Propylene Glycol - does it make a difference?

[UKSam]

Does anybody know if PG makes any difference in the hair regrowing effect of minoxidil? If it is an inactive ingredient, why do rogaine include it in their liquid?

 

[Aplunk1]

It increases the shelf life of Rogaine-brand minoxidil bottles.

It will do nothing for your hair. Actually, it's an irritant, so it might just inflame your scalp some.

 

[Bryan]

It increases the shelf life of Rogaine-brand minoxidil bottles.

How do you think it increases shelf-life?

It will do nothing for your hair. Actually, it's an irritant, so it might just inflame your scalp some.

You're aware, I assume, that Dr. Proctor attributes some hair-growth potential to propylene glycol? He's claimed many times on alt.baldspot that it's responsible for maybe half the beneficial effect of Rogaine.

 

[CCS]

half the effect? Wow. Glad I put that stuff in my shampoo. I just used it has a penetration enhansor, though I hope it does not enhanse the penetration of the fragrance.

PG is used in Rogaine to dissolve more minoxidil. Rogaine regrowth is dose dependent, and alcohol only dissolves 2.9%. PG dissolves like 7%. So 50-50 gives them they're 5%.

 

[techprof]

PPG growth potential might be offset by its irritation potential.
Rogaine foam does not contain propylene glycol and has been found to be more effective in their clinical study.

Some users report that foam is not as effective as the solution. This might be due to what Bryan says.

 

[CCS]

Rogaine foam does not contain propylene glycol and has been found to be more effective in their clinical study.

that is because the participants actually are able to use it every day. Easy to miss doses if it is a hassel.

 

[UKSam]

Thanks for the replies. So, in conclusion, is it significantly better for regrowth to have a solution with PG?

 

[Bryan]

I should add here that I personally am not so sure about the PG-causes-hair-growth theory, showing that I don't ALWAYS go along with what Dr. Proctor says! :wink: While it's true that many topical minoxidil studies have shown an inexplicable hairgrowth effect from even the placebo solution that was used (thus creating the idea that the PG was responsible), not ALL studies have shown such an effect that could be attributed to PG. A notable example of that was Vera Price's 1999 study, which found a "placebo effect" not only in the group getting the placebo solution containing propylene glycol, but ALSO in the control group that received no topical solution at all!

Also, I believe people mention the use of propylene glycol as a "preservative" or something that "increases shelf life" in topical minoxidil solutions simply because that's what Dr. Lee said once. But as far as I know, PG acts neither as an antioxidant nor as an antimicrobial, so I think that term is being misused. I think the real purpose of the PG is, as CCS said, to dissolve minoxidil to a greater extent than alcohol alone can, and to assist in its penetration through the skin. I believe Dr. Lee misspoke when he called it a "preservative", or whatever.