Why I built salz.run

Hi, I’m Sean. I run on trails when I can and sit on the couch when I can’t. I’m not fast. I’ve never been sponsored. I’m signed up for my first 100K next year and I’m currently doing about 42 miles a week, which I’m slowly bumping up because the calendar isn’t on my side.

I’m also a heavy sweater. The kind where my hair gets stuck to my forehead and a salt rim by mile 6 and my eyes start stinging an hour in. I also end most workouts with a bad headache that goes away when I have the proper dose of electrolytes. For years I bought the nice electrolyte powders. Like so many I started with Gatorade, but started to get sick from all of the sugar. Moving to something better I tried Liquid IV and found that it just didn’t make me feel great during my runs. Finally I’ve been using LMNT, but it focuses so much on the salt side of things that it leaves a bad taste and I’m not keeping my energy up through my entire run.

What I didn’t do for years was the math.

The math

After looking at my current running volume of 6 runs a week and going through around a liter of water each run, and that’s before summer, I found myself spending roughly $3 per run on LMNT. This adds up and puts each week at about $20 and $80 per month. Over the course of sprint and summer I spend over $360 on what is effectively salt. This didn’t sit well with me.

Meanwhile a 26 oz canister of Morton salt costs $2 and lasts approximately forever. A 1 kg bag of potassium chloride is $14 and lasts longer. Magnesium powder, dextrose — all in, the four-powder kit runs about $55 once and mixes hundreds of bottles after that.

The math is rude. About 10× cheaper, gram for gram of actual electrolyte.

The catch

The catch is that pre-mixed sachets are tuned for the average person on the couch, not for me on a 4-hour mountain day in July. The sodium dose in an LMNT stick (1,000 mg Na) is great if you’re a moderate sweater going for an hour. For my actual sweat rate and a 4–6 hour run, I need closer to 1,800–2,400 mg of sodium an hour, which is two sticks plus an extra pinch.

By the time I’ve torn open three sachets, dumped them in two bottles, and tried to remember which one I drank already, I’ve spent $3 and I’m still under-dosed.

If I’m going to mix custom doses anyway, why not just weigh the ingredients myself.

What salz.run does

Four ingredients. Kitchen scale. Bottle.

1. Sodium chloride — table salt
2. Potassium chloride — KCl powder
3. Magnesium citrate — Natural Vitality Calm
4. Dextrose — Nutricost glucose powder for the carbs

The calculator does the dosing for me — for my body weight, my sweat rate, the conditions I’m running in, the bottle I’m carrying. Out comes a recipe in grams. I weigh, I pour, I shake.

Per-bottle cost lands around $0.25–$0.40. The salt rim on my hat returns. The eye stinging mostly stays, but my headaches are gone, a fair tradeoff..

What this site is for

Honestly? Mostly for me. The calculator is a thing I needed, and putting it on the internet is more motifivating than using a Google Sheet I’d lose track of by July anyways.

If it’s useful to you too, I’m glad. The Amazon links earn me a few cents per click — that’s the entire monetization. I’m not selling courses, I’m not sliding into your DMs, and I’m not running a Substack to upsell into anything. The blog is just where I write down what I’m trying on my own legs.

I’d love to hear from you if you spot an error in the math or have a protocol I should try. My email and LinkedIn are on the about page. Real person, real legs, real salt rim.

See you out there.