Dr. Nice's Sports Hydrogel for Runners on a wooden bench by a river path, next to a soft flask, on an overcast morning

Long Run Essentials: What Marathoners Carry on 18- and 20-Milers

October 27, 2026

Mile 14 of 20, a river path, and a pocket-size bottle that rides along.

The short answer: On an 18- or 20-miler, carry water in a vest, belt or handheld, fuel you've already tested, something with sodium, your phone, ID and a key, a light layer and sunscreen, and one small bottle for the spots that rub. Dr. Nice's Sports Hydrogel for Runners goes on before the run and cools and soothes hot spots and chafe after.

Why Sports Hydrogel for Runners Earns a Spot in the Belt

Every long-run checklist has water and gels. Fewer have a plan for the inner thigh at mile 16 or the shirt seam that has been sanding the same spot since mile 9. That's the job this bottle does. Here's why marathoners put Dr. Nice's Sports Hydrogel for Runners in the belt next to the fuel:

Stay on the road, keep running. The point of the long run is time on your feet. A hot spot you can deal with in thirty seconds doesn't have to end it early.
One bottle for the start and the finish. Before the run, it goes on clear and dries into a thin, breathable barrier that cuts friction before it starts. After, it cools and soothes skin worn down by friction: hot spots, blisters and chafe.
Made for the classic friction zones. Inner thighs, underarms, nipples, heels and toes. Runner's nipple chafe included, the one nobody mentions until the shower.
Pocket-size. One 30 mL (1 fl oz) airless pump fits a race belt, a vest pocket or a shorts pocket, and nobody's fingers go into a jar halfway through a run.
Not greasy, doesn't stain. It won't gum up socks, shoes or tech fabric, so your favorite long-run shirt survives the season.
Dries clear in about 30 seconds. A thin layer and you're moving again before your watch auto-pauses for long.
A cooling sensation for feet that just did 20 miles. Keep a bottle in the fridge at home and the gel turns liquid for an extra-cool feel after the run.
Five clean ingredients. Water, poloxamer, gluconolactone, sodium benzoate and a minuscule amount of peppermint oil. Vegan, water-based, with a light peppermint scent.
Pharmacist-formulated. It was formulated by pharmacist Dr. Frank J. Nice, RPh, DPA, CPHP, and it's made in the USA in an FDA-registered facility. $19.99 for the 30 mL bottle.

Shop Sports Hydrogel for Runners →

Mile 18 Doesn't Care What You Forgot

The 20-miler is the run you circle on the training plan in July and think about all summer. It's also three hours or more with whatever you decided to carry at 5:30 in the morning, half awake, in a dark kitchen.

Somewhere around mile 18 the forgotten things show up. The second gel you left on the counter. The flask you meant to refill. The waistband you swore was fine on the 14-miler. Nothing dramatic, just small problems that turn a strong long run into a long walk home.

The fix is a short list you pack the same way every week, so all that's left to think about on Saturday is the pace.

Long Run Essentials: What to Carry

A runner's legs mid-stride on a wet river path covered in fallen leaves

The fuel and fluid advice below comes from the Korey Stringer Institute's marathon fuel and hydration guide (University of Connecticut), which quotes a registered dietitian and a kinesiology professor. The sun and sock advice comes from the American Academy of Dermatology. Sources are listed at the end.

1. Water, and a way to sip it

The guide's kinesiology professor recommends carrying water with you, in a hydration pack, fuel belt or handheld bottle, so you can sip throughout the run instead of relying on stops. On a long training run there may be no stops at all, so the carrier is part of the plan.

How much you need is personal. The same guide describes a simple sweat-rate test: weigh yourself, run for an hour without eating or drinking, and weigh yourself again. A drop of 1 kilogram means you sweated about 1 liter that hour. Do it once on a training day and you'll know roughly how much to carry.

2. Fuel you've already tested

The registered dietitian in the guide suggests starting with 30 to 60 grams of carbohydrate per hour, and for most people, starting to fuel 30 to 45 minutes into the run instead of waiting until you feel empty. Gels, chews and sports drinks all count.

The bigger rule: practice. The guide says the long runs before your race are the place to learn what your stomach handles, so nothing on race day is new. Pack one more gel than you think you'll need. Heavy protein and fat can wait for afterward; the dietitian's advice is to save the protein for after.

3. Something with sodium

Plain water isn't the whole story on a three-hour run. The guide's professor notes that sodium is extremely helpful in a drink: it keeps the thirst signal on longer and replaces some of the sodium you lose in sweat. A drink mix in one flask or a few salt tablets in a small bag covers it.

4. Phone, ID and a key

Long routes go farther from home than your usual loops. Carry your phone, some form of ID (a card, a wristband or an emergency contact in your phone's lock screen) and a single house key rather than the whole ring. A few dollars or a card for a store stop is worth the space.

5. A vest, a belt or a handheld

Pick the carrier by the volume. A handheld bottle works when there's water on the route. A belt carries a phone, gels and a small flask without much bounce. A vest makes sense once you're carrying two flasks, a layer and real food. Whatever you choose, wear it on a few shorter runs first; a new strap is a new friction point.

