The "l-" indicates that the molecular configuration of the carnosine is the natural one. Usually the natural configuration is the most active. The non-natural configuration would be "d-", which is often biologically inactive. If this were a synthetic form of the compound, it would contain both d- and l- forms.

Hi, I read that it's the same.

L is the direction of the chemical, if I remember right, the way it faces, like right or left, like one is a mirror image of the other. I just read that it's a type of stereoisomer. One type is like the human hand. Put your hands out in front of you. They are mirror images and you can't put one on top of the other and superimpose them.


All amino acids used in protein synthesis are the L-form.

The “L” also stands for Laevorotatory: Rotating the plane of vibration of polarized light to the left (as seen by an observer looking toward the oncoming light).

The other non useful form is called dextrorotatory.
Surprisingly there are more than 250 naturally occurring nonprotein amino acids in our diet.

L-Carnosine (ß-alanyl-L-histidine) is a dipeptide composed of the two amino acids ß-alanine and L-histidine....

http://www.chemblink.com/products/305-84-0.htm

I may have confused one thing for another and I don't know which applies here:

"Re: d/l: Often confused with the D/L system of nomenclature to which it has absolutely no relationship. The d stand for dextro or 'dextrorotatory' and simply signifies that plain polarised light is rotated to the right (clockwise). The l stands for laevo or 'laevorotatory' and signifies that the molecule rotates plane polarised to the left (anticlockwise). The system is outdated and largely replaced with the (+)/(-) nomenclature.

Re: D/L: Confusing and outdated system of nomenclature for assigning absolute stereochemistry to an asymmetric centre.
The system has NOTHING to do with optical rotation and should not be confused with the 'd/l' system of nomenclature.
The D and L assignments are related back to glyceraldehyde.It has been almost universally replaced with the unambiguous R/S system devised by Cahn, Ingold and Prelog, although it is still often encountered when dealing with carbohydrates and a-amino acids."

http://chemistry.anu.edu.au/Staff/RA...chem/D-L-2.gif

I took chemistry over 40 years ago, so I'm thinking of the outdated system as described in the diagram above. I don't know which applies to l-carnosine. But I do know that it's the same as carnosine for our buying purposes. Sometimes a drug contains a mixture of both stereoisomers, like my zyrtec. Sometimes only one is active, but they don't bother to remove the other inactive one. A third generation antihistamine contains only one isomer but clinically doesn't work better despite claims that it does.

http://64.233.169.104/search?q=cache...lnk&cd=5&gl=us

Re: vitamin E:


All natural forms of Vitamin E occur in their "D" stereoisomer form. Natural forms of Vitamin E are absorbed and retained better than synthetic forms of Vitamin E.

Synthetic Vitamin E is a mixture of eight stereoisomers, and is designated DL-Alpha-Tocopherol. Only one of the eight stereoisomers (12.5%) in synthetic Vitamin E is identical to d-Alpha-Tocopherol. The other seven have varying biological activity, ranging from 21% - 90% as active as d-Alpha-Tocopherol. Synthetic Vitamin E is absorbed and retained far less efficiently than natural Vitamin E.

http://www.scriptit.info/library/VitaminE.htm


Natural Amino Acids

What is the difference between L-Taurine and Taurine, or between L-Glycine and Glycine?

NOW® only sells the natural forms of amino acids. These are typically the “L form”, as in L-arginine, L-cysteine, etc. Synthetic forms are denoted as “D forms”, such as D-Methionine and D-Carnitine. But there are 2 aminos that have only one form without these variations: Glycine and Taurine. These two aminos are sometimes called L-Taurine or L-Glycine, but are more properly called just “Taurine” and “Glycine”. Regardless of the name used, they are always natural amino acids.

Technical explanation:

Most aminos have a property that, when the molecule is put into a solution, it will polarize and rotate light either to the left or right. The Greek words denoting left and right are Levo for left and Dextro for right, so the letters L and D are used to distinguish these forms. This polarization and rotation of light is called “optical rotation”. The differing L and D forms are called stereoisomers. For amino acids that polarize light, the L form is the natural form.

