Plenity Review: How Much Weight Loss is Possible?

Plenity Review: How Much Weight Loss is Possible?

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Disclaimer: None of the information in this article constitutes medical advice. All statements are merely the opinion of the writer(s). We recommend that patients follow their doctor’s guidance in regard to prescription medication.

Plenity is a prescription weight loss medication that's cleared by the Food and Drug Administration (FDA). The idea of a diet pill that can help you lose weight is enticing to many Americans. After all, many are so desperate that they’re using dicyclomine for weight loss (off-label), which we strongly recommend against.

In this article we’ll review medical research on Plenity to provide our determination on whether the drug is likely to be effective for weight loss. We'll highlight side effects, share a real user's review, and explain why we consider one of the inactive ingredients in the drug to be questionable.

Does Plenity Cause Weight Loss?

Plenity funded a clinical trial, published in the Obesity journal, to assess the efficacy of the drug for weight loss. Patients were instructed to consume a diet 300 calories below their maintenance level, and also supplemented with either Plenity or with placebo pills.

The results showed that patients taking Plenity lost more weight (by a small but statistically significant amount) compared with placebo. Over the course of the 24 week trial, patients on Plenity lost 6.4% of their body weight, and patients on placebo pills lost 4.4% of their body weight.

This study was poorly designed in our opinion. The trial participants had fasting blood glucose levels between 90 and 145 milligrams per deciliter (mg/dl) . The range for pre-diabetes is 100-125 mg/dl, and anything over 125 mg/dl is full blown diabetes according to the CDC.

Just because a treatment works on diabetics and pre-diabetics doesn’t necessarily mean it will translate into results for healthy adults. While it's true that some of the trial participants had blood sugar levels ranging between 90-100 mg/dl which would be considered in the "normal" range, we believe the trial should have been conducted exclusively on patients with normal blood sugar levels, because Plenity is marketed to all patients regardless of blood sugar level and is not considered a weight loss medication for pre-diabetics and diabetics.

It appears that this is the only clinical study testing the efficacy of Plenity at the time of updating this article. Most weight loss pills we review have been studied in various clinical trials.

We consider Plenity likely to be effective for weight loss, but we can't say so conclusively until the company funds a study on patients with normal blood sugar levels.

Plenity Before and After Pictures

Since Plenity is a weight loss pill, prospective patients are often curious about viewing before-and-after images of real Plenity users.

One of the most popular Plenity YouTube reviews, published by a channel called "TamkinSpice," shares the creator's experience on the drug and contains a before-and-after image after 5 months of use:

How Does Plenity Work?

Plenity takes up space in the stomach which makes users feel full faster. The drug is composed of two active ingredients: cellulose and citric acid.

Cellulose is an insoluble plant fiber contained in nearly every plant food, such as apples, oranges, kale and bananas. We consider this to be an effective active ingredient for a weight loss drug, given that fiber intake is associated with weight loss.

Citric acid is a preservative and flavor enhancer which may cause whole-body inflammation in a small subset of patients based on a medical review published in the Toxicology Reports journal. We typically recommend avoiding this ingredient unless otherwise instructed by a doctor.

Plenity claims that these two ingredients combine and react with water in the stomach to create a sense of fullness which reduces overeating. We have no reason to disbelieve this since cellulose is a basic fiber obtainable from many other foods and fiber is known for increasing satiation.

Questionable Inactive Ingredient

We find it to be challenging to locate the full ingredients list for Plenity on the manufacturer website, and would urge the manufacturer to more clearly publish this information.

Plenity's FAQ page includes a safety information section which states that patients allergic to the following compounds should not take the drug: cellulose, citric acid, sodium stearyl fumarate, gelatin, titanium tioxide. This suggests that these are the ingredients in Plenity.

Titanium dioxide is an inactive ingredient we typically recommend avoiding. 

The European Union (E.U.), which has much more stringent consumer health and safety regulations than the U.S., recently disallowed use of this ingredient as a food additive due to concerns over genotoxicity, which means that it may damage DNA.

Plenity Side Effects

The clinical trial on Plenity that we cited earlier documented no significant difference in side effects between Plenity users and placebo, which is a good sign. 

