I tend to avoid most chemicals wherever possible, so I tend to just make my own deoderant as follows:
5 tbsp witch hazel extract (Boots/other chemists)
5 tbsp warm water
1 tsp bicarbonate of soda (any supermarket)
30-40 drops essential oil (I tend to use 20 mint, 15 tea tree, 5 rosemary).
Dissolve the bicarb in the water, then add the witch hazel, and essential oils. Put in a small spray bottle. Note - from experience, you can buy spray bottles in boots and in superdrug, but the witch hazel seems to destroy the boots ones! (and superdrug's are cheaper
)
The ingredients work in the following ways:
witch-hazel - kills bacteria, is astringent and closes pores.
bicarb - natural deoderant and again kills bacteria.
essential oils - smell nice, can help kill bacteria.
Its not an antiperspirant, and if you're doing a lot of exercise/sweating a lot, you will start to smell again. Having said that, its very cheap to make (probably a few quid for several months supply) - you can scent it however you want (could use things like pine oils/citronella etc for a bushcraft scent), and I haven't had any complaints from my friends or colleagues since I switched to using it!
(One word of advice - don't put it on immediately after a shower - the witch-hazel/oils can sting a tad if your pores are open!)