# How fast does light degrade THC?



## HowardWCampbell (Aug 9, 2009)

I got to thinking about this the other day, and I haven not seen any good info on it. Does anyone know if there has been any sort of a scientific study as to how quickly light breaks down thc? And what effect light intensity has on it? Does blue light break down thc quicker than red light?

Everyone knows light breaks down thc, but how much light, and what % of thc is lost. For example, nobody I know is going to leave jars of curing bud in the windowsill on a summer day. But in the middle of a big smoke session, not many people are going to put their jar of weed in a dark closet to protect the thc from any lights.

Am I making any sense or am I just stoned and rambling on? One more odd question I've had in mind for a while...Why doesn't light degrade the thc while the plant is growing?

Any thoughts?


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## DaveTheNewbie (Aug 9, 2009)

good question


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## stronggenetics (Aug 9, 2009)

I dont remember where i read it but i know there's study's done on it{mighta been hightimes?} The light prolly doesnt hurt the thc on the plant because its still forming and becoming psychoactive


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## RickWhite (Aug 9, 2009)

It is well known that UV light in particular kills things. UV light is often used for sterilization. But light from a 60w bulb on your ceiling is far different from direct sunlight. Keeping bud exposed in a normally lit room shouldn't hurt anything - just keep it out of the sun.

If you want to find actual scientific data you might need access to a university library catalog to access scientific journals. This is something the university pays for. Of course you could try Google - can't hurt.


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## snail240 (Aug 9, 2009)

RickWhite said:


> It is well known that UV light in particular kills things. UV light is often used for sterilization. But light from a 60w bulb on your ceiling is far different from direct sunlight. Keeping bud exposed in a normally lit room shouldn't hurt anything - just keep it out of the sun.
> 
> If you want to find actual scientific data you might need access to a university library catalog to access scientific journals. This is something the university pays for. Of course you could try Google - can't hurt.


Word go studdy mummys remember some of the oldest canabis was found in a tomb and was smokable. Indirect light is ok sence you wont be storing for thousands of years.

Mummys and curying as well as preserving go hand in hand, in everything. THC is oil based so it can be presurved but keeping the plant from degrading completely(dry bubs like powder) The thc stil hasnt decraded it just burns up really fast because your smoking degraded plant material(dust) held together by oils.

Keeping the oils away from air and light in perfect temp could prolly last longer then well earth. Plant wont though but would still be smokable kinda like the crappy dry but still dank buds you get somtimes.

In the summer time it gets the crystals soft and the rub off on everything but the bowl. Fingers , bag/jar breaking it up could mean removing most of the good stuff when its hot out just throw the hole nug in the bowl or use sissors and be carefull.


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## plantz (Aug 9, 2009)

snail240 said:


> Word go studdy mummys remember some of the oldest canabis was found in a tomb and was smokable. Indirect light is ok sence you wont be storing for thousands of years.
> 
> Mummys and curying as well as preserving go hand in hand, in everything. THC is oil based so it can be presurved but keeping the plant from degrading completely(dry bubs like powder) The thc stil hasnt decraded it just burns up really fast because your smoking degraded plant material(dust) held together by oils.
> 
> ...


throwing whole nugs into bowls/bongs is FAIL shit, never do that, always break it up, when you dont, it burns outside of nugs and never gets the middle, ruins the weed and smoke and makes it taste like shit. Grind up your weed meatcakes.


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## snail240 (Aug 10, 2009)

plantz said:


> throwing whole nugs into bowls/bongs is FAIL shit, never do that, always break it up, when you dont, it burns outside of nugs and never gets the middle, ruins the weed and smoke and makes it taste like shit. Grind up your weed meatcakes.


Nah man put the nug in the bowl then do the little twist. I mean damn you smoking bongs when your in public?

Bust out a break up tray and a grinder bong in the back pocket in public? We where talking about summer time in public chillin not sitting down gettin ripped on the couch with all the survival gear at disposal.

But I do agree when time perments grinding wins.


