PGR Weed

PGR Weed: How to Spot If Your Marijuana Is Toxic

The term Plant Growth Regulators (PGRs) sounds harmless, but PGR marijuana should send fear into the hearts of every cannabis consumer. You’ll have heard about the dangers of fungicides, pesticides and heavy metal contamination in your bud, but here is another chemical risk.

An increasing number of cannabis growers and suppliers use plant growth regulators, sometimes even unknowingly. Using PGRs helps to control the growth of plants.

Adding PGR to cannabis creates dense and tight nugs that are very appealing. Hence the price can be inflated, deceiving unwitting consumers. What’s worrying, however, is the adverse effect they can have on the health of consumers.

We’re going to look in detail at PGR weed so you can learn how to spot if your marijuana could be toxic.

PGR weed : The telltale signs

What Are Plant Growth Regulators?

Plant growth regulators are chemical growth compounds applied to food crops and other vegetation to control their growth significantly. Commercial growers in the cannabis industry are increasingly resorting to PGRs due to their ability to produce bushier plants, denser buds or bigger yields. Furthermore, PGRs also increase plant resistance to fungus.

Not only do PGRs contain some organic ingredients, but most also contain additional synthetic ingredients that are unsafe.

Are Plant Growth Regulators Safe?

There have been justified concerns about both the safety and product quality of marijuana that contains plant growth regulators. Users have reported that PGR marijuana products have an inferior flavour.

There are also safety concerns. Some PGRs contain harmful ingredients like daminozide and paclobutrazol, commonly found in many brand-name cannabis fertilizers. Daminozide has been designated as a probable human carcinogen. 

Likewise, paclobutrazol was listed as potentially toxic in studies that linked it with liver damage.

What Are the Most Commonly-Used PGRs?

The three main types of PGRs typically used in cannabis synthetic plant growth are listed below.


Paclobutrazol interferes with the ability of cells to elongate. This stunting results in tightly packed cells leading to increased density and weight in the buds. 

When you smoke buds that feature paclobutrazol, it decomposes into nitrosamines (a carcinogenic compound included in cigarettes). Studies reveal paclobutrazol can negatively impact sperm in males as well as cause liver damage.


This chemical maximizes the bud yield by slowing down the leaf and stem growth. Since 1989, the U.S. Environmental Protection Agency (EPA) banned daminozide on all food applications due to potential health risks.

Chlormequat Chloride

Chlormequat chloride slows down plant growth and encourages the flowering of bushier plants that are shorter and much more suitable for growing indoors. 

Chlormequat chloride is classified as a hazardous substance, and exposure, either by absorption through the skin or inhalation, may lead to skin, nose and throat irritation. Nausea and vomiting are also common. 

Long-term exposure may cause pulmonary edema. There have been some cases of people ingesting significant amounts of chlormequat chloride and it leading to organ damage.

How To Tell If It’s PGR Weed

We know that cannabis is good and PGRs are bad. So how can you verify whether your weed bud has been laced with PGR?

Thankfully, unlike other pesticides that don’t create obvious visual signs, PGR weed will often stand out. There are a few easy markers for cannabis plants grown with PGRs.

Visual traits to watch out for:

  • Rock-hard, dense and heavy bud.
  • Red or orange hairs (pistils).
  • Moist bud.
  • The bud may feel squishy or spongey.
  • Lack of vibrant green, yellow and purple colours. 
  • Close inspection reveals minimal trichome development (crystals).

How Dangerous Is PGR Weed?

From what has been discovered thus far, immediate exposure to a PGR accidentally may trigger respiratory distress, irritation, vomiting, nausea and other acute conditions.

Should you continue smoking PGR weed? As a smoker, here are the health risks involved:

  • Exposure to known carcinogens.
  • Long term lung damage.
  • Damage to your reproductive health (both men and women).
  • Lower antioxidant capacity in the brain.
  • Decrease in amino acid levels in your brain.
  • Harmful effects on prenatal health.

In areas where cannabis remains illegal or where testing is not yet up to speed, many patients find themselves exposed to PGRs, especially on the black market. It’s in your best interest to ensure that the cannabis available doesn’t expose consumers to these toxic compounds. 

A National Resources Defense Council report shows many PGRs as cancerous, unhealthy and unfit for human consumption. These exist due to prohibition, the lack of enforced regulation in a legal jurisdiction and a thriving black market.

If someone tries to sell you cannabis that’s clearly treated with PGRs, it’s better to walk away. Aside from severely diminished medicinal benefits and the dangers mentioned above, there are other side effects. Some people report paranoia, scattered thoughts and headaches after consuming PGR weed.

Frequently Asked Questions

My Buds Are Dense, Does That Mean They Were Grown Using PGRs?

No—if your marijuana has dense buds, this doesn’t necessarily mean they were grown with PGRs. It could simply be a successful yield. If you don’t see any other indicators listed above (orange hairs, spongy texture, low smell, etc.), the buds are probably fine.

How Can I Differentiate PGR Weed From Good Weed?

Watch out for the following telltale signs of PGR cannabis:

  • Harsh chemical taste.
  • Low THC that results in a decreased and poor high.
  • A chemical high that’s fast-acting and may cause lethargy and headaches.
  • When broken up by scissors or a grinder, it emits little to no smell.


Understandably, commercial growers love PGRs for their ability to easily manipulate the plant cells, creating more desirable shapes with bigger yields. Unfortunately, this creates a drastically inferior product. 

Even though the buds turn out visually appealing, they still possess an inferior cannabinoid content and terpene (scent). Yes, the crop is large, which is good for profits, but the quality isn’t anything close to what you’d get in a chemical-free grow.

Another serious concern is the dangerous effects associated with smoking PGR weed. Immediate exposure risks acute health concerns, and long-term inhaled exposure may damage the antioxidant capacity of the brain, reproductive cycle, prenatal health and many more.

These concerns about PGR weed are legitimate, especially among cultivators and consumers. Keep an eye out for dark orange hairball buds with a spongy interior. With so much cannabis available, there is no reason to risk your health on PGR weed.


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OZ Vapour Team
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