I am the chemist and laboratory director of Steep Hill Lab, the nation's leading laboratory for cannabis analysis. We do not produce or sell anything except for knowledge. We test submitted samples for cannabinoid and terpene potency, pesticides, trace residues, and fungal contamination. I was educated in biomedical engineering at a top tier school and over the past 6 years have read almost every scientific paper on the subject that I could get my hands on, from phenotypic expression in plants to endogenous cannabinoids and receptors. There is a great deal of confusion and misinformation surrounding cannabis outside of the laboratory, and I aim to correct that by answering your questions right here. Visit our website www.steephilllab.com for proof.

All answers will be supplemented with scientific and literary references. So go ahead, Ask Me Anything!!!

UPDATE: This thing got way more upvotes than I could have imagined. You all rock! Especially those who are correcting my oversights and keeping it true to science. I will continue to answer your questions over the next few days. In the mean time please share your knowledge with the world. I LOVE INTERNETS

UPDATE: The website wasn't proof enough, so I sent reddit my business card this morning. Hopefully this post goes back online and we can keep this dialog going. To clarify, I have not been published as of yet. And I am not presenting any of my own research here. The purpose of this post is to dip into the huge trove of research that has been done in the past 10 years on cannabis and bring it to light, so that the public can make its own educated decision on the subject.

Check out this paper. It's all-inclusive and a good general introduction to cannabis facts ranging from plant compositions to biological effects of cannabinoids and terpenes:


UPDATE: I got many questions regarding the use of cannabis to treat cancer. Here is a brief piece I just wrote summarizing some of what's out there:


Comments: 1924 • Responses: 27  • Date: 

UpsideButNotDown320 karma

If you had a teenage son or daughter would you be okay with them smoking weed? (and why or why not..)

hoovervillain739 karma

Not until they were 18

Bevman00287 karma

Caffeine, mango, chocolate, tobacco, banana, have all been anecdotally known to 'prolong' the effects of marijuana. Is this true?

hoovervillain408 karma

Yes, each for a different reason. Mango, for example, is high in myrcene, a terpene found also in cannabis. Myrcene has been found anecdotally to prolonog the high of cannabis. The current theory holds that terpenes affect the binding of THC to the different CB receptors found throughout the body, thus changing the high as well as the physiological effects. Terpenes have also been found to enhance the crossing of cannabinoids and other drugs through various tissue barriers, thus increasing absorption. Here is an article on various terpenes in cannabis :[Cannabis and Cannabis Extracts; DOI:10.1300/J175v01n03_08 ; John M. McPartland & Ethan B. Russo pages 103-132]

hoovervillain192 karma

Chocolate and coffee contain xanthenes (caffeine, theobromine, etc.) which dilate some blood vessels and contract others, causing more blood to rush to certain parts of the brain and body and less blood to flow to others.

Bevman0063 karma

so is that bad? Would consuming these things (mango, chocolate, coffee) make marijuana more unhealthy?

hoovervillain167 karma

Not at all. Unless you are prone to high blood pressure, heart rate, or stroke in which case the xanthenes + cannabis can cause some unpleasant synergystic effects.

tdames268 karma

In your honest professional oppinion, should marijuana be legalized? Should it be on par with alcohol?

hoovervillain619 karma

Yes. It is safer, both in the short and long term, than either alcohol or tobacco, with little-to-no long term functional impairment.

"Long-term effects of frequent cannabis use on working memory and attention: an fMRI study" Gerry Jager, Rene S. Kahn, Wim Van Den Brink, Jan M. Van Ree and Nick F. Ramsey

drakoran203 karma

THC is the active ingredient in marijuana that causes a high. What causes different strains IE Indica vs Sativa to produce different sensations and types of high. Also how does the method of use, ingested vs smoked change the feeling of the high?

hoovervillain256 karma

Different strains have different levels of THC but also CBD, CBN, THCV, and other cannabinoids. Some of these cannabinoids have psychotropic ("high") effects, and some don't. Some enhance the effects of THC and some mitigate it. The terpenes and terpenoids found in cannabis have been shown to have similar effects, though they haven't been studied to the same extent. Each strain group has it's own "profile", it's own combination of cannabinoids and terpenoids that produce a unique type of high.

