Beaners is bothered…I’ve looked everywhere for an answer to this, but can’t seem to find one! Given that retinoids are so good at building collagen, thickening the dermis and making skin texture better, I’d like to use it on my legs (entire circumference of the thighs) to help improve the texture of thinning, slack, crepey skin. I’m worried, though, about absorption into the bloodstream as I’ve heard that retinoids used in large amounts can cause vit. A toxicity. I realize that Tazorac is a synthetic retinoid, but don’t know whether that means it bears no resemblence whatsoever to Vitamin A, or whether it’s simply a synthetic form of the vitamin? And even if it’s not, then could large-scale application of Tazorac still be dangerous? I’d appreciate a response that is backed up by some sort of research (not just laypeople’s opinions).
The Right Brain responds:
We’re cosmetic scientists, not toxicologists, but we did find two interesting references that might help answer your question.
According to the first reference, a study from PubMed (Journal Med Toxicol. 2009 Jun;5(2):73-5) , a massive acute overdose of Retin-A (aka Tretinoin) doesn’t seem to present much a problem. In an suicide attempt, a 31 year old man ingested 1000 mg of Retin-A which is about 100 times the normal dose. The only apparent negative side effect he experienced was diarrhea. So it looks like the body can tolerate a high, one time dose of Retin-A and there’s no way you’d ever absorb that much through your skin! But what about a lower dose over a prolonged period of time?
The second reference (Medscape) is chockfull of info on retinoids and it states that very little (up to 6%) of the retinoids you apply to your skin end up in your blood stream. This was based on a study showing that “levels of retinoic acid in the blood are not increased by twice-daily application of 0.025% tretinoin to more than 40% of the body surface area over a 1-month period.” That comment is as close to a definitive answer as we could find.
Based on the studies we found, it seems unlikely that rubbing Retin-A all over your body will kill you. Regardless of what these studies say, however, you should still check with your doctor before using retinoids (or ANY drug) in a way that’s inconsistent with its directions. And remember, there is another danger besides toxicity: pregnant women are warned about using retinoids because of their potential teratogenic effect on fetuses.
Beaners is bothered…I’ve looked everywhere for an answer to this, but can’t seem to find one! Given that retinoids are so good at building collagen, thickening the dermis and making skin texture better, I’d like to use it on my legs (entire circumference of the thighs) to help improve the texture of thinning, slack, crepey skin. I’m worried, though, about absorption into the bloodstream as I’ve heard that retinoids used in large amounts can cause vit. A toxicity. I realize that Tazorac is a synthetic retinoid, but don’t know whether that means it bears no resemblence whatsoever to Vitamin A, or whether it’s simply a synthetic form of the vitamin? And even if it’s not, then could large-scale application of Tazorac still be dangerous? I’d appreciate a response that is backed up by some sort of research (not just laypeople’s opinions).
The Right Brain responds:
We’re cosmetic scientists, not toxicologists, but we did find two interesting references that might help answer your question.
According to the first reference, a study from PubMed (Journal Med Toxicol. 2009 Jun;5(2):73-5) , a massive acute overdose of Retin-A (aka Tretinoin) doesn’t seem to present much a problem. In an suicide attempt, a 31 year old man ingested 1000 mg of Retin-A which is about 100 times the normal dose. The only apparent negative side effect he experienced was diarrhea. So it looks like the body can tolerate a high, one time dose of Retin-A and there’s no way you’d ever absorb that much through your skin! But what about a lower dose over a prolonged period of time?
The second reference (Medscape) is chockfull of info on retinoids and it states that very little (up to 6%) of the retinoids you apply to your skin end up in your blood stream. This was based on a study showing that “levels of retinoic acid in the blood are not increased by twice-daily application of 0.025% tretinoin to more than 40% of the body surface area over a 1-month period.” That comment is as close to a definitive answer as we could find.
Based on the studies we found, it seems unlikely that rubbing Retin-A all over your body will kill you. Regardless of what these studies say, however, you should still check with your doctor before using retinoids (or ANY drug) in a way that’s inconsistent with its directions. And remember, there is another danger besides toxicity: pregnant women are warned about using retinoids because of their potential teratogenic effect on fetuses.
Image credit: Things I Love