The FDA cleared weight loss pill Plenity is prescription only and available online and not over the counter. Find out how it helps obese people lose weight.

Plenity Review Summary: Plenity holds the title of being the first FDA-cleared products for weight control.
Plenity reviews are a mixture of good bad and indifferent.
Look Elsewhere
If you are searching for an effective weight loss pill over the counter we have reviewed many of the leading diet pill brands.
The American Food and Drug Administration (FDA) rarely grants its approval to new weight loss aids. Plenity is one of the latest additions to a very short list. It gained FDA approval in 2019.[source]
One of the best things about Plenity is it has fewer nasty side effects than many weight loss medications. It’s also stimulant-free and non-habit forming.
Plenity is a little different from the other diet pills available via prescription in the USA because you cannot get it via your normal doctor. It’s is only available via the Roman telehealth website.
In this review, we will endeavor to answer any questions you may have about Plenity and explain all the pros and cons. Hopefully, by the time you have finished reading, you will be armed with all the knowledge you need to decide if Plenity is a good fit for your needs.
Table of Contents
What Is Plenity & How Does It Work?
Plenity is a prescription diet pill you can only buy online. It’s intended for adults who are very overweight or obese. In order to get a prescription, your body mass index (BMI) needs to be 25 to 40.
As with similar options, the pill is designed to be used alongside diet and exercise.
However, there is no restriction on the duration of therapy. FDA-approved weight loss medications, such as Phentermine (Adipex, Duromine etc), have a maximum usage period of only three months. This restriction doesn’t apply to the natural otc Adipex alternatives.
It’s good to see the FDA has finally given its blessing to an option that can provide overweight people with long-term weight loss support.
The Roman telehealth website possibly makes Plenity appear more complicated than it is. The site describes it as an “FDA-cleared weight management tool made from naturally derived building blocks.”
Seriously! How does anybody expect the average person to understand a statement like that?
Don’t worry, a little later in this review, we provide a better explanation, using more sensible terms.
When you take Plenity before meals, before meals it provides a feeling of fullness. This supports your efforts to eat less by saving you from hunger. By controlling hunger, Plenity helps you to attain and maintain the energy shortage that causes your body to begin burning its fat.
There are several ways diet pills can control hunger. Plenity does it by providing a super-absorbent hydrogel that expands when it combines with water. Unlike many other hunger suppressants, it does not affect any biological or chemical functions in the body.
Because the gel that forms in the stomach creates a physical presence rather than influence biological functions, the FDA classes Plenity as a medical device, not a medication.
Plenity Manufacture and Distribution
Plenity was developed by Gelesis. It’s a reasonably new company and, at the time of this review, Plenity was its only product.
Although the FDA has approved Plenity as a weight loss aid, Gelesis has not made it available via traditional pharmacies. You can only buy it online from the Roman telehealth company.
Before you can buy Plenity, you need to pass an online evaluation and convince the telehealth doctors you are a good candidate for a prescription. The first step is to enter your contact details and become a member of the site.
During the assessment, the telehealth doctor will ascertain if you are sufficiently overweight to obtain a prescription. The doctor will also check to see you don’t have any allergies or health conditions that could become an issue while using Plenity.
Gelesis chose to partner with Roman to reduce the cost of marketing and sales. The company did this to try and keep the cost of using Plenity as low as possible. That’s the official story, anyway.
However, the cost of using Plenity is still around $98 per month. That’s a lot more than you’d pay for an over-the-counter alternative so it would be interesting to know how much customers would be paying for Plenity if Gelesis had made it available via normal pharmacies instead.
Advertised Benefits
- Clinically tested and FDA-Cleared
- Stimulant-free and non-habit forming
- Free 2-day shipping
- Free unlimited follow-ups
How to Use Plenity
The dose is three Plenity capsules, two times per day. You take the first dose 20 minutes before lunch and the second one 20 minutes before dinner.
It’s important to take the capsules with at least 16 oz of water. If you don’t the capsules won’t be able to provide maximum appetite suppression.
It’s also important to wait the full 20 minutes before eating your meal. Failure to do this may also interfere with Plenity ability to deliver good results.
You need to focus on your diet and make sensible food choices as well. Exercise should be part of your weight loss program too.
The Ingredients & What They Do
Gelesis does not reveal the inclusion rates but each Plenity capsule provides a combination of cellulose and citric acid. There are no other active ingredients.
The cellulose and citric acid in the formulation form a unique 3D hydrogel matrix. When the pills reach the stomach the matrix disintegrates into individual cells. Each cell can hold 100 times its own weight in water.
When the cells soak up water, they form a gelatinous compound that takes up around 25 percent of the space available in the stomach. The gel mixes with the food that’s present in the stomach, making it feel fuller than it normally would after a small meal.
The presence of the gel-food mix in the stomach and small intestine can suppress appetite for quite a long time, helping you to avoid hunger between meals.
When the mixture eventually arrives in the large intestine, enzymes begin breaking it down. The hydrogel loses its three-dimensional structure and its absorption capacity diminishes.
Once released from the bonds that were holding it, the water is absorbed into the body via the intestinal walls. The material that is left exits the body with the feces.
