Talk:Carnitine/Archive 1

External links

I changed the "FAQ" to another page on the same site that had the same content seemed less about selling the stuff; the old link seemed too much like an ad. I also changed the "Molecule of the Month" to link to the page about carnitine rather than to the index. ajchapman 01:33, 5 March 2006 (UTC)[reply]

What's this stereoisomer for?

I don't see why you need a seperate page for a stereoisomer of a chemical that already has a complete article...I guess a footnote explaining its natural occurrance and an explanation as to why the Levo form is the biologically active form of Carnitine but it shouldn't need a separate article.

L-carnitine is the primary type of carnitine that is used biologically. Although d-carnitine has been used in some studies, the differentiation of carnitine into l-carnitine and d-carnitine is unnecessary. Maybe the difference can be mentioned in the main carnitine page.

The above is incorrect. The d- isomer is not bio-active, whereas the l- isomer is the bio-active version. In fact, it is believed the d- isomer will compete with the l- and can cause deficiency. As folks take this as a supplement, it is important to steer people away from the d- and l- supplements. These are junk, and possibly harmful. The Linus Pauling Institute has useful information on their website.

The dextro-rotary isomer, like the d- amino acids is for experimental and drug use only. Biology does use them, but it's very rare in nature. One reason I can see for using it is in exploring pathogens or metabolic pathways that you don't want to escape into the real world. Another reason would be to enable you to measure the amount of real-world contamination of your experiment -- isolation and error estimation. Brewhaha@edmc.net 12:13, 25 April 2007 (UTC)[reply]

Carnitine Status in Canada

"L-Carnitine products and supplements are not allowed to be imported into Canada (Health Canada)"

Why? Any reason of this ban? I do not see the reason for including the status of Carnitine in Canada without mentioning the reasons for the ban by the Health Authorities of that country.

I just drank a bottle of NOS (energy drink) which I purchased in Canada. The bottle says it contains 550mg of L-Carnitine, therefore this sentence seems incorrect. —Preceding unsigned comment added by 68.144.252.18 (talk) 21:39, 13 April 2008 (UTC)[reply]

Same here. NOS never used to have L-Carnitine--I have an old bottle right in front of me, with no mention of the substance--but the new bottle does have it. The new bottle is also not labelled as a natural health product, so some legislation must have changed. Anyone know more about this? Ψαμαθος 20:48, 28 June 2008 (UTC) —Preceding unsigned comment added by Psamathos (talk • contribs)

Energy drinks & food supliments L-carnitine content

I don't mean to advertise, but was wondering about different energy drinks carnitine content since I'm vegetarian. As such, I was astonished to see Adrenaline Rush containing 94.9mg/100g of carnitine (according to the package). That would rank it second after red meat. Should it get into main page? —Preceding unsigned comment added by 89.28.94.238 (talk) 21:00, 20 January 2011 (UTC)[reply]

Diabetes study removed

The study is of bad quality (small size, not placebo-controlled, margins of error overlap - no way there could be such P-values), so it proves nothing. Removed. --Вадим Араханский (talk) 12:19, 28 June 2011 (UTC)[reply]

Citation #9

Since when was amazon.com a reputable place to cite from? 24.197.101.172 (talk) 02:45, 8 April 2013 (UTC)[reply]

I have removed this as WP:OR reliant on purely primary source material. Abductive (reasoning) 04:32, 8 April 2013 (UTC)[reply]

Microbiota creating TMA or TMAO?

Earlier in the article (quoting the NYT which is writing about Koeth, Robert; et al (2013).): "The study found that gut bacteria use carnitine as energy, and a byproduct of that process is converted to trimethylamine N-oxide (TMAO) in the liver."

Later in the article (cit #29, Koeth, Robert; et al (2013).): "These researchers showed that when certain intestinal bacteria were exposed to carnitine from food, these bacteria produced a waste product, TMAO, that is known to cause atherosclerosis. The authors showed that the presence of TMAO-producing bacteria was a consequence of a diet rich in meat. Vegetarian and vegans exposed to meat produced lower levels of TMAO than omnivorous individuals."

