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Ipriflavone / Methoxyflavone - Supplement Profile

by Bryan Haycock - First came Ipriflavone, sold as an anabolic isoflavone. It was preceded by hype and mystery, both tantalizing and frustrating to anybody "in the know" and not on drugs. A lot of people bought it, including me. A lot of people stopped buying it a short time after. A short time after they didn't notice any new muscle growth, that is. Then came 5-methyl-7-methoxy-isoflavone, a slightly tweaked version of Ipriflavone. It was also preceded by a lot of hype and mystery. As you might expect, a lot of people bought it (not me). It appears people are still buying it.

I have always been one to do my homework on any new supplement I was interested in trying. Not that I'm more savvy than other people, it's just that I've always had a fairly limited supplement budget and couldn't afford to waste my money. When doing your homework on supplements, you have to ask yourself a couple of questions. First, what is being claimed about a particular supplement? Second, do the claims make sense given the mechanism of action? In trying to answer these two questions you will be lead to the right information to help you make savvy supplement purchases.

So what about Ipriflavone and/or 5-methyl-7-methoxy-isoflavone? What are the claims? What is the mechanism of action?

The claims made by those selling the stuff are as follows:

"the ultimate, "perfect" anabolic agent. You may be saying to yourself, "I've heard this story before." Well, you may have, but this time the story has a different ending ? it's true!"

"It [5-methyl-7-methoxy-isoflavone] was originally designed to increase lean mass on animals and humans, without the negatives associated with steroids."

"?potent anabolic?"

"it's [5-methyl-7-methoxy-isoflavone] not only anabolic, it's healthy!"

"it [5-methyl-7-methoxy-isoflavone] significantly increases calcium, phosphorous, potassium, and nitrogen retention, which clearly shows its anabolic horsepower."

"so powerful it's guaranteed to help you pack on up to 10 pounds of rock-hard mass in just 30 days!"

"it [5-methyl-7-methoxy-isoflavone] works."

"?5-methyl-7-methoxy isoflavone (methoxivone), the strongest Nutrient partitioning isoflavone. Potent for gaining muscle, losing fat, and increasing vitality, well-being and endurance. Also useful in suppor[t]ing strong, healthy bones, and maintaining low cholesterol levels"

I could go on and on, but I'll spare you. The point I'm trying to make is that the people making and selling this stuff are telling us it is the "perfect anabolic." That's a pretty hefty claim!

Our second step in determining the value of ipriflavone/methoxyflavone is to figure out the mechanism of action. The mechanism of action refers to what and how it changes the chemistry of the body. Let's review the relevant research. Keep in mind that ipriflavone and 5-methyl-7-methoxy-isoflavone (methoxyflavone) are assumed to have the same mechanism of action, so I will use Ipriflavone and methoxyflavone interchangeably.

Ipriflavone inhibits bone resorption:

Most people familiar with Ipriflavone know that it has been extensively studied with respect to bone metabolism, or more specifically, osteoporosis. For instance, one representative animal study found ipriflavone inhibited parathyroid hormone-, vitamin D-, PGE2-, and interleukin 1߭stimulated bone resorption (1). The effects of Ipriflavone on bone loss have also been demonstrated in humans. The same protocol was used throughout most of these studies (i.e. 200 mg ipriflavone or placebo three times daily). Several two-year studies looked at women immediately postmenopause (age 50-65) and found bone mass was maintained or improved slightly in the ipriflavone groups while those in the placebo groups experienced significant bone loss (2,3,4,5).

This research on bone metabolism doesn't really back up "the perfect anabolic" claims made by the supplement companies. There still may be hope however, as other research has been done looking at slightly different physiological effects.

Ipriflavone acts as an estrogen "sensitizer" in several tissues:

Before you shriek at the thought of enhancing estrogen's effects, read on to see exactly how this happens. While Ipriflavone does not have any significant direct estrogenic effects, it does enhance the effects of estrogen, particularly in bone, the thyroid gland, and the gastrointestinal tract (6,7). In bone, ipriflavone makes estrogen's bone sparing effect more potent. Ipriflavone, like the soy flavone genistein, has decent affinity for the estrogen receptor-beta (8).

OK, so this still doesn't exactly sound like the "perfect anabolic." Ipriflavone and methoxy do have other effects.

Ipriflavone's effects on Ca2+:

In the heart, ipriflavone has been shown to prevent Ca2+ ions from building up in the mitochondria (9). Ca2+ builds up in mitochondria when there is insufficient oxygen. Ipriflavone actually enables heart muscle tissue to survive longer without oxygen. This means less damage due to hypoxia (lack of oxygen). No studies have been performed looking at skeletal muscle function during ipriflavone supplementation however, it is not unreasonable to assume a similar function in skeletal muscle. More research is needed in this area.

OK, I will let you in on a little secret. All of the claims about the "anabolic" properties of ipriflavone and methoxyflavone are based on the claims made in their respective patents. Here is an excerpt from one of the patents on Ipriflavone United States patent number 3,949,085.

