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5-HTP Contaminants Comments
by a 5-HTP Manufacturer & Independent Testing Lab
Feb 22, 2001
(letters received, scanned, OCR'ed, and HTML'ed by
Letter from Kaden Biochemicals, a manufacturer of 5-HTP for human consumption, on the topic of toxic contaminants to Bios Biochemicals.

Kaden Biochemicals, GMBH
Porgesrung 50
22113 Hamburg
Telefon 04V / 73 60 454
Telefax 040 / 73 60 45 45
Bankverbindung Commerzbank Hamburg DU 200 400 00
Kanko-Nr. 55 02 661
To: Ronald G Sturtz, Bios Biochemicals Corp

September 8, 1998

Re: L-5-Hydroxytryptophan (5-HTP)

As you are aware, there have been recent items in the news questioning the purity and safety of L-5-Hydroxytryptophan (5-HTP). Kaden Biochemicals GmbH is a major manufacturer of 5-HTP. We have been marketing the substance, as a bulk raw material, to pharmaceutical and dietary supplement manufacturers for over 20 years. We are communicating with you to ensure you are presented with accurate, factual Information on this subject.

5-HTP sold by Kaden Biochemicals is a naturally occurring substance extracted from the seeds of the Griffonia simplicifolia plant, The seeds are generally collected in Ghana and the Ivory Coast in Africa. We thoroughly test the seeds for identity, cleanliness and quality before drying end milling. The 5-HTP is extracted using an alcohol extraction process. The crude 5-HTP obtained is purified by a series of recrystallization Steps.

Strict manufacturing and quality control procedures are implemented throughout the process. The final product is subjected to extensive testing to ensure it meets our final release specification. Every batch is tested by HPLC with UV detection for assay and the presence of Impurities. Our release specification requires that every batch meets 99% minimum for 5-HTP. The only significant impurity is L-Tryptophan for which our release specification is 0.2% maximum. In practice, all 5-HTP sold by Kaden Biochemicals has less than 0.1 % L-Tryptophan when tested by HPLC with UV detection.

No product sold for pharmaceutical or nutritional use is ever perfectly pure. There are always other minor components. 5-HTP, in the USA, is not regulated as a pharmaceutical. However, we understand the strict FDA Guidelines applicable to pharmaceutical products require identification of impurities greater than 0.1%. Impurities less than 0.05% (500ppm) are classified as trace impurities and do not need to be identified or quantified The HPLC results of every batch of Kaden 5-HTP are routinely reviewed for the presence of other impurity peaks. We have never seen any significant impurity peaks that would necessitate further study.

The current publicity revolves around the alleged presence of a "Peak X" impurity in 5- HTP. This was initially reported in a paper written by Michelson at al and published in The Journal of Rheumatology 1994; 21:12. During our final quality control testing we have never detected any peak similar in magnitude and position to Peak X as depicted in Fig. 2B of the Michelson paper.

On September 1, 1998 Nature Medicine published a 'Letter to the Editor' from a group of researchers at the Mayo Clinic. This group claims they have recently structurally characterized the Peak X compound as 6-hydroxy-1,2,3,4,4a,9a-hexahydro-B-carboline- 3-carboxylic acid. They state this compound is structurally similar to contaminants found in batches of L-Tryptophan which were associated with Eosinophilia-Myalgia Syndrome (EMS).

The Mayo letter also reports that the same researchers then tested six commercial 5- HTP preparations purchased in stores in the Rochester (Minnesota) and New York City areas. These preparations were tested for the presence of Peak X by HPLC with Mass Spectroscopy (MS) detection. Mayo report they found these 6 samples to contain amounts of Peak X varying from 3% to 14% of the amount of Peak X found in the 'Michelson samples'. The researchers do not quantity the actual amount of Peak X found but speculate it could cause another EMS epidemic similar to the L-Tryptophan disaster in 1989.

We believe any attempt to link 5-HTP with the L-Tryptophan contamination is completely irresponsible and not based on sound scientific evidence. Commercially available L- Tryptophan was manufactured synthetically by a fermentation process. It is widely accepted in scientific circles that the 1989 US epidemic of EMS was caused by an impurity, 1,1'-ethylidene-bis[tryptophan] (EBT or 'Peak E') present in the L-Tryptophan released by one particular bulk manufacturer. This impurity was a direct result of that company's manufacturing process for the synthetic material.

