What Is Carnosine?

Carnosine is a substance produced naturally by the body. Classified as a dipeptide, a compound made up of two linked amino acids (in this case alanine and histidine), carnosine is highly concentrated in muscle tissue and in the brain. It's also present in significant concentrations in beef and fish, and in lower concentrations in chicken.

A synthetic form of carnosine sold in supplement form is touted as a natural remedy for a host of health conditions, including:

• Autism
• Cataracts
• Complications related to diabetes
• High blood pressure
• Kidney problems

In addition, carnosine is said to stimulate the immune system, enhance mood, improve memory, fight wrinkles, and preserve eyesight.

What Is Carnosine Used For?

As a 2018 review on carnosine reports, there's great potential for the application of carnosine in health and disease. For instance, it's been discovered that carnosine has powerful antioxidant properties, allowing it to protect cells against free radical damage. It also appears to reduce inflammation, a driver of many types of chronic disease.

Due to these effects, it's thought that carnosine could help protect against a number of aging-related conditions, such as Alzheimer's disease and cardiovascular disease. That said, very few clinical trials have tested the potential health benefits of taking carnosine supplements. Until such trials are conducted, it's difficult to tell how the consumption of carnosine might influence human health.

Here's a look at some of the more promising research on carnosine.

Alzheimer's Disease

Animal and laboratory studies show that carnosine reduces the buildup of amyloid beta, the protein that forms the brain plaques associated with Alzheimer's disease.

In one study on mice published in 2013, oral supplementation with carnosine prevented cognitive decline due to its inhibition of amyloid beta.

In 2016 research on healthy elderly people that supplemented with a formula containing carnosine, scientists reported an improvement in the decrease in blood flow to the brain that occurs in Alzheimer’s disease, as well as better preservation of memory in the participants. Similar results were shown in an animal model of Alzheimer's disease published in 2017.

In light of this evidence, carnosine has been postulated to control the progression of Alzheimer’s disease; clinical studies, however, are still needed.

Diabetes

Carnosine may be especially beneficial to people with diabetes in that it can protect against damage caused by protein glycation. This process, which results from having too much sugar in the body, is a major contributor to diabetes-related complications, such as kidney and nerve damage.

Although evidence is still emerging, both animal and human studies have indicated the potential of supplementation with carnosine (which is diminished in both animals and humans with type 2 diabetes) to delay the progression of diabetes and prevent such complications.

A pilot clinical trial provided evidence of the ability of carnosine supplementation to protect against diabetes development in non-diabetic obese individuals. When overweight and obese adults were randomly assigned to ingest either carnosine (two grams a day) or a placebo for 12 weeks, an increase in fasting insulin and insulin resistance was reported with placebo, but not carnosine. The group receiving carnosine also had improved responses to an oral glucose test (for example, lower glucose and insulin).

Such findings, although promising, require further confirmation.

Cancer

A number of preliminary (cell culture) studies suggest there is potential for carnosine to help fight cancer. For instance, the presence of carnosine decreased growth on many major types of cancer cells, including liver cells, colon cells, and ovarian cells. There's also evidence from studies that correlates low levels of carnosine or high levels of activity of carnosidase, the enzyme that breaks down carnosine, and poor cancer prognosis.

While interesting, it's important to remember that this research is in its infancy.

Autism

One of the few clinical trials involving carnosine is a small study published in the Journal of Child Neurology in 2002. In it, 31 children with autistic spectrum disorders took either a carnosine supplement or a placebo every day for eight weeks. By the end of the treatment period, members of the carnosine group showed significantly greater improvements in certain measures of functioning, including behavior and communication.

The study's authors note that carnosine may benefit children with autism by enhancing nervous-system function. Despite these promising results, no more recent research on carnosine and autism has been conducted.

Possible Side Effects

While little is known about the safety of taking carnosine supplements, there's some concern that carnosine may disrupt your sleep. Since the health risks of carnosine supplements are unknown, it's important to seek medical advice before using carnosine.

Also, be aware that the safety of supplements in pregnant women, nursing mothers, children, and those with medical conditions or who are taking medications has not been established.

Dosage and Preparation

Because there's no proven medical benefit for carnosine, there's no agreement as to what dosage will produce a therapeutic effect. Among proponents, it ranges from between 50 and 150 milligrams a day to around 1,000 milligrams a day.

It's important to note that, other than for vegans and strict vegetarians, there are questions about the necessity of carnosine supplementation since simply eating a meal that includes animal- or fish-based protein will increase your level of carnosine (e.g., a three-ounce portion of beef contains around 300 milligrams of carnosine).

The efficacy of oral supplementation with carnosine is also an issue since most carnosine absorbed from the gut is destroyed in the bloodstream by enzymes called carnosinases.

The bottom line: It's too soon to recommend carnosine supplements as a standard treatment for any health problem. If you're considering the use of carnosine supplements for treatment of a condition, talk to your healthcare provider before starting your supplement regimen. Self-treating with carnosine supplements and avoiding or delaying standard care may have serious consequences.

What to Look For

Keep in mind that supplements haven't been tested for safety and are largely unregulated. That means the content of some products may differ from what's specified on the product label.

As with any other supplement, always choose one from a reputable manufacturer. If you decide to try carnosine supplements, find a brand tested and approved by a recognized certifying body, such as U.S. Pharmacopeia (USP), NSF International, or ConsumerLab. Doing so can ensure the highest quality and safety possible.