What Is ProLon?

By Derek Lakin
HighYa Staff Published on: Jul 31, 2017

ProLon is a scientifically developed and clinically tested periodic meal plan that promises to mimic the effects of fasting, while still providing you with enough plant-based nourishment—including essential vitamins and amino acids—to remain satisfied throughout the process.

The result? When taken just five consecutive days per month, the company tells us it’s been proven to help quickly decrease weight, body fat, and visceral fat; maintain healthy glucose and cholesterol levels, promote healthy blood pressure, decrease IGF-1 (an aging marker), preserve bone density, and “positively impact related health risk factors.”

And compared to water-only fasting, the company tells us that ProLon is convenient, doesn’t require ongoing lifestyle changes, and has been proven safe.

If you’re tired of the dieting merry-go-round and are looking for a quick, easy solution for losing weight, all of these claims might sound wonderful. But what kinds of results can you realistically expect with ProLon, and is it worth your hard-earned money?

Let’s start answering your questions by taking a deeper look at the program.

How Does ProLon’s Fasting Mimicking Diet (FMD) Work?

Created in collaboration with some of the world’s best food scientists and chefs, ProLon’s meals come in five boxes (one for each day) that consist of a variety of plant-based foods like energy bars, soups, snacks, drinks, and dietary supplements that are low in carbohydrates and proteins, while containing good fatty acids.

According to the program’s website, there are no additives, preservatives, or chemicals in these foods, which provide between 770 and 1,100 calories per day. The company tells us that your body won’t recognize these calories as food, thereby helping you to maintain a fasting mode, without actually fasting.

However, this reduced intake has been clinically shown (more next), according to the website, to “trigger a set of protectionist measures that the body developed during natural selection, when food was scarce and not easy to find and store. It allows your body to optimize its performance, rejuvenate its cells, and thrive under such circumstances.”

Specifically, we’re told it can reduce IGF-1, glucose, and inflammation and aging markers.

Depending on body weight, baseline markers, and other health measurements, low-risk or healthy individuals are recommended to undergo ProLon’s five-day fasting periods two to three times a year, while those who are considered high-risk can undergo them three to 12 times.

During these periods, customers are instructed not to consume any other foods, or any additional liquids other than water. When you’re finished, you’ll have a one-day transition period, after which you can resume your normal eating habits.

Have Fasting Mimicking Diets Like ProLon Been Clinically Proven?

Fasting mimicking dieting was the brainchild of Valter Longo, who developed the program at the University of Southern California.

Along with the university, he's also an owner of the company behind ProLon, called L-Nutra, although he’s emphasized in the past that he receives no money from the sale of these products.

Overall, the plan has undergone three clinical studies:

  • One completed on periodically fed yeast, which was shown to have a longer lifespan than those who were fed normally.

  • Another completed on mice, which were fed a reduced calorie and protein diet for four days per month. In the end, they experienced “improved metabolism and cognitive function, gradual weight loss, muscle rejuvenation, higher bone density, 40% fewer malignant lymphomas, immune system regeneration, and longer average, though not absolute, life expectancy.”

  • A third study conducted on 38 individuals (19 who underwent FMD and 19 who acted as the control). Those on FMD were reported to experience an “average 3% reduction in weight, a reduction in visceral fat, a reduction in C-reactive protein, and rejuvenation for the immune system.”

We also encountered 67 clinical studies related to fasting mimicking diets on the National Institutes of Health’s PubMed, referencing everything from its effects on tumors and multiple sclerosis to cancer and circadian rhythm.

Will ProLon Cause Potential Side Effects?

In these studies, most participants reported only mild or no adverse effects on the fasting days, although none of these side effects were specified.

However, the company emphasizes in several places on their website that ProLon is not for everyone and should only be used by “healthy individuals who want to optimize their health and wellbeing.” It shouldn’t be used by those under 18, women who are pregnant or nursing, those who are allergic to soy or nuts, those with a BMI less than 18, or those with diabetes or significant cardiac disease.

Outside of what’s provided in each box, the company emphasizes that no additional multivitamins or supplements should be taken during the diet period. And, unless approved by a licensed physician, ProLon should never be combined with glucose lowering drugs, such as metformin or insulin.

