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PowerBar Isomax High Performance Sports Drink



An excellent all-in-one drink, providing carbohydrates for energy, protein for endurance, minerals to help avoid cramp, plus caffeine for focus and an extra boost. Mild taste and fair value too.

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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With two types of carbohydrate to provide energy, five essential minerals to help you avoid cramp and the addition of protein and caffeine, Powerbar Isomax energy drink is a very effective all-in-one package.

Let's look at the key ingredients one by one.

First, the carbs. This Powerbar Isomax drink includes both glucose and fructose, a combination that Powerbar's marketing team call 'C2MAX'. Why the two types? Because the amount of glucose you can convert to energy is normally limited to around 60g per hour, but fructose enters the bloodstream by a different mechanism, which means you can increase this amount. The end result is more energy (the Powerbar website claims up to 55% extra), which helps you go faster or further, or just go the same speed and distance more easily.

Next, the minerals. Powerbar make much of Isomax containing five minerals: sodium, potassium, magnesium, chloride and calcium. What do they do? They replace the essential minerals or electrolytes in your body that you lose via perspiration when cycling, and this is claimed to help you avoid cramp. Sodium, potassium and magnesium are commonly found in mineral/electrolyte drinks from other brands, but PowerBar Isomax adds chloride and calcium, and claims to be 'the first sports drink on the market to provide the body with all five main electrolytes ... in the ratio lost through sweat.'

Then we come onto the protein, which PowerBar dubs 'PeptoPro'. Why is this added? Because several studies show that protein helps the body take on carbohydrate and more easily convert it to energy. This doesn't necessarily mean you go any faster, but it does mean you can keep going for longer. The studies vary in their opinions on the best ratio of carb to protein, and also when the benefits of protein kick in, although most agree it's after about two hours of exertion. (So for short rides, protein is generally not needed.) In a serving of Isomax, carb makes up 83% and protein just 6%, giving a carb:protein ratio of around 15:1 which is quite low compared to the mix in other brands.

And finally, to finish, a dash of caffeine. This is here for three main reasons: 1. Because (to put it in layman's terms) caffeine helps carbohydrate work better, meaning you get a little extra - and totally legal - energy boost. 2. Because it helps focus the mind. That's why many of us pick up an Americano on the way to the office, but it's also very useful when you need to focus in a sporting environment. 3. Because caffeine acts as a pain-killer, ideal for those times when you've been hanging on to wheels or giving it stick at the front and now with 10 miles to go everything hurts because it's all just so damn hard. In a 50g serving of Isomax, there's 70mg of caffeine.

So there you go. Two sorts of carb, five minerals, plus protein and caffeine. That's a big bundle of ingredients in PowerBar Isomax, each one with a different aim. So does this product work?

I've used this drink on a couple of long training rides, and it definitely works for me. My preferred technique for long rides is to use a carb-only drink in my first bottle, so I started drinking the Isomax in my second bottle (both bottles 750ml) – combined with my usual array of gels and bars. I found the carb-protein drink mix kept me going in the second half of the ride with a good sustained supply of energy, while the minerals also seemed to help me avoid the cramps I sometimes get in my calves after about 70 miles of hard pounding. To be honest, I didn't notice the effects of caffeine in this drink mix (which may be because I'm more accustomed to getting my hit from caffeine enhanced gel in the last part of a long ride). But while I was obviously tired in the final few miles, I felt comfortable and my brain was still in gear.

So PowerBar Isomax works for me, but will it work for you? That depends. For a start, if you mainly ride shorter races and sportives, or if you tend not to push yourself too hard, then this type of energy product is not essential. But if you're doing road-races, long time trials or just like to crack on in a 100-mile sportive, then I'd recommend Isomax as well worth trying.

This Isomax drink is available in just one flavour: Blood Orange. It was certainly blood orange in colour, but the taste was very mild, and neither sweet, sharp or sticky – similar to PowerBar Isoactive in that regard. If you don't like the strong taste of some other energy drinks, then the mild flavour of Isomax will be a good thing. On the other hand, if you need a tasty drink to encourage you to keep hydrating, this mild flavour may not be so useful.