5-HTP manufactured by Kaden Biochemicals is a completely natural product. It has not been subjected to any chemical reaction or further synthesis. We have tested our material for the presence of EBT by HPLC with UV detection. No EBT is detected Our test method Is sensitive enough to detect EBT levels of less than 5ppm if any were to be present. Any reference to 5-HTP in relation to the earlier EMS epidemic is, to the best of our knowledge, completely unfounded.

The Michelson study in The Journal of Rheumatology hypothesizes that high levels of Peak X in 5-HTP may be linked to EMS. The scope of that study was extremely limited and only involved a single family. The authors did not express, imply or establish any direct link between 5-HTP and EMS, We believe it would be very rash to make any dramatic inferences from that report without carrying out much more thorough and statistically significant scientific research.

The Mayo report has been released as a 'Letter to the Editor' and not as a detailed scientific 9". The identification work they claim for Peak X is unpublished and has never been subjected to peer review. It is therefore Impossible to verify the scientific soundness of such identification work. No reference standards are available for Peak X so the conclusions they reach can only be verified by comparing current materials with the original material criticized in the Michelson study. Kaden Biochemicals has riot been able to secure a sample of this material despite contact with the Mayo Clinic, the FDA and the NIMH.

5-HTP manufactured by Kaden Biochemicals has been distributed for more than 20 years. In Europe 5-HTP, in dosage form, is approved by the Authorities as a prescription medication. To the best of our knowledge there have never been any confirmed cases of EMS in Europe linked to 5-HTP. No long term restrictions have ever been placed on 5- HTP by any European country. Kaden Biochemicals takes most seriously any issues regarding the safety of 5-HTP. On hearing initial reports of the Mayo Clinic letter we immediately retested every batch of 5-HTP produced in 1998. This testing reconfirmed our initial QC release data.

We also commissioned an in-depth study by Innovative Scientific Services Inc. (ISSI) in Highland Park, NJ. ISSI is a research laboratory specialized in detecting and identifying trace impurities for major pharmaceutical companies. Dr. Yesu Das, the president of ISSI, personally tested 6 different batches of Kaden 5-HTP using an HPLC procedure specifically developed to detect even minor trace impurities. He also reproduced the Mayo HPLC-MS test using Kaden material. He was specifically looking for the 6-hydroxy- 1,2,3,4,4a,9a-hexahydro-o-carboline-3-carboxylic acid Peak X compound identified by Mayo and reported by Michelson to elute in HPLC testing as a significant peak just after the main 5-HTP peak. He concluded that such an Impurity peak does not exist In the Kaden material.

Dr. Das's extremely sensitive HPLC work did show the presence of 3 very minor impurity peaks eluting just after the main 5-HTP peak. When these were quantified relative to the main 5-HTP peak the results showed quantitative amounts of 0.01 % to 0.02% for each peak. We understand these would be classified as minor trace impurities if 5-HTP were to be subject to the strict FDA Guidelines applicable to pharmaceutical products.

Under the HPLC-MS test conditions reported by Mayo these 3 minor peaks appear to co-elute as a single peak. Dr. Das carried out a Mass Spectroscopy experiment similar to the Mayo Clinic and concluded that the substance detected is not a carboline compound as reported by Mayo but a methyl analog of 5-HTP or a methoxy analog of Tryptophan. To the best of our knowledge, such a compound has never been linked to any case of EMS. A copy of the ISSI report is attached.

Every batch of 5-Hydroxytryptophan manufactured by Kaden Biochemicals is thoroughly tested and supported by an accurate and detailed certificate of analysis. Kaden 5-HTP is not contaminated and contains only minor trace impurities. It has been sold for over 20 years and has never been linked to any case of EMS.

The study of trace impurities in any compound is extremely complex and can be the subject of extensive scientific conjecture. We fully support ongoing study of 5-HTP. We will be continuing our work with outside scientists and will cooperate fully with the FDA wherever possible. However, we cannot condone the use of biased scientific data for the purpose of sensational press and television journalism.

We trust this letter provides you with adequate information to fully assess the current negative reports. We will gladly provide further details of test methods, copies of HPLC and MS chromatograms and all other available data if required.

