“Based on what I see for sale online, this has some of the highest quantity mgs of ingredients for the best possible price. Since my doc recommends this brand, I'm doubly sold.”
Prolon® Intermittent Fasting Bar
A clinically tested intermittent fasting bar that nourishes you without breaking a fast.
- Whole-food ingredients, no fillers
- Formulated to support fasting biology
- Ideal for IF, travel, or on the go
- Clinically tested to not break a fast
- Curbs hunger during fasting windows
- Supports intermittent fasting routines
- Plant-based, gluten-free, dairy-free
- Keto-friendly and low glycemic
- Made with whole-food ingredients
- Convenient on-the-go nutrition
- Backed by 20+ years of fasting science
Prolon® Intermittent Fasting Bar
The science behind our ingredients
Prolon® Intermittent Fasting Bar
Is this right for you?
Prolon® Intermittent Fasting Bar
Is this right for you?
- 01You practice 16:8 or time-restricted eating
The intermittent fasting bar fits cleanly into 16:8 and other time-restricted eating protocols — clinically tested to keep you in a fasting state.
- 02You're new to intermittent fasting
Fasting can be hard at first. The bar makes the transition easier — giving you something to eat during fasting windows without losing the metabolic benefits.
- 03You want clean, whole-food fuel
No protein isolates, sugar alcohols, or synthetic ingredients — just tree nuts, honey, and plant protein in a clinically validated formula.
- 04You're traveling or on the go
Each bar is shelf-stable, pre-portioned, and easy to take anywhere — making it simple to maintain a fasting routine even with a busy schedule.
01
You practice 16:8 or time-restricted eating
The intermittent fasting bar fits cleanly into 16:8 and other time-restricted eating protocols — clinically tested to keep you in a fasting state.
02
You're new to intermittent fasting
Fasting can be hard at first. The bar makes the transition easier — giving you something to eat during fasting windows without losing the metabolic benefits.
03
You want clean, whole-food fuel
No protein isolates, sugar alcohols, or synthetic ingredients — just tree nuts, honey, and plant protein in a clinically validated formula.
04
You're traveling or on the go
Each bar is shelf-stable, pre-portioned, and easy to take anywhere — making it simple to maintain a fasting routine even with a busy schedule.
why we’re different
Not all supplements are created equal.
At Parsley, ‘professional grade’ means every supplement is third-party tested for quality and purity, and manufactured in NSF/USP-certified, cGMP-compliant U.S. facilities that meet FDA standards.
Our clinicians know which supplements actually move the needle — and which don't. Every formula is selected for clinical evidence, optimal bioavailability, and meaningful dosing. Not what's cheapest to manufacture. What actually works.
| Parsley Supplements | Standard Supplements | |
|---|---|---|
| Physician-Formulated | ||
| Third-Party Tested | ||
| Clinically Dosed | ||
| USA-Made | ||
| Most Bioavailable Forms |
"Many of us don’t get the nutrient density we need from our food, even if we eat healthy diets. That includes me, which is why there are certain supplements I take every day."
Dr. Robin Berzin, MD
Founder and Clinician
CUSTOMER REVIEWS
Hundreds of 5-star reviews
4.9 average rating400+ reviews
Mega Omega 3 Fish Oil
Andrea A.Verified Customer
Vitamin D3 + K2 Drops
“This product is amazing. My doctor keeps asking me again and again to remind her how my D level is so perfect. I put my husband on it too with the same results. Thank you Parsley!”
Fredda G.Verified Customer
Rebuild Clean Protein Powder
"My body started to crave this product. With battling malnourishment and malabsorption, this is a super helpful product to buy! Glad my doctor recommended it."
Mary K.W.Verified Customer
Supplement FAQ
Parsley physicians have treated over 50,000 patients using a root-cause, functional medicine approach. That depth of practice informs every ingredient we select, every dose we use, and every formula we craft. The result is a standard most supplement brands can't meet: physician-formulated, third-party tested for purity and potency, clinically dosed, and manufactured in NSF/USP-certified, cGMP-compliant U.S. facilities that meet FDA standards.
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Metabolic Health
If you're dealing with weight, blood sugar, or metabolic health challenges, the most powerful thing you can do is understand what is driving them. Parsley Health physicians use advanced testing and a root-cause approach to build a plan around you — not just your symptoms.
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