ThermaCare is currently made by Pfizer Consumer Healthcare, one of the world's largest pharmaceutical companies and headquartered in New York City. It was first introduced in 2001 by Procter & Gamble.
THERMACARE ACTIVE INGREDIENTS
ThermaCare Pain Relieving Cream has the following active ingredients:
CAMPHOR This waxy solid has a strong aromatic odor. It is found in the wood of the evergreen tree Cinnamomum camphora; Dryobalanops aromatica; Ocotea usambarensis; and dried rosemary leaves (Rosmarinus officinalis).
It is a large contributor to the product's scent, but it is also easily absorbed through skin and produces a cool-feeling like menthol.
Speaking of menthol, this an organic compound is made synthetically or obtained from mint oils.
Menthol's ability to enhance cooling sensations via stimulating the cold-sensitive transient receptor potential channel melastatin 8 (TRPM8). This receptor is responsible for the well-known cooling sensation it provokes when inhaled, eaten, or applied to the skin.
Menthol also has weak analgesic (pain-killing) effects due to select activation of the κ-opioid receptor. This receptor is a protein that mediates a variety of effects including changing our perception of pain, consciousness, motor control, and mood.
Also called wintergreen oil, this organic ester is naturally produced by many species of plants, particularly wintergreens.
Wintergreen oil (along with menthol, eucalyptus oil, camphor, and turpentine oil) is known as a counter-irritant. Counter-irritants create a feeling of cold or heat that can overpower the painful joint or muscle.
Wintergreen oil is also a salicylate, as evident by its proper name: methyl salicylate. Salicylates are compounds related to aspirin. By using them topically, it may help a patient avoid most of the negative side effects of taking aspirin or aspirin-related compounds by mouth, such as:
ulcers of the stomach and small intestine,
gastritis (inflammation of the stomach), and
even serious gastrointestinal bleeding from ulcers.
A study published in 2014 on collagen-induced arthritis in mice concluded, "[methyl salicylate] has great potential to be developed into a novel therapeutic agent for the treatment of rheumatoid arthritis." But, in its pure form, methyl salicylate is toxic, particularly when taken internally. People should never exceed the directions on the label due to the risk of salicylate toxicity (aspirin poisoning). A single teaspoon (5ml) of methyl salicylate contains 7g of salicylate, which is equivalent to more than twenty-three 300 mg aspirin tablets. It has proven fatal to small children in doses as small as 4ml.
Every rose has its thorn, right? To lighten things up (literally), when mixed with sugar and dried, methyl salicylate is triboluminescent. Which is almost as fun to say, as it is to see. It's an optical phenomenon in which light is generated through the breaking of chemical bonds in a material when they are pulled apart, ripped, scratched, crushed, or rubbed. Next time you've got some Wintergreen Life Savers and a dark room, try it out.
Capsaicin is an active component of plants belonging to the genus Capsicum (chili peppers). It is an irritant for all mammals and produces a sensation of burning when it comes in contact with tissue. Capsaicin warms the skin when applied over a joint and temporarily blocks a chemical called substance P, which delivers pain messages to the brain.
A study published in 2011 summarized that topical capsaicin reduces skin hypersensitivity and pain by a process described as "defunctionalization" of nociceptor fibers. A nociceptor is a nerve cell gives a shout out to the spinal cord and brain when it senses potentially damaging stimuli and usually causes the perception of pain. This "defunctionalization" process is rather complex, so I'd suggest reading the study to learn more.
THERMACARE SIDE EFFECTS
There are no known major side effects for using ThermaCare topically (on the skin, external use only) as directed. Although one should seek medical attention if severe allergic reaction occurs. Not a good idea to use on broken or damaged skin, and be sure to keep it clear of the eyes - ouch.
PRECAUTIONS & WARNINGS:
Methyl Salicylate (wintergreen oil) might cause an allergic reaction in people who are allergic to aspirin or other salicylate compounds, or have asthma or nasal polyps. Use wintergreen with caution if you have one of these conditions.
Wintergreen oil can be poisonous for children. Taking 4-10 mL of wintergreen oil by mouth can be deadly. So keep away from the kiddos and do not use wintergreen oil on the skin of children less than 2 years old.
If you are pregnant or breast-feeding, wintergreen is safe in amounts found in food, but there's inconclusive evidence to know if it's safe in the larger amounts internally or topically. Either clear usage by your doctor, or select a topical gel that does not include wintergreen oil (methyl salicylate) in the ingredients label on the back of the box.
I found an established body of research that may suggest the use of menthol, camphor, capsaicin, and wintergreen oil for mild pain relief. Given the very low risk and very limited side effects, it would seem worth a try for individuals seeking a complementary and/or off-the-shelf product for pain relief.
You can purchase ThermaCare at most major pharmacies. You can also find it on Amazon.