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SiS Whey Protein



Easy to mix with a pleasant taste and does seem to boost performance. The downside would be the ongoing cost

At every product is thoroughly tested for as long as it takes to get a proper insight into how well it works. Our reviewers are experienced cyclists that we trust to be objective. While we strive to ensure that opinions expressed are backed up by facts, reviews are by their nature an informed opinion, not a definitive verdict. We don't intentionally try to break anything (except locks) but we do try to look for weak points in any design. The overall score is not just an average of the other scores: it reflects both a product's function and value – with value determined by how a product compares with items of similar spec, quality, and price.

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SiS Whey Protein is designed to help your muscles grow and develop. Since adding it to my diet for the purposes of this test, my riding performance certainly seems to have improved in endurance terms. I have stepped up a level, riding six days a week and feeling that I am able to push harder for longer.

For me, the key to nutritional products is the taste. If you can't stomach it then you'll be reluctant to use it. The Whey Protein is pleasant on this score, with none of that artificial aftertaste you get with some energy products.

It also needs to be an easy mix: you need to be able to add the powder, shake vigorously and be presented with a smooth drink. Again, no complaints here with the Whey Protein. After a few vigorous shakes the three scoops of powder mix well without leaving any lumps and it forms an almost milkshake like texture.

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The daily recommended protein intake for a male training regularly and weighing 75kg is 120g. You can't do this all in one go, though. As SiS states: "Your body can only process up to 25g of protein at a time, so a graduated intake of 20-25g every 3-4 hours throughout the day is recommended by sports nutritionists to support lean muscle mass." This lets your body absorb the protein and use it.

There are various factors that can affect how you perform on the bike: rest, training, work, family life and so on. There is a lot going on in most people's lives that can have a detrimental impact on how you can train, race and recover. That's another reason why the Whey Protein appeals: it's easy to add to your daily diet, either with meals or between them as mid-morning or mid-afternoon snacks (as suggested by SiS). 

The science recommends that you take it before or after training. If you use it after training, try to consume it within 30 minutes of finishing so you get the maximum benefit (a good idea is to have the mixture prepared before your exercise, so it's ready to drink straight after you stop).

To clarify, it does contain milk and soy, but it is gluten free and suitable for vegetarians.

It is available in either 1kg or 2kg tubs and in four flavours: banana, chocolate, strawberry or vanilla. The 1kg tub provides 33 servings.


Easy to mix with a pleasant taste and does seem to boost performance. The downside would be the ongoing cost test report

Make and model: SIS Whey Protein

Size tested: Chocolate, 1kg

Tell us what the product is for, and who it's aimed at. What do the manufacturers say about it? How does that compare to your own feelings about it?

SiS says:

About SiS Whey Protein

SiS Whey Protein contains a blend of high quality whey protein isolate and concentrate. The product formulation provides a source of rapidly digesting protein, with an amino acid profile which supports lean muscle growth and maintenance, with at least 5g of BCAAs per serving.

Each serving contains 22-23g of protein per serving, depending on the flavour you choose. Whey protein has some of the highest digestion rates known, and has a high leucine content, either 2.5g per 30g serving for strawberry, banana and vanilla flavour, or 2.4g for chocolate flavour. Leucine is an amino acid which is not only a building block for new muscle protein, but also increases the rate of muscle protein synthesis.

Why should I take SiS Whey Protein?

SiS Whey Protein is a great tasting, convenient way to ensure you have enough protein in your diet. For individuals that exercise regularly and want to promote a low body fat percentage, around 1.4-1.6g of protein per kilo of body mass is recommended. For a 75kg male who trains regularly that would equate to 120g of protein per day.

Your body can only process up to 25g of protein at a time, so a graduated intake of 20-25g every 3-4 hours through the day is recommended by sports nutritionists to support lean muscle mass. Many people have larger servings of protein at their mealtimes, meaning that there is an over consumption at some times and a lack of intake at others. SiS Whey Protein is easily added to the diet to allow you to spread out your protein intake with very little additional and unnecessary carbohydrate or fat.

As with all SiS products, SiS Whey Protein is produced at our Informed Sport accredited factory and is rigorously screened to ensure a clean, safe product that athletes of all levels trust.

Recommended Usage

SiS Whey Protein can be used throughout the day with or between meals (such as at breakfast or mid-morning and mid-afternoon snacks) to provide a convenient way to increase daily protein intake.

After training consume one serving within 30 minutes of finishing your session for maximum benefit."

Having used it regularly I have seen an increase in my endurance.

Tell us some more about the technical aspects of the product?

"SiS Whey Protein 1kg

High protein formula to aid muscle growth and development:

* Whey protein isolate & concentrate blend

* Contributes to lean muscle mass growth & maintenance

* Fuelling gold medal winners since 1992

* Wheat & Gluten Free

* Informed Sport tested

Rate the product for performance:


The SiS Whey Protein has been formulated to aid muscle growth and development. It's easy to mix, has a pleasant taste and has helped boost my performance. 

Rate the product for value:

This is a difficult conundrum. If you feel you need to tweak your training using the science that SiS has developed then it does come at a price. It does seem to work, but you would have to consider the long-term cost. On top of other nutritional products used when racing or riding, the cost would soon add up, so you need to weigh this up against how you are able to perform.

Tell us how the product performed overall when used for its designed purpose

SiS Whey Protein ticks a lot of boxes. It's easy to mix, tastes pleasant and, in regards to the purpose it has been designed for, it ticks that box too.

Tell us what you particularly liked about the product

As stated above, those three features are what you want from a nutritional aid.

Tell us what you particularly disliked about the product

My only concern would the ongoing cost of using the SiS mix.

Did you enjoy using the product? I have been impressed by the taste, the ease of mixing and the end result.

Would you consider buying the product? Yes

Would you recommend the product to a friend? Yes

Use this box to explain your score

Despite a little scepticism I have been impressed on a number of fronts by the SiS Whey Protein. It mixes easily and without lumps, tastes pretty good, and has improved my performance over the period I have used it. The cost of ongoing use would be a negative.

Overall rating: 8/10

About the tester

Age: 45  Height: 178cm  Weight: 80kg

I usually ride: Pinnacle Evaporite Three  My best bike is: As above

I've been riding for: Under 5 years  I ride: Every day  I would class myself as: Experienced

I regularly do the following types of riding: road racing, commuting, sportives, mountain biking, and looking to dip my toe in the world of TT


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Ginsterdrz | 8 years ago

Rego is SIS version with soy.

StraelGuy | 8 years ago

Over-priced cobblers. Basic powdered soy protein contains the same balance of amino acids as human muscle and can be bought a heck of a lot cheaper than this  35 .

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