PowerBar Isomax is available in various quantities: a big 1200g tub of powder (making 12 litres of drink at the recommend levels of 50g per 500ml) costs £23.49 on the PowerBar website. The same amount of powder in a pack of 20 sachets (each 50g) is 27.80; and a pack of five sachets is £6.95. This product is also available at bike/sport shops and at the usual on-line stores. It's not cheap when compared to carb-only sports drink-mix powders, but it's fair value when compared to similar carb-and-protein products from other brands.


An excellent all-in-one drink, providing carbohydrates for energy, protein for endurance, minerals to help avoid cramp, plus caffeine for focus and an extra boost. Mild taste and fair value too. test report

Make and model: PowerBar Isomax High Performance Sports Drink

Size tested: Blood Orange

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?

This is an energy drink power which you mix with water in the bottles on your bike. According to Powerbar, you can use it during events and for carb-loading beforehand.

The Powerbar website says this about Isomax:

"... the first sports drink on the market to provide the body with all 5 main electrolytes (Sodium, Chloride, Potassium, Magnesium and Calcium) in the ratio lost through sweat.

Delivers fast hydration through its isotonic formulation and industry leading 5 Electrolytes mix. Including 840mg per litre of the key electrolyte, sodium, this is one of the highest amounts on the market.

The C2MAX carb mix contains a special ratio of glucose and fructose sources. Consumed regularly during exercise, this mix can increase the amount of energy to muscles by as much as 55%.

Contains 70mg caffeine to boost mental focus and alertness.

Contains no artificial flavours, colours or preservatives.

3750mg of very fast acting PeptoPro protein hydrolysate allows you to perform longer by delaying the onset of fatigue. It also kick starts your recovery."

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

The Powerbar website lists the ingredients as:

"Glucose, fructose, maltodextrin, casein hydrolysate (from milk) (7,5%), minerals (sodium citrates, sodium chloride, calcium gluconate, potassiumc hloride, magnesium citrates, calcium lactate), citric acid, flavouring, safflower concentrate, beetroot juice powder, caffeine, anticaking agent (silicon dioxide). May contain traces of gluten, egg, soy and nuts."

The PowerBar website also includes some nutritional information. A 50g serving of powder (the recommended amount to add to 500ml of water) gives 756KJ or 178 Kcal of energy, consisting of 41g of carb and 3g of protein. There's virtually no fibre or fat. The proportion minerals per 50g serving are quoted as: sodium 0.4g; chloride 315mg; potassium 80mg; calcium 60mg; magnesium 20mg.

Rate the product for performance:

Performance is very impressive. I haven't used this stuff in a 100-mile sportive yet, but based on performance in long training rides, I definitely will. I'll fill my first bottle with carb-only drink and second bottle with Isomax in the usual way. Compared to training rides, I tend to drink more during sportives (because there are feed stations to provide top-ups) so I'll also carry a couple of sachets of Isomax to refill bottles on the way.

Isomax drink mix is available in a big tub or in 50g sachets - very handy for tucking in the back pocket and adding water bottles during a ride.

Rate the product for value:

Isomax is not cheap, but it's fair value when compared to similar carb-and-protein products from other brands.

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

Overall this product performs very well indeed. The mix of carb, protein, minerals and caffeine is just what you need on a long hard ride.

Tell us what you particularly liked about the product

Mile taste. All-in-one mix of carb, protein, minerals and caffeine.

Tell us what you particularly disliked about the product

There's a possibility that the carb:protein ratio may be too low for my personal preference (in the past, I've used products with a higher protein component and they've been fine too), but I won't know for sure until I've used this drink mix 'for real' in a long hard sportive.

Did you enjoy using the product? Yes

Would you consider buying the product? Yes

Would you recommend the product to a friend? Yes

Anything further to say about the product in conclusion?

As with any energy or nutrition product, you should test Isomax in training before using it in a race or sportive. Riders have different levels of need and tolerance, especially when it comes to stuff such as sodium and caffeine, so you need to be sure the amounts in this drink are right for you.

Overall rating: 9/10

About the tester

Age: 51  Height: 5ft 10 / 178cm  Weight: 11 stone / 70kg

I usually ride: an old Marin Alp, or an old steel classic  My best bike is: an old Giant Cadex (can you see a theme here?)

I've been riding for: Over 20 years  I ride: A few times a week  I would class myself as: Experienced

I regularly do the following types of riding: touring, club rides, sportives, general fitness riding,


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