Actual study (Koeth, Robert; et al (2013). "Intestinal microbiota metabolism [. . . ]"): "Intestinal microbiota metabolism of choline and phosphatidylcholine produces trimethylamine (TMA), which is further metabolized to a proatherogenic species, trimethylamine-N-oxide (TMAO). We demonstrate here that metabolism by intestinal microbiota of dietary L-carnitine, a trimethylamine abundant in red meat, also produces TMAO and accelerates atherosclerosis in mice."

The way it reads to me is, before this study, it was generally thought that the intestinal microbiota were only producing TMA, which was turned into TMAO by the liver. However, this study now demonstrates that the microbiota are producing TMAO from the L-carnitine as well. However, I really know nothing about this subject, I just want to make sure the article is accurate. Can someone verify my impression and make sure the article lists the finding correctly? --71.193.217.159 (talk) 04:25, 8 April 2013 (UTC)[reply]

It is best to look for secondary sources to interpret what the (horribly written) primary source says. Perhaps in a couple of days somebody will publish something online to clear all this up. Abductive (reasoning) 04:41, 8 April 2013 (UTC)[reply]

There is mounting evidence that Carnitine through TMAO can be pro-atherogenic. If I have time I will add some resources. LuxMaryn (talk) 05:42, 19 April 2023 (UTC)[reply]

Query regarding efficacy

Does taking Acetylcarnitine or Propionyl-L-Carnitine lead to the same effects? Count Iblis (talk) 15:33, 10 April 2013 (UTC)[reply]

@Count Iblis: the only certain longterm efficacy of broad, uninformed supplement use is to contribute to natural selection, that is, the thinning of the herd prior, with related impacts on the survival of ones lineage. See for instance [1]. The same can be said with regard to coming to Wikipedia for information about pharmacologic efficacy and the equivalence of agents. Cheers. Le Prof Leprof 7272 (talk) 05:19, 23 January 2016 (UTC)[reply]

Hmarque22 (talk) 17:02, 29 June 2017 (UTC)Why is it not mentioned in this article the efficacy of L-Carnitine and Acetyl L-Carnitine in oligoesrpemia? This product is prescribed by Andrologists with excellent results. Treatments of 1 to 2 even 3 grams daily of L-Carnitine, associated to Fructuose for 60 to 72 days are recommended. https://www.ncbi.nlm.nih.gov/pubmed/16169400, https://www.ncbi.nlm.nih.gov/pubmed/15193480, https://www.ncbi.nlm.nih.gov/pubmed/15149558 Hmarque22 (talk) 17:02, 29 June 2017 (UTC)[reply]

Too much quoting

There are entire sentences that are direct quotes all over this article. Please paraphrase. In fact, the whole article is rather disjointed and could use some help. Avoid primary sources. Abductive (reasoning) 04:50, 8 April 2013 (UTC)[reply]

Talk Page Guidelines - Recent Modifications - NYTimes Red-Meat/Carnitine/TMAO article

I'm a new contributor. I created this account specifically for the purpose of addressing a situation I outline below. I don't usually address situations like this in this fashion. However, I believe the recent modifications to at least 2 Wikipedia pages were done for the specific purpose of mass distribution of a news article that makes red meat look bad. If I understand correctly, this is not allowed by the Talk Page Guidelines, which in my view should also be valid for the Read pages as well, if it's not already part of those guidelines.

A recent NYTimes article by Gina Kolata published 2013-04-07 claims red meat is bad due to L-carnitine, Trimethylamine N-oxide (TMAO), and gut bacteria. Wikipedia pages for L-carnitine and TMAO were modified the same day to include both a direct link to the NYTimes article and to the study cited therein. The NYTimes article was modified (title/content) only hours after its first publication according to newsdiff.org, yet original title remains on Wikipedia entry for TMAO, showing that Wikipedia modifications were made within hours of NYTimes first publication.

I'm a frequent reader of Wikipedia, and I rely on it as first reference after reading news articles mostly on health, physiology and nutrition, specifically for the purpose of discussing the content of these news articles on a discussion forum. This situation is ironic in that my usual activities revealed suspicious modifications made to Wikipedia pages, almost simultaneously as the first publication of a NYTimes article. Instead of discussing the content of this news article, I ended up discussing the fashion in which it was distributed, specifically the Wikipedia modifications. In my view, this situation makes the author of the NYTimes article, the NYTimes, the authors of the study, and Wikipedia all look bad. The NYTimes doesn't need any more visibility, as demonstrated by the already extensive visibility it enjoys through a simple Google search of the news article title, most likely as a result of established automated distribution mechanism across news networks. Wikipedia's reputation shouldn't suffer just for a few more hits.

