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10 reasons the Prolon 5-Day works on your whole body, not just the scale
Five days of precision nutrition that keeps your body in a fasting state while you still eat real food. Backed by 47 clinical trials, with results measured everywhere from body fat to skin hydration. Here are the ten reasons one box covers so much ground.
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★★★★★
4.4 program rating
Backed by 47 clinical trials
1M+ happy customers
5 lbs
average fat-focused weight loss per cycle*
47
clinical trials behind the program
200+
patents held on the science
25+ yrs
of clinical research with 18 leading institutions
*User-reported average per 5-day cycle. Individual results vary.
TLDR: One box, five days, real food. The Prolon 5-Day is precision nutrition that keeps your body in a fasting state while you eat, with a user-reported average of 5 pounds of fat-focused weight loss per cycle and benefits measured from muscle protection to skin hydration. Individual results vary. Here are the 10 reasons it earns a place in your year.
Fat-focused weight loss, muscle protected
1
Lose the fat. Keep the muscle.
Skin hydration rose by 25% after three consecutive monthly cycles*
Most attempts at losing weight take muscle down with the fat. The Prolon 5-Day is built to do the opposite: it targets fat, not muscle. In Prolon's clinical research, participants lost an average of 5.7 pounds and 1.6 inches off the waist across three cycles, with muscle protected. In one study, it was shown to protect more muscle than the Mediterranean diet.
Averages from Prolon's clinical research. Individual results vary.
One day of the 5-Day, unpacked
2
You eat real food, all five days
One day of the 5-Day, unpacked
This is the part that makes people look twice. Each day's box holds soups, nut bars, olives, kale crackers, and herbal teas: precision nutrition formulated to keep your body in a fasting state while you eat. Some people may feel hungry at some points, especially during their first cycle (users report it gets easier with each round), and that's normal - but staying hydrated helps! It comes structured, and easy to follow - nothing to count, weigh or cook. Everything for the five days arrives in one box.
Day 3: autophagy, the body's cellular clean-up
3
The only nutrition program clinically proven to trigger autophagy in humans
Day 3: autophagy, the body's cellular clean-up
Autophagy is the body's cellular clean-up: cells clear out damaged components to make way for younger, healthier functioning ones. Around Day 3 of the program, your body has been in a fasting state long enough for that clean-up to begin. The Prolon 5-Day is the only nutrition program clinically proven to trigger autophagy in humans. The science behind the mechanism of autophagy earned the 2016 Nobel Prize in Medicine.
Renewal can continue into Days 6 and 7
4
Cellular renewal
Renewal can continue into Days 6 and 7
Autophagy clears. Renewal is what follows. As the clean-up winds down, your body gets to work making way for healthier, younger functioning cells. And the arc doesn't stop when the box is empty: cellular renewal can continue into Days 6 and 7, after you've already returned to your normal meals. That's why five days of the program keeps paying you back after it ends.
Grounded in the research of Dr. Valter Longo, USC Longevity Institute
5
Patented to support longevity
Grounded in the research of Dr. Valter Longo, USC Longevity Institute
The 5-Day is the only nutrition program patented to support longevity through cellular rejuvenation. It helps your cells function as younger versions of themselves. In Prolon's research, the 5-Day reduced biological age by up to 2.5 years after three consecutive monthly cycles. A patented way to slow aging, with food.
Biological age finding tied to three consecutive monthly cycles in Prolon's research. Individual results vary.
Skin hydration rose by 25% after three consecutive monthly cycles*
6
Radiant skin from within
Skin hydration rose by 25% after three consecutive monthly cycles*
Skin is where cellular renewal becomes visible. In Prolon's clinical study, here's what was measured for your skin: hydration increased by 25% after three consecutive monthly cycles, and improvements remained significant 71 days after the program ended. The program has also been shown to enhance skin appearance, radiance, clarity, and tone. It's cellular renewal showing up where you can actually see it.
Skin findings from Prolon's clinical study, measured after three consecutive monthly cycles. Individual results vary.
