Unlisted chemical additives are a worry for many health-conscious consumers - and for cannabis users, one of the more troubling classes of these chemicals is PGRs, or Plant Growth Regulators.

Sold under a variety of names, PGRs are used to make decorative plants grow to a uniform height, and keep foliage under control on golf courses and around power lines. They reduce the need for trimming by suppressing gibberellin, a natural growth hormone that lengthens cells in plant stems.

Even though PGRs aren't tested for human consumption, they're sometimes used by cannabis growers as a shortcut to produce weightier, shorter, more uniform plants with a denser flower, and a lot of orange hairs (but also, according to High Times, a poor flavour profile.)

Dangerous in high doses

All desirable traits from a grower's perspective - if it weren't for the fact that PGRs are dangerous when consumed in high doses, and the effects of long-term, lower-dose consumption are unknown.

The fuss over PGRs recalls other incidents of poor regulation in the cannabis fertilizer industry: according to Americans for Safe Access as late as 2011 hydroponics stores were still briefly selling Alar, or Daminozide (Alar), a known "probable" human carcinogen banned for use in fruit and vegetable cultivation in 1989.

Developing a regulatory body overseeing the fertilizer industry could help stymie the addition of unlisted, toxic ingredients. In the meantime, lab-testing cannabis using a mass spectrometer, also used to test for pesticides, can reveal whether it's been grown with Plant Growth Regulators.

In short: yet another reason to put in extra effort to find out where your cannabis comes from (or grow your own) - and to watch this educational video on PGRs from WeedMaps.

h/t High Times, Safe Access Now