Reflex Nutrition One Stop Xtreme Review

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Written By
Andy Williams
Last Updated on

Reflex One Stop Xtreme is an all-in-one bodybuilding supplement that’s designed to help you bulk up, recover faster after your workout, and gain more strength.

Creatine, BCAAs, and protein powder are just 3 of the supplements you’ll no longer need if you buy Reflex One Stop Xtreme.

While the ingredients seem great on paper, I wanted to take a closer look, so I decided to order a tub of the Vanilla Ice Cream flavour to give it a try.

In my Reflex One Stop Xtreme review, I'll talk about the taste, mixability, digestability, value for money, when to take it, and, of course, the effectiveness of this all-in-one muscle-building supplement.

all-in-one shake
Reflex Nutrition One Stop Xtreme
A tub of Reflex Nutrition One Stop Xtreme
Taste: 9.3/10
Mixability: 9.5/10
Ingredient Quality: 9.2/10
Mass-Building Potential: 9/10
Overall Rating: 9.3/10
  • Contains over 500 calories per shake to support your muscle-building ambitions
  • Supplies 55g of quality protein from whey and casein for rapid yet sustained amino acid delivery
  • Includes 70+ grams of low GI carbs for bulking up
  • Supports muscle recovery with 13.3g of BCAAs and 10g of glutamine peptides
  • Maximises muscle strength and fullness with 5g of premium creatine monohydrate
  • Enhances muscular endurance and improves work capacity with 1.8g of beta alanine
  • Some people prefer to take their creatine separately
  • Taste reviews, although generally positive, were still mixed

Reflex Nutrition One Stop Xtreme Ingredients

The Reflex Nutrition One Stop Xtreme ingredients are listed per daily serving, which is 290g of powder. However, Reflex actually recommends taking 145g twice per day, so to give a fair comparison in relation to other supplements, I’m basing the nutrition info on a single, 145g serving.

The nutrition facts for Reflex One Stop Xtreme
  • 531 calories
  • 55g of protein
  • 71g of carbs
  • 2.75g of fat
  • 13.3g of BCAAs
  • 5g of Creapure® creatine monohydrate 
  • 10g of glutamine peptides
  • 2.6g of betaine anhydrous
  • 1.8g of beta alanine
  • 1.8g of taurine
  • A selection of digestive enzymes

That’s a lot of ingredients to unpack, but I’ll do my best. Although One Stop Extreme is more expensive than the other popular Reflex mass gainer (Instant Mass), it has a lot more different ingredients.

Whey and Casein Protein

If there’s one phrase that I’d use to describe One Stop Xtreme’s protein blend, it’s cleverly formulated.

A person opening a tub of Reflex Nutrition One Stop Xtreme

Let me explain.

A sizeable 30% of One Stop Xtreme’s calories come from whey protein, which is the ideal post-workout protein source due to its fast absorption and ability to produce a massive muscle protein synthesis spike.

Another 12% of One Stop Xtreme’s calories come from milk protein, which is naturally 80% casein and 20% whey. While casein isn’t necessarily as anabolic as whey (at least not in the short term), it’s far more anti-catabolic because it provides a slower yet steadier supply of amino acids.

This anabolic and anti-catabolic protein combination is why this Reflex One Stop protein power is so effective at provoking muscle growth; you’re getting a consistent supply of quality amino acids.

Carbohydrates and Fats

Per serving, Reflex Nutrition One Stop Xtreme contains 71g of low GI carbohydrates so that you can recover quicker from your workouts by achieving complete muscle glycogen replenishment.

The Reflex One Stop Xtreme ingredients

I love how there are not way more carbs than protein. There are enough carbs to facilitate rapid recovery, but not so many that you end up feeling bloated and lethargic.

While mega-calorie gainers do have their place, with most gainers, it often feels like you’re paying a premium for cheap carbs. This isn’t the case with One Stop Xtreme by Reflex Nutrition.

On the fat side of things, Reflex Nutrition keeps things low at 5.5g per daily serving (per 2 shakes). This means that you can start recovering sooner because the protein and carbohydrate absorption won’t be slowed down by a bunch of unnecessary fat.

To be sure, fat should be an important part of your diet, especially when you’re trying to bulk up. 

