If I’m understanding this correctly, topically applied ALA absorbs relatively easily. I don’t know how well plain water will work. Seems to me some should soak in if the skin is dry to start with and is kept damp with the solution for long enough, but I really don’t have a clue.
Biochem Pharmacol. 1996 Aug 23;52(4):627-33.
Kinetic study of cutaneous and subcutaneous distribution following topical application of [7,8-14C]rac-alpha-lipoic acid onto hairless mice.
Podda M, Rallis M, Traber MG, Packer L, Maibach HI.
University of California Berkeley, Department of Molecular and Cell Biology 94720-3200, USA.
To diminish oxidative injury, topically applied antioxidants must reach susceptible cells. alpha-Lipoic acid is a potent thiol antioxidant that might be useful for skin protection; therefore, its skin penetration kinetics were assessed. The cutaneous and subcutaneous distributions of [7,8-14C]rac-alpha-lipoic acid were studied in anesthetized hairless mice after application of a 5% solution in propylene glycol for 0.5 to 4 hr. The mice were killed; then the skin was washed, and the stratum corneum was removed by 10 cellophane tape strippings. A punch biopsy of the frozen, stripped skin was sectioned, and amounts of [14C]-alpha-lipoic acid were determined in strippings and slices of epidermis (4 x 5 microns), dermis, and subcutaneous fat (10 x 10 microns, 20 x 20 microns). The rate of [14C]-alpha-lipoic acid absorption into skin was constant by 30 min (0.10 +/- 0.01 nmol/cm2/min); maximum skin concentrations were reached by 2 hr. The [14C]-alpha-lipoic acid penetration kinetics into the first layer of the stratum corneum predicted its penetration through the stratum corneum and subsequent percutaneous absorption (r2 = 0.96, P < 0.02). Cutaneous absorption of unlabeled alpha-lipoic acid and its reduction to the more potent antioxidant form, dihydrolipoic acid, were also demonstrated, using HPLC analysis with electrochemical detection. In conclusion, alpha-lipoic acid topically applied to skin penetrated readily, and was reduced to dihydrolipoic acid. Thus, alpha-lipoic acid could potentiate skin antioxidant protection.
PMID: 8759036 [PubMed - indexed for MEDLINE]
Last night I added just enough water to about 50 mg ALA (cheap stuff from Wal-Mart) to make a watery paste and applied it to my shaft, rubbing it in for about 5 minutes. Not knowing how the acid would affect my skin I cut the test run short. After 10 minutes or so I felt the beginnings of a tingly sensation, so I washed it off and rubbed on a paste of baking soda and water, then rinsed again.
Figuring that mixture was too potent, I decided to make a roughly 1% solution of ALA. It has been a long time since chemistry class. This page says:
Quote
5. Percent SolutionsMany reagents are mixed as percent concentrations. When working with a dry chemical it is mixed as dry mass (g) per volume where #g/100 ml = percent concentration. A 10% solution is equal to 10 g dissolved in 100 ml of solvent.
Example 1: If you want to make 3 % NaCl you would dissolve 3.0 g NaCl in 100 ml water (or the equivalent for whatever volume you needed).
Assuming this is how one arrives at a certain percentage of ALA solution, I used about 1/3 of a 100mg ALA capsule dissolved in 3cc warm water. If I’m wrong on this, please correct me. It sure looked like it was a lot stronger than what I’d deem a 1% solution.
It didn’t want to dissolve thoroughly in the short time I mixed it. Maybe a longer soak would help. I applied this slowly, rubbing it in well. Next time I’ll substitute some of my arnica lotion for part of the water. It contains propylene glycol. I assume the pg is for helping stuff absorb, but I’m not sure about this.
Someone asked earlier in this thread if arnica would interfere with absorption. Some arnica mixtures contain vaseline (petrolatum). I’d think the grease would plug skin pores and reduce or prevent absorption, not only of the ALA but also of the arnica. The standard advice here has been to avoid greasy arnica mixtures. Bib said the only kind that worked for him was in liquid.