Studies I can’t stop thinking about · Research

Can You Turn Down a Sweet Tooth?

What happened when researchers switched off sweetness on the tongue, then kept offering people their favorite candy.

By Christopher Walker · October 13, 2026 · 8 min read

I found another study this week I haven’t stopped thinking about.

It starts with a climbing plant from India called Gymnema sylvestre. In Hindi it’s known as gurmar, usually translated as “sugar destroyer.” For once, a folk name turns out to describe something you can measure.

What Gymnema actually does

The leaves contain a family of compounds called gymnemic acids. When they come into contact with the tongue, they interfere with the sweet taste receptor (T1R2/T1R3) and temporarily dampen how sweet things taste. Lab work has identified which specific gymnemic acids are most active at the human receptor, and noted that they are also intrinsically bitter.⁸

Other tastes are largely unaffected. Sugar still tastes like something; it just stops tasting sweet for a while. People who try it often describe chocolate as waxy or chalky.

That raises an obvious question: if sugar stops being rewarding to taste, do people eat less of it?

The 2017 candy experiment

Researchers at the Oregon Research Institute ran a double-blind, placebo-controlled experiment with 67 adults.¹ Each person picked their favorite candy and ate one standard serving. Then they were randomly given either a gymnemic-acid lozenge or a placebo lozenge.

After that, the researchers kept offering more candy, one serving at a time. Accept it, eat it, rate it, and you’d be offered another.

The part that caught my attention: the drop in people choosing the first optional serving happened before they had tasted any candy after the lozenge. The authors read that as evidence the effect isn’t only about candy tasting worse in the moment. Knowing your sweet receptors are offline may change how much you want it to begin with.

The 2018 brain scan

So the same group put people in an fMRI scanner. In a crossover design, 40 adults who reported liking sweets came in twice, once with the gymnemic-acid lozenge and once with a placebo, and were scanned while anticipating and tasting a high-sugar milkshake.²

With the gymnemic-acid lozenge, activation in the striatum and orbitofrontal cortex, regions involved in reward and valuation, was significantly lower in response to the anticipated taste of the milkshake. Response in the dorsolateral prefrontal cortex to actually tasting it was also lower. And they replicated the earlier result: people ate less candy afterward.

Two 2020 experiments: chocolate, and what happens after you swallow

A team at Massey University in New Zealand tested a mint containing 4 mg of gymnemic acids against a taste-matched placebo in 56 young adults, using each person’s favorite chocolate.³ After the gymnema mint, people ate about half a bar less (0.48 bars, a 21.3% reduction) over 15 minutes, and rated the chocolate as less pleasant and less desirable. People who described themselves as having a sweet tooth showed the larger drop in desire.

A separate Japanese study asked a different question.⁴ Fifteen people rinsed with a Gymnema solution or water before eating sweet foods. Sweetness and liking dropped, but gastric emptying, blood glucose, insulin and hunger didn’t change. And afterward, people reported a higher desire for sweet taste and lower satisfaction. Turning down sweetness in the mouth doesn’t mean the body treats the sugar any differently once it’s swallowed.

What happens over two weeks?

This is where the story gets more honest. In a 2022 randomized trial, 58 adults used gymnema mints (or placebo) daily for 14 days alongside a healthy-eating guide.⁵ On day one, the gymnema group ate fewer chocolates in the lab. By day 15, there was no difference between groups in the lab test, and food-frequency questionnaires showed no differences in everyday intake of sweet food categories.

A 2025 crossover trial focused on 32 people who identified as having a sweet tooth.⁶ When people used gymnema mints whenever they wanted (up to six a day), daily sugar-sweetened drink intake fell 42% and overall sugar cravings fell 28% compared with placebo. A fixed three-times-a-day schedule didn’t produce those same reductions, though both schedules made chocolate less pleasant and less wanted. In follow-up interviews, participants said the mints made sweets unpleasant and made them more mindful about eating them.⁷

The counterpoint worth knowing

A 2017 Cornell study used Gymnema tea to dull sweet taste in 51 people, then let them mix their own drinks to their preferred sweetness.⁹ With sweetness dulled, people added more sugar to get to a level they liked. A blunted signal can make you chase a stronger one. Whether Gymnema reduces intake seems to depend on the setup: whether you’re offered a fixed sweet food that now tastes worse, or free to adjust how sweet things are.

What the evidence does and doesn’t establish

Reasonably well supported: gymnemic acids in contact with the tongue reduce perceived sweetness and pleasantness for a while, and in lab settings that reliably translates to eating somewhat less of a sweet food offered immediately afterward.

Promising but early: reduced reward-region response to anticipated sweetness (one fMRI study), and reduced cravings when used on demand by people with a sweet tooth (one small crossover trial).

Not established: lasting changes to sweet preference, weight, or everyday sugar intake. The one longer trial with a lab follow-up found the effect gone by day 15.

The tongue versus the stomach

Every study above depends on oral contact. The lozenges, mints, rinses and teas all put gymnemic acids directly on the tongue, right before the sweet food. That is the mechanism being tested.

Swallowing a Gymnema capsule is a different thing. A capsule doesn’t coat the tongue, so you shouldn’t expect it to make chocolate taste waxy or reproduce any of these taste experiments. Gymnema is also studied for other reasons, including how the body handles glucose, but that is separate research with its own evidence, and not what these experiments measured.

If you take medication that lowers blood sugar, talk to your clinician before adding Gymnema in any form.

Where Gymnema shows up in what I make

Disclosure: I co-founded Monthlees, a supplement membership company, and I have a financial interest in the product below.

Gymnema is one of the ingredients in GlucoStasis, a formula I helped put together at Monthlees. To be clear about what it is: GlucoStasis is a swallowed capsule. It isn’t designed to recreate the tongue-contact experiments above. Gymnema is in it as part of a blend aimed at supporting healthy glucose metabolism, alongside chromium, cinnamon and bitter melon.

GlucoStasis™

Chromium, cinnamon, bitter melon and Gymnema leaf in two daily capsules, with every amount on the label.*

See why Gymnema made the formula →

Why I can’t stop thinking about this one

Most advice about sugar is about willpower. These experiments poke at something more interesting: how much of a craving is the taste itself, and how much is the expectation of the taste? When people knew their sweet receptors were offline, some of them wanted the candy less before they’d even tasted it.

I don’t think a lozenge rewires anyone’s relationship with sugar. But as an experiment you can run on yourself, once, it’s a strange and memorable way to find out how much of your sweet tooth lives on your tongue.

— Chris

Curious about the formula?

GlucoStasis is a capsule, not a lozenge. It isn’t meant to change how sweets taste. Here’s what’s in it and why.*

See GlucoStasis →