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## cerebralvibrator (Aug 10, 2009)

HowardWCampbell said:


> I got to thinking about this the other day, and I haven not seen any good info on it. Does anyone know if there has been any sort of a scientific study as to how quickly light breaks down thc? And what effect light intensity has on it? Does blue light break down thc quicker than red light?
> 
> Everyone knows light breaks down thc, but how much light, and what % of thc is lost. For example, nobody I know is going to leave jars of curing bud in the windowsill on a summer day. But in the middle of a big smoke session, not many people are going to put their jar of weed in a dark closet to protect the thc from any lights.
> 
> ...


HC,

If there IS any scientific evidence I too would like to see it! Personally I have almost always hung buds in my growroom to dry, lights and fans running. I've been smoking it for over 30 years and growing it for 13 years and all I know is that I have never noticed any degredation of THC. I too have read it a hundred times over the years but never seen any factual evidence to back it up. In summer I lay larger buds out in the sun to dry........ I recall a trip to Morrocco back in the late seventies, to Tangier and the Riff mountains..... the stems are cut, often 'shaken' for hashish then just left to dry under the hot sun.....believe me it still did its stuff !!!! Its the way they still do it and have done for hundreds of years.


Just my thoughts on the question


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## HowardWCampbell (Aug 10, 2009)

I have done a bit of googling, but didn't find much except this thread over at IC: http://www.icmag.com/ic/showthread.php?t=47174

It's a little bit over my head, but I did find one paragraph that relates to this particular discussion:

The stability of cannabis and its preparations on storage
Fairbairn JW, Liebmann JA, Rowan MG
J Pharm Pharmacol 1976 Jan;28(1):1-7

Abstract:
Solutions of pure cannabinoids, nine samples of herbal and two of resin cannabis (one freshly prepared) were stored in varying conditions for up to 2 years. *Exposure to light (not direct sunlight) was shown to be the greatest single factos in loss of cannabinoids* especially in solutions, which should therefore be protected from light during analytical and phytochemical operations. Previous claims that solutions in ethanol were stable have not been substantiated. The effect of temperature, up to 20 degrees, was insignificant but air oxidation did lead to significant losses. These could be reduced if care was taken to minimize damage to the glands which act as "well filled, well closed containers". Loss of tetrahydrocannabinol after exposure to light does not lead to an increase in cannabinol, but air oxidation in the dark does. It is concluded that carefully prepared herbal or resin cannabis or extracts are reasonably stable for 1 to 2 years if stored in the dark at room temperature.


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## RickWhite (Aug 10, 2009)

cerebralvibrator said:


> HC,
> 
> If there IS any scientific evidence I too would like to see it! Personally I have almost always hung buds in my growroom to dry, lights and fans running. I've been smoking it for over 30 years and growing it for 13 years and all I know is that I have never noticed any degredation of THC. I too have read it a hundred times over the years but never seen any factual evidence to back it up. In summer I lay larger buds out in the sun to dry........ I recall a trip to Morrocco back in the late seventies, to Tangier and the Riff mountains..... the stems are cut, often 'shaken' for hashish then just left to dry under the hot sun.....believe me it still did its stuff !!!! Its the way they still do it and have done for hundreds of years.
> 
> ...


If you are a grower in Morocco harvesting 50,000lbs of outdoor bud that's probably an issue of productivity. You might be able to leave buds in the sun for a day or two with no major break down but that's not to say there isn't some going on.

Light just isn't good for things. That is why wine and beer seldom come in clear bottles. It's never a good idea to leave any organic substance in direct sunlight. Hell, if you live in AZ and don't cover your dash board it will disintegrate in a couple of years.

Intense light and chemicals or organic matter are just a no-no in general.


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## probo24 (Aug 10, 2009)

If you smoke enough, fast enough,
you never need to worry about it.
1-2 years? man i'd never need my
weed to keep that long. I'd never 
have my weed that long.


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## RsdZ... (Jul 9, 2010)

That would be about 8% degraded on a 6 month cure according to the ICmag article. I highly suggest reading thanks Howard.


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## craptree (Nov 11, 2012)

I know this is an old thread, but found a free full text journal entry on the subject. Jist of it is that the half-life of THC in buds at 20C under indirect light is 330days.

A 2 week dry with light in the grow room would only result in a 2% drop in potency.

http://www.tandfonline.com/doi/abs/10.1080/00450610903258144


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