However, Taurine is an amino acid that does not polarize light. It thus is properly called just “Taurine”, without L or D configurations. While some label Taurine as “L-Taurine”, that name is not technically correct. “Taurine” is the same exact molecule and form as what is commonly mislabeled as “L-Taurine”.

There is another amino acid that lacks a potential optical rotation. Glycine is a very simple molecule that comes only as “Glycine”, also lacking different L or D stereoisomer forms.

The D forms of amino acids sold commercially are considered to be synthetic. However, D forms of amino acids are not always synthetic. There are several D forms that exist in nature. In addition, amino acids can be racemized by the body and go back and forth between the D form and the L form quite easily. However, only L forms can be incorporated into proteins. For the purposes of dietary supplements, the L forms are natural and the D forms are synthetic. DLPA and DL-methionine are actually racemic mixtures of both L and D forms.

But there is no such thing as D-Taurine or D-Glycine; in other words, no synthetic forms exist of these two aminos since each only comes as one isomer that doesn’t polarize and rotate light to the right. Nor are there really L forms of these, since they do not polarize and rotate light to the left, either. There are simply single, natural isomers of just plain Glycine and Taurine.

Don’t assume that all D or L forms of molecules are good or bad, since it really depends on the individual substance concerned. For example, the D isomers of vitamin E are the natural forms and the L isomers are synthetic; just the opposite of amino acids. Thus the terminology and forms of what is natural or synthetic will vary by substance. Some natural molecules exist as L form, some as D form and some have only one form, whether in food or if synthesized.

NOW® prides itself as being science-based. We only sell natural form amino acids and Vitamin E and we use the correct scientific names for substances and compounds on our labels.

Provided by Neil E. Levin, CCN, DANLA
Board certified clinical nutritionist with diplomate in advanced nutritional laboratory assessment
6/8/2007

http://64.233.169.104/search?q=cache...nk&cd=13&gl=us

***************************************

Natural compounds are often single enantiomers (e.g. levothyroxine, levodopa, l-noradrenaline). In contrast, many commercially synthesized drugs are racemic mixtures (e.g. adrenaline, warfarin, fluoxetine, omeprazole).

http://www.ti.ubc.ca/node/55

A huge amount of info I am still trying to process! Thanks for looking it all up, collecting it, and sharing with us here. We are also going to try the carnosine-what kind and where are you going to get it from? The Ethos stuff is quite expensive.

I will buy the NOW brand at iherb.com and take the same amount they used in the trial. I don't have time to check on the dose, but I think this is the one:

Now Foods, L-Carnosine, 500 mg, 100 Vcaps
SRP: $49.99
Our price: $27.98
(4 for $109.12
12 for $318.9)

Savings of: $22.01(44.03 %)

Shipping for one bottle for me is only $1.68.

October Super Special!
Flat $1.99 Priority/ Airmail, Domestic Orders

http://www.iherb.com/ProductDetails....1&pid=457&at=0

In the clinical trial they took 500 mg 3x a day for 30 days.

http://www.pdease.com/Ethos_PD_Ease.pdf

I believe that the Carnisone/carnosine (sp?) thing is a typo - although unusual to find in a title.

I just ordered the same product from iHerb mentioned by Zflower and hope that you, Z - and anyone else using this - will post after around 30 days and lets see how we are doing! Of course, we will have the placebo effect to help out, but my stiff body needs all the help it can get! Any ideas how to measure progress?

Thanks.

Sasha

i've orded some, too.... will stay tuned! ibby

IHerb has a $1.99 flat shipping fee for this month only. So I'm going to order heavy things, like whey protein powder (MRM brand) and chia seeds. You get a discount on their protein shaker with roller ball if you buy it with powder or the seeds (28oz mixer for only $4.81).

I'm going to check out their groceries now!

Remember, today is the last day for flat fee shipping charge of $1.99 at IHerb. I'm ordering almost 20 lbs. Big savings.

~Zucchini