Plants - Drugs Mind - Spirit Freedom - Law Arts - Culture Library  
More than 2 million people use Erowid every month.
Only 250 of those contribute $1 or more.
If you use Erowid, Please Donate.
From: (Boinky Dude)
Newsgroups: alt.drugs.psychedelics
Subject: San Pedro Dosage Discussion
Date: Tue, 04 Jul 1995 07:41:54 -0800

Hello!  A friend and I have been working on this for a few weeks now. Hope
it helps to clarify things!



San Pedro Dosage Discussion

S: San Pedro is *highly* variable.  compared to a 1% (dried) peyote it
has been measured anywhere from 2.4X stronger to 1/10th as strong.  see
the potency FAQ for a discussion:

G:  How strong do you think the San Pedro's YOU'VE run into are?
What's your personal sense of the average?

S:  well, as i said in the potency FAQ, 400g (fresh) of any i've tried
have been an entheogenic "all-day lollipop".

G:  lessee...28g/ox x 16 =448g=1 pound.  This makes our experiences
vastly different.  The most recent time, we weighed out 2-3 pounds
fresh for two of us.  It was slightly over 2 feet of a cactus that once
was huge in diameter, but due to my growing conditions for the past
year, was much narrower on the top end. Ended up being about 4 or 5
16oz glasses each.  Yuck.

And it wasn't that strong.  approx equiv to about 2g shrooms.  I've had
somewhat stronger trips in the past on similar quantities.

S:  i've only tried cuttings from two different growers.  as a cactus
collector i've got far more strains than i'll ever try... i grow 'em
for looks and am trying to get reliable flowering in pots (latest
theory is that they must be at least 3' tall before they will flower.
we'll see.)  in fact, i've never eaten any *i've* grown, although i've
rooted out and planted many cuttings i'd had other plans for.  i kinda
don't want to cut into them to get more statistics.  i'm curious as to
whether the kind of care i give them makes them stronger or weaker,
but... they're my babies!

G:  I've only eaten ones I've grown.  Usually I find them at really
mainstream home/garden/hardware stores (grin).  So, I have several very
different specimens.  And about 40 sprouts which will be ready in a few
years(thanks otj!).

S:  that's pretty responsible, actually.  i figure that those are from
growers who aren't going to cut deeply into their mother-stock.  no
chance of eating the only surviving example from the collection of a
retired bolivian botanist who, etc., etc., &c.

G:  It just amazes me that I can find them in such mainstream, public
places.  I've seen them mostly unlabeled.  A couple times labeled "San
Pedro" and a couple times recently as "cleistocactus".  The
"cleistocactus"' were all much fatter and bigger than my other San
Pedros.  They were also much lighter green.  I haven't had them long
enough to see if the new growth will be dark green like my other ones.
It's just a little weird seeing these pretty different sorts of cacti
labeled cleistocactus, and looking pretty different than my other
SP's.  But I did some research on cleistocactus, and couldn't find any
descriptions that sounded like San Pedro, so they've just got to be a
variety of T. pachanoi.  Have you ever seen a fat, too light colored
San Pedro labeled cleistocactus?

S:  i haven't come across any.  a quick look thru backeberg turns up
some light-green, small-spined, columnar cleistocacti, so i'd be really
wary of yours... they might *really be* cleistocacti.  still, i've seen
some very pale San Pedro... difference in culture is one thing that
comes to mind.  but i'd be cautious... some of the tricho's were only
placed in that genus when someone got them to bloom... at night!  if
they'd bloomed during the day they'd be helianthocereus...  as long as
they had a "hairy perianth", too.  it *is* easy to mistake non-trichos
for trichos.

to return to the question "how strong were my cuttings", if i'd ever
had a professionally calibrated dose of mescaline i might try the
exercise of guessing how strong they were, but i haven't and won't.  12
oz (340 g) was a fair "museum dose", and well over threshold.  markedly

G:  I've never had a "professionally calibrated dose of mescaline"
either.  I'd agree that 12oz would be ok in public.

S:  at 16 oz (450 g) i wouldn't want to try to keep it together in
public...  episodes of "mind-melting", as i believe you said, began to
occur during the peak.  i'm not ready to try 24 oz.

G:  I've not had experiences on San Pedro that (yet) qualify as
"mind-melting".  I've taken over 16oz fresh before and still not been
there...(but tripped pretty hard).

S:  if you want to guess that my descriptions sound like 340 mg and 450
mg experiences, then you could guess that these stocks were 0.1 percent
fresh or ~ 1.5 percent dried... but that *would* be stronger than some
peyote.  still well within the range of published potencies, though.

