Summary and Results: I conducted a six-month study on myself to test the hypothesis that daily supplementation with potassium chloride (KCl) would lead to weight loss. My experiment consisted of three phases, each lasting two months. The baseline phase didn’t involve any intervention. During the second two-month phase, I consumed 15.2 grams of KCl (equivalent to approx. 8000 mg of potassium) each morning. Finally, during the washout phase, I stopped the KCl. My diet and exercise habits remained constant during all three phases.
I weighed myself every morning using a scale that had a resolution of 0.2 pounds. I found that KCl supplementation resulted in a modest weight loss of approximately 4.2 pounds (1.9 kg) over a two-month period, corresponding to a rate of about 0.48 pounds (0.22 kg) lost per week. Note that my weight varied considerably from day to day, so the 4.2-pound weight-loss figure is based on a linear regression model encompassing all the data points during the KCl phase. My raw data (CSV file) is available here.
The following figure shows my daily weights, along with linear regression lines for each of the three phases. Click on the graphic to see the full-size version.
Background: My self-experiment was prompted by earlier crowdsourced studies organized by the pseudonymous bloggers at Slime Mold Time Mold (SMTM). The blogging team first conducted a community study showing that a diet high in potatoes led to weight loss that was quite substantial: subjects lost an average of 10.6 lbs. (4.8 kg) over just four weeks. Since potatoes contain relatively high levels of potassium, the SMTM bloggers decided to conduct a follow-up experiment on potassium chloride (KCl) supplementation. The protocol dictated that participants should gradually increase their KCl intake until they hit one teaspoon per day (approx. 2600 mg of potassium) — or until they started experiencing adverse effects. As in the earlier potato study, the KCl subjects lost weight, though the results were considerably more modest. Participants lost an average of 0.89 lbs. over four weeks of daily KCl supplementation. While the outcome of the KCl study was less impressive than the earlier potato trial, the results were still promising and suggested the possibility that a higher dose would be more effective.
Pseudonymous blogger “Krinn” was inspired by the earlier community trial and conducted an n=1 replication using a higher dose of KCl. Her results were more impressive, perhaps because of the increased dosage (she also reports that she increased her exercise levels after starting the KCl). She ended up losing 30 pounds (13.6 kg) over six months by consuming an average of 11000 mg of potassium daily. (Krinn varied her specific intake by day of the week, and 11000 mg is a weighted average of her doses.)
Methods: I wanted to repeat the earlier KCl studies, partly because I was eager to lose weight myself. My starting BMI was about 30.6, and the intervention seemed like a fairly effortless way to get slimmer. I was also motivated by a general interest in self-experimentation and in the science of weight loss. Unlike the earlier studies, my experimental design included a wash-out phase.
My source of KCl was Nu-Salt, a sodium-free salt substitute that’s available in most US supermarkets. I started with a dose about 30% lower than Krinn’s average intake. I used a small kitchen scale to determine that two heaping teaspoons of Nu-Salt weighed 15.2 grams, corresponding to about 8000 mg of potassium. Each morning, I would dissolve two heaping teaspoons of KCl in a bottle of sugar-free Gatorade. I would slowly sip the drink over a few hours, and I would chase the KCl solution with regular (untreated) sugar-free Gatorade. My plan was to increase my dose until I reached the same level Krinn had been using, but I ultimately decided against the increase.
I found that the KCl solution produced unpleasant effects. I would feel slightly weak and lightheaded even before I finished the bottle of “kaliated” Gatorade. I also would get a runny nose, and I experienced burning when I urinated. Also, the KCl solution tasted pretty awful. That description makes the problem sound worse than it actually was. My reactions were mild and didn’t really affect my functioning, but they were still a bit concerning. After a few weeks, I started dissolving the KCl in a larger, 20 oz. bottle of Gatorade (versus the earlier 12 oz. size I had been using), but I still experienced unpleasant side effects.
Discussion: Taken together, the three studies of potassium supplementation suggest that there is a dose-dependent effect on weight loss, though we should also keep in mind that Krinn said she considerably increased her exercise intensity following the start of her KCl trial:
| Study | Avg. daily potassium dose | Avg. weekly weight loss |
| SMTM community study | Variable by subject, up to 2600 mg | 0.21 lbs. (0.10 kg) |
| My n=1 experiment | 8000 mg | 0.48 lbs. (0.22 kg) |
| Krinn’s n=1 experiment | 11000 mg | 1.15 lbs. (0.52 kg) |
The effect is hardly linear, consistent with the observation made by the SMTM bloggers, who found wide variability in responses among the participants in the community trial. That trial involved 104 subjects, and due to the nature of the protocol, they were not all taking the same dose of KCl. The results showed a slight but statistically significant dose-dependent relationship to weight loss across the 104 subjects. Overall, the presumed dose-related nature of the response is suggestive of some physiological mechanism versus a non-specific placebo effect.
The SMTM bloggers and Krinn have interesting discussions where they relate the results of the potato studies to the KCl studies, as well as other thoughts. I don’t have much to add to those discussions, so interested readers can consult those sources directly (see links up above).
Overall, I’m glad I did the experiment, despite the fact that the KCl made me feel slightly ill. If anyone is interested in conducting their own study on potassium supplementation, I would encourage you to be careful – start with a low dose and ramp up gradually. And definitely don’t do it at all if you have any type of kidney disease or other serious health conditions. The bloggers at SMTM have more detailed safety advice that you should read carefully before you do anything.
I’d be happy to correspond with anyone who has questions or otherwise wants to discuss aspects of this project.