Energy gel 101: what it is, how it works, when to take it

An energy gel is a small packet of carbohydrate you can swallow in a few seconds, mid-stride, without chewing. The gels we sell were first made for ultra-trail runners more than 30 years ago; the same packets now fuel first-time 10K runners in Bengaluru, Sunday club rides and gym sessions. This page covers what a gel is, what is inside it, why timing matters, and how to choose between Original, Liquid and Roctane.

What an energy gel is

Working muscles run on carbohydrate. For a short or easy session, the glycogen stored from your normal meals is plenty. Work hard, or go longer than about 45 minutes, and that stored supply starts to run out. Performance drops with it, and no amount of willpower refills the tank.

A gel is the most portable way to put carbohydrate back in. Each packet is a concentrated blend of simple and complex carbohydrate, a little sodium and a dose of amino acids, in a smooth texture a working stomach can handle. Tear, squeeze, sip some water, carry on.

Two carbohydrates, two express lanes

Every gel here uses two carbohydrate sources rather than one: maltodextrin and fructose. The body absorbs each through its own pathway, which is why we call them express lanes. Two lanes move more fuel into the bloodstream, faster, than a single source can, so you can take in more without stomach upset.

The two sources also arrive at different speeds. Maltodextrin is converted into a form your muscles can burn within minutes. Fructose follows several minutes later. The overlap gives you a steady stream of energy rather than one big sugar rush and the crash that follows it.

What is in one packet

Figures are for an Original Energy Gel (a 32 g packet); Liquid and Roctane differ slightly, see the comparison table further down.

Per packet	Amount	Why it is there
Energy	100 kcal	One feed; two or three an hour is the usual budget
Carbohydrate	21–23 g	Maltodextrin plus fructose, the two express lanes
Sodium	60–125 mg	The electrolyte you lose in sweat; varies by flavour
Amino acids	450 mg	A BCAA blend that helps protect muscle from breakdown, contributes to energy production and helps hold off mental fatigue†
Caffeine	0, 20 or 40 mg	Optional, by flavour; see the flavour and caffeine chart

Original gels are vegan, gluten-free, dairy-free and kosher, and tested for banned substances.

Why you cannot simply eat more

During exercise the body can digest only about 120–240 kcal per hour. Anything beyond that does not become extra speed. It sits in the stomach, and the more you push in, the more blood the body diverts from your muscles to your gut to deal with it. The heavy, sloshing feeling many runners blame on gels is usually the dose, not the gel.

One packet is 100 kcal, so two or three an hour is the whole budget. Where you sit in that range depends on your gut and your effort, and the only way to find out is to test it in training, not at 30 km of a marathon.

The 20–30 minute rhythm

A packet's effect lasts around 45 minutes, varying with intensity and metabolism. Taking the next one at 20–30 minutes means you top up before the level drops rather than after you have felt it drop.

Length of effort	What to do
Up to 1 hour	Start well fed and well hydrated. For a top-up, take one gel five minutes before you begin, with a few sips of water.
1–2 hours	Refuel on the move: one gel every 20–30 minutes, and keep drinking as you take them.
2–3 hours	Your body needs more now: keep the gel rhythm and add an electrolyte drink to cover what you sweat out.
3+ hours	You cannot replace everything you burn. Eat as much as you can comfortably process, and switch some packets to Roctane for the extra amino acids that help protect muscle over a long day.†

Set a timer. Start a repeating 25-minute alarm on your watch at the first gel. It removes the guesswork once you are tired, which is exactly when people forget to eat.

Always with water

Take every gel with a few sips of water. Water helps the body absorb the carbohydrate efficiently, and in Mumbai humidity or on a May morning in Delhi those sips also replace sweat.

Do not squeeze the gel into your bottle. It is meant to be taken directly, with the water drunk separately. How much to drink alongside is its own question; see energy vs hydration.

Original, Liquid or Roctane?

All three deliver 100 kcal of dual-source carbohydrate. The differences are texture, sodium, amino acids and caffeine.

Per packet	Original	Liquid	Roctane
Form	32 g smooth gel	60 g light liquid	32 g smooth gel
Energy	100 kcal	100 kcal	100 kcal
Carbohydrate	21–23 g	24 g	19–21 g
Sodium	60–125 mg	75 mg	125–180 mg
Amino acids	450 mg	450 mg	1,425 mg
Caffeine	0–40 mg	0–40 mg	0–70 mg
Best for	Most training and racing	Early starts, transitions, a change of texture	Long, hot or very hard efforts

Original Energy Gel

The all-rounder, and the right default for most people reading this page. Seventeen flavours, ten of them with 20 or 40 mg of caffeine, from fruity (Lemon Sublime, Salted Watermelon) to dessert (Salted Caramel, and Chocolate Outrage, one of the four launch flavours from 1993). Shop the Original Energy Gel.

Liquid Energy Gel

The same fast-absorbing carbohydrate as Original in a lighter, smoother liquid you sip rather than squeeze. It suits early starts when you cannot face anything thicker, triathlon transitions, and a change of texture deep into a long day. Shop the Liquid Energy Gel, or read liquid vs traditional gels.

Roctane Energy Gel

Built for long-duration and high-intensity work, with up to three times the sodium (it varies by flavour) and three times the branched-chain amino acids of Original. This is the packet for a marathon in Mumbai humidity, a Western Ghats climb or a trail ultra, and for the back half of any day longer than three hours. Shop the Roctane Energy Gel, or compare the two in Roctane vs Original.

Storage and handling

Store sealed packets somewhere cool and dry, out of direct sun, and go by the best-before date on the box.

Cold is the only weather that changes them. A gel will not freeze unless the temperature is well below zero, but it does thicken in the cold. On a 6 °C January start in Delhi or a pre-dawn climb in Ladakh, keep the packets against your body, in a jersey pocket or a running belt, so they stay warm enough to squeeze easily. Cold-weather fuelling has more.

Pocket the empty packet; a tab on a trail is litter. For ways to carry a race's worth, see 7 ways to carry gels.

FAQ

How fast does a gel work?

Straight away. The maltodextrin is converted to usable energy within minutes; the fructose takes several minutes longer. Expect the effect to last about 45 minutes, varying with your intensity and metabolism.

Can I squeeze a gel into my water bottle?

Better not. Take the gel directly and drink the water separately; that is how the packet is designed to be absorbed.

Do I need a gel for a 5K or a 45-minute gym session?

Usually not. Stored carbohydrate covers shorter and easier sessions; it starts running out once you work hard or pass about 45 minutes. For a hard hour, one gel five minutes before the start is worthwhile.

Are gels safe for children?

They are formulated for adults. An active child on a hike or at a sports day can use them, but check with a doctor first and stick to caffeine-free flavours.

Are they vegan and gluten-free?

Original Energy Gel is vegan, gluten-free, dairy-free and kosher, and tested for banned substances. See gluten-free and vegan gels for all three lines.

What if a gel upsets my stomach?

It usually means too much, too fast or too dry. Drop to one every 30 minutes, take it with more water, and build the dose up gradually in training. Train your gut walks through it.

Next steps

• Choose the right gel: which line and flavours suit your sport and the weather.
• Fuel calculator: how many packets your next session needs, and when.
• Train your gut: practise the rhythm so race day holds no surprises.

† These statements have not been evaluated by a regulatory authority. This product is not intended to diagnose, treat, cure or prevent any disease.