G:  My experiences all have been less strong than an equivalent weight
of peyote should have been (total conjecture based on lots of

S:  i've heard a couple of reports on alt.drugs from people who boiled
a pound or so and had no effect.  that makes sense; the *weakest* SP's
reported in the scientific literature would require you to eat 5 or 6
lbs to get a minimum dose.  so the weak ones *are* out there for sale,

my guess is that most cuttings for sale fall around the mid-point, but
there is still considerable variability.

G:  Yep.  I've always gotten an effect from a pound or so, but on a
couple occasions it was disappointing.

S:  these days i am using a centrifugal juicer (sanyo), so there is no
chance of thermal degradation.  also, there are no solids to buffer
absorbtion.  but i think that the base stock is probably the difference
between our experiences.

G:  a couple juicer questions:

1) what weight do you usually juice up?

2) do you attempt to extract any mescaline from the squeezed pulp?

3)What results does your chosen dosage/weight get you?

S:  usually only a pound at a time.  the screen on mine needs to be
scraped clean of cuticle fragments about that often.  and i only juice
up as much as i am going to use near-term.

i'll usually toss a mild sol'n of citric acid dissolved in 6-8 oz water
into the marc in a blender jar & puree it.  then i spoon that slush
back into the juicer for a final extraction.  i've eaten the remaining
pulp (and once a methanol extraction of the final marc from ~ 1 kg) with
little-or-no effect & estimate that approx 98% of the available juice
has been rinsed out of the pulp by my process.

G:  I know that some just boil it all day, and then concentrate it to a
cup or two.  My opinion on that is that it degrades the quality of the
trip, hence my further experiments with the fresh juice.

S:  well, as a cook i object to treating any food-stuff in such a
beastly way, and as a *californian* cook i incline towards treatments
(esp. raw) that highlight the unique character of the food... hence
*my* juice experiments.  even tho a friend of mine is a well-known
"boiler".  :-)

i will digress to say that variability of dosage is a general issue
with all natural products, not just SP; that's why i worked thru the
exercise for the peyote question.  i'm not lecturing at *you*, gordon,
this is something of a Frequently Asked Question on this alt.drugs.
this pertains to 'shrooms, brugmansia, etc.:

G:  But variability in dosage seems particularily wide in San Pedro.
Much more so than in say Psilocybe cubensis.  2g of P. cubensis will
usually affect you in a predictable way. 2# San Pedro is much more

S:  yes, i think so.  i've seen papers in, err... psychedelic review?
t. lyttle, ed.?  that said that psilocybin production was greatly
influenced by available N in substrate.  and claims are made about, say
amazonian P. cubensis being 3X or 5X floridan, etc.  and i raised some
completely inactive ps. cyanescens on ground corn-cob and alfalfa
pellets.  but still, the SP variance is strikingly large.

with an unknown stock it is prudent to "nibble up".  what's the worst
that could happen?  well, you might take more than the maximum safe
dose.  WRT mescaline, we have ott's figure of 1000 mg.  ok, let's not
do that.  so let's ask ourselves how much of the *strongest possible*
SP it would take to get 1000 mg of mescaline, and let's not take more
than that much of any untried SP.  threshold dose is 150 mg, so you know
you need to take *at least* that much to have any effect at all with an
unknown SP.  or peyote.

G:  So, unless you are using cuttings or growing from seed (so you
would always know what strain you were taking), one runs the
possibility of never having a strong enough trip because of the
possibility of overdose.  If you don't know your strain and take
cautious doses, then it might take a _really_ long time before you have
fully satisfactory trips.  Obviously this has been my experience.  I've
had two trips that were quite strong, but I still would have liked to
go further.  Both were on about 1-1.5feet of 3" dia. cactus.

S:  yes, i think so.  i would *really* like some means of quant. assay
using only a small sample.  spectrophotometry only takes a couple of
grams, but i don't have a spectrophotometer!  and growing from seeds
would only be stable given self-fertile seed.  any crosses, hybrids,
etc. might be variable.

even with cuttings, there is some thought that cuttings taken in
spring, grown in shade, various magic :-P cause variance in potency.  i
think that a large stock plant grown under constant conditions is the
best bet.  that's pretty much what i've had... i found a guy who was
thinning out a pachanoi *thicket* in his back yard to make room for a
greenhouse and got a *large* amount of material grown in constant
conditions.  :-)  mostly rooted out, now.

