N-Acetylcarnosine compared to L-Carnosine

Why have N-acetylcarnosine eye drops been shown to have this action upon cataract and yet L-carnosine (which is its sister di-peptide) appears to have little benefit? Dr. Mark Babizhayev, one of the principal Russian researchers behind the clinical trials with N-acetylcarnosine eye drops gave us this reply to that very same question.

"I believe that the application of simple L-carnosine for the treatment of human cataracts is misleading. This is because L-carnosine, by itself, readily becomes a substrate for the activity of natural peptidases (i.e. carnosinase) in the aqueous humour to the degree that there is virtually no sign of L-carnosine in the aqueous humour within 15 minutes after instillation.
Furthermore, I consider that L-carnosine, in the form of eye-drops, may be harmful to the eyes because it gradually releases histamine, which, located as it would be in the presence of the eye-lens, is a very toxic agent. NAC eye-drops however are resistant to hydrolysis with natural carnosinase. Therefore, our patented NAC is the only currently known agent which reverses and prevents human cataracts."
- Mark Babizhayev MA, PhD

What is the difference between Carnosine,
L-Carnosine and N-Acetylcarnosine?

There are different forms of carnosine naturally found in the human body. The best known is the di-peptide L-Carnosine and much has been published as to its impressive anti-oxidant and anti-aging benefits. L-Carnosine was discovered around 1900 by another Russian scientist named W.S. Gulewich. A great deal has been learned about L-carnosine over the past century. N-acetylcarnosine is naturally found in the body and is a unique time release carrier form of L-carnosine. It is the acetylation of L-carnosine that makes N-acetylcarnosine suitable and stable in the eye. Unfortunately L-carnosine is not very lipid (fat) soluble and can not easily pass through the outer membranes of the eye. N-acetylcarnosine is lipid soluble and can pass easily into the eye where it then releases L-carnosine into the aqueous humour. When L-carnosine is applied topically to the eye, it is easily broken down by an enzyme on the surface of the eye called carnosinase and therefore is not substantially deliverable into the aqueous humour. Carnosinase breaks down L-carnosine into its constituent peptides, β-alanyl and L-histidine. Over time, L-histidine can be broken down to a chemical called histamine. You may have heard histamine mentioned when talking about allergic reactions. Histamine can actually damage the eye by promoting further oxidation reactions. L-carnosine by itself is not suitable for eye drop use as it is either ineffective or could even be damaging to some tissues over time.

The acetylated version of L-carnosine, N-acetylcarnosine makes it very stable and highly resistant to carnosinase. Additionally this stabilized compound protects against oxidative stress in the lipid phase of biological cellular membranes and in the aqueous environment by a gradual, time release of L-carnosine, thus maintaining a longer active therapeutic concentration of carnosine directly within the aqueous humour and the lens of the treated eye. The purity level of this particular N-acetylcarnosine is critical to its effectiveness.

Years of research were spent to identify a specific purity level of N-acetylcarnosine that would ensure both safety and optimal results. This purity level is critical and only the N-acetylcarnosine products with this specific clinically proven purity should be applied to the eyes. Only the Nu-Eyes ™ N-acetylcarnosine formula was used in the clinical trials. Look for the following statement on the box of any N-acetylcarnosine eye drop product prior to applying to the eyes. "Approved by Innovative Vision Products". Nu-Eyes ™ carries this statement on every box.

"Cataract is a widespread age-related affliction and NAC eye-drops appear to be a highly efficacious and safe treatment for cataract. As such, I suspect that this supplement is going to become one of the most important new discoveries, and will have a major impact on the way that cataract is controlled."
- Mark Babizhayev MA, PhD

References:

1. Babizhayev, M. A., Deyev, A.I.  Free radical oxidation of lipid and thiol groups in genesis of cataract. Biophysics, 1986; 31:119-125.
2. Babizhayev, M.A., Deyev, A.I., Linberg, L.F.  Lipid peroxidation as a possible cause of cataract.  Mech Ageing Dev, 1988; 44: 69-89.
3. Babizhayev, M.A., Deyev, A.I.   Lens opacity induced by lipid peroxidation products as a model of cataract associated with retinal disease. Biochim Biophys Acta, 1989; 1004: 124-133.
4.  Babizhayev, M.A.   Antioxidant activity of L-carnosine, a natural histidine-containing di-peptide in crystalline lens. Biochem Biophys Acta, 1989; 1004: 363-371.
5. Babizhayev, M.A., Bozzo Costa E "Composizioni farmaceutiche contenenti N-acetilcarnosina per il trattamento della cataratta." A61K gruppo 37/00 cap 20122 MI 15.10.1993. (Italian patent)
6. Babizhayev, M. A., Bozzo Costa, E.  Pharmaceutical compositions containing N-Acetylcarnosine for the treatment of cataract. European Patent PCT/EP 94/03340 10.10.1994 Ref. SCB 238 PCT.
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19.  Wang, A.M., Ma, C, Xie, Z.H., Shen, F. Medical application of carnosine Department of Biochemistry and Neurobiology, Harbin Medical University, China.
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DISCLAIMER: ALL INFORMATION IS EDUCATIONAL AND DOES NOT, AND SHOULD NOT, REPLACE THE ADVICE OF YOUR PHYSICIAN.