Optimum Nutrition Gold Standard 100% Plant Protein review

Our take: a good vegan protein with a small-tub problem

Gold Standard 100% Plant is Optimum Nutrition’s answer for people who do not want whey. A 32 g scoop gives 24 g of protein from pea and rice, with a short ingredient list, about 143 kcal and 1 g of sugar. On the core job — adding protein to a vegan or dairy-free diet — it does well.

It also has something most of the brand’s range does not: Optimum Nutrition names Gold Standard 100% Plant on its own list of Informed Sport registered products. Our reviews of its creatine, casein and Serious Mass could not say that.

The drawback is price and pack size. The UK tub is 684 g, about 21 scoops, and the price per gram of protein is roughly the same as Gold Standard whey — fair on offer, expensive at full price.

This is a desk review. We have read the published label details, UK retailer listings and the research on plant protein and resistance training. We have not used this product, tested its contents or run a trial. We could not open the brand’s GB product page while writing, so the next section says where each figure came from.

What exactly are you buying?

The UK tub is 684 g, in vanilla and double rich chocolate. A serving is one level 32 g scoop mixed with 300 ml of cold water, and listings give about 21 servings for vanilla; some flavours are listed at 19.

Per 32 g scoop, UK listings give:

• 24 g of protein, including about 4 g of naturally occurring BCAAs
• About 143 kcal
• About 4.2 g of carbohydrate, of which 1 g is sugar, and 1.3 g of fibre
• About 2.4 g of fat
• About 0.8 g of salt

The ingredient list for vanilla is short: pea protein, rice protein, natural flavours, a thickener (xanthan gum), cinnamon and the sweetener sucralose. There are no artificial colours or flavours, and nothing from milk or egg.

The salt is the figure worth noticing. At 0.8 g a scoop, it is about 13 per cent of the 6 g daily maximum the NHS recommends for adults — not a problem on its own, but more than most whey powders, and worth knowing if you are watching your salt.

Why pea and rice together?

Plant proteins tend to be lower in one or more essential amino acids than milk protein. Pea protein is relatively low in methionine; rice protein is relatively low in lysine but higher in methionine. Blending them gives a more complete amino acid profile, which is why so many vegan powders pair the two. At 24 g of protein a serving, the blend delivers a useful dose of all the essential amino acids.

Does plant protein build muscle as well as whey?

For most people, yes, provided total protein is enough. In a 2015 randomised trial by Babault and colleagues, 161 young men doing 12 weeks of resistance training took pea protein, whey or a placebo twice a day. Muscle thickness increased similarly with pea and whey, and the pea group gained significantly more than placebo.

At the level of the whole diet, a 2021 study by Hevia-Larraín and colleagues compared habitual vegans with omnivores on protein-matched diets of about 1.6 g per kilogram of body weight a day over 12 weeks of training. Muscle mass and strength gains were similar. A 2018 meta-analysis by Messina and colleagues found the same for soy against animal protein.

The practical rule is the one that applies to any protein powder: reach your daily total first. A 2018 meta-analysis by Morton and colleagues found gains in fat-free mass levelled off at around 1.6 g of protein per kilogram of body weight a day. Our protein calculator works out your figure. Some researchers suggest slightly larger servings of plant protein to match the effect of whey, which is easy to do with a slightly heaped scoop.

Testing: one of Optimum Nutrition’s registered products

Optimum Nutrition’s customer-service page on Informed Sport names three products as Informed Sport registered: Gold Standard 100% Whey England Rugby, the Optimum Bar and Gold Standard 100% Plant. That makes this the only protein powder in the brand’s standard UK range with a product-level registration claim.

For a drug-tested athlete that is a meaningful advantage. Strict liability still applies, so look up the batch number on your tub in the Informed Sport database before relying on it. We did not search the database ourselves, so we are reporting what the brand states.

Price: work it out per 100 g of protein

At 24 g of protein per 32 g scoop and about 21 scoops, the 684 g tub holds roughly 500 g of protein. In listings read on 28 September 2026, the tub was £21.95 at one sports-nutrition retailer and £28.00 at Boots — about £4.36 to £5.56 per 100 g of protein, or roughly £1.05 to £1.33 a scoop.

That is similar to Gold Standard whey, which we priced at £5.55 to £6.94 per 100 g of protein, and more than the value wheys. The brand’s own store also sells a two-tub bundle, which may bring the price down. We read these prices from listings rather than taking an order through checkout; check the price per 100 g of protein on the day.

Best alternatives

The ones we have fully reviewed are linked, and appear in the comparison cards below this article. 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 Vegan Protein (reviewed) — a pea and fava bean blend listed at up to 24 g of protein per serving, from the brand that usually leads on price. Compare the price per 100 g of protein on the day.
• Bulk Vegan Protein Powder (reviewed) — listed at 23 g of protein per serving and 28 servings per 1 kg, a larger pack than Optimum Nutrition’s.
• Soya milk, tofu, tempeh and lentils — the food route. A 500 ml glass of soya milk gives roughly 15 to 18 g of protein, and most vegans can reach their daily target without a powder if they plan meals around these.
• Optimum Nutrition Gold Standard 100% Whey (reviewed) — if you eat dairy, the sister product at a similar price per gram, and one a member of our team has used.
• Myprotein Impact Whey (reviewed) — if you eat dairy and want a value whey; it scores the same 7.6 as this product, with a higher mark for value.
• Myprotein Slow-Release Casein (reviewed) — if you eat dairy and want a slower-digesting shake before bed or between meals.

Who should skip it, and what to watch for

Most people tolerate pea and rice protein well, though some find pea protein causes wind or bloating at first. Anyone with a pea or legume allergy should avoid it, and anyone with other allergies should check the tub’s may-contain statement, since it is made in a facility that handles other allergens.

If you are watching your salt — for example because of high blood pressure — count the 0.8 g per scoop. Anyone with kidney disease should ask their GP or dietitian before increasing protein.

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.

Sources and shopping: our UK buying checklist

Before you order, check the flavour, the servings listed for it, the delivered price and the seller. Work out the cost per 100 g of protein — price ÷ (servings × 24) × 100 — and compare it with a vegan own-brand powder on the same day. If you compete, note the batch number when the tub arrives and look it up.

When the tub arrives, check the seal, the batch code and the best-before date, and read the allergen statement for your flavour.

Our commercial link for this product is our Gold Standard Plant Protein link. It earns us a commission at no extra cost to you, and it has no influence on the score above — which is a 7.6, the highest of the Optimum Nutrition products we have reviewed, held back by a small tub, a brand price per gram and more salt than most protein powders.

The fair summary is this. Gold Standard 100% Plant is a clean, tested vegan protein that works as well as whey for most people. Buy it on offer, or compare it with an own-brand vegan powder first.