Comparison of Lignans

Ground Flax SDG Extract HMR Extract
Products 15, 25*, 30, and 35* mg capsules and 7.6 oz bulk 20 mg SDG peanut butter flavored tablets 10, 20 and 40 mg capsules and 20 mg HMR peanut butter flavored tablet
Does the product contain fiber? Yes, with the 15 mg, 30 mg and bulk containing the most fiber, followed by the 25 mg and then the 35 mg. No No
Lignan metabolites Both metabolites–enterodiol (ED) and enterolactone (EL). The metabolism is a 4-step process, thus providing a longer release time than the HMR lignan, which is metabolised in a single step. Same as for ground flax. Only EL is produced, and this happens in a one-step metabolism, so there is no “time-release” effect. EL is generally the more bioactive of the 2 enterolignans, so lower doses may be possible.
Does the product contain flax oil? The 15 mg, 30 mg, and bulk products contain 11-15% flax oil–the best vegetarian source for Omega-3 fatty acids. The 25 mg and 35 mg products contain a smaller proportion of oil. No No
Anti-oxidant properties Each step of the 4-step metabolism releases antioxidants, thus resulting in a “time-release” effect. EL and ED are both powerful anti-oxidants Same as for ground flax. No “time-release” effect. However, EL is itself a powerful anti-oxidant.

* Our 25 mg and 35 mg products are a blend of partially-defatted flax hulls and SDG extract.


Each person or animal will respond differently to different lignan types. The ground flax products confer two important benefits that the extract-based products do not. Specifically, they contain fiber and omega 3 fatty acids. Both the ground flax and SDG extract-based products have the added advantage of producing a time-release effect both with respect to the release of enterolignans and of anti-oxidants. They also produce both enterolignans, which may be valuable as some may respond better to one or the other. If the animal or dog cannot tolerate fiber and/or omega 3 supplementation is not desirable, then either an SDG or HMR extract product may be indicated. In choosing between the two extracts, key considerations are whether “time-release” effects are desirable and the relative bio-receptivity of the patient’s body to the two enterolignans (vs just the one of them–EL).

One other thing to note is that it was the combination of ED and EL that was studied in that University of Tennessee paper that the lignan and melatonin Cushings treatment is based on. And although not at a statistically significant level, the study showed different responses to each. That said, extensive clinical experience since then has also shown the HMR also to be effective, and both HMR and SDG lignans are currently recommended by UT.