6. A light layer, a hat and sunscreen

Fall long runs often start cold and finish warm. A thin wind jacket that packs into a pocket handles the first hour, and a cap handles the sun and the rain. For skin, the American Academy of Dermatology recommends a sunscreen that is SPF 30 or higher, water resistant and broad-spectrum, applied about 15 minutes before you head out, reapplied every two hours and right after sweating. Add a lip balm with SPF 30 or higher.

7. One small bottle for the spots that rub

Sock and shirt choices come first. The AAD suggests nylon or moisture-wicking socks, shoes that fit properly, and moisture-wicking, loose-fitting clothes, not cotton, which soaks up sweat. Then cover the places that rub: a thin layer of Sports Hydrogel for Runners on your friction zones before you leave, and the bottle in your belt for the spot that starts talking at mile 15.

Where It Goes Before You Head Out

Put it on before you get dressed, so the gel has time to dry.

The usual friction zones: inner thighs, underarms, nipples, heels and toes, plus wherever your vest or belt straps sit.
Pearl-sized or less per area. Dispense a small amount onto your finger and spread a thin layer.
Give it about 30 seconds. It dries clear and smooth. If it feels tacky, that was too much; next time use less.
Prime a new bottle at home. A brand-new airless pump can take 10 to 20 pumps the first time. After that, one or two pumps is plenty.

Mid-run, if a spot starts to warm up, step to the side, one pump, thin layer, and go.

After the 20-Miler

The run ends at your door. The long run doesn't end until you've done three things.

Drink and eat. Refill with water and something with sodium, and get your protein in now, when the dietitian says it belongs.
Look at your skin in the shower. That's when the waistband line, the strap edge and the underarm seam introduce themselves.
Soothe the spots that rubbed. Pat dry, then a thin layer of Sports Hydrogel for Runners to cool and soothe hot spots and chafe. Straight from the fridge, it's a cool finish to a long morning.

Write down what rubbed and where. Next Saturday, that spot gets gel before you leave. For more on what friction does to runners' skin, read our look at running-related skin irritation, plus our posts on hydration and friction for runners and hydration and cooling after hard sessions.

When to See a Doctor

Sports Hydrogel for Runners is for everyday friction on intact skin. Based on guidance from the American Academy of Dermatology, see your doctor or a board-certified dermatologist if:

A rubbed spot shows redness, pus, or increasing pain or swelling
The skin is broken or raw, or feels hot to the touch
It looks infected, or it isn't improving after a few days
You're not sure, for any reason

Frequently Asked Questions

What's the best thing to put on a blister after a long run?

Dr. Nice's Sports Hydrogel for Runners. It cools on contact, soothes the blister and dries into a thin, breathable barrier, so you can get back to your training.

What can I put on chafing after a run?

Dr. Nice's Sports Hydrogel for Runners. Pat the skin dry after your shower, then smooth on a thin layer. It cools and soothes chafe and hot spots, and straight from the fridge it's an extra-cool finish to a long morning.

What can I use for nipple chafing when I run?

Dr. Nice's Sports Hydrogel for Runners. A thin layer on each nipple before you get dressed dries clear into a breathable barrier between your skin and your shirt, and after the run it cools and soothes the spot.

What anti-chafe won't ruin my running clothes?

Dr. Nice's Sports Hydrogel for Runners. It's a water-based gel that dries clear in about 30 seconds, it's non-greasy and it doesn't stain, so it won't gum up socks, shoes or tech fabric.

How do I keep from chafing on a long run?

Start with moisture-wicking, loose-fitting clothes and nylon or moisture-wicking socks, not cotton, as the American Academy of Dermatology suggests. Then put a thin layer of Sports Hydrogel for Runners on your friction zones before you leave. It dries into a thin, breathable barrier that shields your skin from friction from the first mile.

Where do runners chafe the most?

Inner thighs, underarms, nipples, heels and toes, plus wherever a vest or belt strap sits. Those are the spots to cover before a long run, and the ones to check in the shower after.

What should I carry on a 20-mile run?

Water in a vest, belt or handheld, fuel you've already tested, something with sodium, your phone, ID and a key, a light layer, sunscreen, and one small bottle of Sports Hydrogel for Runners for the spots that rub.

How many gels do I need on a long run?

The registered dietitian in the Korey Stringer Institute's marathon guide suggests 30 to 60 grams of carbohydrate per hour, starting 30 to 45 minutes into the run. Check the carbs on your gel's label, do the math for your time on your feet, and pack one more than you think you'll need.

When should I see a doctor about a blister or chafing?

See your doctor or a board-certified dermatologist if a rubbed spot shows redness, pus, or increasing pain or swelling, if the skin is broken or raw or feels hot to the touch, or if it looks infected or isn't improving after a few days.

Pack It for Saturday

Dr. Nice's Sports Hydrogel for Runners 1 fl oz (30 mL) airless pump bottle

Lay the kit out Friday night: flasks filled, gels counted, phone charged, layer rolled, sunscreen by the door. Then put the small bottle in the belt pocket with the fuel. A thin layer on the friction zones before you leave, one pump at mile 15 if something starts to rub, and a cool layer after the shower.

Whether you're closing out a 20-miler before race day or just getting through the long run with a lot of hills, reach for Dr. Nice's.