WRT the strongest SP on record, you would not want to take more than
about 1 1/2 lbs.  but this means that you can confidently take 1 1/2
lbs of *any* known SP w/o overdose.  and you need to take a minimum of
~ 4oz of this SP to have any effect, so don't waste your time with any
less than this of *any* SP.

then you need to define what "oops" means:  "oops, sweet jeezus i'm
'one toke over the line' at thanksgiving dinner with grandma", or
"oops, this is a boring party and i'm baseline."  then you decide what
your first cut is going to be.  it's not as if the FDA or USDA is
guaranteeing quality for you, and you're just trying to make up your
mind what dosage is appropriate in your set and setting.  based on that
initial experience(s), adjust dose for next time.

G:  Except that you can't adjust your dose for next time if next time
involves an unknown San Pedro.  I have no way of knowing if the SP I
just brought home is strong or weak.  And with the rate of growth and
re-sprouting it could take years to accurately determine

S:  yup.  that's what i think, too.

of course, if you buy 8-10 4'-6' cuttings all at once, you'll have a
chance to calibrate *that batch*... barring changes of potency as they
sit in your garage, absorb fluorescent light, metabolize M to grow
roots, transpire away water & become more concentrated, etc., etc.

G:  So what's your preferred dosage, fresh or dried?

S:  340-450 g (fresh) of the ones i've tried.  when i dried samples,
they were ~94% water (YMMV).  so... arghh, i'm on decaf today, can't
easily do this in my head...  22-30g, dried?

G:  I've read internet reports that 25g dried didn't do much at all.

.... Based on Ott's Pharmacotheon, I think an appropriate dose would
be 100g dried, which is approximately 2 feet.

S:  beware of footage; i've got a mature SP stem, grown unirrigated in
the shade, that is barely over 1" dia.  my prize specimens are ~ 4"
dia.  as the bakers say, "half pies are square", so 2 feet of the
latter would be ~16 times as heavy as the former, *per foot*.  beware,

G:  I know, hence my conversation with you about _weight_.  I too have
some skinny ones.  All the more reason to dry and weigh rather than use
the common "foot" terminology.

S:  or weigh it while fresh.  but we are agreed that weight, not length
is the metric.  also, i have enormous respect for ott, but there are
some inaccuracies WRT SP in the pharmacotheon.

G:  What inaccuracies did you find?  And if SP is this variable, how
does he feel about publishing mescaline content that is sure to be
inaccurate for some people?

S:  Pharmacotheon fails WRT SP in these regards:  no recognition of the
variability, inaccurate description of the cuticle and sub-cuticle
layer (he seemed to think that the cuticle was where the M is, but 15
seconds with a cutting and a steak knife would change his opinion, i
think).  and he repeats the peruvianus UL.  he gives
pachanoi/peruvianus comparisons in terms of length, but mature
peruvianus is easily 8", 2-3X as thick as pachanoi, etc.  silly little
stuff like that.

i don't think he realizes how variable it is.  i heard him speak, he is
something of an unabashed indole-ring bigot, probably figures others
have got the phenethylamines covered & feels no need to double-check
their figures.  he propagated fungus cultivation techniques and
ayahuasca analogues, really signal work for a single individual... i'll
cut him a little slack!

i think your 100g dried would come to ~1.5 kg fresh.  if you got the
strongest SP measured that's about a 2X overdose.  better pray you got
sold the weak stuff!  =:-O  *odds are* you'll be ok, but no

G:  Well, this conversation is fortuitious.   Later this month I have
scheduled (I'm a busy guy, I have to schedule my trips) a SP trip.  Was
going to use 95g dried and powdered.  Now you've made me wonder.  These
SP's were mail ordered from Texas, so strain is totally unknown.

My choices look like:

1) assume caution to be the best course (I had an extremely unpleasant
experience a few years ago that taught me about caution), and take 50g

2) go with my personal experience based on about 6-7 SP trips and munch
the whole thing.

What would YOU do?  option 1 will probably produce a mild but enjoyable
and not satisfactory trip.  Option 1 guarantees no overdose.

option 2 seems more likely to produce a proper strength trip, but the
possibility of overdose, while extremely unlikely in my experience, is
still there.


