Pain Relief Products
Externally applied products which are intended to treat or relieve pain or discomfort are generally classed as analgesics (relieves pain), antipruritic (relieves itching), or anesthetic (reduces feeling). All of these are drugs. They include, for example, products to address the discomfort of bruises, muscle strains or sprains, sore muscles, bug bites, or poison oak or ivy. Depending on the statements made, it could also include products addressed to sunburn, burns, cuts, or scrapes.
If you make any claims that make the consumer think that the intended use of the product is to treat any of these types of physical problems, then the product is a drug.
OTC External Analgesic Products
There are non-prescription topical analgesic products on the market that often look like cosmetics but are, in fact, over-the-counter drugs. In order to be marketed to treat any type of pain or discomfort, products must meet the OTC Monograph for external analgesic drug products, using only approved ingredients, label claims, directions, and warning statements.
Reality vs Regulation
There are formulations based on natural substances which have traditionally been used treat bruising (e.g. arnica), itching (e.g. jewelweed), sunburn (e.g. aloe vera), or muscle pain (e.g. methyl salicylate, camphor, menthol, capsicum). However, most of these active ingredients are not on the list of approved ingredients to treat pain.
Rightly or wrongly, only products which meet all the requirements in the OTC monograph for external analgesic products may be promoted and sold for the purpose of treating or relieving pain or discomfort.
Also keep in mind that even if you could get the ingredients and make a product that meets the requirements, in order for the product to be legally marketed it must be manufactured in a facility that is registered as a drug manufacturer with the FDA1 and which follows drug good manufacturing practices as contained in federal regulations.2 It is likely there are state-level drug manufacturing registration and licensing requirements.
1 21 CFR 330.1(b)
2 21 CFR 330.1(a)
