As people try to find non-drug solutions for pain, lots of old treatments are getting dusted off with fresh press. Epsom Salt baths, yoga, that kind of thing. The question is, what really works?
Before there was ibuprofen, chronic conditions mandated a trip to a spa town for frequent bathing. The original therapeutic baths contained Epsom salts, from magnesium rich deposits in a town south of London. When marinating in magnesium for hours a day, enough may have been absorbed to help.
While the research on Epsom soaks is muddied with other-ingredient sitz baths studies, a growing body of literature supports that for the 50% of people with low magnesium, increasing magnesium intake decreases pain in several ways.
1. Smooth Muscle Relaxer
Smooth muscles live in your body’s tubes - blood vessels, airways, uterus, that kind of thing. Magnesium in high doses has been used for decades in emergency departments to relax tight, asthmatic airways. Turns out magnesium is also good for migraine headaches, and has brain-protective effects as well. While relaxing skeletal neck muscles to reduce a headache makes sense, the impact on smooth muscles by blocking calcium channels may be part of how magnesium relieves body pains. Several German studies in the early 90’s found magnesium to help menstrual cramping - totally makes sense.
2.Enhancing pain relief
Ok, strap in for some SCIENCE (physiology to be exact). Pain stimulates receptors in nerve cells called N-methyl-D-aspartate (NMDA) receptors. One of the reasons opioids are addictive is that when they are used to block pain, the NMDA receptors can overcompensate just to make sure you’re getting all the pain you’re entitled to. You then need more opioids over time to get the same effect (tolerance) which makes opioids a bad choice for chronic pain. Here’s the cool thing: magnesium acts as a blocker of an NMDA subunit. It can decrease pain some on its own, but seems REALLY good at making a small dose of opioid go farther for pain relief.
3. Reducing Inflammation
Magnesium impacts cells’ ability to create the pain messages that get sent out in the first place. These messages are sent in the form of molecules called “inflammatory cytokines”. When tissues are inflamed, they let the world know with cytokines. These molecules are related to acute pain, but when you keep cranking them out, the body’s immune system gets revved up which causes more damage. Magnesium supplementation worked at reducing inflammation for people whose baseline inflammation was high, as measured with a test called a CRP. Normal CRPs are around 1, and taking extra mag didn’t do anything for them. For people who had CRP levels over 3 (ie. Most people with rheumatoid arthritis) taking extra magnesium DID lower CRP. Lower whole body inflammation, less pain.
4. Stopping Ongoing Damage
Babies born to women who got magnesium IV to slow labor (by relaxing smooth muscles in the uterus) seem to have less brain damage. By extrapolation, look to see new concussion studies testing magnesium, and magnesium for athletes.
5. REDUCING DEPRESSION
Depression and increased pain perception are well linked. In a study of depressed people with low magnesium, 500mg a day reduced depression more than placebo.
Bottom line, when you’re low on magnesium, taking more likely makes lots of stuff gets better. As of 1990 half of people with random lab draws had low magnesium, and the percent is likely higher now. As far as Epsom salt baths go, if you’re bothering to soak, adding magnesium rich Epsom salt can’t hurt. For pain relief, hedge your bets and take some orally if you might be low.