To make sure you’re a candidate, you’ll need to take a short self-assessment evaluation when purchasing (indicating age, height, weight, BMI, any prescription medications, and so forth), or reach out to your healthcare provider. The website seems to be strict about this, as it rejected a mock order during our research after only indicating that we took prescription medication.

How Much Does ProLon Cost?

The price you pay for ProLon depends on the number of boxes you purchase at a time:

  • 1-2 boxes: $299 per box
  • 3-6 boxes: $250 per box

All orders come with free standard shipping and no sales tax, except in CA.

In addition to the self-assessment we discussed in the previous section, once your purchase is complete, you’ll also need to complete a guidance call with the company’s dietitian or nurse practitioner to finish processing your order.

ProLon offers a 30-day refund policy on all unopened boxes, less S&H, any discounts received for purchasing multiple boxes at once, as well as a 15 percent per-box restocking fee.

In order to speak to a representative or process a refund, you’ll need to contact customer support at 323-580-6855 or admin@l-nutra.com.

What Are Dieters & Professionals Saying About ProLon?

While there seems to be mounting clinical evidence that infrequent fasting mimicking diets could provide some measure of weight loss and other potential benefits, there is some concern that this doesn’t extend much beyond calorie restriction.

Specifically, that the control group in the previously noted human study didn’t reduce their calorie intake, so it’s not quite clear whether FMD’s benefits stemmed from fasting or from calorie restriction.

Interviewed for a 2017 Forbes article, David L. Katz, founding director of the Prevention Research Center at Yale University, explained it this way:

“As far as I can tell, this proves nothing about fasting. Going days without food produces a calorie deficit, and that causes weight loss. Weight loss, in turn, ameliorates all of the metabolic markers studied here. So, what we've got is: eating less leads to short-term weight loss, and weight loss improves diverse metabolic markers in the short term. Which part of that didn't we know already? To show a direct benefit of fasting, it needs to outperform an alternative diet pattern matched for calories. That was not done here.”

Furthermore, after interviewing several Registered Dietitians, Korin Miller, writing for Women’s Health, delivered the following verdict:

“Don't expect the Fasting Mimicking Diet to give you long-term results. If weight loss and maintaining that goal weight are your main objectives, experts recommend taking a closer look at your overall diet instead and figuring out where you can make smarter choices.”

Despite this, blogger Quantified Bob perused the program’s studies and came up with his own FMD (not ProLon specifically) in April 2016, finding that it reduced his body fat by about two percent, while actually increasing his muscle mass. He also reported good energy and mental clarity during the process.

After undergoing blood work, he found his white blood count went down, his testosterone levels increased by one point, and his stress (cortisol and adrenal) and liver levels were “optimized.” Overall, he reported being “very impressed” with his FMD results.

Finally, Erin Van Der Meer tried out ProLon specifically, noting that she’d “100 percent do it again,” since it was simple and helped her face, stomach, and thighs look slimmer. However, she also noted that the gained back 25 percent of the weight she lost once she resumed normal eating.

Our Final Thoughts About ProLon

Based on the available clinical evidence (although preliminary), as well as reports from actual users, it appears that a fasting mimicking diet like ProLon could help you lose a quick few pounds, as well as boost several biological markers associated with good health.

But unless you’re clearly someone with a lot of background knowledge (like blogger Bob from earlier), only you can decide whether this weight loss is worth the $250 or more price tag for each pre-filled box.

As consumers ourselves, we’re focused on helping you get the most bang for your buck. Which is why we’d strongly recommend speaking with your healthcare provider about ProLon, and whether or not it might meet your expectations (and budget), prior to placing your order.

The company strongly emphasizes on their website that the program should only be conducted under the supervision of a doctor anyway, so this will provide an opportune time to address more than one issue during the same visit.

Read Next: How Walking 30 Minutes a Day Can Benefit Your Health in a Big Way

Sign Up for HighYa Newsletter

Sign up for HighYa newsletter and get our best content delivered in your inbox as well as 3 free eBooks to help you save money and shop smarter. Enter your email below to get started!