Cardiometabolic support
7
Cardiometabolic support
Cardiometabolic support
Here's what the research points to: 20 days of Prolon is as effective as 120 days of the Mediterranean Diet on heart health. The 5-Day is also clinically shown to support healthy metabolic markers.
Based on Prolon's clinical research. Individual results vary.
User-reported: energy, focus, clarity
8
The energy and clarity users keep coming back for
User-reported: energy, focus, clarity
Ask repeat customers why they schedule another cycle and the scale is rarely the first answer. Users report more energy, steadier focus, and mental clarity, along with reduced cravings and feeling lighter. Days 4 and 5 are when many users report peak mental clarity. These are user-reported benefits, and we label them that way on purpose: real customers describing how the five days felt.
Paired with balanced eating and a healthy lifestyle
9
Results that hold after you go back to normal eating
Paired with balanced eating and a healthy lifestyle
The rebound is what ruins most five-day efforts: the scale drops, then snaps right back. In Prolon's clinical research, even after participants returned to normal eating, the majority of the weight loss stuck. Combined with balanced eating and a healthy lifestyle, each cycle is worth more than the five days it takes. Users also report reduced cravings and a healthier relationship with food after the program.
Individual results vary.
HSA/FSA eligible
10
It fits a real life, and your HSA/FSA can cover it
HSA/FSA eligible
Five days. One box. Every meal planned, portioned, and shelf-ready, so the program travels with your actual schedule instead of fighting it. Most users follow three to four cycles yearly, with the benefits compounding over time. And because the 5-Day is HSA/FSA eligible, you can put pre-tax health dollars toward it. Plant-based, gluten free, and dairy free, with nothing to figure out on your own.
Real customers, on camera
Customers documenting their own five days: in their kitchens, on their schedules, eating real food the whole way through.
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What's happening inside, day by day
Five days, one arc. Here's what your body is doing while you eat.
Transition to a fasting state
Feels close to a normal day, just a little lighter. Your body begins drawing down glucose stores and switching fuel sources.
Body shifts to fat for fuel
Glucose stores run low and your body turns to fat for energy, producing ketones as an efficient fuel source.
Autophagy: the body's cellular clean-up
Your cells begin clearing out damaged components.
Autophagy and fat-burning in full swing
The clean-up continues. This is when many users report peak mental clarity.
Cellular renewal
The clean-up gives way to renewal, making way for healthier, younger functioning cells. And it doesn't end here: cellular renewal can continue into Days 6 and 7, after you've returned to your normal meals.
In their own words
★★★★★
"I experience great sustained energy, better-looking skin, better sleep, and a sense of achievement every time I complete the five days. As a scientist myself, the work and science behind the program drove me to try it."
Liz · Verified user
★★★★★
"A radical game changer. Every time I do it, I feel 100% better. Clears up low energy, blurry vision, mental fuzziness, body aches and pains, and skin issues."
Cecile · Verified user
★★★★★
"I lost weight, my energy level peaked to a point where I feel 20 years younger. I feel like I can be me again and I can have the energy to play with my kids. I've never done another program of any kind that gave me such relief."
Jennifer · Verified user
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★★★★★
4.4 program rating · 1M+ happy customers
Prolon 5-Day Fasting Mimicking Diet
Five days of precision nutrition that keeps your body in a fasting state while you eat real food, with benefits measured from fat loss to skin hydration.
Real food every day: soups, nut bars, olives, kale crackers, herbal teas
The only nutrition program clinically proven to trigger autophagy in humans
Targets fat, not muscle
Nothing to count, weigh, or cook; everything's in the box
HSA/FSA eligible · plant-based, gluten & dairy free
Subscribe & Save 15%
Free Welcome Kit with Subscribe & Save (subscriber-only) · HSA/FSA eligible. One cycle is five days; most users follow three to four cycles yearly. The Prolon 5-Day is a food-based nutrition program, not a medication. If you're managing a health condition or take medication that requires food, talk with your healthcare provider before starting. Individual results vary.
Patented Formula
47 clinical trials
Secure Checkout
HSA/FSA eligible