Reviewer Background

I enjoy walking in all its manifold forms, from a simple stroll in the woods to multi-day backpack excursions. Though by no means an extreme ultra-light enthusiast, from spring to fall my preference is to carry a pack weight (before food and water) of 12 lb (5.5 kg), more or less. In recent years, I've rapidly moved to a philosophy of “lighter is better,” within the constraints of budget and common sense.

Reviewer Information

Name: Edward Ripley-Duggan

Age: 53

Gender: Male

Height: 6’ 1” (1.85 m)

Weight: 215 pounds (98 kg)

erd@wilsey.net

Catskills, New York State

Product information in brief

Manufacturer: Sports Street Marketing (GU Sports)
URL: http://www.gusports.com
Product type: Sports drink for electrolyte replacement
Year of manufacture: 2006
MSRP: n/a
Stated ingredients: Maltodextrin, fructose, sodium citrate, citric acid, potassium citrate, natural flavors, and natural colors.
Nutritional information (as stated on drum, Lemon-lime flavor)

Serving size: 2 level scoops to 16 fluid ounces

Servings per container 35 (0.9 oz, 26 g, according to manufacturer)

Calories per serving 100

Calories from fat 0

Total fat per serving 0 grams

Saturated fat 0 grams

Cholesterol per serving 0 milligrams

Sodium 240 milligrams

Potassium per serving 40 milligrams

Carbohydrates per serving 26 grams

Dietary fiber 0 grams

Sugar 4 grams

Protein 0 grams

Flavor: Lemon-lime (also available in orange and raspberry)
Manufacturer's stated net weight (i.e. food contents) for drum: 2 lb (910 g)
Measured net weight (i.e. food contents) analog scale: 2 lb (910 g)
Weight of drum: 4 oz, (113 g)
Included in drum: Measuring scoop (weight under measurable limit for scale)

Website

The GU website offers much helpful information on the firm's products and history, although a couple of links (including stats/charts) are broken.

Introduction

GU2O is a source of replacement electrolytes, i.e. potassium and sodium. It also provides a small amount of carbohydrate and sugar, for energy. The product is designed for hikers, backpackers, cyclists, runners etc., and is designed to be palatable while not overly sweet or cloying. Those who practice such sports tend to lose electrolytes, as a result of sweating, and this (depending on degree) may cause cramping or decreased performance.

I have used GU2O in all seasons, from -15 F (-26 C) to 85 F (29 C). I usually carry my water in a Platypus (with or without hose), occasionally in a Nalgene bottle or the equivalent. I've used the product on outings between 500 ft (152 m) and 5000 ft (1520 m), in the Catskills, Adirondacks, and the 'Gunks of New York State, as well as trips elsewhere in the NE United States. I tend to reserve its use for backpacks and more difficult off-trail hikes, but I like the flavors well enough that I've been known to use it in mild weather and gentle terrain if I'm in the mood.

I am not as good as I should be at staying well hydrated when I hike and backpack. This probably stems from my younger years, when misguided instructors recommended such procedures as rinsing the mouth with water but not swallowing! What were they thinking? With me, dehydration shows up at day's end in the form of nasty leg cramps, which often occur as I lie down in my sleeping bag. This is an exceptionally unpleasant place and position in which to get a cramp, since getting into a posture where the leg can be extended is virtually impossible once the cramp has begun.

Using a hydration system is helpful, but not, I find, a total solution, and one not generally practicable in weather well below freezing. Also, a couple of favorite summer day packs are not equipped to handle one. I've even been hit with cramps a few times in the past when I felt that I had hydrated well, which may argue that the problem has more to do with loss of salts than lack of water. The problem is not just a seasonal one, either, as I have also had it in winter (winter water loss can be quite rapid).

I believe that much of this is due to the fact that I tend to sweat prodigiously (except in winter, when I dress to minimize sweating). This results in the loss of potassium and sodium, both present in sweat. My body should in theory have sufficient sodium so that loss in this manner should never be an issue, but potassium is another story. Potassium and sodium, in the correct proportions, are crucial to the transmission of nerve impulses, among other things. While it seems the exact mechanisms of exercise-induced cramp are still medically debated, most athletes (myself included) strongly believe that both adequate (but not excessive) hydration. combined with electrolyte replacement, are helpful in preventing many episodes of cramp. Since I started to use GU₂O regularly about a year ago, I have had no serious episodes of cramping, other on those occasions when I have not used it. I now always carry some for emergencies in my First Aid bag, for myself or others. I've come to consider this product an essential.