Both the key ingredients in Plenity come from natural sources. Cellulose is an insoluble plant fiber that’s present in many fruits and vegetables such as kale, oranges, apples, and bananas. As you may be aware, dietary fiber is very good for filling the stomach.
Citric acid is also present in a lot of fruits and vegetables. Especially oranges, limes, lemons, and other citric fruits.
It’s unfortunate that Gelesis fails to provide a full ingredient profile because there is no way to be certain Plenity does not contain chemical-based binders, fillers, or colorants.
Some of the secondary ingredients that are present in many medicines and supplements carry certain risks.
For instance, titanium dioxide is a popular colorant. Although the FDA permits manufacturers to use it in small amounts, the European Food Safety Authority (EFSA) has concerns about the ingredient’s toxicity level and its ability to accumulate in the body.
What the Research Shows
Most of the Plenity weight-loss claims are based on the results of a single study.
Although the results of the study are promising, it’s important to be aware Gelesis provided the funding. That makes it hard to consider the study results unbiased.
The GLOW (Gelesis Loss of Weight) clinical trial was conducted over 24 weeks and 436 people took part. Some of the participants got Plenity. Others got a placebo. All of them had to make similar efforts with diet and exercise.
The people taking Plenity lost slightly more weight but did not meet the predefined weight loss super-superiority margin of 3% over placebo. (https://pubmed.ncbi.nlm.nih.gov/30421844/)
The study design was less than ideal for a couple of reasons.
Firstly, the researchers only accepted people who had fasting blood glucose levels between 90 and 145 mg/dl. This seems strange.
Pre-diabetes glucose levels are 100-125 mg/dl. According to the Center for Disease Control (CDC), anything over 125 mg/dl is full-blown diabetes.
This is an important consideration because it means most of the study participants were likely to be either diabetic or pre-diabetic.
The way Plenity affected the average study participant may be very different from the way it may affect people who have normal blood sugar levels and are in reasonably good health.
Gelesis also fails to identify the placebo. This is an issue too.
Was the placebo another form of fiber, such as rice flour or psyllium husk?
If the researchers put Plenity head to head with another form of fiber, the modest improvement in weight loss would be more notable. If the placebo was not something that can increase satiety, the results are less impressive still.
Putting Plenity up against a non-fiber ingredient would be like testing the lubrication abilities of a new motor oil by putting it up against water instead of an alternative type of oil.
We have no way to discover the truth but, choosing a non-fiber placebo would be a good way to ensure more favorable results.
Plenity Side Effects
The GLOW study states there is no significant difference in side effects between Plenity and the placebo.
However, the FAQ page on the Plenity website provides a list of potential side effects. Most of them are stomach/gut-related and are similar to the issues many people may face when they increase their intake of dietary fiber.
The FAQ page also reveals how many Plenity users experienced each side effect compared to the placebo. Although the researchers did not deem the difference significant, it’s clear that people taking the Plenity had more side effects than those taking the placebo.
- Diarrhea 13% (placebo 9%)
- Abdominal distension 12% (placebo 7%)
- Infrequent bowel movements 9% (placebo 5%)
- Flatulence 9% (placebo 5%)
Could the difference be because Plenity provides dietary fiber and the placebo did not?
Plenity Reasons to Buy
- FDA-Approved
- Appears to work better than a placebo
- Easy to use
- Costs less than most other prescription weight-loss options
- Fewer side effects than other prescription weight loss options
- Suitable for long-term use
Plenity Reasons to Avoid
- Only available to people who have a high BMI
- Not available through traditional pharmacies
- Manufacturer funded study
- Failed to achieve weight loss super-superiority margin of 3% over placebo
- Costs more than over-the-counter weight loss alternatives
Plenity Review Conclusion
Plenity certainly has some advantages over prescription weight loss medications like Phentermine and Orlistat. It’s doesn’t present the same risk of side effects and people who are eligible for a prescription may be able to use it for longer.
Of course, when a Plenity user’s BMI drops below 25, the prescription will stop. At that point, they will still be overweight but will need to either learn to go it alone or find a suitable alternative to use instead.
If we presume the GLOW study was unbiased, the results are not particularly impressive. However, the Roman website does a good job of making Plenity appear better than it is. A large pie chart shows 59% of the GLOW study participants lost an average of 22 pounds.
You need to read the small print below it to discover the study did not meet the predefined weight loss super-superiority margin of 3% over placebo.
Many non-prescription weight loss options can provide superior weight loss and don’t have a reputation for side effects.
The best non-prescription diet pills also offer a greater level of support than Plenity. In addition to controlling hunger, they also speed metabolism, boost, energy, and/or provide extra benefits on top. You can also use them for as long as you want, without the need for an overly high BMI.
So, although it’s great to finally see the FDA approve a safe prescription weight loss option, Plenity still leaves a lot to be desired. There are cheaper non-prescription options that will undoubtedly offer superior results.
In addition to offering greater support, the best over-the-counter diet pills are also considerably cheaper than Plenity and have money-back guarantees.
Other Similar Weight Loss Products
There are several comparable weight loss pill and capsules.