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41 clinical trials · HSA/FSA Eligible
Better skin starts from within
Serums, lasers, needles: they work at the surface. The Prolon 5-Day Fasting Mimicking Diet supports cellular rejuvenation through autophagy, with a clinically shown 25% increase in skin hydration after one cycle.
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★★★★★
4.4 program rating
41 clinical trials
Trusted by 1M+ users
Clinically Supported Results
25%
increase in skin hydration after one cycle
2.5 years
Biological age reduction after three consecutive monthly cycles
41
clinical trials behind the science
1M+
users who trust Prolon
TLDR: Not a starvation diet. Not another trend. The Prolon 5-Day FMD is the only nutrition program clinically proven to trigger autophagy in humans. Real food. Real science. Here are 10 reasons people are making the switch.
1
Clinically studied skin results that go deeper than any serum
Every skincare product works on the surface. Prolon 5-Day FMD has a published clinical study showing what happens when you address skin at the cellular level. In a clinical study, skin hydration rose 25.1% five days after the first Prolon cycle, compared with 8.52% in a control group. After three consecutive monthly cycles, participants reported better skin texture and more even skin tone.Even after 71 days, hydration remained significantly higher. These aren't topical results. They're cellular.
2
Your skin is the only organ that shows you the results
Here's a line worth repeating: your skin is the only large organ you can actually see. Every other benefit of cellular renewal, including metabolic reset, has to be measured with blood work and scans. Your skin is the one place where the body gives you a visible progress report. When the Prolon 5-Day FMD visibly improves it, you're seeing proof of what's happening at the deepest level.
3
Real food, every day of the fast
Without real food, your body pulls resources away from non-essential systems, and skin is first on the chopping block. The Prolon 5-Day FMD is precision nutrition, designed to keep your body in a fasting state while you eat. Every day, your body gets plant-based soups, nut bars, olives, kale crackers, and herbal teas. Real food, real nutrition; you're nourishing your skin while your body still enters a fasted state at the cellular level.
4
The cellular renewal behind the glow
By day three, your cells enter a state called autophagy, where old, damaged cell components are cleared out, making way for newer, younger functioning ones. The Prolon 5-Day FMD is the only nutrition program clinically proven to trigger autophagy in humans. In the skin, that can mean damaged cells clearing faster, the cells that build collagen functioning the way they're supposed to, and the whole system running cleaner.
5
25 years of research from USC. Not a skincare trend.
Another collagen powder. Another glow serum. Another "protocol" that'll be forgotten by next quarter. A majority of them do not have published studies, and most of them won't last. L-Nutra's founder Dr. Valter Longo developed the FMD at the Longevity Institute at USC, with 25 years of research, 41 clinical trials, research collaborators including Stanford and Mayo Clinic, 200+ issued or pending patents. Prolon is the first and only patented nutrition program to support longevity through cellular rejuvenation. When something this well-studied produces a visible skin result, it's not a trend. It's science.
6
Results that hold long after the five days are done
One of the most common questions about the 5-Day program: does it actually last? In the published skin study, the skin improvements were measured again 71 days after the program ended, and the benefits remained significant. Five days, weeks of visible payoff. The recommended protocol is 3 onboarding cycles over 3 consecutive months, then 3 to 4 cycles a year.
7
Your skin shows you the renewal first
Your skin is the only large organ you actually see. The cellular renewal the Prolon 5-Day FMD is designed to support happens mostly out of view, measured in lab tests and bloodwork. Your skin is the part you can actually watch. The bigger insight: when your skin looks renewed after three cycles, that's a visible sign of the cellular renewal the 5-Day program is built to support. You see it on your skin first.
Skincare that starts from within. Clinically shown 25% increase in skin hydration after one cycle.
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What happens inside your body
Five days. Five phases. Here's the transformation happening at the cellular level.
Transition to fasting state
Feels like a normal day with less on the plate. Your body begins depleting glucose stores and switching fuel sources.
Fat-focused weight loss begins (ketosis)
Glucose stores are depleted. Your body shifts to using fat for fuel. You're now producing ketones, a clean, efficient energy source.
Autophagy activates
Your cells begin cleaning house, recycling and removing damaged components. This is clinically verified, not theoretical.
Cellular rejuvenation
Autophagy is in full swing, making way for newer, younger functioning cells. This is when many users report peak mental clarity.
Deep renewal and reset
Cellular clean-up and renewal at its peak. Your body has undergone a measurable reset, supporting healthy aging, metabolic health, and the kind of renewal that shows up on your skin over the following weeks.
The glow is real
Verified quotes from Prolon customers who finished three cycles.
★★★★★
"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 · scientist
★★★★★
"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 · repeat customer
★★★★★
"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
Real people, real glow
Real Prolon customers, in their own words.
★★★★★
Trusted by 1M+ users
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★★★★★
4.4 Stars
Trusted by 1M+ users
Prolon 5-Day Fasting Mimicking Diet
A five-day program clinically formulated to target fat, protect muscle, and reset your body from the inside.
Designed to target fat and protect lean muscle mass
The Prolon 5-Day FMD is the only nutrition program clinically proven to trigger autophagy in humans
No long-term food deprivation
Plant-based: soups, nut bars, olives, kale crackers, herbal teas
HSA/FSA eligible
That's roughly what you'd spend on meals for the week anyway.
Choose your flavor:
The original powdered soups in familiar flavors: Minestrone, Tomato, Mushroom, Vegetable, and Minestrone Quinoa.
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One cycle is 5 days. Most customers run three to four cycles per year.
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