I ask that this situation be addressed according to Wikipedia guidelines.

For reference: http://forum.lowcarber.org/showthread.php?t=451727

Martin Levac — Preceding unsigned comment added by MartinLevac (talk • contribs) 02:25, 9 April 2013 (UTC) 02:25, 9 April 2013 (UTC)[reply]

I'm not sure I understand your objection. People always edit Wikipedia in this way, reading something online and then "updating" the articles on the topics mentioned. Wikipedia requires secondary sources to back up statements, and the NYT article is certainly secondary. Do you think that carnitine is not a culprit in atherosclerosis? The text says "may be a link". Do you think bad information is being widely disseminated? This article got only 27,000 views yesterday, or about 0.0075% of the English-speaking population of the world. Abductive (reasoning) 05:04, 9 April 2013 (UTC)[reply]
- As I said, I'm a new contributor. So I'm not familiar with standard practice. However, I believe this situation isn't "somebody reading something online, then modifying relevant Wikipedia pages". Instead, considering the facts, I believe this situation is more like "study author provides NYTimes with source material for article, NYTimes author notifies study author of publication, study author modifies relevant Wikipedia entries as means to expand visibility of study by way of linking to NYTimes article". If the two situations are equally acceptable, then I retract my objection. However, in my opinion, the NYTimes article is not secondary source (rebuttal, criticism or discussion thereof) for the study. It's merely an equivalent primary source, moreso if the Wikipedia modifications were also made by anybody directly involved with the study or NYTimes article. If this is true for the carnitine entry, then it's also true for the TMAO entry, where the direct link to the NYTimes article still remains: http://en.wikipedia.org/wiki/Trimethylamine_N-oxide Martin Levac — Preceding unsigned comment added by MartinLevac (talk • contribs) 06:46, 9 April 2013 (UTC)[reply]
  - I assure you that I am not employed (in any capacity, alas). Usually people with WP:COIs doing some academic boosterism do a horrible job of it, and obvious too. Then other editors drop by and rewrite material in a more neutral way. Abductive (reasoning) 13:47, 9 April 2013 (UTC)[reply]
    - Yes, this one is obvious even to me, even though it's the very first time I see academic boosterism in action. Also, the actual text of the modifications is generally poorly written, and poorly re-written as well, in my opinion. Ambiguous, bad sentence structure, vague, inaccurate. For example "carnitine from food". The carnitine used in the experiment was used on its own, not combined with food, nor contained in food. Thus, it's not "carnitine from food", but simply "carnitine".MartinLevac (talk) 19:03, 9 April 2013 (UTC)[reply]
- Aside from the situation described above, here's a factual argument invalidating the study as evidence implicating carnitine in CVD. Reference #2 in the study itself is PMID 20479151 "Red and processed meat consumption and risk of incident coronary heart disease, stroke, and diabetes mellitus: a systematic review and meta-analysis." This study found no link between red meat consumption and CVD, but found a link between processed meat consumption and CVD. The carnitine/TMAO/gut bacteria study cites in the abstract "well-established link between high levels of red meat consumption and CVD risk." The assertion that carnitine is implicated in CVD relies exclusively on the existence of a link between red meat consumption and CVD. Since this link is non-existent, as demonstrated by a reference in the cartnitine study itself, the carnitine implication actually implicates nothing that can be shown through this reference. In spite of this obvious anomaly, the NYTimes article reads as if the link did exist, and as if carnitine was implicated in CVD through this link. I remind contributors that the NYTimes link still remains on the TMAO Wikipedia page. — Preceding unsigned comment added by MartinLevac (talk • contribs) 08:39, 9 April 2013 (UTC)[reply]
  - Do you have a secondary source that says that? Abductive (reasoning) 13:47, 9 April 2013 (UTC)[reply]
    - The study is invalid by virtue of including a reference that refutes the sole basis for its conclusions. A secondary source is not required to demonstrate this. A simple reading of the study itself and of the references therein reveals the anomaly. However, if you insist, wait a couple days, I anticipate the net will be flooded with rebuttals, and you will have ample choice of secondary sources.MartinLevac (talk) 19:03, 9 April 2013 (UTC)[reply]
      - That's what is needed. Wikipedia editors cannot construct those connections per WP:SYNTHESIS. Abductive (reasoning) 19:17, 9 April 2013 (UTC)[reply]
- Many studies looking at fish intake vs CVD risk found an inverse relationship between fish intake and CVD risk. The TMAO page explains that fish contains more TMAO than other meats. It's impossible to reconcile those two facts, when we also consider the carnitine/TMAO gut bacteria study, which implicates carnitine and TMAO, suggesting more carnitine = more TMAO = more CVD. PMID 11939867 MartinLevac (talk) 09:15, 9 April 2013 (UTC)[reply]
  - Not if TMAO is digested in the stomach. Abductive (reasoning) 13:47, 9 April 2013 (UTC)[reply]
    - Unfortunately, the carnitine study itself contradicts your assertion. From the abstract: "dietary supplementation with TMAO or either carnitine or choline reduced in vivo reverse cholesterol transport". Thus, my assertion stands. The carnitine study is invalid by virtue of refutation from other studies which found an inverse relationship between fish (containing high amounts of TMAO compared to other meat) intake and CVD risk.MartinLevac (talk) 19:03, 9 April 2013 (UTC)[reply]
      - I'm sure there are many contradictions. It is best to wait for secondary sources to point out these flaws. Abductive (reasoning) 19:17, 9 April 2013 (UTC)[reply]
I find that this is an utterly inadequate forum for debate. I will not argue further on this topic. I've had my say, and I believe it is sufficient to warrant a review of the recent modifications.MartinLevac (talk) 19:03, 9 April 2013 (UTC)[reply]
- Sure. But of course you could always pitch in and edit the article. Abductive (reasoning) 19:17, 9 April 2013 (UTC)[reply]
  - If it was up to me, I'd remove the entire carnitine/TMAO/gut bacteria entry, with prejudice toward the editor who put it there in the first place. The fashion in which the modifications were made, the anomalous nature of the entire study, the misleading modifications themselves, all demonstrate a clear non-adherence to what I've come to know as Wikipedia standards, thanks to your many kind references to rules and guidelines. Shall I proceed?MartinLevac (talk) 12:49, 10 April 2013 (UTC)[reply]