_kvl_147 karma

What would you say the biggest misconception there is out there regarding potency of marijuana or just marijuana in general?

hoovervillain360 karma

The biggest misconception is that it is in some way poisonous to people or that you can get some kind of brain damage from a potency that is too high. It is completely safe at any dose ... unless you inject concentrated THC directly into your brain.

AClassyGentleman126 karma

  1. What do you see for the future of science regarding cannabis?

  2. What do you enjoy the most about your job?

hoovervillain235 karma

  1. I see FDA rescheduling to Schedule II or III sometime in the future because they can't ignore science forever. This will mean very tight regulations everywhere, even california.

  2. I like science that is used ultimately to heal, not prolong illness. Also, this is a frontier area that hasn't been explored much until very recently

Samarang115 karma

Most marijuana usage is focused around the brian, as a cardiovascular researcher I lean more towards the heart. What is your position on the evidence, albeit small, on cannabis causing cardiac dysrythmias? From my understanding it can cause atrial flutters and premature ventricle contractions. While these are easily enough reversed when the drugs effects where off, what do you feel would happen to a regular or heavy user? Would there be any cardiac remodeling from consistent pressure and would you recommend that anyone prone to some cardiovascular diseases not use cannabis?

hoovervillain136 karma

From what I've read, cannabis can cause dysrythmias and even coronary ischaemia but it always seems to happen in patients with existing cardiovascular disease of some kind. So yes, I would caution those with known conditions to be careful, consult a real doctor, and start at a very low dose. But I don't see long term cannabis use actually causing a blockage or other condition, based on current evidence. No long-term studies have dealt with cardiac remodeling but if anybody out there happens to run clinical laboratory it is definitely something to look into.

sma92176us111 karma

How often do you receive MJ that has adulterants? What are they typically? Do you get many with mold?

hoovervillain143 karma

We haven't seen many with the specific pesticides that we test for, but we are constantly improving our sensitivity and cross-checking with other labs. We do get many samples that have mold. Most commonly it is penicilium which is harmless. Occasionally we get aspergillus which can be toxic, but most often to those with compromised immune systems (patients with AIDS, cancer, advanced age)

finnmau5109 karma

What is the highest percentage of THC and CBD you've seen in a single strain?

hoovervillain179 karma

Highest THC: 22% - LA OG Highest CBD: 12% - Cannatonic

I've only been at it for a year with this lab though.

pmains94 karma

Just posted this to /r/trees :) Thanks for doing this!

What do you feel is the biggest risk for daily users?

What are some resources that can help educate the public on the subject?

Are there any intern type opportunities in your lab? I'm studying bioengineering currently in the Bay Area!


hoovervillain166 karma

The biggest risks are those that come with smoking anything. Burning plant material produces ammonia, polycyclic aromatic hydrocarbons (carcinogenic), and air that is at a temperature too high for lung tissue to deal with, among other things. Unfortunately, there aren't too many resources on the subject that the general public would benefit from. That's why I'm starting this.

pmains129 karma

Awesome - exactly what I thought! Vaporization rather than combustion takes care of many of these problems though, right?

hoovervillain195 karma

Absolutely right

spicywasabi91 karma

What are the studied side-effects of smoking? Long-term?

Is it true that one can be at risk during developmental years, and become unaffected of the side-effects after teenage years?

hoovervillain184 karma

Smoking cannabis is risky for those whose brains have not fully developed. There is an increased risk of later psychosis[see: Cannabis use in adolescence and risk for adult psychosis: longitudinal prospective study (BMJ 2002; 325 doi: 10.1136/bmj.325.7374.1212 (Published 23 November 2002))] There was also a recent study that found adolescent smokers were an average of 8 IQ points below those who did not smoke when tested later in life. However, studies have failed to show long term deficits in those who started after age 18, when the brain is fully developed.

