Synethic menthol and Testosterone

[Gormur]

This may not be a straight forward question. Based on the little I could find through medical journals, synthetic menthol is made in a few different ways

Anyway, I ask because this topic has never been covered here and since I'm curious about trying a nasal snuff that contains menthol I assume it contains synthetic menthol, since I read that 75% of commercial products using menthol contain synthetic menthol, rather than the natural form from mint or peppermint oil. Rather they are derived from thymol, which comes from thyme and a few other things can produce synthetic menthol as well

Apologies in advance for not being knowledgeable about chemistry, but I'm curious. Does anyone know if a synthetic menthol would have the same effect on humans as a natural menthol?

I know that peppermint is known to lower testosterone levels while mint doesn't do this

 

[G_Chem]

This may not be a straight forward question. Based on the little I could find through medical journals, synthetic menthol is made in a few different ways

Anyway, I ask because this topic has never been covered here and since I'm curious about trying a nasal snuff that contains menthol I assume it contains synthetic menthol, since I read that 75% of commercial products using menthol contain synthetic menthol, rather than the natural form from mint or peppermint oil. Rather they are derived from thymol, which comes from thyme and a few other things can produce synthetic menthol as well

Apologies in advance for not being knowledgeable about chemistry, but I'm curious. Does anyone know if a synthetic menthol would have the same effect on humans as a natural menthol?

I know that peppermint is known to lower testosterone levels while mint doesn't do this

Good question I too have wondered this lately. I’d love to have that minty taste without killing my testosterone.

-GC

 

[Nagelfar]

I'd assume that menthol's testosterone effect may be mediated via kappa-receptor affinity, therefore in a manner likened to other opioids.

Synthetic menthol's very likely only difference is being racemic. As to the effects of the other isomer, well the intended effects probably have a reduction in potency by fifty percent (unless shared affinity exists for either). Perhaps some synthesis intermediates in minute amounts too.

I really think ingredient lists could be more exhaustive and then we'd know such things and not have to investigate.

I'd rather look at it, beyond chemical considerations, much like vanillin to vanilla extract.

Hope someone who knows more of the specifics can fill you in, I apologize for being rather general.

 

[sekio]

synthetic menthol is almost always chirally pure (the chiral synthesis is easy and starts from citronellal I rhink) and is indistinguishable from the natural product because the "other isomers" are different in flavor/aroma

I know that peppermint is known to lower testosterone levels

source?

 

[Gormur]

synthetic menthol is almost always chirally pure (the chiral synthesis is easy and starts from citronellal I rhink) and is indistinguishable from the natural product because the "other isomers" are different in flavor/aroma

Cheers for that. I wasn't sure about what I'd read

source?

My only source is this: https://pubmed.ncbi.nlm.nih.gov/15302514/ I probably shouldn't have said that definitively though I've read that both spearmint and peppermint lower testosterone. Of course those could be dubious claims so I'll refrain from posting them here. Overall, real results seem inconclusive

 

[atara]

If menthol were that active at kOR at normal dietary doses it would make you trip nuts. Peppermint contains all sorts of compounds, not just menthol:

http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.919.9042&rep=rep1&type=pdf

Inferring an activity of menthol based on peppermint is quite eager. Menthol primarily affects TRPM8, which is sensitive to testosterone and alters sexual function:

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faseb.onlinelibrary.wiley.com

If menthol affects testosterone, it probably does so by binding the very same receptor responsible for the minty flavor. It wouldn't matter which analog you use, or how it is synthesized, in that case.

EDIT: To add, while I have heard occasional reports of antiandrogenic effects of peppermint, many more reports exist for the same effects in spearmint, which contains very little menthol and primarily carvone. See e.g.

Evaluation of possible toxic effects of spearmint (Mentha spicata) on the reproductive system, fertility and number of offspring in adult male rats

Objective: In this study we investigated the effects of spearmint (Mentha spicata Labiatae) on the reproductive system, fertility and number of offspring in adult male rats. Materials and Methods: Adult Wistar male rats in one control (C) and three ...

www.ncbi.nlm.nih.gov

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onlinelibrary.wiley.com

Role of Essential Oil of Mentha Spicata (Spearmint) in Addressing Reverse Hormonal and Folliculogenesis Disturbances in a Polycystic Ovarian Syndrome in a Rat Model

Purpose: Given the antiandrogenic effects of spearmint, in this study we evaluated the effects of its essential oil on polycystic ovarian syndrome in a rat model.Methods: Female rats were treated as follows: Control, normal rats which received 150 mg/kg ...

www.ncbi.nlm.nih.gov

 

[Nagelfar]

synthetic menthol is almost always chirally pure ... because the "other isomers" are different in flavor/aroma

Interesting, being an alcohol, I wonder what the others would 'taste' like.