Deletion of Nature l-carnitine study

Dbrodbeck deleted the reference to the Nature study on l-carnitine and atherosclerosis, because it was a single primary study, rather than a review. [2]

If that's the criteria for removing text from the article, we should delete almost the entire "Potential uses as a pharmaceutical" section, because most of those claims are based on single studies, and some of them are 20 years old or more. --Nbauman (talk) 21:26, 24 April 2013 (UTC)[reply]

Indeed. We have to be very careful with medical claims. We are not in the position to evaluate secondary studies so we really ought to rely on secondary sources. Dbrodbeck (talk) 22:58, 24 April 2013 (UTC)[reply]

So are you going to remove all those claims in the Potential uses as a pharmaceutical section? --Nbauman (talk)

I don't think that would be a bad idea actually. However, I would want others to weigh in. Anything that is backed by secondary sources, that would be ok by me.Dbrodbeck (talk) 01:27, 25 April 2013 (UTC)[reply]

The bulk of "Potential Uses As A Pharmaceutical" entries indicates beneficial effects. Removing this entire section significantly alters the balance of evidence for/against L-carnitine use for various purposes. Of particular importance is the entry "Heart Conditions", which on the whole appears to contradict the entry "Atherosclerosis" in the "Physiological Effects" section. Consequently, removing the entry "Heart Conditions" will leave the entry "Atherosclerosis" unchallenged, giving the impression of significantly more detrimental effects than is otherwise indicated at present. Points to consider:

-- The Nature study on L-carnitine and atherosclerosis (which was removed from the "Potential uses..." section) is exactly the same primary source as the "Atherosclerosis" entry. -- 3 Secondary sources rebut this one thoroughly both individually and as a whole, specifically with respect to the link between red meat / L-carnitine / TMAO / atherosclerosis -- [3] -- [4] -- [5] -- A previous primary source from the same study author (Stanley L. Hazen) as the current TMAO study attempted to implicate choline and TMAO in atherosclerosis, which has also been rebutted thoroughly as well by at least one secondary source -- [6] -- All rebuttals to both L-carnitine/TMAO and choline/TMAO primary sources refer to some of the sources cited (or equivalent) in the "Potential Uses..." section to support their rebuttals -- The primary source L-carnitine/atherosclerosis study also exists on the Trimethylamine N-oxide (TMAO) page, therefore should also be removed following removal of same primary source on the L-carnitine page -- [7]MartinLevac (talk) 06:33, 25 April 2013 (UTC)[reply]

MartinLevac, since you are a new user, you should carefully read WP:RS which is a basic guideline for writing on Wikipedia. For one thing, blogs are not reliable sources (with certain exceptions such as newspaper blogs written by journalists). --Nbauman (talk) 02:28, 26 April 2013 (UTC)[reply]

I'm not the one who added the Nature study to begin with. Maybe you should advise the editor who did. Dbrodbeck deleted it for "single primary source" reason. The same "single primary source" appears elsewhere, notably as the "Atherosclerosis" entry, and as "Health Issues" entry on the TMAO page. Incidentally, a recent Gina Kolata/NYTimes article published April 24th 2013 implicating lecithin/TMAO is now cited on the TMAO page in the "Health Issues" entry. I already pointed out previous recent additions to the L-carnitine and TMAO pages, also from the same primary source Gina Kolata/NYTimes. This recent lecithin/TMAO addition is also being discussed on the lecithin talk page. I cite user Jytdog: "We do not add health information to Wikipedia based on primary studies. This violates not only wikipedia's foundational policy on sourcing content (see WP:PSTS) but also the guidelines that have been created for sourcing health content, which are more rigorous (see WP:MEDRS)."MartinLevac (talk) 04:42, 26 April 2013 (UTC)[reply]

Did you read WP:RS? Many of your questions and objections will be answered there. And you must understand WP:RS if you want to edit Wikipedia. --Nbauman (talk) 14:55, 26 April 2013 (UTC)[reply]

Yes, I read them and I understand. According to those guidelines, all references to the Nature/TMAO study, and all references to the lecithin/TMAO study should be removed from Wikipedia. They are primary sources, and they fall under the more rigorous health content sourcing guidelines.MartinLevac (talk) 15:24, 26 April 2013 (UTC)[reply]

I've gutted that particular section. From what I can tell, cartinine is not an accepted medical intervention for any indication. WLU (t) (c) Wikipedia's rules:^simple/_complex 14:32, 1 May 2013 (UTC)[reply]

Way better, thanks! Dbrodbeck (talk) 15:11, 1 May 2013 (UTC)[reply]

According to Colpo they used mice in the study, not people. Mice are vegans, not omnivores. The authors of the study has filed a patent for TMAO-testing. Ref: http://anthonycolpo.com/bullshit-study-of-the-year-carnitine-causes-heart-disease/ — Preceding unsigned comment added by 85.224.97.129 (talk) 15:29, 14 July 2013 (UTC)[reply]

WP:MEDRS

Scientific findings are often touted in the popular press as soon as the original, primary research report is released, and before the scientific community has had an opportunity to analyze the new results. For a short time afterwards, the findings will be so new that they will not be reflected in any review articles or other secondary sources. If the findings involve phase I or phase II clinical trials, small studies, studies that did not directly measure clinically important results, laboratory work with animal models, or isolated cells or tissue, then these findings are probably only indirectly relevant to understanding human health; in these cases, they should be entirely omitted. In other situations, such as randomized controlled trials, it may be helpful to temporarily cite the primary research report, until there has been time for review articles and other secondary sources to be written and published. When using a primary source, Wikipedia should not overstate the importance of the result or the conclusions. When in doubt, omit mention of the primary study (in accordance with recentism) because determining the weight to give to such a study requires reliable secondary sources (not press releases or newspaper articles based on them). If the conclusions of the research are worth mentioning, they should be described as being from a single study, for example:
"A 2009 U.S. study found the average age of formal autism spectrum diagnosis was 5.7 years." (citing PMID 19318992)

After enough time has passed for a review in the area to be published, the review should be cited in preference to the primary study. Using a secondary source often allows the fact to be stated with greater reliability:

"In the U.S., the average age of formal autism spectrum diagnosis is 5.7 years." (citing a review)

If no review on the subject is published in a reasonable amount of time, then the text associated with the primary source should be removed.
If the same material could be supported by either a primary source or a secondary source of otherwise equal quality, it is normally preferable to cite the secondary source.

