SGLT2 Inhibitors Supercharge Human Hearts by Activating Pantothenate Kinase

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For over a decade, clinicians remained baffled by why sodium-glucose cotransporter 2 (SGLT2) inhibitors slashed cardiovascular mortality and heart failure hospitalizations, even though the human heart does not express the SGLT2 protein. A study published in Science uncovers the molecular target: SGLT2 inhibitors directly bind and allosterically activate pantothenate kinase 1 (PANK1), the rate-limiting enzyme in coenzyme A biosynthesis. In human heart tissue, this off-target activation restores depleted coenzyme A reserves, accelerates cellular fuel burning across ketones, lactate, and amino acids, and directly enhances myocardial contraction and relaxation velocities.

Cardiologists have spent the past decade celebrating a major clinical victory that they could not explain. SGLT2 inhibitors such as empagliflozin were engineered for type 2 diabetes to force the kidneys to dump excess glucose into urine. Large clinical trials subsequently demonstrated that these drugs caused dramatic reductions in heart failure hospitalizations and cardiac deaths, benefiting patients regardless of whether they had diabetes. Yet, the heart does not express SGLT2. Rodents lacking the transporter entirely still gain cardiac protection from the drugs, proving that the primary cardiac benefit does not rely on renal glucose excretion.

A research team at the University of Pennsylvania has identified the missing target. Rather than acting through secondary hormonal shifts or systemic changes, empagliflozin acts directly on myocardial tissue through an unexpected off-target mechanism.

To investigate, researchers developed an ex vivo system to perfuse functional blocks of human heart tissue taken directly from transplant recipients with failing hearts and organ donors. Perfusing these tissues with 700 nanomolar empagliflozin, a concentration matching standard clinical patient blood levels, immediately stimulated broad metabolic fuel consumption. The treated human heart muscle pulled significantly more ketones, lactate, and branched-chain amino acids from the perfusate and channeled them directly into the mitochondrial Krebs cycle, raising cellular ATP and overall energy balance.

Metabolomic tracing pointed to a specific biochemical bottleneck. Treated tissues showed a steep depletion of vitamin B5 (pantothenate) accompanied by an increase in phosphopantothenate. This specific shift highlighted pantothenate kinase 1 (PANK1), the rate-limiting pacemaker enzyme that cells use to synthesize coenzyme A (CoA). Failing human hearts suffer from severe metabolic starvation characterized by depleted pools of free CoA, the obligate cofactor required to burn fats, ketones, and carbohydrates.

Using structural modeling, cellular thermal shift assays, and biophysical scattering, the investigators proved that empagliflozin binds directly to the PANK1 homodimer. The drug slots into an allosteric pocket with an effective concentration (EC50) of roughly 13 nanomolar, well below standard human therapeutic blood levels. Binding causes the enzyme to fold into a more compact, active configuration, stimulating CoA production without blocking the catalytic core. Other approved gliflozins, including dapagliflozin and canagliflozin, demonstrated identical PANK1 stimulation, confirming a broad drug class effect.

In single-cell assays of failing human heart muscle cells, empagliflozin directly increased contractile force and accelerated muscle relaxation. When researchers chemically blocked the downstream CoA pathway, these improvements completely vanished. Conversely, synthetic PANK activators reproduced the identical benefits. These findings confirm that SGLT2 inhibitors treat heart failure by rescuing cardiac energy production at its molecular origin.

Actionable Insights

This discovery provides practical clarity for clinicians and health-conscious adults evaluating the cardiometabolic benefits of SGLT2 inhibitors.

In isolated failing human heart cells, empagliflozin produced substantial physical improvements. The drug increased fractional shortening by an absolute 1.3 percentage points, representing a 37 percent relative gain in contractile performance (moving from 3.5 percent to 4.8 percent). Relaxation speed improved by an absolute 0.35 micrometers per second, a 50 percent relative increase that reflects much faster calcium handling in exhausted muscle cells. In intact human heart tissue, the drug stimulated a 225 percent increase in ketone fuel uptake and elevated cellular energy charge by roughly 85 percent.

The primary practical takeaway is that standard clinical doses (such as 10 to 25 milligrams of empagliflozin daily) achieve peak blood concentrations between 500 and 1500 nanomolar. This provides a 40-fold to 115-fold margin above the 13 nanomolar threshold required to activate PANK1 and drive coenzyme A synthesis. Because PANK1 uses pantothenate (vitamin B5) and cysteine as essential raw ingredients to build coenzyme A, individuals taking SGLT2 inhibitors should ensure sufficient dietary intake of dietary B5 and cysteine precursors to avoid substrate depletion during accelerated metabolic turnover.

