Berberine⁵

Berberine⁵ is Marek's metabolic and glucose-support formula, built around 100 mg of GlucoVantage® dihydroberberine (DHB) — a berberine derivative with substantially better bioavailability and GI tolerability than standard berberine HCl.‡ The formula adds thiamine (Vitamin B1), chromium, and myo-inositol as supporting cofactors for glucose and metabolic pathways.‡

It supports healthy glucose metabolism, metabolic signaling, and cellular energy metabolism.‡

The Marek protocol is one capsule with each of your two largest carb-containing meals — typically breakfast and lunch.

Dihydroberberine is a reduced derivative of berberine — chemically, it's berberine with two extra hydrogen atoms. That small structural difference produces a substantial difference in how the body absorbs the molecule.‡

Standard berberine HCl is notoriously poorly absorbed. Oral bioavailability of standard berberine is typically below 5%. To reach blood levels associated with metabolic effects in research, the standard protocol is 500 mg multiple times per day — and even then, a significant fraction of each dose stays in the gut, which is why high-dose berberine HCl is well known for causing diarrhea, cramping, bloating, and other GI side effects.

Dihydroberberine is absorbed roughly 5x more efficiently. In the gut wall and liver, DHB is converted back to berberine, so the active molecule reaching systemic circulation is the same — DHB just gets there more reliably, with much less left behind to irritate the gut.

Practical translation: 100 mg of DHB taken twice daily delivers metabolic exposure comparable to substantially larger doses of berberine HCl, in two capsules instead of six, without the frequency of bathroom problems that often come with the older standard form.‡ Berberine⁵ uses GlucoVantage® — the patented DHB ingredient developed by NNB Nutrition, and the form used in the more recent human research on DHB specifically.‡

Reference: Berberine and glucose metabolism (systematic review and meta-analysis) — https://pubmed.ncbi.nlm.nih.gov/36467075/

Three supporting nutrients chosen for complementary roles in glucose and metabolic pathways.

Myo-inositol is a cellular signaling molecule deeply involved in insulin receptor signaling. Insulin doesn't just bind its receptor and stop there — the signal has to propagate inside the cell, and inositol-derived second messengers are part of how that happens. Myo-inositol is one of the most-studied nutrients for insulin signaling, glucose metabolism, and metabolic physiology. Berberine⁵ provides 200 mg per capsule.‡

Chromium is a trace mineral involved in carbohydrate, fat, and protein metabolism. The exact mechanism is still being characterized, but chromium appears to support normal insulin action and has been studied in glucose-related metabolic contexts. Berberine⁵ uses 100 mcg of chromium as chromium picolinate — the form used in most of the clinical research literature.‡

Thiamine (vitamin B1) is required for cellular energy metabolism, particularly carbohydrate metabolism — the pyruvate dehydrogenase and transketolase enzyme complexes both depend on thiamine as a cofactor. Adequate thiamine status is foundational for any pathway that processes glucose for energy. Berberine⁵ provides 5 mg of thiamine HCl per capsule as foundational support.‡

These three supporting ingredients aren't intended as the primary metabolic intervention — DHB is the centerpiece. They're included to round out the cofactor side of the formula and complement the DHB mechanism rather than duplicate it.

References:

• Myo-inositol and insulin signaling — https://pmc.ncbi.nlm.nih.gov/articles/PMC6286734/
• Chromium and glucose metabolism — https://pubmed.ncbi.nlm.nih.gov/24635480/

Take one capsule with each of your two largest carb-containing meals — typically breakfast and lunch in the Marek daily protocol.‡

The "with carbs" part matters. Berberine⁵ supports glucose metabolism in the context of carbohydrate intake; taking the capsule alongside a meal that contains carbs is when the formula is doing the work it's designed for.

The "twice daily" part matters too. Dihydroberberine clears the body relatively quickly, so splitting the dose across two carb-containing meals provides metabolic support across more of your eating window than a single morning dose would.

Practical notes:

• If your two largest carb meals are at different times of day — lunch and dinner, for example — adjust accordingly. The schedule is "with your two biggest carb meals," not "breakfast and lunch specifically."
• If you eat one substantial carb-containing meal per day (some people on lower-carb eating patterns), one capsule with that meal is fine.
• Don't double up. Taking both capsules at once may increase GI sensitivity in some people.
• Daily consistency over weeks matters more than perfect single-dose timing. Stay close to a meal with carbohydrate content and you'll get the formula's intended exposure.

Much less likely.‡

The GI side effects associated with standard berberine — diarrhea, cramping, bloating, constipation — are largely a consequence of berberine HCl's poor absorption. Most of the dose stays in the gut and irritates the lining, an effect that becomes more pronounced at the high daily doses (500–1500 mg/day) needed to compensate for low bioavailability.

Dihydroberberine sidesteps most of this. Because DHB is absorbed roughly 5x more efficiently than berberine HCl, far less of the dose remains in the gut, and comparable metabolic exposure is achieved at much lower quantities.‡ The customer feedback on Berberine⁵ — and the broader research on GlucoVantage® DHB specifically — consistently reports substantially better GI tolerability than standard berberine.‡

Individual sensitivity still varies. If you have an unusually sensitive GI tract or have had problems with berberine products in the past, take Berberine⁵ with a full meal, start with one capsule daily before working up to two, and monitor how you feel. If you experience persistent GI issues, talk to your healthcare provider before continuing.

Talk to your healthcare provider before starting Berberine⁵ if you:

• Take any glucose-lowering medication — insulin, metformin, sulfonylureas, GLP-1 agonists (Ozempic, Wegovy, Mounjaro, Zepbound), SGLT2 inhibitors, or other diabetes medications. Combining these with berberine can affect glucose handling and may increase the risk of hypoglycemia.
• Have a diagnosed metabolic condition — type 1 or type 2 diabetes, prediabetes, metabolic syndrome, PCOS, or other glucose- or insulin-related conditions.
• Take blood pressure medications. Berberine has been studied in cardiovascular contexts and may affect blood pressure in some people.
• Take statins, fibrates, or other cholesterol-lowering medications.
• Take blood-thinning medications (warfarin, clopidogrel, aspirin, others).
• Take medications metabolized by CYP3A4 or CYP2D6. Berberine inhibits these liver enzymes, which can affect drug levels for a wide range of common medications, including some antibiotics, antifungals, statins, antidepressants, and immunosuppressants.
• Have liver disease, kidney disease, or are managing a chronic condition with multiple medications.
• Are pregnant, nursing, or trying to conceive. Berberine is generally contraindicated in pregnancy.
• Are under 18.

Berberine⁵ is a dietary supplement and is not intended to diagnose, treat, cure, or prevent any disease. If you're managing a condition or under medical supervision, work with your provider to determine whether Berberine⁵ fits your protocol.