2A02:2F0C:B06F:FFFF:0:0:567E:62D7 (talk) 18:03, 9 May 2013 (UTC)[reply]

In other situations, such as randomized controlled trials, it may be helpful to temporarily cite the primary research report, until there has been time for review articles and other secondary sources to be written and published.

Are you sure all of those claims were to be removed instead of mentioning that they are claimed by a primary source? 2A02:2F0C:B06F:FFFF:0:0:567E:62D7 (talk)

Nope, this is way too preliminary. It's been getting press because it's a surprising finding, which means it's preliminary, which means it's unconfirmed. There is no intervention yet, there's no confirmation of health effects, at this point it's an interesting starting point for further research. It's not comparable to the autism example given as autism is an established diagnosis, and the paper cited gives a prevalence about a recognized condition. This would require a whole bunch of caveats, and it would still come down to "maybe, maybe, maybe". WLU (t) (c) Wikipedia's rules:^simple/_complex 11:01, 10 May 2013 (UTC)[reply]

Exactly, which would be a whole bunch of OR. Dbrodbeck (talk) 11:12, 10 May 2013 (UTC)[reply]

Possible health effects section

states: "Carnitine has been proposed as a supplement to treat a variety of health conditions including heart attack,[11][12] heart failure, angina,[13] and diabetic neuropathy,[14] but not fatigue, improving exercise performance,[13] nor wasting syndrome (weight loss),[14] though in all of these cases the results are preliminary, proposed, and not part of routine treatment.[14]"

This passage seems to embody some un-arbitrated controversy. Carnitine certainly _has_ been _proposed_ as a supplement to reduce fatigue and improve exercise performance. Whether it is actually effective in these departments may be disputable ... 120.18.148.224 (talk) 02:43, 22 October 2013 (UTC)[reply]

The section is unclear because it is poorly worded. But I think the whole section should simply be removed. It doesn't comply with Wikipedia guidelines for medical information (WP:MEDRS). We should wait until there are reviews in secondary sources before reporting on these potential health effects. -- Ed (Edgar181) 10:26, 22 October 2013 (UTC)[reply]

Correcting a small error - confusion between acylcarnitine and acetyl-carnitine

The following sentence appears to be in error: "Fatty acids must be activated before binding to the carnitine molecule to form acetyl L-carnitine" Specifically, it should read acylcarnitine, not acetyl L-carnitine, unless I am missing something. The remainder of the section accurately refers to acyl carnitine.

I will fix this soon unless I hear otherwise. Sbackues (talk) 19:04, 5 January 2016 (UTC)[reply]

Edits of this date

I have placed a tag calling for expert attention form the Chemistry and Molecular and Cellular Biology Wikiprojects, to address the article's indecisiveness as to whether it is about the chemical entity (in all of its details, preparation, uses, etc.) or solely about the biosynthetic intermediate and nutrient L-carnitine (levocarnitine), in which case its bacterial, plant, and further mammalian biochemical detail is needed.

If it is about levocarnitine, the article image should represent the L- enantiomer, and round out its presentation of the narrow subject, with broadened coverage of plant and bacterial biosynthetic pathways, images for mammalian anabolic pathways, content on its metabolic deficiency syndromes, etc.

In about the chemical more generally, balance has to be found between the current thrust (one enantiomer, biochemistry only) as broadened in the foregoing way, and more standard content of articles about chemical, which include coverage of preparations in laboratory and industrially, as well as content about its states, forms, properties, etc. and its non-biological uses and research (including, again, better images).