We greatly appreciate your past orders. We look forward to working with you during the current difficulties and to ongoing business on 5-HTP.


Heinrich Kaden
Managing Director

Letter from Independent Lab about testing 5-HTP from Kaden Biochemicals

ISSI Laboratories Inc
515 Blue Ridge Avenue
Piscataway, NJ 08854-5013
732.246.3939 / fax 732.247.4977

5-Hydroxy-L- Tryptophan Analysis and Identification

This has a reference to the samples of 5-hydroxy-L-tryptophan (5-HTP) (Batch No. J 025 11).

Analytical Chem

In our High Performance Liquid Chromatography (HPLC), the unknown minor substances that elute very close to 5-HTP were well separated into 3 peaks. However, none of these individually exceeded 0.02% relative to 5-HTP There is no peak, per so, that could be associated with the peak that was designated as "peak X" by Michelson, et al. (J. Rheumatol. 1994; 21:2261-5). No match ran be made between these minor peaks and 'peak x", since the latter was never structurally identified, nor an authentic reference substance synthesized. Moreover, any structural information obtained on the minor substance(s) cannot be directly related to "peak X", since the chromatographic integrity of 'peak X" itself is questionable by the present day advances In the chromatographic methodology.

In my laboratory, using HPLC and Mass Spectrometry (LC-MS: APCI*), I have identified a minor substance eluting next to 5-HTP that has a molecular weight of 234 (C12H14N203). I have tentatively proposed this substance to be either a methyl analog of 5-HTP or a methoxy analog of tryptophan. (The chromatography did not employ methyl alcohol as a solvent in order to preclude any methylated artifacts.) Williamson at al. (unpublished) claim this substance to be a carboline- related compound. A final resollullIon to this situation can only occur when authentic reference substances for all the candidate substances are available for both chromatographic and structural confirmation. Until then, both "peak X" and its proposed Identity remain elusive.

Clinical Effects

1 . 'An Eosinophilia-Myalgia Syndrome Related Disorder Associated with Exposure to L-5- Hydroxytryptophan' by Michelson, at al., J. Rheumatol. 1994: 21:2261-5."

A hypothesis was advanced by the above authors that a combination of an unidentified impurity and host of other factors are important in pathogenesis (EMS). However, the initiating factors in L-5-HTP related EMS were not fully defined by the authors, since the hypothesis was based on only 2 children and their mother. Even in these cases, it is unclear whether 5-HTP itself, or the other drugs in the regimen (tetrahydrobiopterin and L-dopa), or the handling/dispensing practice was responsible for the onset of the syndrome. The facts that the symptoms resolved quickly with a change of dispensing practice and that there was no direct evidence of an EMS causing impurity in 5- HTP raise basic questions on the the validity of the assoc iation between EMS and 5-HTP. In fact, the authors (Michelson et al.) did not imply, express, or establish any direct link between 5-HTP and EMS; their numerous other cited cases suggest to the contrary. The authors only suggested that the hypothesis be tested with an authentic standard of the impurity (peak X).

2. "Problems with over-the-counter 5-hydroxy-L-tryptophan' by Williamson at al. (Nature Medicine September 1998).

A claim has been made on the Ida" of "peak X" based on their unpublished work However, since no experimental date was ever published, no credibility can be given to either the structural identity or its relationship with "peak )V. Moreover, it is contradictory to the original finding of Michelson at al., who suggested the substance to be a methyl analog-not a carboxylic acid. Also, their concern over its toxicity. based an "similar chemical structures" is unfounded. Even the original health concerns expressed by Michelson at al., which were based on an ill-defined Case history, have never been confirmed or supported by any other case over these long years of commercial use of 5-HTP.


1. 'Peak X" does not exist in the natural product of 5-HTP

2. "Peak X", if it Is not proven to be an analytical artifact should be considered as an isolated instance, which has no bearing on the purity of the commercially available natural products of 5-HTP. 3. Them are some minor substances associated with 5-HTP that appear to be analogs of 5-HTP,

none of which individually exceed 0.02% relative to 5-HTP These amounts are too little to be of concern to human health, unless they are proved to be so with definitive identification of the substance(s) and their toxicological evaluation.

Please do not hesitate to call me if you have any questions on my findings.

Sincerely yours,

Yesu T. Des, Ph.D.