LightLab Dashboard is here. Create your account now!

Testing for Truth Part 9: Caps vs Stems – Where Does the Psilocybin Hide?


One of the common questions asked about psychedelic mushrooms is whether the caps contain significantly more active ingredients than the stems.  Most would guess caps pack more punch than the stems – after all, the top of a cannabis plant certainly packs more punch. We decided to put this Caps vs Stems anecdote to the test, and the results were a bit more complicated than we anticipated.

LightLab 3 Psychedelics Analyzer

We employed a LightLab 3 Psychedelics Analyzer (PSY) to analyze psilocybin and psilocin in dried mushroom material. This device is similar to a standard LightLab 3 Cannabis Analyzer, however, column, reagents and a few other components are modified to work optimally with the water-soluble psilocybin and psilocin.  Much like a LightLab 3 Cannabis Analyzer, LightLab 3 PSY is calibrated directly using certified reference materials. 

LightLab 3 PSY can measure down to 0.05% for psilocin and psilocybin in dried mushroom material.  In addition, the same device can be used to analyze chocolates, gummies, extracts and other infused products. Other analytes measured or calculated include 4-AcO-DMT, total tryptamines and total psilocin.

Mushroom Materials

Two different psiloybe cubensis strains were selected: Golden Emperor and Penis Envy. Both are fairly common varieties with significantly different physical characteristics. The Penis Envy strain has a light, rounded cap and thick stem whereas the Golden Emperor has a light brown cap and thin stem.

Golden Emperor Mushrooms
Golden Emperor Mushrooms
Penis Envy Mushrooms Psychedelic
Penis Envy Mushrooms

The caps of multiple mushrooms were separated from the stem and homogenized in a bladed sample grinder provided with LightLab 3 PSY. 200mg of each powder was weighed and extracted with 30ml of LightLab PSY extraction solvent.  The solvent choice here is important to ensure good extraction of both psilocybin and psilocin without destruction of the analytes or conversion of psilocybin into psilocin due to the commonly discussed “blueing” effect. 

After extraction the samples were injected into LightLab 3 PSY per on-screen instructions.

Homogenized samples of golden emperor and penis envy mushrooms

(Left to right homogenized samples: Golden Emperor stem, Golden Emperor cap, Penis Envy stem, Penis Envy Cap.

To help interpret these results, it’s important to note that “Total Psilocin” here is calculated as follows:

Total Psilocin = Psilocybin x 0.719 + Psilocin

Total Psilocin is an indicator of overall potency, much like “Total THC” for cannabis analysis.  The psilocybin is a precursor molecule that gets converted to psilocin via a dephosphorylation reaction.  It is generally understood that psilocin is the molecule responsible for most of the psychedelic effects in humans.

What we found was that the two strains had exactly opposite results:  The Golden Emperor cap was stronger than the stem, while the Penis Envy cap was weaker than the stem. 

We also noted that the Penis Envy strain had double the potency of the Golden Emperor.  This shows how important it is to understand the potency of mushroom products!  After all, the overall effect would be approximately half if the Golden Emperor was consumed. This is of course important for someone looking for a psychedelic experience but may be even more important for a microdose regimen. Someone consuming a 250 mg capsule of Golden Emperor would receive under 2mg, which is a typical microdose dosage, while the Penis Envy capsule would deliver over 3.5mg.  That may be enough to impair driving and affect the ability to function normally, especially in an inexperienced consumer.



If you look at the pictures of the two mushrooms, you can see significantly different structures.  The Golden Emperor has brown, crusty caps that account for a majority of the weight of the mushroom while the Penis Envy has a small cap that is less distinguishable from the stem.  It’s only conjecture, but it seems as if the Golden Emperor generally places more energy and emphasis on building a cap, hence the higher potency found there, while the Penis Envy places more energy and emphasis on the stem.  It would be interesting to explore how the natural environment these two strains grow best in dictates both their structure and final potency.

Attempting to make a comparison of mushroom potency with cannabis potency is flawed.  Cannabis almost always has higher potency buds near the top of the plant, while at least in this small sample size the potency of mushrooms can vary. 

Possibly more important here though is that the potency variation between the two strains was so high.  This highlights the need in the burgeoning mushroom industry to embrace testing to provide a consistent, high-quality product.