we score

Every supplement in this section is judged on the same six criteria, weighted as below. We score the product that left the factory — the formula, the dose, the pack — not the way a retailer has written the listing. Marketing wording is worth pointing out, and we do, but it does not move the score.

Formulation · 25%
Do the ingredients, and the forms they come in, match what the product is sold to do? Fillers, padding ingredients and missing co-factors count against it.
Dosing vs evidence · 25%
Does a daily serving reach the amounts used in published research? Under-dosing and over-dosing both cost marks — one does too little, the other charges you for more than the trials asked for.
Real-world record · 20%
The customer rating converted to a 10-point scale, weighted by how many ratings stand behind it. Tens of thousands of buyers tell you something a desk review cannot; a few hundred tell you very little.
Value · 15%
Cost per day against comparable products, across the whole pack range rather than the priciest size.
Practicality · 10%
Capsule or scoop size, taste, dosing routine, availability — whether it is a thing people keep taking.
Transparency · 5%
Whether the label states the amounts, names the forms and declares the elemental content, and whether any third-party testing is specified.

Each criterion is scored out of 10 against the norm for its category, not against an ideal: 10 is best practice, 8 solid with minor gaps, 6 works but with a real limitation, 4 a serious shortfall, 2 should not be on the shelf. The overall figure is the weighted average, printed to one decimal place, and the paragraph under the table explains where the marks went.

SourcesProduct label, ingredient list and Amazon UK listing (ASIN B00T7L20AQ), accessed August 2026 · GB nutrition and health claims register, authorised claim for creatine · Kreider et al., International Society of Sports Nutrition position stand: safety and efficacy of creatine supplementation, Journal of the International Society of Sports Nutrition, 2017 · NHS, Sports supplements · molecular weights of creatine and creatine monohydrate · Ten full-length Amazon reviews and Amazon’s review-topic breakdown, read August 2026. The listing showed no price at the time of access, so cost per serving is not stated in this review rather than estimated.

How we review: every supplement is scored on the same six criteria — formulation 25%, dosing against the evidence 25%, real-world record 20%, value 15%, practicality 10%, transparency 5%. The real-world score reflects the product’s customer rating and, just as importantly, how many ratings stand behind it: tens of thousands of buyers tell you something a desk review cannot, while a few hundred tell you very little. We buy nothing from the brands we cover and take no payment for placement. General information, not medical advice.

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