Optimum Gold Standard Casein Review


When you hear people talking about protein supplements in the gym, most of the time the discussion will be about whey protein, simply because it has been the proven benchmark for pre and post workout protein supplements. It’s easily digested and breaks down into it’s various amino acid components quickly for maximum absorption.

Recently however, there has been a growing interest and trend towards adding Casein supplements to any well rounded supplement regime.

Optimum Nutrition one of the companies who are always at the leading edge of supplement development has once again shown the whey ahead (sorry…bad pun) with their Gold Standard 100% Casein.

Before we review ON’s product, let’s take a brief look at why Casein is proving to be popular and beneficial.

Slow but sure wins the race

As I’ve already mentioned, whey protein and the amino acids they contain are absorbed by the body quickly and when they’re needed most, shortly before or after a heavy workout.

Casein on the other hand, tends to “gel up” when it comes into contact with stomach and digestive acids. It’s this gelling up which causes it to be absorbed over a longer period of time, therefore giving you a slower and more sustained release of nutrients.

The gelling effect and slow breakdown also result in you feeling full for a longer period of time, which can help curb between meal snacking, giving you a double win.

The sustained release of Casein can be most beneficial if you take it during rest periods and especially before sleep, because it’s during these times with little or no food intake, that your body is building and repairing tissue.

The result is that by using whey as you normally would and adding casein to your supplement stack, your body is getting 24 hours of high quality protein to give you the gains you’re looking for.

About the Ingredients

optimum casein wheyProtein
Okay, I took issue with the 100% claim when I reviewed ON’s Gold Standard Whey, suffice to say there are other ingredients in the tub when you buy it. The 100% denotes the fact that the protein contained in the product is 100% derived from Casein.

ON have recognised this in their labeling stating it is 75% protein by weight or to put it in easy terms 24gm of protein per 32gm scoop.

Each serve contains over 5 Grams of BCAAs the main ones being Leucine, Isoleucine and Valine. Their functions in bodybuilding are as follows.

Valine: Vital for the growth and repair of tissue. It also helps to maintain the nitrogen balance in your body. It can also be used as a source of energy for muscles, therefore preserving glucose stores.

Leucine: Leucine is another BCAA that assists in sustaining nitrogen balance and supplies energy to the body during training, therefore preserving glycogen used for muscle contraction. Leucine also gives you better alertness or focus during your workout. Possibly the most important factor for bodybuilders is that Leucine is one of the most important aminos for protein synthesis. If your Leucine levels are depleted, your body can’t convert protein, no matter how much you take.

Isoleucine: Is a precursor for glutamine and alanine, needed for intense physical activity like weight training. Another amino that is used as fuel by muscle cells, again preserving others. Like many BCAAs, Isoleucine is important for protein synthesis and also for its anabolic and anti-catabolic properties.


However, after intense training, that figure is almost halved. Glutamine is also important for protein metabolism and can help reduce muscle deterioration.

Nutritional Info

Gold Standard 100% Casein has pretty much the same nutrition profile of most protein supplements with no big surprises to be found.

Serving size: 32gm (1 level scoop)
Calories: 120
Calories from fat: 10
Protein: 24gm
Carbs: 4gm
Fibre: 1gm
Sugars: 1gm
Fat: 1gm
Saturated: 0.5gm

Taste and Mix-ability

Here is maybe the first Achille’s heel of ONs Casein. Although they offer 8 flavors, none of them rank exceptionally well. The best ranking from 15000 plus users at Bodybuilding.com is only an 8.2/10 for Chocolate Supreme.

I’ve personally tried the vanilla and have to admit it was less than great with a sickly taste. I know we don’t use supplements for the taste, but come on, it should be reasonably palatable.

Something you will notice if you’ve not used a Casein supplement before is the thicker texture compared to whey proteins. This is normal due to the source of the protein. In terms of mix-ability, I found it was fine after about 30-40 seconds of vigorous shaking, with no sludgy sediment in the bottom of my cup.

A plus with the thicker mix is that you do feel full for longer and I never woke up with feelings of hunger.


Gold Standard Casein comes in 2lb (26 serves) and 4lb (52 serves) tubs with a recommended price of $45 and $75 respectively. Once again Bodybuilding.com have slashed the prices to $32 and $54 each.

It’s pretty good value at the promotional price of between $1.03-$1.30 per serve, but there are cheaper alternatives around.

The difference being that Optimum Nutrition have an established good reputation for supplying high quality supplements.

Summing it up

Just to recap the main points on Optimum’s Gold Standard Casein.

+ Provides a sustained release of protein, essential and non essential BCAAs.

+ Ideal for periods of rest and sleep.

+ Can be added to your supplement stack to give you 24 hour protein supplementation.

+ Mixes well.

+ Thicker texture keeps you feeling fuller for longer, reducing hunger and snacking.

+ 8 Flavors.

+ Promotional prices available.

– Although it has 8 flavors, they leave a little to be desired.

– Even with promotional prices it can be expensive.


If you’re after 24 hour protein supplementation, adding ONs 100% Casein to your stack is well worth the cost and maybe putting up with a taste you don’t particularly like.

The people at Optimum are always working on improving their products so who knows, maybe soon they’ll have the flavor issue ironed out.

Overall, I have no problem recommending it to you, but as always, shop around for the best price on this or any other Casein product.