"Test of anabolic effect: The investigation was carried out with castrated rats by means of the musculus levator ani test and vesicula seminalis test. The preparations were administered orally for a period of three weeks. The tests were performed by the method of Eisenberg and Gordan (Eisenberg, E., Gordan, G. S. J.: J. Pharmacol. 99, 38, 1950). In addition to that, also the weight of the prepared diaphragm of the animals was established. According to these tests, the weight of musculus levator ani rose by a Student significance of p 0.01, the weight of vesicula seminalis did not increase while the weight of the prepared diaphragm of the animals increased by a Student significance of p 0.05. On the basis of these results the preparations proved to possess the anabolic activity free from androgen effect."

The patent goes on to relate?

"The weight yield increasing effect induced by doses of 2 g/100 kg of feed was in the various animal species as follows:

8 to 15% in calves

7 to 10% in cattle

7 to 10% in hogs

8 to 20% in poultry

10 to 20% in rabbits

8 to 12% in guinea pigs"

The amount of feed given to these animals did not increase, only their body weights increased. They did test their new compound on ill humans as well:

"The anabolic effect of the composition was tested on thinned (asthenic), reconvalescent, dystrophic patients suffering from pathological thinness. It has been found that as a result of a treatment lasting for some weeks the patients have gained 2-3 kg of weight. According to our experiments the physical condition of the patients has also improved."

In the patent on 5-methyl-7-methoxy-isoflavone (U.S. patent 4,163,746), the details on increasing ipriflavone's effectiveness are outlined. Several compounds are mentioned, namely 5-methyl-7-methoxy-isoflavone; 5-methyl-7-ethoxy-isoflavone; 5-methyl-7-(2-hydroxy-ethoxy)-isoflavone; and 5-methyl-7-isopropoxy-isoflavone. The same guys filed the 5-methyl-7-methoxy-isoflavone patent some 3 years after they filed the ipriflavone patent. Basically, all this patent does is show that when you methylate the isoflavone, you make it nearly twice as anabolic compared to ipriflavone. The claims are the same except that I noticed the claim that the "compounds are useful as anorexigenic agents. A significant advantage of these compounds over known catabolic agents is that they do not exhibit a central stimulating effect." Now this is quite a claim to add to the fact that they profess that it is an anabolic, as well. So not only does it cause a shift towards more muscle, it also decreases appetite at the same time. Thus far, no manufacturers that I have seen make the claim that ipriflavone or 5-mthyl-7-methoxy-isoflavone is a good appetite suppressants. But if they wanted to I guess they could, based on this patent.

One note about patents; just because an individual or company gets a patent, does not mean that their claims are accurate about their invention. It only means that whoever was assigned their file at the US patent and trademark office approved their file for a patent. It would certainly be nice to see someone do a little research on these flavones to see if in fact there are measurable anabolic effects when given to humans at reasonable doses.

Still, I do feel that ipriflavone/methoxyflavone is a valuable supplement to anybody who trains regularly. It "should" help to strengthen bones and tendons and even enhance cellular metabolism. If the patents are true, it may even increase muscle mass and decrease fat mass if used long enough. Keep in mind that we only answered the first question completely. There is still NO good explanation of how ipriflavone or its methylated derivatives could produce non-hormonal, or hormonal for that matter, anabolic effects.



1. Tsutsumi N, Kawashima K, Nagata H, et al. Effects of KCA-098 on bone metabolism: comparison with those of ipriflavone. Jpn J Pharmacol 1994;65:343-349.

2. Adami S, Bufalino L, Cervetti R, et al. Ipriflavone prevents radial bone loss in postmenopausal women with low bone mass over 2 years. Osteoporos Int 1997;7:119-125.

3. Gennari C, Adami S, Agnusdei D, et al. Effect of chronic treatment with ipriflavone in postmenopausal women with low bone mass. Calcif Tissue Int 1997;61:S19-S22.

4. Agnusdei D, Crepaldi G, Isaia G, et al. A double blind, placebo-controlled trial of ipriflavone for prevention of postmenopausal spinal bone loss. Calcif Tissue Int 1997;61:142-147.

5. Valente M, Bufalino L, Castiglione GN, et al. Effects of 1-year treatment with ipriflavone on bone in postmenopausal women with low bone mass. Calcif Tissue Int 1994;54:377-380.

6. Effect of ipriflavone on the response of uterus and thyroid to estrogen. Life Sci 1986 Feb 24;38(8):757-764.

7. Yamazaki I, Kinoshita M. Calcitonin secreting property of ipriflavone in the presence of estrogen. Life Sci 1986;38:1535-1541.

8. Arjmandi BH, Khalil DA, Hollis BW. Ipriflavone, a synthetic phytoestrogen, enhances intestinal calcium transport In vitro. Calcif Tissue Int. 2000 Sep;67(3):225-9.

9. Feuer L, Barath P, Strauss I, Kekes E. Experimental studies on the cardiological effects of ipriflavone on the isolated rabbit heart and in rat and dog. Arzneimittelforschung 1981;31(6):953-8.