Features, performance, and design

GU₂O drum

Sports drinks for electrolyte replacement have been around for a long time. The ubiquitous Gatorade is one (though that always seems to me to be pretty heavy on sugars, and is closer to a soft drink). There's also Gookinaid, a long-time runner's standby, developed by Bill Gookin, himself a runner. GU₂O was developed by Dr William Vaughan, who (according to the firm's website) formulated the first energy bar. Presumably this doesn't count pemmican, which with pulverized dried meat, fat and berries, comes fairly close to the modern idea. He also developed GU energy gel (a product that I also use on occasion), and most recently GU₂O.

GU₂O is available on the market in two forms, both of which I have used. There are individual packets, each with sufficient powder for 24 fl oz (710 ml) of water. While these small foil packets are extremely convenient, they are also more expensive then buying the equivalent amount of powder in the standard 2 lb (910 g) drums, and for backpacking they add extra trash (albeit a small amount) that must be toted about. It's easy to use the small plastic scoop to put the powder directly into a water vessel, or into a zip-top bag for storage pre-trip.

The drum is standard HDPE plastic (recyclable), with a screw-off lid and a safety seal that must be removed upon opening the first time. The label provides the recommended ratios of GU₂O to water. nutrition facts, ingredients, and a general discussion of the product. It measures about 6 in (15 cm) in height and 4.7 in (12 cm) in diameter. In practice, I think it's unlikely that backpackers will carry an entire drum without repackaging.

I have a couple of small cautions to share regarding mixing the product. In the recommended proportion of two scoops to 16 fl oz (473 ml, or approximately one pint of fluid), I find the mix overly strong. I prefer to use a proportion closer to a scoop per liter (quart), and that generally seems adequate for me. Sometimes, while I'm setting up camp, I'll heat some water and make a really strong batch (it makes a palatable hot drink), especially if I'm concerned that I might be a bit dehydrated. Of course, concentration is one of those areas where individual taste and needs dictate how to proceed.

My second comment on mixing is that the powder should always be added to approximately half the amount of water that will eventually be used. I've found through experience that if the powder is added dry to the Platypus, Nalgene, or whatever vessel is used, and then water is added to it, a high proportion tends to clump, and some sticks to the walls. In fact, I've spilled some powder in the sink before now, and it is so gummy that is takes a fairly good scrubbing to remove it.

I have used the lemon-lime flavor under review, as well as the raspberry, the orange, and a variety that appears to be discontinued, Mango Madness. This last stained my Platypus pale yellow, and the flavor persisted to later fillings of plain water (but this was not offensive). I did rather like the taste, as I'm a fan of all things mango, though this was a distant cousin to the fruit, a very distant cousin. I've noticed this tendency to stain with the orange flavor, as well. The drink is not that brightly colored (unlike some), and the lemon-lime is essentially clear, so the staining is slightly surprising, and must be a product of the natural colors used.

I like the fact that the ingredient list is short. GU₂O contains a small amount of sugar (fructose is a fruit sugar, as well as being one of the three blood sugars, along with glucose and galactose). Maltodextrin, the main ingredient, is also fairly sweet, though it is not a sugar but a polysaccharide, a class of carbohydrate. It's closer to corn starch (its precursor in manufacture), which may help to explain the slight problems with solubility mentioned earlier, given how gummy corn starch can become in water. These two components are present to enhance palatability and (I presume) for the slight energy boost they provide.

The key ingredients for electrolyte balance are the citrates of sodium and potassium, especially the latter. As noted previously, it's mostly potassium depletion that tends to cause cramping (salt tablets, i.e. sodium chloride, used to be provided to rangers in desert areas, though there's a good deal of dispute as to how necessary these were). Are these components indeed effective? I can only state my experience. I have had very little cramping since I started adding this product to my drinking water, and drinking a cup of strong GU₂O seems to head off incipient cramping. That's good enough for me, and I intend to keep using the product as needed. The citric acid may be present as a preservative, and to give the flavor some zest. In its dry state, the powder tastes like a candy from my childhood. I have eaten it dry at least once, but can't advocate the experience.

The manufacturers state that the product reduces fatigue and lactic acid in the muscles (two sides of the same coin, I would have thought, since lactic acid accumulation is closely related to muscle fatigue). It's harder for me to comment on this claim, as the benefits are likely to be subtle, as some fatigue is part and parcel of the experience of backpacking and hiking. It seems common sense to me that if my muscles are cramp-free, I will have less fatigue as well, but quantifying this benefit is not something I can easily manage.

Summary

This is a product that has saved me a good deal of anguish. It's now part of my First Aid kit, in case I or someone with me suffers cramps or dehydration. My experience over a year has demonstrated that it's extremely effective, both drunk during the course of the day, and also when used at the first signs of muscle cramping.

Pro

Effective preventative and treatment for cramps
Mild taste, not too sweet
No offensive food additives

Con

Can be difficult to mix if water is added to dry powder

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Read more gear reviews by Edward Ripley-Duggan

Owner Review by Edward Ripley-Duggan