St. John's wort is claimed to offer anti-oxidant, anti-microbial, astringent, emollient, wound and burn healing, and skin protecting qualities. Does it do all these amazing things?
St. John's wort contains condensed tannins or catechin tannins (about 6.5% to 15%), which means it will feel very astringent on your skin, about on par with green tea extract. They offer anti-oxidizing, anti-microbial, and anti-fungal properties to our products. It also contains chlorogenic acid, which is a great anti-oxidant, anti-fungal, anti-bacterial, and anti-inflammatory. It contains luteolin, a good anti-inflammatory and anti-oxidant found in chamomile, honeysuckle, and chrysanthemum extracts.
You'll find our old friends, quercetin and its glycosides, which offer anti-oxidizing and anti-inflammatory properties, and rutin and its glycosides, which offer UVA protection, increased blood circulation, and chelating properties to our products. Included in this mix is hyperoside, which is a galactoside of quercetin.
The main features of St. John's wort are the xanthones, which are anti-inflammatory, and hypericins. The hypericin in St. John's wort should be standardized as it can be a serious photo-sensitizer and can cause allergic reactions. This photo-sensitivity is caused by an increase in skin inflammation, and should not be included in products that might be used outside.
The powdered extract can contain capsules, flowers, leaves, and stems from St. John's wort, and should be used at no more than 0.5% in the cool down phase of your products after being dissolved in warmish water.
The oil extract is generally from the flowers only, but it is mixed with something like almond or olive oil to extend it. You would add this to the oil phase of your creations at 1% to 10%. The oil is considered astringent, and has the added bonus of offering increased wound and burn healing. It also acts as an emollient - as does every other oil - so that's another bonus.
Although I've seen claim after claim about St. John's wort used for arthritis and muscle pain, I was not able to find good evidence that it works topically.
Have fun formulating with St. John's wort! I can't offer suggestions for formulations I've tried as I don't use this ingredient as my husband has vitiligo and I have very pale skin, so the sun sensitivity is a huge issue in our house! (I did, however, use it in a class I attended on pet care - I don't know how Blondie felt about it...although Raymond does a great impression of what her voice should sound like, he's not able to interpret her actual thoughts!)
Isn't she a vicious looking pup? I think she's holding us at cute-point for bacon!