Read this before making your own Topical Solutions.

http://journal.scconline.org/pdf/cc1969/cc020n08/p00487-p00499.pdf

" The toxicity of substancesentering the skin has been reviewed by
Malkinsonand Rothman (2), Suskind(3), and Idson (4). Somesubstances
will passthroughthe skin without eliciting an untoward reactionwhilst
otherswill produceskin reactionsby penetratingonly the upperlayersof
the stratum corneum.

Primary irritant reactionsare causedby substanceswhich directly
damageor kill epidermal cells. Relatively strong acids and alkalis, and
substanceswhich are readily oxidisedor reducedmay act as primary
irritants. The severity of the reactionmay dependon the concentration
applied, the frequencyof reapplication,contact time, and the type of
vehiclein whichthe substanceis incorporated.Occasionallythe skin may
recoverfrom the effectsof a primary irritant and becomeresistantto
further irritation (5).
Substancesproducingsensitivity reactionsmust penetrate the skin
sufficientlyto stimulatethe formationof antibodies.Thisalmostcertainly
meansthat they penetratethrough the stratum corneumand into the
Malpighianlayer. Many substanceshavebeenshownto producesensitivity
reactions;of those which have been used in cosmeticpreparationsthe
p-phenylenediamineoxidationtype hair dyes,eosintype lipstickcolorants,
the easilyoxidisableaidehydeand ketonecontainingperfumesand lanolin
may be mentionedand of the topically applied drugs,sulphonamides,
penicillins,theantihistamines,localanaesthetics,andthehydroxybenzoic
acid esters.

Many substances,however, produce serious systemic effects after
penetratingthroughthe skin and into the bloodstream.Piquet and Hem-
meler(6) reportedthe occurrenceof fatal poisoningfrom the percutaneous
absorptionof tetraethyl lead containedin petrol. "

Good to know, but I always patch test and would never apply something that irritates my skin regularly.

I would look more into Ph side of things and I have mentioned before high ratio's of alcohol will cause hair loss.