ZoneX Buffer Mix

What is ZoneX?
ZoneX is a performance-focused drink mix built to help endurance athletes train harder and race faster. It’s formulated with a precise blend of sodium bicarbonate, sodium citrate, and citric acid—ingredients clinically shown to buffer lactic acid, delay fatigue, and improve high-intensity performance. No stimulants. No sugars. No BS. Just pure metabolic support.

How does it work?
During high-intensity efforts, your body rapidly produces lactic acid as a byproduct of anaerobic metabolism. This acid accumulates in your muscles which lowers pH — leading to that familiar burning sensation, muscular fatigue, and a drop in power output; fatigue.

ZoneX helps combat this by buffering the production of lactic acid. The sodium bicarbonate in our blend neutralises excess lactate before it interferes with performance. The addition of sodium citrate and citric acid improves absorption, reduces the risk of GI issues, and helps maintain electrolyte balance—making the product more tolerable than standalone bicarbonate.

Who is it for?
ZoneX is for runners, triathletes, and endurance athletes who want to train at a higher intensity, recover faster between efforts, and compete at their true physiological ceiling. Whether your aim is to train more effectively, set new PB's, or beat your rivals - if you're serious about improving, ZoneX is for you.

When should I take it?
ZoneX is designed for any session where intensity matters—interval workouts, threshold runs, time trials, or races from 800m to the marathon. It’s particularly effective in events that require prolonged effort above lactate threshold, where acid accumulation would otherwise limit output.

Mix one sachet with 300-500ml of water and drink it 60–90 minutes before your session or race. You’ll feel the biggest difference during hard efforts—intervals, tempo runs, races, or anything that pushes you near your limit.

Every sachet of ZoneX contains a blend of performance-enhancing compounds, backed by science and built for endurance.

Sodium Bicarbonate - A powerful buffering agent that helps neutralize lactic acid buildup in muscles — delaying fatigue and helping you push harder, for longer. Proven effective in dozens of endurance performance studies.

Sodium Citrate - Works alongside bicarbonate to support acid buffering while improving taste and reducing stomach distress.

Citric Acid - Naturally found in citrus fruits, citric acid aids digestion and pH regulation. It also helps improve solubility and flavour balance in the mix.

Natural Lime Flavouring - Used in trace amounts to give ZoneX its zingy lime punch taste. No artificial dyes, no nonsense — just a clean, punchy flavour that goes down easy.

Sucralose - A sweetener added in a tiny amount to smooth out the taste. Chosen for its clean taste with no added sugar or calories.

Choose from 3-5 day standard shipping (free when you order 20 sachets or more) or express next day shipping. Prices shown at checkout.

We're so confident in the quality of our blend that we offer a 99-day money back guarantee on all orders. If you don't love your fastr products for any reason whatsoever, we'll give you a full refund; no questions asked.

1. Shake one full sachet into 250–300ml of water. Shake or stir well until fully dissolved. This can be prepared the night before a race for ease of use.

2. Drink 60 to 90 minutes before your run. This gives your body time to absorb and activate the ZoneX blend.

3. Sip over 10-15 minutes - ZoneX is best consumed gradually to reduce stomach discomfort.

4. Go to work - ZoneX is built for race day, hard sessions, or any time you're pushing the pace.