Marijuana Potency
Through the Years

As you can see below, the prospects of ever more potent types of marijuana have kept the fires stoked over the devil's weed. Obviously, the same claims can be heard today about how super potent weed is even more dangerous than the mild benign weed your parents and grandparents were smoking. To assuage fears about what happens when the THC content hits 100 percent, simply observe that "hippies" figured out how to make synthetic THC back in 1967, hash oil clocked in as strong as 90 percent THC by the mid-70's, and that you can now easily obtain 100 percent pure synthetic THC by prescription. Visit the manufacturer's site: What they have to say about the safety of their THC product and their advice about driving while under the influence of it are particularly interesting -- especially when contrasted with the hysteria over "drugged driving."

By the way, you can get a free sample of 100 percent THC -- Marinol: ask your doctor if it's right for you.

And here is something really fun: apparently, pot plants are documented as having been kicking out some prodigious THC levels at least as far back as the 50's ... (wait for it) ... the eighteen fifties.

"The whole plant collected when in flower, and dried without the removal of the resin, is called Gunjah. The larger leaves and capsules without the stalks form bang, subjee, or sidhee, which is less esteemed than the gunjah. The gunjah, when boiled in alcohol, yields as much as one-fifth of its weight of resinous extract, and hence this method of preparing the drug in a pure state has been recommended as the most efficient and economical."

Source: "The Narcotics we Indulge in -- Part II", Blackwood's Magazine, Nov 1853, pp 617-618

Apparently, the plants back then were yielding as much as 20 percent THC content by weight, meaning that claims about today's pot being stronger than ever are simply ridiculous. See the data on THC content of seized marijuana samples.

How Potent Can It Possibly Get?

Lately, hippie chemists have learned to synthesize THC, which seems to be the active mind changer in marijuana, in a complex 17-step operation. Their formula, says a Government chemist, is "crude but effective." p.21

Source: Time, The Hippies, July 7, 1967, pp.18-22

Dr. James W. Teague, psychiatrist and Vietnam veteran, now with the Neuropsychiatric Institute at UCLA: "I used to think that marijuana was not a dangerous drug. Now I believe that it can be. It would be a good idea if a lot of American psychiatrists were given a chance to see the drug at work in Vietnam. ... The quality of marijuana available in Vietnam is reported by the Army Chemical Laboratory in Japan to be about twice as potent ... as that normally sold or found in the United States." p.32

Source: U.S. News & World Report, Fresh Disclosures on Drugs and GI's, Apr 6, 1970, pp.32-33

One thing that worries some authorities is that most marijuana available in the U.S. today is quite mild compared with strains grown, for example, in Southeast Asia (some Thai marijuana is reportedly three times as strong as high-grade Mexican varieties). Today's normal social high, they may be ready to grant, is fairly harmless, but what may happen if the stronger strains or even pure THC become available? p.27

Source: Newsweek, Marijuana: Is It Time for a Change in Our Laws?, Sep 7, 1970, pp.20-32

It varies widely. One strain is said by a Mississippi scientist to be as much as 70 times as strong as another. p.27

A point made in many of the scientific studies is that most of the marijuana commonly available in the U.S. today is really rather weak -- weaker than some of the earlier stuff. p.27

It does not compare in potency, or effect, with the product used by American GI's in Vietnam, for example. The difference is so great that some GI's returning from Vietnam are reported by scientists to have given up the use of "pot" rather than "play" with the weak American domestic variety. p.27

Source: U.S. News & World Report, Latest Findings on Marijuana, Feb 1, 1971, pp.26-27

For centuries, the viscous, dark-brown liquid was used as a skin ointment in far-out Afghanistan, but now it is the latest thing among the hipper members of the American drug set. It is so powerful that some devoted users have dubbed it "The One," and a single gram is enough to get 50 people very, very high. pp.62-63

"If you want to fly quickly at 30,000 feet," warns one Federal narcotics agent, "just put a few drops of hash oil on a marijuana cigarette and you will go right into the stratosphere." p.63

But hash oil has three big drawbacks: it is illegal, it is expensive ($100 an ounce) and sometimes it is too powerful. "I've had it three times and I won't take it again," reports one marijuana user. "It's not a heavy kind of trip or a grass thing. It's just weird and sort of intense. Who needs to get that stoned?" p.63

Source: Newsweek, 'The One', Sep 11, 1972, pp.62-63

Before 1970, most marihuana consumed in the United States was a very weak domestic variety with an average THC content of about 0.2 percent. As consumption increased after 1970, Mexican marihuana edged out the domestic variety; this imported weed had an average THC concentration of about 1.5 to 1.8 percent. Beginning about 2 years ago, the predominant variety in the eastern United States became Jamaican and Colombian marihuana with an average THC concentration estimated by the Drug Enforcement Administration to be 3 to 4 percent. Even this may not be the end. If Mexican marihuana were harvested with a bit more sophistication, says Coy Waller of the University of Mississippi, its THC content could be increased to 5 percent or more.

