Pruvit K1 Ketones (C5 Formula) – Available Now | Dr. Monica Mogne

K1 Ketones by Pruvit: The C5 Formula That Changes How Fasting Feels

Most exogenous ketone products on the market today are built around the same molecule: BHB, or beta-hydroxybutyrate. BHB works. I have recommended it for years. But after studying the K1 formula and testing it alongside my clinical protocols at FastingON, I can tell you there is something meaningfully different happening here.

K1 introduces C5 ketones, a distinct ketone substrate that the body metabolizes through a different pathway than BHB. In practice, what that means for my patients is a ketone experience that feels less like a spike and more like a steady floor of energy, exactly what you want when fasting for 16, 18, or 20 hours.

K1 is now available to purchase in the US and Canada. Europe opens April 28. Here is everything you need to know before you order.

What Are K1 Ketones? (And Why C5 Changes the Equation)

K1 is Pruvit’s next-generation exogenous ketone formula. Unlike previous Pruvit products that deliver ketones exclusively as BHB mineral salts, K1 includes a C5 ketone component listed on the label as (D)-3-hydroxypentanoic acid sodium.

A quick chemistry note (without the jargon)

Standard ketone supplements give your body C4 ketones, four-carbon molecules that your cells burn for energy when glucose is not available. C5 ketones are five-carbon molecules that follow a different metabolic pathway, specifically through anaplerosis, which means they feed directly into the Krebs cycle as an additional energy source rather than simply replacing glucose.

This is not new science. C5 ketones are produced naturally in the body from odd-chain fatty acids, particularly heptanoic acid (C7), and have been studied in peer-reviewed research published in journals including PubMed and Nature Scientific Reports. What is new is their inclusion in a drinkable exogenous ketone formula. The physiology behind them is well established. What K1 does is make that pathway accessible in a practical daily format.

This may explain why people who have already tried standard BHB ketones sometimes respond differently to K1.

They are not getting more of the same thing.

They are getting a second substrate that works through a different route.

The M3 Matrix Blend , what is actually in the formula

Each K1 sachet (16.9g) contains:

• DL-3-hydroxybutyric acid sodium, calcium and magnesium (the BHB mineral salts)
• (D)-3-hydroxypentanoic acid sodium, the C5 component
• Glycine, an amino acid that supports metabolic function
• Vitamin B6 (100% DV) and Vitamin B12 as methylcobalamin (100% DV)
• Calcium (35% DV), Magnesium (21% DV), Sodium (47% DV)
• Only 20 calories and 4g of carbohydrate per serving

FastingON Note: The high sodium content (1070mg per sachet) is relevant for people who fast. Fasting and low-carb eating naturally deplete electrolytes, so this level of sodium is a feature, not a concern, for most fasters. If you have a medical reason to restrict sodium, speak with your doctor first.

 

Why I Use K1 Myself – Dr. Monica’s Clinical Perspective

I have been using exogenous ketones personally and recommending them professionally since 2020. In that time, I have worked extensively with Pruvit’s NAT formula and seen consistent, positive results. NAT remains a solid product and I have recommended it without hesitation for years.

What K1 adds is a second ketone substrate, the C5 component, that extends the effective window beyond what BHB alone produces. With K1, the energy curve feels more gradual and sustained. I describe this as a metabolic handoff: as BHB levels begin to taper, the C5 substrate continues to provide fuel for energy production. The result is an experience that several of my patients described with the same word, unprompted: smoother.

In my practice, I had a patient, a 44-year-old woman doing 18:6 fasting for perimenopause-related metabolic slowdown, who had plateaued with her previous ketone protocol. I introduced K1 in the first week of testing. Her response: “It just feels smoother.” That single word captures what I have now heard from multiple patients. It is not dramatic. It is consistent. And consistency is what changes metabolism long-term.  Dr. Monica Mogne | FastingON

I also want to be direct about what K1 is not: it is not a weight loss pill, not a replacement for a solid fasting protocol, and not going to produce results without your commitment. What it does is lower the friction of fasting, less hunger, better focus, more stable energy, so that you actually follow through with the protocol that produces results.

Who K1 Ketones Are For and Who They Are Not

K1 is a strong fit if you practice intermittent fasting (16:8, 18:6, OMAD) and want to extend your fasting window without hunger, if you struggle with afternoon energy crashes and want a clean non-stimulant solution, if you are in a GLP-1 recovery phase (post-Ozempic/Mounjaro) and want to rebuild metabolic flexibility, if you are an athlete or high-performer who uses fasting for cognitive edge, if you have tried standard BHB ketones and want to add a second substrate for a more sustained experience, or if you are new to ketones and want to start with the most advanced formula available.

Some people should take extra care before starting K1. If you are pregnant or breastfeeding, if you have a medical condition that requires sodium restriction, or if you are on medication that affects electrolyte balance, K1 may still be appropriate for you but the conversation with your doctor comes first. These are not exclusions. They are situations where clinical guidance makes the difference between a good experience and a poor one.

How to Use K1 Ketones | Dr. Monica’s Protocol

The timing of exogenous ketones matters more than most supplement guides acknowledge, and it depends on what you are trying to achieve. Here are the main situations I use with my FastingON patients.

• For fasting support, take 1 K1 sachet 30 to 45 minutes after waking, during the first hours of your fasting window. This is the period when the body is transitioning away from overnight glycogen and the ketone signal is most useful. Dissolve in 12 to 16 oz cold water, shake well, and drink within 15 minutes of mixing.

• For appetite control and cravings between meals, K1 can be taken outside of a fasting window, between meals during the day, to reduce the urgency of hunger and support better food choices inside your eating window. This is particularly useful in the first weeks of building a fasting habit.

• For cognitive performance, take 1 sachet 20 to 30 minutes before intense mental work such as presentations, deep focus sessions, or studying. Do not stack with other caffeine sources. K1 contains caffeine and the total daily caffeine budget applies.

• For the GLP-1 recovery protocol, use 1 sachet in the morning within the first hour of waking during the metabolic re-training phase post-GLP-1. Combine with a 14:10 fasting window minimum and see the FastingON GLP-1 Rebalance program for the full protocol.

• If you want to take K1 in the evening, Pruvit offers a caffeine-free version that fits this window without affecting sleep. It delivers the same ketone and electrolyte benefits without the stimulant effect.

And one point I want to make clearly: you do not need to be fasting to benefit from K1. The C5 and BHB substrates provide metabolic energy regardless of your eating pattern. Fasting amplifies the results, but K1 works as a standalone metabolic support tool even for people who are not following a structured fasting protocol.