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A scientifically designed protocol
Are you losing the wrong kind of weight?
Most diets can't tell the difference between fat and muscle. Your body can. The Prolon 5-Day Fasting Mimicking Diet is clinically formulated to help you lose the fat you don't want and protect the muscle you do.
Start your reset
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★★★★★
4.4 Stars
41 clinical trials
Trusted by 1M+ users
Stanford
· Mayo Clinic · Harvard
20K+
physicians
25+
years of research
Patented
formulation
Head to head · published clinical study
Prolon vs. the gold-standard Mediterranean diet, over 120 days
Mediterranean diet
Lost weight. Maintained muscle.
✕ Considered the gold standard for cardiometabolic health
✕ Delivered cardiometabolic benefits
✕ Helps maintain muscle mass
✕ Months of dietary change required
Prolon 5-Day FMD
Lost the fat. Kept the muscle.
Matched the Mediterranean diet's cardiometabolic benefits
Protected more muscle than the Mediterranean diet in the study
5.7 lbs lost and 1.5 inches off the waist after three consecutive monthly cycles
Five days at a time, not months of restriction
7 reasons it works
Why the weight comes off
What you lose matters more than how much you lose
Most diets can't tell the difference between fat and muscle. They just drop the number on the scale. Prolon is formulated to know the difference, targeting stored fat for fuel while protecting the lean muscle mass that supports your metabolism, immunity, and longevity.
The weight you lose is the weight you wanted to lose.
5.7 lbs lost · 1.5 inches off the waist · published clinical results after three consecutive monthly cycles
Five days at a time, not months of dieting
Most weight-loss approaches ask for forever — daily counting, weekly weigh-ins, restriction that drags on. The Prolon protocol runs five days at a time, then you go back to eating the way you normally eat.
Those published clinical results, 5.7 lbs lost and 1.6 inches off the waist, came from three cycles. Most customers run three to four cycles per year. Five days a few times beats five months once. The takeaway:
the body responds to it like water, not like a meal.
You can eat while you fast
Prolon is different: plant-based soups, nut bars, olives, kale crackers, and herbal teas, precisely formulated to keep your cells in a fasting state while you stay nourished.
Precision nutrition, not deprivation.
The cellular work that makes the loss real
By day three, your cells enter autophagy: damaged cellular components clear out, making way for healthier, younger functioning cells. The Prolon 5-Day FMD is the only nutrition program clinically proven to trigger autophagy in humans.
For weight loss, that means the body isn't just dropping water and muscle. It's resetting metabolism from the inside out.
The Prolon 5-Day FMD is the only nutrition program clinically proven to trigger autophagy in humans
Reduced biological age, on top of pounds lost
Clinical trials show a median 2.5 year biological age reduction after three consecutive monthly cycles. So the weight you lose isn't the only thing that changes. What's happening inside does too.
The compound effect: a feeling of being lighter and younger, at the same time.
Published clinical results support that reduction in biological age.
No extreme diets.
It works with your body's own fasting response.
Five days a few times a year, no prescriptions
25 years of research from USC, not a wellness trend
L-Nutra's founder Dr. Valter Longo developed the FMD at the Longevity Institute at USC. 25+ years of research, 41 clinical trials, research collaborators including Stanford and Mayo Clinic, and 200+ issued or pending patents.
Prolon is the first and only patented nutrition program to support longevity through cellular rejuvenation.
From a customer
★★★★★
"I can't believe I went down 9.9 pounds in five days and lost two inches off my waist."
Whitney
Verified Prolon customer · shared on social
Individual results vary. Whitney's experience reflects her own use of the 5-day protocol and is not a guaranteed outcome.
The 5-day arc
How the body shifts, day by day
Day 1
Body adjusts to lower glucose
Day 2
Stored fat starts mobilizing, ketones rise
Day 3
Autophagy activates, cellular cleanup begins
Day 4
Fat-burning state in full swing
Day 5
The cycle completes.
★★★★★
Trusted by 1M+ users
+ FREE Welcome Kit
Skincare no serum can touch
A 5-day program that rejuvenates your cells for more radiant skin — clinically proven, delivered to your door.
That's roughly what you'd spend on meals for the week anyway.
Your order includes
Prolon 5-Day Kit (soups, nut bars, snacks, herbal teas)
Free Welcome Kit (includes Prolon water bottle) — subscribers only
Free Getting Started Guide
15% off subscription pricing, cancel anytime
Choose your flavor:
The original powdered soups in familiar flavors: Minestrone, Tomato, Mushroom, Vegetable, and Minestrone Quinoa.
Choose your offer:
Starting at
+ Free Welcome Kit · HSA/FSA Eligible
One cycle is 5 days. Most customers run three to four cycles per year.
Patented Formula
Clinically Tested
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Questions
What people ask before their first program
How much weight will I lose?
Individual results vary. In published clinical research, participants saw an average of 5.7 lbs of weight loss and 1.5 inches off the waist after three consecutive monthly cycles, with muscle mass preserved. Most customers follow three to four cycles per year for compounding results.
Will I be starving?
You eat every day of the five-day program: plant-based soups, nut bars, olives, kale crackers, and herbal teas, precisely formulated to keep your cells in a fasting state while you stay nourished. Some people do feel hungry at points, especially on the first cycle, and that's normal. Most find it more manageable than they expected, and it tends to get easier with each cycle.
Will the weight come back?
What you do after the program matters. In published research, the majority of the weight loss stayed off even after participants returned to normal eating. Combined with balanced eating and a healthy lifestyle between cycles, the 5-Day program is built for sustained results, not a yo-yo. Most people repeat it three to four times a year.
Is it safe?
The 5-Day Fasting Mimicking Diet has been studied in 41 clinical trials and is trusted by more than 20,000 physicians. As with any nutrition program, talk to a clinician about decisions specific to your care.
Can I subscribe, and is Prolon HSA/FSA eligible?
Save 15% on every order with Subscribe & Save. HSA/FSA eligible.
Five days. Real change.
Lose the fat. Keep the muscle. Reset the body, from the inside out. The protocol that 20,000+ physicians trust.
Start your RESET
Subscribe & Save 15% · HSA/FSA eligible
© Prolon · L-Nutra. Patented fasting mimicking technology developed with the USC Longevity Institute.
These statements have not been evaluated by the FDA. Not intended to diagnose, treat, cure, or prevent any disease.