However, it’s really hard to get good-quality fats into a mass gainer, which is why I always recommend getting most of your fat from whole food sources like eggs, fish, meat, and other nutritious foods.

Creatine Monohydrate

A tub of One Stop Xtreme by Reflex Nutrition

Whereas most other gainers only have 2-3g of creatine, One Stop Xtreme includes 5g of Creapure® creatine monohydrate per serving.

So if you have two shakes per day, that’s 10g of creatine, which could be beneficial for some people while bulking, especially if they’re larger in size or don’t really respond to low doses of creatine.

It’s also good to see that Reflex uses a pure form of creatine that’s rapidly absorbed. This is exactly what you want when you’re trying to get strong and build muscle mass.

BCAAs and Glutamine

The ingredients in Reflex Extreme One Stop

Each Reflex One Stop Xtreme serving includes a generous 13.3g of BCAAs and 10g of glutamine peptides. That’s quite the recovery blend.

Both BCAAs and glutamine are known to reduce muscle soreness, enabling you to push yourself in the gym and stimulate more muscle growth without any fear of not recovering in time for your next session.

BCAAs are also integral for stimulating muscle protein synthesis, which ultimately leads to hypertrophy.

The fact that each serving of One Stop Xtreme contains more BCAAs than your typical intra-workout drink is a sure sign that we’ve got a quality all-in-one muscle builder on our hands.

Beta Alanine

A tub of Reflex Nutrition One Stop Xtreme

Included at a daily dose of 3.6g, beta alanine is one of those supplements that you feel straight away but which actually takes a couple of weeks to begin working.

You see, like creatine, beta alanine needs to saturate your muscles in order to take effect, which can take a couple of weeks.

But the benefits of increased muscular endurance and work capacity are well worth the wait.

Now you can add beta alanine to the growing list of supplements that you won’t need to buy once you purchase Reflex Nutrition One Stop Extreme.

Digestive Enzymes

If you’re a bodybuilder, then you might not care too much about digestive enzymes.

And while the likes of lactobacillus acidophilus and lactobacillus rhamnosus might not be particularly anabolic, they can help you to better utilise the muscle-building nutrients that you consume.

This means less wasted nutrition and more fuel for muscle growth and repair.

all-in-one formula
A tub of Reflex Nutrition One Stop Xtreme
Reflex One Stop Xtreme

Reflex One Stop Xtreme Results and Effectiveness

To get the fastest and best Reflex One Stop Xtreme results possible, it’s best to take two shakes per day on both training and rest days. This way, you’ll get an extra 1,062 calories, 142g of carbs, and 110g of protein every day, which can make a massive difference to your results.

The results you get from making a shake of Reflex One Stop Extreme

While your calorie requirements won’t be as high on your day(s) off from the gym, you can still utilise that extra caloric energy to support muscle recovery and to make sure that you’re at your best for your next workout.

As I mentioned earlier in my Reflex Nutrition One Stop Xtreme review, this all-in-one muscle-building supplement will help you to gain size by feeding your muscles with quality protein from both whey and casein.

The low GI carbs will help to fuel your workouts so that you can gain strength and set new PRs while at the same time ensuring that your muscles have plenty of glycogen for your subsequent training sessions.

Thanks to the 20g of glutamine and 26g of BCAAs in each daily serving, you’ll also experience a reduction in muscle soreness, enabling you to train more frequently if you so wish.

Reflex One Stop Xtreme Taste and Mixing

Now for the most fun part of my Reflex One Stop review; the taste test!

A person tipping powder from a tub of Reflex One Stop Xtreme into a shaker cup

Having really enjoyed the Chocolate Perfection flavour last time around, I decided to give the Vanilla Ice Cream flavour a try for this Reflex Nutrition One Stop review.

Here are my thoughts…

This is a very nice-tasting shake, especially when you mix it with milk. It still tastes good with water, which is a big plus if you want to make your shake up on the go.

Does it taste like a vanilla milkshake? No, definitely not. But it does have a pleasant vanilla flavour to it—and nothing too overpowering, which is ideal for those who prefer sweet yet drinkable shakes.

The mixability is excellent. You won’t need a blender. I just added 145g of powder to around 600 ml of liquid and gave it a shake. Easy and clump-free, which is all you can ask for.