On Plenity's site, fullness, bloating, abdominal pain and flatulence are listed as potential side effects. Dietary fiber intake alone can cause these side effects, and we would assume these are caused by the cellulose. These side effects are relatively mild for a prescription drug.

In our opinion, Plenity has a much superior side effect profile to many other weight loss medications. Many of the weight loss drugs that we've reviewed on Illuminate Health have carried a "black box" warning from the FDA that detailed risk of severe side effects, but Plenity has no such warning.

Plenity Cost

At the time of updating this article, Plenity costs $98 per month out-of-pocket. However, some health insurers may fully or partially subsidize the cost. We recommend that patients considering Plenity call their health insurance company first to check on whether the medication is covered.

This price is relatively low for a retail price of prescription medication. In our Wegovy reviews article, we documented a weight loss medication that costs over $1,500 without health insurance.

What Does "FDA-Cleared" Mean?

Plenity is "cleared" but not "approved" by the FDA because the pills are actually classified as medical devices rather than drugs. According to the FDA, the clearance process involves a manufacturer submitting information proving that their medical device is safe and effective.

FDA approval, which is required for most prescription drugs, involves the FDA reviewing clinical trial data on a drug to determine if it's safe and effective.

The FDA categorizes Plenity as a medical device because it has a physical mechanism of action. It takes up space in the stomach, rather than having a metabolic effect like most drugs do. 

For the most part, the ingredients in Plenity are not absorbed by the body. As documented in the drug's FDA clearance letter, "Plenity passes through the digestive system."

Our Weight Loss Supplement Recommendations

There exist several over-the-counter (OTC) weight loss supplements that don't require a prescription, and which have medical research backing.

We are not suggesting that these products are as effective as Plenity; just that it may be worthwhile for an overweight patient to discuss these options with their doctor given their documented efficacy and lack of significant side effects. They may also be used in addition to prescription weight loss medication.

We recommend dietary fiber as a safe and effective weight loss supplement, especially when combined with caloric restriction.

landmark medical study found that moderate caloric restriction (750 calories per day below baseline) combined with dietary fiber intake (a minimum of 20 grams per day) caused an average weight loss of 16.03 pounds over 6 months. That’s a pace of 32 pounds per year of weight loss in overweight individuals simply by adding fiber to a moderately-restricted-calorie diet.

The fiber supplement we recommend is SuperGut Fiber Mix. It contains a clean and effective formulation: a blend of three different types of unflavored dietary fiber and zero additive ingredients. It can be mixed into liquids or foods. Interested consumers can buy SuperGut fiber at this link.

We recommend using two fiber mixes per day, which provides 16 grams (g) of total fiber. Diet should provide the remaining fiber necessary to meet the 20 g minimum threshold.

Medium-chain triglyceride (MCT) oil is another dietary supplement which has been shown in clinical trials to cause weight loss.

MCT oil is quickly absorbed by the body and increases metabolic rate, which causes fat loss. A meta-study on MCT oil documented weight loss of 1.12 pounds over 10 weeks. This equates to a potential annualized weight loss of 5.84 pounds with MCT oil supplementation.

We recommend Bulletproof MCT Oil as our top MCT oil product, because it has a clean and effective formulation. The only ingredient is MCT oil derived from coconuts, and the product has no questionable additives. Interested consumers can buy Bulletproof MCT Oil at this link.

The effective dose range of MCT oil for weight loss (based on the medical review) is 1.7 g to 10 g per day. Bulletproof's MCT oil provides 14 g in one tablespoon, so around two-thirds of one tablespoon should be a maximally-effective dosage.

Stay up-to-date on our research reviews


Plenity is likely to be effective for weight loss, and appears to have a more favorable side effect profile than many prescription weight loss medications. A clinical trial found Plenity to cause 2% greater body weight loss than dieting alone.

This drug does contain a few questionable ingredients that patients may wish to speak about their doctor about, specifically citric acid and titanium dioxide.

We hope that in the future Plenity publishes clinical trials proving the efficacy of their drug in patients with normal blood sugar levels, because the sole clinical trial that we could access used a patient population with relatively high blood sugar levels.

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