As it stands, the article tips its hat at being a chemical article (one line in lede, and the infobox), but then is devoted to the purely biologic. In trying to do both, it does neither completely, or well. My perspective. Le Prof. 50.179.252.14 (talk) 02:35, 23 January 2016 (UTC)[reply]

Moved sentence and citation to Talk

This is a single, moderate quality primary source written in Italian. It should not be the basis for adding medically related content to the article. It sets a bad precedent (observation dumping, by non-experts, based on primary sources, which defies WP:VERIFY as it applies to the sciences). Here is the sentence, and citation, in case it helps someone find if the observation is more broadly supported, and is notable (or is just a one-off research report):

"There is also some suggestion that use of acetyl carnitine and L-arginine may improve sperm motility in men with sperm abnormalities.^[1]

^ http://www.ncbi.nlm.nih.gov/pubmed/20940690

(The URL only was the form of the citation to Pubmed was all that appeared in the article, before moving it here.) Le Prof 50.179.252.14 (talk) 03:00, 23 January 2016 (UTC)[reply]

Here is another one:

"Vitamin C (ascorbic acid) is not essential to the synthesis of carnitine."^[1]

^ Furusawa, H; Sato, Y; Tanaka, Y; Inai, Y; Amano, A; Iwama, M; Kondo, Y; Handa, S; Murata, A; Nishikimi, M; Goto, S; Maruyama, N; Takahashi, R; Ishigami, A (September 2008). "Vitamin C is not essential for carnitine biosynthesis in vivo: verification in vitamin C-depleted senescence marker protein-30/gluconolactonase knockout mice". Biological & Pharmaceutical Bulletin. 31 (9): 1673–9. doi:10.1248/bpb.31.1673. PMID 18758058.

(Interesting, but once again, unnecessary and a primary source, in a field where there is no need for such except as accents to strong secondary sourcing.) Le Prof Leprof 7272 (talk) 05:33, 23 January 2016 (UTC)[reply]

Assessment comment

The comment(s) below were originally left at Talk:Carnitine/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.

This protein metabolite is of commercial importance for being widely distributed in pills with claims that may be falsifiable or be at a competitive disadvantage. A natural source or a key to internal synthesis would put it at such a disadvantage. Brewhaha@edmc.net 12:23, 25 April 2007 (UTC)[reply]

Last edited at 12:23, 25 April 2007 (UTC). Substituted at 10:57, 29 April 2016 (UTC)

Carnitine and CoViD

At the "Immune System" paragraph the claim is made "As a supplement, L-Carnitine it appears to assist against COVID-19"

There is only one reference, which doesn't even mention L-Carnitine. Please back up the claim or remove it! LuxMaryn (talk) 09:05, 10 September 2020 (UTC) I agree with this, the reference doesn't mention carnitine, that entire paragraph is unsubstantiated. — Preceding unsigned comment added by 98.35.162.23 (talk) 02:42, 10 March 2021 (UTC)[reply]

L-carnitine and lipid profile: umbrella meta-analysis (September 2023)

The effect of L-carnitine supplementation on lipid profile in adults: an umbrella meta-analysis on interventional meta-analyses (Musazadeh et al., 2023) -- I wonder if this a good-quality analysis, worthy of mentioning in the article, or not. --CopperKettle (talk) 08:44, 25 September 2023 (UTC)[reply]

Nice find, unfortunately Frontiers Media are generally unreliable and are considered a possible predatory publisher. It is not a high-quality journal. We don't normally cite Frontiers on Wikipedia articles for medical and nutritional topics. Psychologist Guy (talk) 19:41, 22 October 2023 (UTC)[reply]

[1] ttp://www.ncbi.nlm.nih.gov/pubmed/20940690

[2] Furusawa, H; Sato, Y; Tanaka, Y; Inai, Y; Amano, A; Iwama, M; Kondo, Y; Handa, S; Murata, A; Nishikimi, M; Goto, S; Maruyama, N; Takahashi, R; Ishigami, A (September 2008). "Vitamin C is not essential for carnitine biosynthesis in vivo: verification in vitamin C-depleted senescence marker protein-30/gluconolactonase knockout mice". Biological & Pharmaceutical Bulletin. 31 (9): 1673–9. doi:10.1248/bpb.31.1673. PMID 18758058.

[1]

[1]