Context/Source

  • Paywalled Paper: SGLT2 inhibitors activate pantothenate kinase in the human heart
  • Institutions: Cardiovascular Institute, Department of Medicine, Department of Biochemistry and Biophysics, and Department of Physiology, Perelman School of Medicine at the University of Pennsylvania; Lewis Katz School of Medicine at Temple University; Children’s Hospital of Philadelphia
  • Country: United States of America
  • Journal Name: Science
  • Journal Impact Evaluation: The impact score of this journal is 56.9, evaluated against a typical high-end range of 0–60+ for top general science, therefore this is an Elite impact journal.

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#2

Follow-on Prompt:

What are the best food-based sources of dietary B5 and cysteine precursors? What is the optimal dosing for a person taking 10 to 25 milligrams of empagliflozin daily?

From Gemini Pro (paid):

Dietary Sources of Vitamin B5 and Cysteine Precursors

Optimizing the intake of vitamin B5 (pantothenic acid) and cysteine precursors (cystine and methionine) is highly practical through whole foods. Because these nutrients are critical for basic cellular function, they are widely distributed in protein-dense and plant-based foods.

Top Sources of Vitamin B5 (Pantothenic Acid)

According to the National Institutes of Health, vitamin B5 is naturally present in almost all living cells. The most concentrated sources include:

  • Organ Meats: Beef liver and kidney.

  • Animal Proteins: Beef, chicken breast, and seafood.

  • Vegetables: Shiitake mushrooms, avocados, potatoes, and broccoli.

  • Grains and Seeds: Whole wheat, brown rice, oats, peanuts, and sunflower seeds.

  • Dairy and Eggs: Milk and whole eggs.

Top Sources of Dietary Cysteine and Methionine

Cysteine is synthesized in the body from methionine, making high-protein foods the best dietary precursors. According to recent nutritional data, optimal sources include:

  • Lean Meats: Pork chops, beef skirt steak, and lean chicken breast.

  • Seafood: Tuna, salmon, tilapia, and clams.

  • Plant-Based Proteins: Lentils, soybeans (edamame), oatmeal, and sunflower seeds.

  • Dairy and Eggs: Low-fat yogurt, Swiss cheese, and eggs.

Optimal Dosing Considerations with Empagliflozin

To address the question of optimal dosing for an individual taking 10 to 25 milligrams of empagliflozin daily (which represents the standard clinical therapeutic range), we must separate verified pharmacological mechanisms from the current lack of clinical trial data.

The Mechanistic Rationale Recent research published in Science demonstrated that SGLT2 inhibitors, including empagliflozin, directly bind to and activate pantothenate kinase 1 (PANK1) in human tissues. PANK1 is the rate-limiting enzyme that initiates the conversion of vitamin B5 into coenzyme A (CoA). The downstream process of synthesizing CoA also requires cysteine. Because empagliflozin accelerates CoA synthesis, it increases the cellular consumption of these precursors, as evidenced by a marked depletion of pantothenate and cysteine in ex vivo heart tissues treated with the drug.

The Knowledge Gap

While this biochemical mechanism is established, there are currently zero clinical trials that define a specific, optimal supplemental dose of vitamin B5 or cysteine explicitly for patients taking SGLT2 inhibitors. Formulating an exact empirical dosage requires additional long-term in vivo data to determine if the accelerated CoA turnover practically depletes systemic vitamin B5 or cysteine reserves over time. It is currently informed speculation that co-supplementation is strictly necessary, though the underlying logic is sound.

Practical Baseline Dosing (Metabolic Protocols)

In the absence of SGLT2-specific guidelines, individuals seeking to support metabolic pathways often look to established clinical dosing ranges used in general longevity and metabolic research:

  • Vitamin B5 (Pantothenic Acid): The standard US Recommended Dietary Allowance for adults is 5 mg per day. In clinical studies evaluating lipid metabolism and dyslipidemia, dosages ranging from 600 mg to 1,200 mg daily have been used safely. However, a conservative approach utilizing a high-quality B-complex containing 10 mg to 50 mg is generally sufficient to prevent substrate depletion without risking gastrointestinal upset.

  • Cysteine (via N-Acetylcysteine / NAC): Because dietary cysteine is unstable, targeted supplementation usually relies on NAC. Standard clinical protocols for antioxidant and metabolic support typically range from 600 mg to 1,200 mg daily. Due to the short plasma half-life of NAC (approximately 6 to 8 hours), splitting the dose into morning and evening administrations maintains more consistent systemic levels.