Even more alarming to many people is the increase in importation of hashish oil, a more concentrated -- and thus more readily smuggled -- form of cannabis. Hashish oil may contain as much as 90 percent THC, although the average is probably closer to 40 or 50 percent.

Source: Science, An Escalation of Potency, Nov 28, 1975, p.867

All this fuss is over grass that doesn't even produce a very good high. One Kansas State University study shows that imported Columbian [sic] marijuana is ten times more effective than wild American grass. Still, Indiana Ditch sells for as much as $100 a pound. p.13

Source: Newsweek, Picking Off Pot Pickers, Oct 18, 1976, p.13

What's more, the marijuana smoked today is stronger. In 1974, confiscated samples of Mexican marijuana contained 0.2 percent of a substance known as THC -- the substance that gives the user a "high." Today, marijuana from the same Mexican source contains 2 percent THC. p.72

Source: U.S. News & world report, New Light on What Marijuana Does, and How, Nov 26, 1979, p.72

They are also troubled by the stepped-up potency of some present- day pot -- as much as seven times stronger than the "grass" available four years ago -- although the street variety has changed little over the years. p.42

Source: Newsweek, New Look at Marijuana, Jan 7, 1980, pp.42-46

Cultivation today is a mix of science and tender loving care. It involves selective breeding, force-feeding with fertilizers, and commercial boosters, precise irrigation and systematic removal of male plants to yield a more potent kind of pot. Known as sinsemilla, these ungerminated tops of the female plant contain 10 to 12 times as much tetrahydrocannabinols (THC) as the varieties first grown. It is the THC that gives smokers a "high." p.59

Source: U.S. News & World Report, California's Farm Boom -- in Marijuana, May 19, 1980, pp.59-60

Major reasons for growing concern: Some of the marijuana available today is up to 20 times more potent than it was a decade ago, and its frequent use by young children is rapidly increasing.

Source: U.S. News & World Report, Drug Dealers Hustle While Officials Argue, Jul 14, 1980, pp.51-53

Experts report that American marijuana farmers now are growing a strain of pot, cannabis indica, that is far stronger than Colombian or Mexican varieties. Some are specializing in trying to grow sinsemilla, seedless and unfertilized female buds that contain nearly 10 times as much THC -- the intoxicating agent -- as ordinary plants. p.64

Source: U.S. News & World Report, Marijuana: A U.S. Farm Crop That's Booming, Oct 12, 1981, pp.63-64

Sinsemilla is simply the Spanish word for "seedless" -- but in practice, it means a complex growing technique that sharply increases the plant's percentage of delta-9 tetrahydrocannabinol, or THC, the active ingredient that produces the smokers' high. Common sativa averages 1 to 1.5 percent THC; some sinsemillas and hybrids now reach 12 or 13 percent -- a stupefying blast of intoxication that is only for the daring or the dissolute. As a result of such selective breeding, all sides in the great drug debate agree, homegrown American weed is now among the finest and most sought-after marijuanas in the world. p.38

Source: Newsweek, Guns, Grass -- And Money, Oct 25, 1982, pp.36-43

For the marijuana being smoked today is 5 to 10 times more powerful than the pot some people tried 10 or 15 years ago -- the THC, tetrahydrocannabinol, factor has gone up from half a percent to 5 to 6 percent.

-- former DEA Administrator Peter B. Bensinger

Source: Newsweek, An Inadequate War Against Drugs, Jul 28, 1986, p.8

"Cannabis is the drug that teaches our kids what other drugs are all about," says Charlie Stowell, the DEA's cannabis coordinator in California. He says today's marijuana is considerably more potent and expensive than the pot of the '60s because the amount of THC -- the ingredient that provides the high -- has risen from 2% or 3% to 12%.

Source: Time, Choose Your Poison, Jul 26, 1993, pp.56-57

"Parents are often unaware that today's marijuana is different from that of a generation ago, with potency levels 10 to 20 times stronger than the marijuana with which they were familiar."

-- U.S. Drug Czar John P. Walters, The Myth of 'Harmless' Marijuana, Washington Post, May 1, 2002, p.A25

But Marinol turned out to have shortcomings. Because it enters the blood through the stomach, it doesn't work as fast as smoked marijuana. Because it is essentially pure THC, its users can get too high. "Marinol does tend to knock people out" says Abrams, the San Francisco doctor who has conducted trials with both Marinol and pot. "Our patients [taking Marinol] spent a lot of time in bed, and that wasn't the case with those smoking marijuana." p.66

Source: Time, Is Pot Good For You?, Nov 4, 2002, pp.62-66

"First, marijuana potency has more than doubled within the past 10 years. "

-- U.S. Drug Czar John P. Walters, Marijuana Policy Just Right, USA Today, May 18, 2005, p.10A

Actually, it's gone up about 47 percent (comparing 1993 and 2003*):

US (1972 - 2004) UK (1975 - 1981)

* 2004 data is not yet complete, but the increase from 1994
is still only 66 percent, not "more than doubled."

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