RMaximus87 karma

Are the carcinogens in weed any better than those in tobacco?

hoovervillain270 karma

Weed has less carcinogens than tobacco when smoked, in particular polyaromatic hydrocarbons. In addition, cannabinoids prevents tumor formation/proliferation, which is why no study has been able to link lung cancer to long term smoking of cannabis.

mike808hawaii82 karma

Did you smoke weed before your top tier education and 6 years of research?

hoovervillain227 karma

I didn't try cannabis until I was 18 and accepted to college. I didn't smoke regularly until I was 21 and needed to mitigate some of the engineering-induced anxiety that was keeping me from getting my work done.

whiteonyx74 karma

Marijuana as a medicine for migraines? Your take?

hoovervillain136 karma

It works for some. I find that people that are prone to motion sickness tend to get the same symptoms from cannabis. BUT strains that have a high content of limonene (lemon-orange smell) tend to aid in reducing migranes (as does smelling pure limonene which is found in orange oil)

ctoatb51 karma

Are there any strains that I would be able to legally grow as a garden feature? (No specific location)

hoovervillain107 karma

No. Unfortunately all Cannabis is illegal in the US, including the non-psychoactive hemp varieties. They are great plants though, and provide natural pest-deterrents and soil remediation.

Vaypo50 karma

Does smoking a lot of weed cause bad breath?

hoovervillain346 karma

Smoking anything can cause bad breath as it interferes with the natural bacteria which live on the tongue.

hoovervillain339 karma

Smoking anything can cause bad breath as it interferes with the natural bacteria which live on the tongue.

Cannaseur40 karma

Many believe that mangoes contain enough Myrcene to make a noticeable difference in the high. Is there any truth to this, or is it merely a placebo?

hoovervillain58 karma

See above post

swayXchamp36 karma

How does one go about testing thc potency I am majoring in structural engineering and trying to get into minoring in a chemistry degree, would that minor degree help me to achieve knowledge and practice for testing?

hoovervillain62 karma

Yes, but mostly you just need experience in chromatography. That is what we use to determine potency. We do liquid and gas chromatography with mass spec, and also created an NIR equivalent.

mike808hawaii36 karma

Is there a Scoville scale-equivalent for potency levels?

hoovervillain68 karma

Currently we report the concentration of cannabinoids (THC, CBD, CBN, etc.) by weight as potency. No Scoville-esque scale exists for cannabis.... yet....

ibrokethedishes32 karma

Is this technically a Quality Control job? Like, do you get inspected by the FDA and do you have to follow GMP/GDP?

hoovervillain58 karma

We are currently working on ISO 17025 compliance

aManHasSaid28 karma

Are you the guy who posted about the hallucinogen that's only found in mass produced pot? (Ie, closet grows don't have any.) Do you know anything about this?

hoovervillain46 karma

No but if you find something please post it here I'd love to look into it

dbarkcasa27 karma

Do you see large variations in the same genetics based on other variables?

hoovervillain48 karma

We don't do any genetic testing at this time but always have it in mind for future endeavors.

hoovervillain23 karma

Here is a piece I just finished for my facebook page WhatAreYouSmoking that summarizes the current body of research concerning cannabis as a cancer treatment. Any scientists out there with something to add/correct please do so. ---Hoovervillain

Cancer, as you may know, is the unregulated growth of cells in biological tissues. The process involves an interruption to the homeostasis (natural balance) of the cell: DNA becomes damaged, or misread/mistranslated by faulty proteins, or the extracellular matrix (structural and chemical environment in which the cells exist) becomes irregular and facilitates the growth of irregular cells. In any case, the natural biochemical switches that determine when a cell should grow and multiply can then become essentially broken, stuck in an “on” or “off” position. The irregular cell multiplies indefinitely, forming a tumor that deprives nearby healthy cells of space and nutrients.

One of these switches is the MAPK pathway which sends a signal from receptors to DNA and is a controlling switch for many different genes to activate or deactivate. Another is TNFa, a prime defense against DNA-damaging viruses that induces fever, inflammation, and reduces overall cell function until the affected cell is isolated and destroyed. If any of these becomes stuck in the “on” position then the cell can become cancerous and multiply out of control. For a large mass of cancerous cells to eventually form (i.e. tumor), the protein MMP must be produced and released to break down the current extracellular matrix of collegen and other fibers so that it can be reformed into a new shape and grow new blood vessels to feed the tumor.

