Dr. Brandon Brooks, DVM - "Many (if not most) Over The Counter (OTC) or non-prescription flea control products are very toxic to cats and kittens- especially the ones only approved for use in dogs. Many people mistakenly buy these for their pet (it's not always their fault, the companies that make them want you to buy it, they don't really care about the dangers involved) so it pays to be extra careful when buying flea control products." Our animals are sicker than ever. Veterinarians have never seen such an increase in the rate of liver disease, nervous system disorders, cancers, diabetes, renal failure and other diseases. Our animals are being routinely poisoned with pet food and pet medicine. Popular anti-flea and anti-tick medications are extremely toxic to the liver. According to Dr. Brooks, even though the cat or kitten does not have the OTC flea control product directly applied to it, the cat or kitten may still become ill through indirect exposure if it is applied to a dog in the household, household furnishings, bedding, etc.. Also, many OTC dog flea control products are not only toxic to cats, but dogs as well.
Most modern maladies are caused by prolonged exposure to a combination of negative lifestyles and toxic environmental factors, including junk food and malnutrition, pesticides, antibiotics, microwaves, chemical pollution of food, water and air, lack of exercise and chronic stress. These factors are further aggravated by the failure of modern medicine to recognize them as agents of dis-"ease" and death and the consequent failure to take preventative measures against them. The same chemical companies that produce toxic chemicals also produce prescription drugs, veterinary medicines, a wide array of medical products. Families with toxin induced illnesses often spend large sums for drugs and medical treatment. This circle of profit is not conspiracy theory, but an easily provable fact. What you don't know can hurt you."
The structure of cyclocreatine is fairly flat (planar), which aids in passive diffusion across membranes. It has been used with success in an animal study, where mice suffered from a SLC6A8 (creatine transporter at the blood brain barrier) deficiency, which is not responsive to standard creatine supplementation.  This study failed to report increases in creatine stores in the brain, but noted a reduction of mental retardation associated with increased cyclocreatine and phosphorylated cyclocreatine storages.  As demonstrated by this animal study and previous ones, cyclocreatine is bioactive after oral ingestion   and may merely be a creatine mimetic, able to phosphorylate ADP via the creatine kinase system.