Reflex One Stop Xtreme Side Effects

There are a couple of potential Reflex One Stop Xtreme side effects that you might experience when you take this supplement.

The first—and this applies to the usage of any weight gainer—is fat gain. While it’s normal to gain some fat during a bulk, overconsumption of calories can lead to excess fat gain.

Back view of Reflex One Stop Xtreme detailing the side effects

Obviously, fat gain isn’t the result of one particular supplement; it’s because of an excessive calorie surplus.

For this reason, stick to two shakes per day. This will make your tub/bag last longer and mostly ensure that you gain quality muscle and some fat rather than a load of unnecessary body fat.

Another possible side effect which, again, applies to most mass gainers, is bloating and stomach discomfort.

If you’ve never taken a high-calorie, high-protein shake before, then you could feel a bit bloated after drinking this Reflex One Stop protein shake. This feeling should lessen or even go away altogether as your body gets used to the extra calories.

Still, on a per-serving basis, One Stop Xtreme isn’t as calorie-heavy as some other gainers, so the shakes are unlikely to sit heavy on your stomach.

quality ingredients
A shaker bottle and scoop next to a tub of Reflex One Stop Xtreme
Reflex Nutrition One Stop Xtreme

Reflex One Stop Xtreme Price and Value For Money

The scoop size of Reflex One Stop Xtreme

I’ve always thought that Reflex Nutrition offered good value for money. And nowhere is that more true than with One Stop Extreme. A big 4.35 kg tub costs less than a meal out for two.

While there are cheaper alternatives available, such as Serious Gainz, One Stop Xtreme completely negates the need to buy BCAAs, creatine, glutamine, beta alanine, and, for most people, protein powder as well.

If you look at it like that, Reflex Nutrition One Stop Xtreme offers truly excellent value for money, especially at the current low price.

Who Should Use Reflex One Stop Xtreme?

A serving of Reflex Nutrition One Stop Xtreme in a shaker bottle

If you like the convenience of having all your key supplements in one effective muscle-building formula, then I highly recommend giving Reflex One Stop Xtreme a try.

Whether you’re a hardgainer or a seasoned bodybuilder seeking a quality mass-building supplement, One Stop Xtreme’s powerful hypertrophic formula has the potential to deliver massive results. All you need to do is train hard and eat right.

Also, if you want a shake that tastes good (in my opinion) and mixes easily without a blender, then One Stop Xtreme from Reflex Nutrition is a fantastic option.

Who Should Give Reflex One Stop Xtreme A Miss?

A shaker bottle and scoop next to a tub of Reflex One Stop Xtreme

Let’s be honest; no supplement—regardless of how well it works—is right for everyone.

If you’re cutting or tend to put on fat really easily, then One Stop Xtreme might not be the right supplement for you due to its relatively high carbohydrate content. If this is you, I recommend Reflex Nutrition Growth Matrix instead, which is lower in calories but still nutrient-packed.

Also, if you prefer to take your supplements separately for whatever reason, then One Stop Xtreme probably isn’t what you’re looking for because it contains creatine and beta alanine.

The Verdict On Reflex Nutrition One Stop Xtreme

As you probably gathered from reading my Reflex One Stop Xtreme review, I don’t really have any complaints about this all-in-one bodybuilding supplement.

Sure, it’s not for everyone, but if you’re looking to simplify your supplementation without sacrificing quality, then Reflex Nutrition One Stop Xtreme is an excellent choice.

While the Reflex One Stop Xtreme reviews were a bit mixed with regard to taste (as is the case with any nutritional shake), everyone agreed that this all-in-one muscle-builder really delivers where it matters; it produces results plain and simple.

great uk supplement
A tub of Reflex Nutrition One Stop Xtreme
Reflex Nutrition One Stop Xtreme
A picture of Best Mass Gainer UK founder, personal trainer Andy Williams
Andy Williams
Andy Williams is a UK-based personal trainer and bodybuilder who coaches gym-goers of all levels using proven evidence-based techniques in strength training, nutrition, and supplementation. He’s tested over 70 different mass gainers for their ingredient quality and muscle-building effectiveness and regularly shares his findings in his mass gainer reviews.
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