Mammals have natural regulators that keep cells in balance. Included in these are the endocannabinoids, a recently discovered network of biochemicals that regulate immune function, memory, cognition, and digestion just to name a few. These biochemicals can act through receptors: CB1 is found throughout the brain, central nervous tissue, reproductive tissue and digestive system; CB2 is found primarily on cells of the immune system; GPR55 is found in the brain and bone tissue.

Some cannabinoids (THC, THCV, CBN) and larger terpenes (beta caryophyllene) found in the cannabis plant will bind to these receptors and alter cell function accordingly. Activation of the CB2 receptor has been shown to inhibit both TNFa formation and induction of the MAPK pathway; inflammation will then recede. This effectively halts further growth of the tumor and begins the process of apoptosis (“cell suicide”) that will eventually cause the mass to die and once again free resources for normal, healthy cells. This has shown very effective in cancerous cells of the lungs, colon, and liver.

Some cannabinoids (CBD, CBG) do not bind directly to the receptors above but still exhibit similar changes in cell function. CBD can inhibit the MAPK pathway, halt inflammation, and cause apoptosis in cancerous cells of the blood (leukemia), breast tissue, and skin. CBD also increases the production of TiMPS in the cell; these proteins inhibit the MMPs and thus prevent the tumor from breaking down the extracellular matrix to form new blood vessels. Without new blood vessels to deliver nutrients, the tumor ceases to grow and eventually dies.

Monoterpenes found in cannabis have also proven to be very effective chemotherapeutic agents. D-limonene inhibits some processes required for cell growth and therefore prevents the multiplication of cancerous cells with almost no toxicity to normal cells. It is also useful in combination with other chemotherapy drugs. When combined with docetaxel it dramatically decreases the effective dose needed to destroy cancerous cells of the prostate, thus sparing the patient some of the illness and discomfort associated with chemotherapy.

The particular research described above, while promising, is not relevant for all tissues of the body. A cannabinoid can activate a receptor on one type of cell and deactivate that same receptor on another type of cell. What works for breast tissue might not be what works for lung tissue, and no one treatment can work for all. One study even showed that while higher concentrations of THC induce tumor death, very low concentrations will actually cause cancer cells to multiply faster by aiding in cell-signalling. That being said, there is over 2000 years of recorded empirical evidence that points to cannabis being a safe and effective medicine and nothing as of yet to indicate it has ever worsened a cancerous condition in any animal or person.


Jürg Gertsch et al; Anti-inflammatory cannabinoids in diet : Towards a better understanding of CB2 receptor action? ; Communicative & Integrative Biology 1:1, 26-28

Pamela L. Crowell; Selective Inhibition of Isoprenylation of 21-26-kDa Proteins by the Anticarcinogen d-Limonene and Metabolites; THE JOURNAL OF BIOLOGICAL CHEMISTRY Vol. 266, No. 26, Issue of September 15, pp. 17679-17685,1991

Anupam Bishayee* ; d-Limonene sensitizes docetaxel-induced cytotoxicity in human prostate cancer cells: Generation of reactive oxygen species and induction of apoptosis ; Published: 21 May, 2009 ; Journal of Carcinogenesis 2009, 8:9 ; DOI: 10.4103/1477-3163.51368

Alexander Greenhough; The cannabinoid δ9-tetrahydrocannabinol inhibits RAS-MAPK and PI3K-AKT survival signalling and induces BAD-mediated apoptosis in colorectal cancer cells; International Journal of Cancer; Volume 121, Issue 10, pages 2172–2180, 15 November 2007

Sean D. McAllister; Cannabidiol as a novel inhibitor of Id-1 gene expression in aggressive breast cancer cells; Mol Cancer Ther 2007;6(11). November 2007

Ramer R, Merkord J, Rohde H, Hinz B, Cannabidiol Inhibits Cancer Cell Invasion Via Upregulation Of Tissue Inhibitor Of Matrix Metalloproteinases-1, Biochemical Pharmacology (2008), doi:10.1016/j.bcp.2009.11.007

Ashutosh Shrivastava, Cannabidiol Induces Programmed Cell Death in Breast Cancer Cells by Coordinating the Cross-talk between Apoptosis and Autophagy; Mol Cancer Ther July 2011 10; 1161