 

[S.J.B.]

synthetic menthol is almost always chirally pure (the chiral synthesis is easy and starts from citronellal I rhink)...

Historically it was made from citronellal, but since the 1980s it has been made from achiral myrcene via a rhodium-catalyzed asymmetric alkene isomerization process. This is one of the most famous asymmetric industrial chemical processes and the work that Ryōji Noyori did on it contributed significantly to his earning the Nobel Prize in Chemistry in 2001.

 

[sekio]

but since the 1980s it has been made from achiral myrcene via a rhodium-catalyzed asymmetric alkene isomerization process.

citronellal is an intermediate in that process

Interesting, being an alcohol, I wonder what the others would 'taste' like.

Leffingwell says:
(1S,3S,4R)-(+)-menthol - fresh, some cooling, sweet-minty with musty, bitter, phenolic and herbaceous notes
(1R,3R,4S)-(-)-menthol (natural menthol) - very cooling, fresh, sweet, minty
(1S,3R,4R)-(-)-neomenthol - minty, musty, fresh, earthy-camphoraceous, some cooling
(1R,3S,4S)-(+)-neomenthol - sweet, musty, fresh, some cooling, minty
(1S,3R,4S)-(-)-isomenthol - musty, sweet, herbaceous, earthy-camphoraceous, hay, slight cooling
(1R,3S,4R)-(+)-isomenthol - musty, woody, fresh-carrot-minty, earthy-camphoraceous, slight cooling
(1S,3S,4S)-(-)-neoisomenthol - musty, earthy-camphoraceous, sweet, minty, woody, slight cooling
(1R,3R,4R)-(+)-neoisomenthol - musty, earthy-camphoraceous, woody, carrot, herbaceous, minty, very little cooling

 

[Nagelfar]

^ didn't imagine getting a reply that involved; wouldn't have at all from anyone other than you. Thank you, interesting that none of them sound all that offensive, wonder if any of them are put to use elsewhere.

 

[Gormur]

I guess I'll hijack my own thread, but I didn't want to open a new one or just one about tobacco

I'm contemplating ordering menthol crystals but I can't find any direct information on adding it to tobacco, well nasal snuff (think moist snuff for chew/dip, dry snuff for the very floury type for snuffing up your nose). I even looked at how to do it for a liquid but all I got was vapor liquid solution or using Everclear. It has to be something nontoxic and as far as I know one can't directly add let's say dissolved menthol crystals to snuff as it would be caustic

I know the papertowel method using water in a sealed container sat next to exposed tobacco for 24 hours. That's for rehydrating it. I'm not sure if this method could mentholize tobacco though. Any ideas?

 

[sekio]

menthol is volatile with steam, you could put the tobacco in a steamer and boil a mixture of metnhol and water to expose it to mentholated steam

alternatively you can dissolve menthol in some volatile solvent (acetone is perfect, bp of around 60c, you can make a fairly concentrated solution, and also it won't kill you if you ingest some either) and spray it onto the tobacco

as for amounts to use:
The amount of menthol measured in the whole cigarettes ranged from 2.9 to 19.6 mg/cigarette for menthol-flavoured cigarettes(ref)

I think an average commercial cigarette is 1 gram, so try to aim for between 1mg/g and 20mg/g menthol

 

[Gormur]

menthol is volatile with steam, you could put the tobacco in a steamer and boil a mixture of metnhol and water to expose it to mentholated steam

alternatively you can dissolve menthol in some volatile solvent (acetone is perfect, bp of around 60c, you can make a fairly concentrated solution, and also it won't kill you if you ingest some either) and spray it onto the tobacco

as for amounts to use:
The amount of menthol measured in the whole cigarettes ranged from 2.9 to 19.6 mg/cigarette for menthol-flavoured cigarettes(ref)

I think an average commercial cigarette is 1 gram, so try to aim for between 1mg/g and 20mg/g menthol

It's a carefully guarded secret what these snuff makers do, but acetone sounds like the way to go for me