S:  ask a power-animal?  1/2 :-)  and then cross-check as follows:

(rounding your 95g to 100g 'coz i'm still drinking decaf):  if we chow
the whole thing we are saying, in effect "gawd, hope this's < 1
percent" (0.01 * 100g == 1000 mg).  if it's 1 percent, then 150 mg M
dose is 15 g of powder.  (i forget the mg/kg ratios, but ott says 150
mg is threshold, AFAIR... don't know if you're a big guy or little guy,
but will use 150 mg).  so i'd take 15 g the first day, if i didn't get
buzzed at all i'd take 85 g the next day, reasoning that it is less
than 1 percent and i can take the whole thing w/o OD, yet still 85
percent of the "whole experience".

if i got buzzed on 15 g i'd have to guess... :-)

another approach:

if "max safe" is ~7X "threshold" you can safely follow any
"ineffective" dose with 7X increase.  so take 95g/8 == 11.87 g to see
if (7/8)*95g == 83.12 g is reasonable.

you could take the small dose & large dose on successive days.  if the
small dose does not buzz you, then tachyphylaxis (sp?) won't keep you
from a strong trip the next day.  of course, if it *does* buzz you, you
don't want to try to trip hard the next day anyway.  in that case wait
a day and take "somewhat" less than the whole "large dose".

G:  I only do this a couple times a year, so it's very important to me
to get all this figured out. It's a drag to be fully prepared for it
and not have it happen properly.  And with the next trip months away.
Yet, that's still better than an overdose.

I have just got to grow a bunch of the same kind for the next 20 years
so I can have the luxury of being able to accurately calibrate doses.

S:  yep, that sounds like a what a "long term alliance" would involve.
if you find a more-palatable alternative to "chunky-snot tea" please
email me the recipe!

G:  I haven't yet, that's why I'm trying dried, powdered, capsuled this
time.  I just don't want to drink any more of that stuff!  Also, my
stomach capacity seems to be part of the limiting trip strength

To summarize: Guestimating dosage of San Pedro is extremely hard to do
because the mescaline content can vary widely.  Ideally, one would have
a bunch of a particular strain/batch and after several trips, be able
to more accurately estimate dosage(based on fresh or dried weight).

If one has an San Pedro of unknown potency, one should start with small
amounts and work up.

Unfortunately, if you only do this once or twice a year, this process
could take forever!

S:  not really forever.  you want to nibble up across a 24:1 possible
range.  if you stride (increase dosages) 1:7 you can do this, i.e. zero
in on any particular dosage in 1 1/2 strides (2 1/2 sessions). ;-)

let's be conservative and span the *minimum* dose of the *strongest*
and the *maximum* dose of the *weakest*:  4 oz => 1 3/4 lbs => (*urp*)
11 lbs are the first two strides.  then, since (*hurl!*) 37 lbs is the
*maximum* safe dose of the *weakest* on record, you only have 1/2
stride still to go... 8-P (*buick!*)  quit when you've had enough!

so, if your unknown SP turned out to be the weakest SP known to science
you could work up to a *maximum* dose in *at most* four sessions on
successive days, w/o ever overdosing or ruining a trip by tachyphylaxis
caused by the previous day's dose!  aren't you *happy*, gordon?  you've
calibrated this *a lot* faster than "forever"!!! :-) :-) ;-) just set
aside four days for your trip and you can nibble-up to a guaranteed
total mind-melter without risking an OD!

just be sure you buy no less than 50 lbs of uniform SP at a time.  ;-)

personally, i'll bet you trip your ass off on either day 2 or 3. :-)

let's be agressive dare-devils instead:  if i were going to *seek* the
mind-melter, i'd start with 1 3/4 lbs (maximum safe dose if i lucked
out and got the strongest).  if i got any kind of a trip at all, i'd
rest on day 2 to defeat tachyphylaxis and make my judgement call as to
whether and how-much i'd do on day 3.  *at most* this would be 24X, so
this strategy takes only 40 lbs!  guaranteed mind-melter in only 2
sessions with only the risk brought about by that pesky judgement
call.  don't do this at grandma's, tho!  (well, maybe at *your*

G:  One pound (fresh) seems to be a good starting point for most San
Pedros, but more than a pound is ultimately desirable after beginning
estimates on mescaline content have been established.

S: for most *likely* San Pedros, and *absolutely* needed for "maximum
safe dose" of any SP known to science.  i think that about 1/2 MSD is a
pretty strong trip from all published reports, so i *personally*
wouldn't take more than 3/4-1 lb. of any unknown SP.

G:  So basically, we're all doomed to milder trips, unless we take the
risk of ingesting a large amount of a potentially quite potent San

But I've never heard of anyone "overdosing" on San Pedro.  Nontheless,
there are San Pedro's on record that do have much higher mescaline
contents than most.