Monitoring physical response, adjusting dietary intake first, and utilizing conservative supplementation ranges is the most practical framework until targeted clinical guidelines for SGLT2 inhibitor co-supplementation are published.

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#3

Vitamin B5 and the Failing Heart: A New Explanation for Why SGLT2 Drugs Work

This is a short News and Views commentary in Nature Reviews Cardiology. Two cardiovascular researchers discuss a 2026 Science paper by Forelli and colleagues at the University of Pennsylvania, which reported that SGLT2 inhibitors (empagliflozin, dapagliflozin, canagliflozin) bind directly to an allosteric pocket on pantothenate kinase 1 (PANK1), the rate-limiting enzyme that converts vitamin B5 into coenzyme A. Binding displaces the acyl-CoA molecules that normally shut the enzyme down, so CoA production rises. Because free CoA and acyl-CoA species are depleted in failing human hearts, the authors argue the drugs restore the heart’s capacity to burn fat, sugar, amino acids and ketones, rather than simply supplying ketones as a superfuel. The commentators note that this fits with a separate finding that these drugs also directly activate HMGCS2 in the liver, and with evidence that empagliflozin protects mouse hearts even when SGLT2 is genetically absent. They propose that PANK1 activation itself could become a drug target.

For a decade, cardiologists have had a drug class that works and no agreed explanation for why. SGLT2 inhibitors, developed to flush sugar out through the kidneys, cut heart failure hospitalizations and cardiovascular deaths. The awkward part is that the target protein, SGLT2, is barely present in adult human heart muscle. The benefit begins within days, too fast for the heart to have structurally remodelled.

A commentary in Nature Reviews Cardiology by Alessia Riccio of Sapienza University and Gaetano Santulli of CUNY lays out what may be the clearest answer yet, drawn from a study published in Science in August 2026 by Nicholas Forelli, Zoltan Arany and colleagues at Penn.

The leading theory until now was fuel switching. These drugs raise blood ketones, and ketones were proposed to be a more efficient fuel for a struggling heart. That idea has been losing ground. Ketones supply only a small fraction of the heart’s energy, and the EMPA-VISION trial found that empagliflozin did not improve the heart’s phosphocreatine-to-ATP ratio in patients with heart failure, a direct measure of energy reserve.

The Penn team looked elsewhere. Using slabs of heart muscle from transplant recipients and from donor hearts, perfused outside the body so each heart served as its own control, they found that empagliflozin more than doubled the uptake of pantothenate, better known as vitamin B5, and pushed it into coenzyme A.

Coenzyme A is a universal carrier molecule. Nearly every fuel the heart burns, whether fat, sugar, protein or ketones, has to be attached to CoA before it enters the Krebs cycle. Failing human hearts turn out to be depleted of free CoA and its derivatives. The problem may be less a shortage of fuel than a shortage of the handles needed to carry it.

PANK1 is the rate-limiting enzyme that makes CoA, and it is normally switched off by its own downstream products in a feedback loop. Structural and biochemical work showed that SGLT2 inhibitors slot into that same inhibitory pocket, displacing the brake without touching the enzyme’s active site. Mutating the binding residues abolished drug-induced activation while leaving the enzyme’s baseline activity intact, which is a strong argument that PANK1 is a genuine target and not a bystander.

Functionally, SGLT2 inhibitors made isolated adult human heart cells contract harder and relax faster. The same effects appeared with PZ-2891, an unrelated synthetic PANK1 activator, and disappeared when CoA synthesis was blocked. That is a reasonably tight pharmacological argument.

The commentators place this alongside a parallel discovery that these drugs directly activate HMGCS2, the enzyme controlling ketone production in the liver. One drug class, two distinct metabolic enzymes, two organs. The emerging picture is of molecules that tune several nodes of energy handling at once.

The obvious question follows: could a pure PANK1 activator deliver cardiac benefit without glucosuria, yeast infections or ketoacidosis risk? PZ-2891 already exists, developed for a rare neurodegenerative disease. That compound has never been tested for heart failure in humans.

Context and Source

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#4

Yes, but if that indeed is the MOA by which SGLT2i work in heart failure, then it is also clear why those without heart failure - such as the vast majority of biohackers taking these drugs - will experience no benefit in heart health, because they don’t have the defect which these drugs fix. There are certainly benefits for other organs, but not the heart in the absence of heart failure.