4 Consumer Reviews for ProLon

Average Consumer Rating: 3.0
Rating Snapshot:
5 star: 2 4 star: 0 3 star: 0 2 star: 0 1 star:  2
Bottom Line: 50% would recommend it to a friend
Showing 1-4 of 4
Sort reviews by:

  • 1 out 1 people found this review helpful

    Doesn’t work

    • Austin, TX,
    • May 30, 2018
    • Verified Reviewer

    I just finished my first go with the ‘starvation box,’ and if you can believe it, I gained 2 lbs by the end of it. I normally fast once a week for religious reasons, so I wonder if intermittent fasting does not any have the same effect on someone who can tolerate a 24-hour fast. I maintained my normal (rigorous) workout routine with no issue. In conclusion, I’m frustrated that I wasted $250 and my energy on this useless plan.

    Bottom Line: No, I would not recommend this to a friend

    Help others find the most helpful reviews

    Was this review helpful?

    yes no
    Comments (0)
    View all 0 commentsHide comments

    Do you have an account? Log In before commenting.

    (If you don’t have an account – don’t worry, you can create it after)

  • I am half way through.

    • Cleveland, OH,
    • Apr 18, 2018
    • Verified Reviewer

    It is 5:00 on Wednesday afternoon. My brother gave me a box of Prolon on Sunday afternoon and didn't say anything. He just told me to do it. I was 255 and even though knew a lot about losing weight from wrestling in college, just didn't seem to be able to lose weight anymore. On top of that, at 255 I was getting all of the pre-diabetes issues and injuries that you get from being overweight.

    Along comes Prolon. I am halfway through and have had no cravings and have lost 8 pounds. I cannot wait to see where this ends up because I feel like I have already won.

    An additional note. You might be losing weight, but health and longevity are really the goals here. Weight loss is a very wonderful byproduct. You feel good, and you think clearly.

    One of my friends has already got a new package coming.

    Bottom Line: Yes, I would recommend this to a friend

    Help others find the most helpful reviews

    Was this review helpful?

    yes no
    Comments (0)
    View all 0 commentsHide comments

    Do you have an account? Log In before commenting.

    (If you don’t have an account – don’t worry, you can create it after)

  • 3 out 28 people found this review helpful


    I ordered one circle, as they said each circle contained 5 boxes. I believed the price was decent for a 5-month supply.

    When I received the package, I thought it appeared small, but in fact, one circle has 5 boxes, one box PER DAY. I immediately asked for a refund, but ProLon refused to refund me under the pretense "I opened the seal in the box." I escalated this to PayPal but have not gotten back anything.

    ProLon is a scam as they ignore consumers rights.

    Bottom Line: No, I would not recommend this to a friend

    Help others find the most helpful reviews

    Was this review helpful?

    yes no
    Comments (3)
    View all 3 commentsHide comments
    • Feb 7, 2018


      Oh no! You really did it! And you go public with this? Five months, I can't believe it. Haha. Where have you read that?

    • Feb 8, 2018

      Francesca T Spagnoli

      I generously share my knowledge to those who can access it. I'm not sure if that is your case.

    • Feb 22, 2018


      I don’t know what one circle is. It’s clear that one order has 5 boxes inside, one for each day, and costs $300 USD (rounded off) for the 5-day FMD program.

    Do you have an account? Log In before commenting.

    (If you don’t have an account – don’t worry, you can create it after)

  • 6 out 7 people found this review helpful

    Very positive

    • Port Harcourt, Nigeria,
    • Feb 1, 2018
    • Verified Reviewer

    I have completed my ProLon cycle yesterday, and it ended very well. I was already fit enough but lost 2 kgs while maintaining my lifestyle and keeping my lean mass. I will repeat it again after three months also to encourage companies to invest in anti-aging, however, I think it would be impossible to achieve the same results without the strict guidance and psychological commitment of the food in the 5 boxes.

    Bottom Line: Yes, I would recommend this to a friend

    Help others find the most helpful reviews

    Was this review helpful?

    yes no
    Comments (0)
    View all 0 commentsHide comments

    Do you have an account? Log In before commenting.

    (If you don’t have an account – don’t worry, you can create it after)

Showing 1-4 of 4

Write a Review for ProLon!

Share your experience to help others shop smarter & discover great products.

Write a Review